Qiantang River

The Qiantang River or alternatively Tsientang River is a river in East China. An important commercial artery, it runs for through Zhejiang, passing through the provincial capital Hangzhou before flowing into the East China Sea via Hangzhou Bay south of Shanghai. Its original name, the "Zhe River" or "Zhe Jiang", is the origin of the name of Zhejiang province. The river is also known, along with Hangzhou Bay, for having the world's largest tidal bore, a phenomenon where leading edge of the incoming tide forms a wave (or waves) of water that travels up a river or narrow bay against the direction of the river or bay's current.
Etymology.
Its upper stretch near the AnhuiJiangxi border is also known as the Xin'an River (, "Newly Peaceful"); its middle stretch through the mountains of Zhejiang is also known as the Fuchun River (, "Abundant Spring River"); and the former name of its lower stretchthe Zhe () or Crooked Rivergave Zhejiang Province its name.
Historically, it was first documented in the "Classic of Mountains and Seas" () as Zhejiang River (), later in "Zhuangzi" ()as Zhe River (), and in the "Water Classic" () as Jianjiang River (). All those names probably originate from the language of extinct Baiyue peoples. In the early 18th century, the "Kangxi Dictionary" () regarded Zhejiang River () as Crooked River for its crooked lower stretch and countercurrent tidal bore.
The origin of its current name, the Qiantang River (), literally the River of King Qian's Dyke, however, has nothing to do with the King Qian of Wuyue. It previously referred to the lower stretch within the Qiantang County(, former name of Hangzhou City) and later in the 20th century began referring to all stretches of the river.
History.
It was linked by the Eastern Zhejiang Canal to Shaoxing during the Spring and Autumn Period and to Ningbo's Yong River during the Three Kingdoms Period. It was linked by the Grand Canal to Beijing during the Sui Dynasty. Its present name derives from a major dyke constructed near Hangzhou by the Tang warlord Qian Liu, who established the Wuyue Kingdom in the early 10th century.
Basin.
Qiantang River is one of the largest rivers on the southeast coast of China. It runs through Zhejiang, Anhui, Fujian, Jiangxi, provinces, which is the largest river in Zhejiang. "Qiantang" originally refers to the name of the river below the gate of Hangzhou, but now refers to the whole river basin. Qiantang River basin generally is abundant rainfall with developed water system (total of 60 tributaries), which is feather distribution. If count from the north source (Xinan river), the length of Qiantang river is 588.73 km. While if count from the south source (Qu river), the length of Qiantang river is 522.22 km. The main rivers of Qiantang river basin are Majin river, Changshan river, Qu river, Lan river, Xinan river, Fuchun river and Qiantang river.
Hydrological characteristics.
Overall, the runoff of Qiantang River is abundant. However, the incoming water of Qiantang River is strongly impacted by seasonal variation. In general, the runoff from April to June can occupy about 50% of the total annual flow. Because Qiantang River valley is located in the southeast coastal monsoon climate zone, the main source of runoff is atmospheric precipitation. The runoff and precipitation in Qiantang river valley show obvious consistency in both regional distribution and annual variation. The average annual discharge is 2.905×1010 cubic meters, and the average annual sediment discharge is 6.68×10^6 tons. In addition, the annual runoff of the Qiantang River and its tributaries showed significant changes in abundance and drought.
Tidal bore is one of the symbolic features of the Qiantang River. Due to The riverbed of the estuary (Hangzhou bay) sharply shrank and lifted, he tidal range increases along the way, resulting the sharp deformation of tide waves. The average tidal range of Zhenhai on the south bank of Wankou was 1.69 meters, the average tidal range of Ganpu was 5.45 meters. Tidal current hangzhou bay is a clockwise rotating tidal current and the speed is generally 15~20 m/s, The north shore can up to 3~4 m/s. The average income tidal current of Ganpu station was 18,850,000 cubic meters per second. On the other hand, the river bed at the estuary of the Qiantang river is wide and shallow, forming a broad intertidal zone. Under the influence of seasonal runoff and tidal fluctuation, the riverbed is easy to produce violent deformation. In autumn, due to the strong tide, the main trough oscillates along the direction of the rising tide crest. In the season of abundant runoff, the main trough swings along the direction of ebb tide. Because of the process of main trough oscillation, the beach ground is easy to collapse and retreat quickly.
Tidal bore.
The river and Hangzhou Bay are known for the world's largest tidal bore. The oldest known tide table is for the Qiantang River and may have aided ancient travelers wishing to see the famous tidal bore. The tide rushing into the river mouth from the bay causes a bore which can reach up to 9 meters (30 ft) in height, and travel at up to 40 km per hour (25 miles an hour). Known locally as the Silver (or Black) Dragon, the wave sweeps past Hangzhou, menacing shipping in the harbor.
In August 2013, the tidal bore turned out stronger than expected due to Typhoon Trami, reaching more than twice its usual height as it broke on the flood barrier, sweeping it and injuring numerous spectators.
There have been attempts to surf the tidal bore. The first person to ride the bore was Stuart Matthews from England. The 1988 record was 1.9 km by Stuart Matthews. Then, in October 2007, a group of international surfers brought by Antony Colas, did several attempts, one wave being ridden continuously by French Patrick Audoy and Brazilian Eduardo Bagé for 1h10min, for 17 km. In September 2008 a group of American surfers convinced the Chinese government to allow them to surf a section of the river.
In November 2013, Red Bull held the first surf competition on the river, called the Qiantang Shoot Out. The bore was considered the most unusual wave in the world for a surfing contest.
Ecology.
The Qiantang River basin is rich in ecosystem types. Forest ecosystems are mojor distributed in the west and south which are composed by evergreen and deciduous broad-leaved forests. The forest ecosystem with complete functions as well as the widely wetland breeds a variety of species. However, with the development of industry, the ecological environment of Qiantang River basin has deteriorated and soil erosion is becoming serious. Although the forest coverage is high, the trend of islandization and fragmentation of wildlife native habitats is obvious and biodiversity is under threat.
In recent years, the government tries to combine the environmental protection, prevention and control of water conservancy projects. The construction of "sea pond" is the symbolic part of "green barrier" of Qiantang River.
Notable points.
Qiantang river tidal bore.
Qiantang River Tidal Bore is an important scenic spot of Qiantang River. Generally, around August 15, Lunar Calendar is the best time to observe the tides. At that time, the largest Qiantang river tidal bore can be several meters. Before the arrival of the sea tide, a tiny white dot appeared in the distance, which turned into a silver thread in a blink of an eye. Later on, accompanied by waves of dull thunder, the white line rolled to the sea. In ancient Hangzhou, Phoenix mountain, Jianggan area were the best place to watch. Due to the change of geographical location, from the Ming dynasty, Haining, Hanguan was the first resort for tide observation, so it was also called "Haining Tidal Bore".
Qiantang river bridge.
Qiantang river bridge, also called the first Qiantang River Bridge designed by Chinese bridge expert Yisheng Mao, which is a double-deck truss girder bridge spanning the Qiantang river in Hangzhou city, Zhejiang province, China. It is located at the southern end of Hangzhou city and about 700 meters to the east of Liuhe pagoda, between Nanxing bridge station of Zhejiang-jiangxi railway. It is the first double-deck railway and highway bridge designed and built by China itself, which is a milestone in the history of Chinese Bridges. Qiantang river bridge is 1453 meters long, 9.1 meters wide and 71 meters high. The upper deck of the bridge is a two-way two-lane highway with a design speed of 100 km/h, and the lower deck is a single-track railway with a design speed of 120 km/h. During World War II, the Qiantang River Bridge was hit by Japanese air raids. And then, the Qiantang River Bridge was blown up to the piers only, to resist the Japanese attack. It was repaired in 1948.
Culture.
Qiantang River has been regarded as the birthplace of Wuyue culture. The characteristics of Wuyue culture are pardon, inclusive, intelligent, realistic, pioneering and brave, which also have been the cultural deposits displayed by Qiantang River. In addition, Liangzhu culture, southern Song dynasty culture, West lake culture and other regional cultures are also distributed in the area of Qiantang River basin. Liangzhu culture has a long history, which adds the thick and simplicity tone to the Qiantang River. The secularization and leisure of the southern Song dynasty culture, combined with the river crossing, have the charm of Qibao teahouse and Jianqiao old street, and contributed to the economic development of the dynasty.
Qiantang River has been deeply loved by ancient Chinese writers and writers." Dwelling in the Fuchun Mountains" by painter Gongwang Huang. It was regarded as the culmination of ancient Chinese landscape painting and the peak of art. Zhou Mi's "observation tide" was praised as a literary classic and it still listed as a point article in the textbook of ancient Chinese literature. Sun Quan, as a hero and the ruler of the kingdom of Wu in The Three Kingdoms period. In modern times writer Dafu Yu, revolutionary writer and artist Yan Xia, and scientist Wang Chong are the famous persons born in Qiantang River Basin, and these people made an important contribution to the development of Qiantang culture.
Qiantang River is mentioned in The Tale of Kieu as the place where committed suicide.


Geysers of Triton (moon)


Concurrent-range zone


Carbonates on Mars

Head (vessel) Evidence for carbonates on Mars was first discovered in 2008. Previously, most remote sensing instruments such as OMEGA and THEMIS—sensitive to infrared emissivity spectral features of carbonates—had not suggested the presence of carbonate outcrops, at least at the 100 m or coarser spatial scales available from the returned data.
Though ubiquitous, a 2003 study of carbonates on Mars showed that they are dominated by Magnesite (MgCO3) in Martian dust, had mass fractions less than 5%, and could have formed under current atmospheric conditions. Furthermore, with the exception of the surface dust component, by 2007 carbonates had not been detected by any in situ mission, even though mineralogic modeling did not preclude small amounts of calcium carbonate in Independence class rocks of Husband Hill in Gusev crater (note: An IAU naming convention within Gusev is not yet established).
Remote sensing data.
The first successful identification of a strong infrared spectral signature from surficial carbonate minerals of local scale (< 10 km²) was made by the MRO-CRISM team. Spectral modeling in 2007 identified a key deposit in Nili Fossae dominated by a single mineral phase that was spatially associated with olivine outcrops. The dominant mineral appeared to be magnesite, while morphology inferred with HiRISE and thermal properties suggested that the deposit was lithic. Stratigraphically, this layer appeared between phyllosilicates below and mafic cap rocks above, temporally between the Noachian and Hesperian eras. Even though infrared spectra are representative of minerals to less than ≈0.1 mm depths (in contrast to gamma spectra which are sensitive to tens of cm depths), stratigraphic, morphologic, and thermal properties are consistent with the existence of the carbonate as outcrop rather than alteration rinds. Nevertheless, the morphology was distinct from typical terrestrial sedimentary carbonate layers suggesting formation from local aqueous alteration of olivine and other igneous minerals. However, key implications were that the alteration would have occurred under moderate pH and that the resulting carbonates were not exposed to sustained low pH aqueous conditions even as recently as the Hesperian. This increased the likelihood of local and regional scale geologic conditions on Mars that were favorable to analogs of terrestrial biological activity over geologically significant intervals.
, the absence of more extensive carbonate deposits on Mars was thought by some scientists to be due to global dominance of low pH aqueous environments.
Even the least soluble carbonate, siderite (FeCO3), precipitates only at a pH greater than 5.
Evidence for significant quantities of carbonate deposits on the surface began to increase in 2008 when the Thermal and Evolved Gas Analyzer (TEGA) and WCL experiments on the 2007 Phoenix Mars lander found between 3–5wt% calcite (CaCO3) and an alkaline soil. In 2010 analyses by the Mars Exploration Rover Spirit, identified outcrops rich in magnesium-iron carbonate (16–34 wt%) in the Columbia Hills of Gusev crater, most likely precipitated from carbonate-bearing solutions under hydrothermal conditions at near-neutral pH in association with volcanic activity during the Noachian era.
After Spirit Rover stopped working scientists studied old data from the Miniature Thermal Emission Spectrometer, or Mini-TES and confirmed the presence of large amounts of carbonate-rich rocks, which means that regions of the planet may have once harbored water. The carbonates were discovered in an outcrop of rocks called "Comanche."
Carbonates (calcium or iron carbonates) were discovered in a crater on the rim of Huygens Crater, located in the Iapygia quadrangle. The impact on the rim exposed material that had been dug up from the impact that created Huygens. These minerals represent evidence that Mars once had a thicker carbon dioxide atmosphere with abundant moisture. These kind of carbonates only form when there is a lot of water. They were found with the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument on the Mars Reconnaissance Orbiter. Earlier, the instrument had detected clay minerals. The carbonates were found near the clay minerals. Both of these minerals form in wet environments. It is supposed that billions of years age Mars was much warmer and wetter. At that time, carbonates would have formed from water and the carbon dioxide-rich atmosphere. Later the deposits of carbonate would have been buried. The double impact has now exposed the minerals. Earth has vast carbonate deposits in the form of limestone.


Funston Limestone

The Funston Limestone is a geologic formation in Kansas. It preserves fossils dating back to the Permian period.


Cinder

A cinder is a pyroclastic material. Cinders are extrusive igneous rocks; they are fragments of solidified lava. Cinders are typically brown, black, or red depending on chemical composition and weathering. Cinders are similar to pumice.
Characteristics.
The following geologic characteristics define a cinder:
Uses.
Cinders have been used on track surfaces and roads to provide additional traction in winter conditions. Cinders are also employed as inorganic mulch in xeriscaping, because of excellent drainage properties and erosion resistance. In this context, they are referred to frequently with the name "lava rock".


Raiff Limestone

The Raiff Limestone is a geologic formation in Nevada. It preserves fossils dating back to the Cambrian period.


Antelope Valley Limestone

The Antelope Valley Limestone is a limestone geologic formation of the Pogonip Group in southern Nevada.
It is found in the Antelope Valley region of Eureka County and Nye County.
It preserves fossils dating back to the Ordovician period.


Dutchtown Formation

The Dutchtown Formation is a geologic formation in Missouri. It preserves fossils dating back to the Ordovician period.


Pyroclastic surge

A pyroclastic surge is a fluidized mass of turbulent gas and rock fragments that is ejected during some volcanic eruptions. It is similar to a pyroclastic flow but it has a lower density or contains a much higher ratio of gas to rock, which makes it more turbulent and allows it to rise over ridges and hills rather than always travel downhill as pyroclastic flows do.
The speed of pyroclastic density currents has been measured directly via photography only in the case of Mount St. Helens, where they reached . Estimates of other modern eruptions are around 100 m/s. Pyroclastic flows may generate surges. For example, the city of Saint-Pierre in Martinique in 1902 was overcome by one. Pyroclastic surge include 3 types, which are base surge, ash-cloud surge, and ground surge.
Base surge.
First recognized after the Taal Volcano eruption of 1965 in the Philippines, where a visiting volcanologist from USGS recognized the phenomenon as congruent to base surge in nuclear explosions. Very similar to the ground-hugging blasts associated with nuclear explosions, these surges are expanding rings of turbulent mixture of fragments and gas that surge outward at the base of explosion columns. Base surges are more likely generated by the interaction of magma and water or phreatomagmatic eruptions. They develop from the interaction of magma (often basaltic) and water to form thin wedge-shaped deposits characteristic of maars.
Ash-cloud surge.
These are the most devastating. They form thin deposits, but travel at great speed (10–100 m/s) carrying abundant debris such as trees, rocks, bricks, tiles etc. They are so powerful that they often blast and erode material (like sandblasting). They are possibly produced when conditions in an eruption column are close to the boundary conditions separating convection from collapse. That is, switching rapidly from one condition to the other.
Ground surge.
These deposits are often found at the base of pyroclastic flows. They are thinly bedded, laminated and often cross-bedded. Typically they are about 1 m. thick and consist mostly of lithic and crystal fragments (fine ash elutriated away). They appear to form from the flow itself, but the mechanism is not clear. One possibility is that at the head of the flow expands through entrainment of air (which is then heated). This then results in the flow front surging forward, which is then over-run by the rest of the flow.


Chainman Shale

The Chainman Shale is a geologic formation in Utah, mostly identical to the White Pine Shale. It preserves fossils dating back to the Carboniferous period.


Hanson Creek Formation

The Hanson Creek Formation is a geologic formation in Nevada. It preserves fossils dating back to the Dapingian-Katian (Ibexian-Richmondian in the regional stratigraphy) stages of the Ordovician period.


Lebacher Schichten Formation

The Lebacher Schichten Formation is a geologic formation in Germany. It preserves fossils dating back to the Permian period.


Lava coil

A lava coil is a spiral or scroll-shaped lava formation occurring when relatively low viscosity lava such as Pahoehoe solidifies along a slow-moving shear zone in the flow. The shear produces a Kelvin–Helmholtz instability that forms spiral-shaped patterns. Depending on the side of the flow the spiral is clockwise or anti-clockwise. They have been observed on flows near Kilauea on Hawai'i, in Kenya and possibly on Mars.


Esther Applin

Esther Applin (November 24, 1895 – July 23, 1972) was an American geologist and paleontologist. Applin completed her Bachelor of Arts degree in 1919 from the University of California, Berkeley. Later, she completed a Master's degree which was focused on microfossils. She was a leading figure in the use of microfossils to determine the age of rock formation for use in oil exploration in the Gulf of Mexico region. Her job was to examine microfossils, especially the Foraminifera, that were collected in drill holes to determine the age of the rock into which the company was drilling. Applin's discoveries were crucial to successful drilling operations across the entire oil industry. Additionally, her contribution to geology, more specifically in the study of micropaleontology, put women geologists on the map, and was pivotal in making them as respected as men in the geological field of science.
Early life and education.
Applin was born as Esther Richards on November 24, 1895, in Newark, Ohio, to Gary Richards, a civil engineer with the United States Army, and Jennie DeVore. Because of her father's work, she lived in various cities in Ohio, then later lived in Fort Des Moines, Iowa, and eventually moved to San Francisco at the age of 12. Richards lived on Alcatraz Island with her family from 1907 until 1920, while her father worked on the construction of Alcatraz Prison. From Alcatraz Island, she traveled to school (high school and later University) via the ferry.
Richards attended the University of California, Berkeley, graduating in 1919 with an honors degree in paleontology, geology, and physiography. In 1920, she left California and moved to Houston to work for the Rio Bravo Oil company, where she was hired by Edwin T. Dumble. While at Berkeley, Richards focused her studies on larger fossils; however, this theoretical education proved to be of little value for underground drilling because remnants of the fossils in drill cuttings were too small to effectively identify. She determined that the microfossils found in the drill cuttings could be useful in the correlation of underground rock formations. She then returned to California and studied micropaleontology, earning her Master's degree.
In 1923, Edwin T. Dumble frequently assigned Esther Richards to work in outdoor fields with Paul Applin(a bachelor field geologist). Their relationship later develops from there.
In 1923, Richards married Paul Applin, who was also a geologist. She had two children: a daughter, Louise (born in 1926), and a son, Paul Jr. (born in 1927).
Career and achievements.
In 1921, Applin presented a paper in Amherst, Massachusetts, stating her theory that microfossils could be used in oil exploration, specifically the dating of the rock formations in the Gulf of Mexico region. Her theory was ridiculed by geologists with more experience and disputed by professor J.J. Galloway of the University of Texas at Austin. Galloway was quoted saying "Gentlemen, here is this chit of a girl, right out of college, telling us that we can use Foraminifera to determine the age of formation. Gentlemen, you know that it can't be done." Galloway would later capitalize off her discoveries and would use their process to consult for various oil companies. In 1925, Applin co-authored a paper with Alva Ellisor and Hedwig Kniker, which reported her findings that oil-bearing rock formations in the Gulf Coast region could in fact be dated using microfossils. Applin remained with Rio Bravo until 1927, continuing to lead the use of micropaleontology in the oil industry. Applin was able to have a successful career with the Rio Bravo Oil Company due to the fact her micropaleontology studies provided index fossils to the company which was vying for the best oil bearing stratigraphic layers. The matching of micro index fossils between stratigraphic layers in not only the Gulf Coast region, but other regions as well, was the main form of oil exploration for oil companies. Applin's discoveries proved to be essential and irreplaceable to drilling operations, up until the use of electric logs became more feasible. Applin contributed a lasting impact on both women previously in, and soon entering, the relatively newer field of geology. Applin's discoveries transformed geology into a field of study that women could feel much more open in—much more than other, more established fields.
After her stint working for Rio Bravo Oil that lasted from 1920-1927, Applin was sought after to work as a consultant to various other oil companies and did so until 1944. It was then, in 1944, that Applin and her family moved to Tallahassee, Florida where she worked alongside her husband at the United States Geological Survey, with the task of linking the oil fields of East Texas, across the southeaster United States, and into Florida, using micropaleontology and other methods. Mesozoic formations were highly focused and stressed upon.
In 1960, Applin received a well-earned plaque from the Gulf Association of Geological Studies, in recognition of her accomplishments and contributions to the field.
Following the "oil boom" decline, Applin and her family moved to Jackson, Mississippi. From there, Applin still wrote papers on stratigraphy, structure of southeastern states, and foraminifera. In 1962, she retired from the Geological Survey, but following retirement, she still continued to do research and publish works.
By 1975, Edgar Owen wrote "The Trek of the Oil" Finders that minimize Esther and her fellow female paleontologists' roles in the discovery. Instead, the author praised men who do not acknowledge foraminifera's efficiency and accuracy in biostratigraphy


Arbuthnott Group

The Arbuthnott Group was a geologic group formerly recognised in Scotland but now superseded by the Arbuthnott-Garvock Group. It preserves fossils dating back to the Devonian period.


Imuruk Volcanics

The Imuruk Volcanics is a geologic formation in Alaska. It preserves fossils dating back to the Neogene period.


Conasauga Group

The Conasauga Group is a geologic group in West Virginia. It dates back to the Cambrian period.


Chanute Formation

The Chanute Formation is a geologic formation in Kansas, Missouri, and Oklahoma. It preserves fossils dating back to the Carboniferous period.


Copenhagen Formation

The Copenhagen Formation is a geologic formation in Nevada.
Areas it is found include the Antelope Valley region of Eureka County and Nye County.
It preserves fossils dating back to the Ordovician period.


Evacuation Creek Formation

The Evacuation Creek Formation is a geologic formation in Utah, United States. It preserves fossils dating back to the Paleogene period.


Cabochon

A cabochon (, from Middle French "caboche" "head") is a gemstone which has been shaped and polished as opposed to faceted. The resulting form is usually a convex (rounded) obverse with a flat reverse. Cabochon was the default method of preparing gemstones before gemstone cutting was developed.
Application.
Cutting "en cabochon" (French: "in the manner of a cabochon") is usually applied to opaque gems, while faceting is usually applied to transparent stones. Hardness is also taken into account as softer gemstones with a hardness lower than 7 on the Mohs hardness scale are easily scratched, mainly by silicon dioxide in dust and grit. This would quickly make translucent gems unattractive—instead they are polished as cabochons, making the scratches less evident.
In the case of asteriated stones such as star sapphires and chatoyant stones such as cat's eye chrysoberyl, a domed cabochon cut is used to show the star or eye, which would not be visible in a faceted cut.
The usual shape for cutting cabochons is an ellipse. This is because the eye is less sensitive to small asymmetries in an ellipse, as opposed to a uniformly round shape, such as a circle, and because the elliptical shape, combined with the dome, is attractive. An exception is cabochons on some watches' crowns, which are round.
The procedure is to cut a slab of the rough rock with a slab saw, and next to stencil a shape from a template. The slab is then trimmed near the marked line using a diamond blade saw—called a trim saw. Diamond impregnated wheels or silicon carbide wheels can be used to grind the rough rock down. Most lapidary workshops and production facilities have moved away from silicon carbide to diamond grinding wheels or flat lap disks.
Once the piece is trimmed it can be "dopped" or completed by hand. "Dopping" is normally done by adhering the stone with hard wax onto a length of wooden dowel called a "dop stick". The piece is then ground to the template line, the back edges may be bevelled, and finally the top is sanded and polished to a uniform dome.


Spherulite

In petrology, spherulites () are small, rounded bodies that commonly occur in vitreous igneous rocks. They are often visible in specimens of obsidian, pitchstone and rhyolite as globules about the size of millet seed or rice grain, with a duller luster than the surrounding glassy base of the rock, and when they are examined with a lens they prove to have a radiate fibrous structure.
Structure.
Under the microscope the spherulites are of circular outline and are composed of thin divergent fibers that are crystalline as verified with polarized light. Between crossed Nicols, a black cross appears in the spherulite; its axes are usually perpendicular to one another and parallel to the crosshairs; as the microscope stage is rotated the cross remains steady; between the black arms there are four bright sectors. This shows that the spherulite consists of radiate, doubly refracting fibers that have a straight extinction; the arms of the black cross correspond to those fibers that are extinguished. The aggregate is too fine-grained to directly determine what minerals it is composed of using visible light microscopy.
Occurrence.
Spherulites are most common in silica-rich glassy rocks. Sometimes they compose the whole mass; more usually they are surrounded by a glassy or felsitic base. When obsidians are devitrified, the spherulites are often traceable, though they may be more or less completely recrystallized or silicified. In the center of a spherulite there may be a crystal (e.g. quartz or feldspar) or sometimes a cavity. Occasionally spherulites have zones of different colors, and while most frequently spherical, they may also be polygonal or irregular in outline. In some New Zealand rhyolites the spherulites send branching cervicorn processes (like stags horns) outwards through the surrounding glass of the rock. The name axiolites is given to long, elliptical or band-like spherulites.
Megaspherulites.
Occasionally spherulites are found that are many centimeters and, even more rarely, up to two or three meters in diameter. Those spherulites, which are more than 20 centimeters in diameter, are called megaspherulites. Near Silver Cliff, Colorado, megaspherulites, which range in diameter from 0.30 to 4.3 meters occur within a thick layer of rhyolitic vitrophyre. Megaspherulites as large as 0.91 meter occur within rhyolite exposures on Steens Mountain, Oregon and ones as large as 1.83 meters in diameter occur within welded tuffs exposed near Klondyke, Arizona. The best known occurrence of megaspherulites are stone balls, which range in diameter from 0.61 to 3.35 meters, found around Cerro Piedras Bola in the Sierra de Ameca between Ahualulco de Mercado and Ameca, Jalisco. As often happens with considerably smaller spherulites, these megaspherulites have been released by weathering from an ash flow tuff, in which they originally formed, to create natural stone balls.
Lithophysae.
Very large and cavernous spherulites are called lithophysae; they are found in obsidians at Lipari, in Yellowstone Park and other places. The characteristic radiate fibrous structure is usually conspicuous, but the fibers are interrupted by cavities that are often arranged as to give the spherulite a resemblance to a rosebud with folded petals separated by arching interspaces. Some of these lithophysae are several centimeters or more in diameter. Tridymite, fayalite and other minerals in the lithophysae may be precipitates from the vapor phase that occupied the cavities. The fibers of these coarse spherulites are alkali feldspar (sanidine or anorthoclase) and tridymite.
Artificial glass.
Artificial glass sometimes crystallizes and contains spherulites that may be as large as a marble. As the glass has little similarity in chemical composition to volcanic obsidians, these spherulites when analyzed throw little light on the mineral nature of spherulites in rocks. They show, however, that in viscous semi-solid glasses near their fusion point crystallization tends to nucleate at certain centers and to spread outwards, producing spherulitic structures. Many salts and organic substances exhibit the same tendency, yielding beautiful spherulite crystallizations when melted and cooled rapidly on a microscopic slide.
Variolites.
Variolites are a type of radiate fibrous growth, resembling spherulites in many respects, consisting of minute feathery crystals spreading outwards through a fine grained or glassy rock. In variolites there are straight or feathery feldspar crystals (usually oligoclase) forming pale-colored spherulites a quarter to half an inch in diameter. The same rocks often contain similar aggregates of plumose skeleton crystals of augite. Many volcanic rocks have small lath-shaped crystals of feldspar or augite diverging from a common center.


Gemmological Association of Australia

The inaugural meeting of The Gemmological Association of Australia (GAA) was held in the School of Arts Building, Pitt Street, Sydney on 29 October 1945.
The Association was formed to promote the education of the science of gemmology and the study of gemstones as a safeguard to the public against spurious stones.
The association has divisions in six states of Australia, the smallest being Tasmania Division.


Smoking Hills Formation

The Smoking Hills Formation is a geologic formation in Northwest Territories. It preserves fossils dating back to the Cretaceous period.


Ludicharadripodiscus

Ludicharadripodiscus is a Mesozoic bird ichnogenus. It is similar to the ichnogenus "Aquatilavipes", but more frequently preserves impressions of the hallux.


Oclese Sand Formation

The Oclese Sand Formation is a geologic formation in California. It preserves fossils dating back to the Neogene period.


Mule Spring Limestone

The Mule Spring Limestone is a geologic formation in the Saline Range of eastern California and Split Mountain and Goldfield Hills of Nevada.
Inyo Mountains and White Mountains.
It preserves fossils, such as trilobites, dating back to the Cambrian period.


Octochara

"Octochara" is a genus of fossil charophyte (aquatic green alga) from the Famennian (Late Devonian). It is one of two genera of charophyte described from the Waterloo Farm lagerstätte in southern Africa. It and "Hexachara", from the same locality provide the oldest record of reconstruct able charophytes with in situ oogonia. "Octochara" is derived from a Greek word “octo”, meaning eight, a reference to the octoradial symmetry; chara, referring to membership of the Charales. In "Octochara", a whorl of eight laterals are borne at each node. Each lateral is branched to produce four secondary branches and bears an oogonium. Two species of "Octochara" have been described, "Octochara crassa" and "Octochara gracilis". The two species differ in the size and the shape of their secondary branchlets and oogonia.
The specific name of "O. crassa" is derived from Latin, “crassus”, meaning fat or thick, a reference to the branchlets. This species has whorls up to 14mm in diameter and the branchlets are relatively broad with rounded terminations. In "O. crassa", the internode parts of axis are unknown at this stage but, based on measurements of the central hole through the whorls, they are estimated to be about 0.7 mm in diameter. Oogonia in "O. crassa" are attached to the junction at which the radial branches divide and are supported within the four secondary branchlets. Each oogonium is almost spherical, about 1.7 mm long and 1.6 mm wide at widest point but tapering slightly towards the point of attachment They are helically striated in a sinistral direction with 3 5 stria visible in plan view. O. crassa is differentiated from O. gracilis by the relatively greater width of its branches and branchlets which have rounded lobate, as opposed to pointed terminations. The whorls also have a larger diameter.
The specific name of "O. gracilis" is derived from Latin, “gracills”, meaning slender, a reference to its more slender branchlets. "O. gracilis" comprises whorls up to 10 mm in diameter in which branchlets are narrow with slender tapering terminations. The internode portions of axis in this species appear uncorticated and vary in diameter up to 0.6 mm. In "O. gracilis" Chains of whorls show that whorl diameter diminishes distally. Each whorl has eight radial branches that quadrifurcate after about one-third of their length. Branchlets of "O. gracilis" are slender with sharply pointed terminations. The oogonia are attached at the point of division of the branches and is supported within four branchlets. Each oogonium is ellipsoidal, about 1.5mm long and 0.9 mm wide at its broadest point.
Charophyte algae are non marine and can currently be found in lakes and less saline parts of estuaries. Likewise the charophytes at Waterloo Farm have been interpreted as being derived from less saline portions of the palaeo-estuarine environment.
The charophyte algae genus is formed in less saline portions of the estuarine system.


Eric J. Essene

Eric J. Essene (April 26, 1939, Berkeley, California – May 20, 2011, Ann Arbor, Michigan) was a professor emeritus of geosciences and a metamorphic petrologist at the University of Michigan. In 2010, Essene was awarded the Penrose Medal by the Geological Society of America.
 He was a leader in the development of geothermobarometry as a tool in understanding the rock assemblages of high grade metamorphic suites and the evolution of continental crust.
Essene earned his BS in geosciences from the Massachusetts Institute of Technology in 1961 and his Ph.D. from the University of California, Berkeley in 1967. He served post-doctoral positions at Cambridge University and Australian National University after gaining his doctorate from Berkeley, then began his long career in teaching and research at the University of Michigan in 1970.
The mineral Esseneite was named for Essene.


Chouteau Group

The Chouteau Group is a geologic group in Missouri. It preserves fossils dating back to the Mississippian subperiod.


Crockett Formation

The Crockett Formation is a geologic formation in Texas. It preserves fossils dating back to the Paleogene period.


Rosella Formation

The Rosella Formation is a geologic formation in British Columbia. It preserves fossils dating back to the Cambrian period.


Minona Corona

Minona Corona is a corona found on the planet Venus at . It is located in quadrangle V-27 (Ulfrun Regio) and was named after the Beninese goddess Minona, who grants fertility to both women and the land.
Geography and Geology.
Minona Corona covers a circular area of approximately in diameter.


Becscie Formation

The Becscie Formation is a geologic formation in Quebec. It preserves fossils dating back to the Silurian period.


Assise de Kusel

The Assise de Kusel is a geologic formation in France. It preserves fossils dating back to the Permian period.


Martinez Formation

The Martinez Formation is an Eocene Epoch geologic formation in California.
Geology.
The formation regionally overlies the Chico Formation and regionally underlies the Tejon Formation or the Ione Formation.
It is exposed in the Clevelin Hills in Riverside County, Santa Ana Mountains in Orange County, northwestern Santa Monica Mountains near Calabasas in Los Angeles County, and north of Mount Diablo/south of the Sacramento Delta in Contra Costa County.
Fossils.
The formation preserves fossils dating back to the Paleogene period.


Irma Thesleff

Irma Thesleff is a Professor Emerita at the University of Helsinki. Strome received a degree in dentistry from University of Helsinki and a Ph.D. in 1975, as well as post-graduate work at the National Institute of Dental Research, Bethesda. Thesleff has received several major science awards, served as president of the European Orthodontic Society and the Finnish Society for Developmental Biology. She is also an Academician of Science in Finland.
Thesleff's work is in mammalian organs, and she is best known for studies on tissue interactions regulating tooth formation. This research has clinical implications for the diagnosis, prevention and treatment of congenital defects.
Thesleff is a Foreign Associate of the United States National Academy of Sciences.


Susan S. Hubbard

Susan Sharpless Hubbard is an American hydrologist and geophysicist, and an Associate Laboratory Director at the Lawrence Berkeley National Laboratory. She was elected a Fellow of the National Academy of Engineering in 2020.
Early life and education.
Hubbard was inspired to work in science in an effort to develop insights and approaches important for sustaining our Earth. She studied geology at the University of California, Santa Barbara. She moved to Virginia Tech for her graduate studies, where she earned a master's degree in geological sciences. Her early research focused on tectonic reconstruction of the Southern Appalachians using seismic reflection and other datasets. Hubbard joined the University of California, Berkeley for her doctoral research, where she focused on stochastic methods for hydrogeology, and completed her doctorate in Civil and Environmental Engineering in 1998. She is recognized as a distinguished alumni from UC Berkeley and UC Santa Barbara. Between degrees, Hubbard worked as a geophysicist in industry and as a geologist at the United States Geological Survey in Menlo Park, California.
Research and career.
After earning her doctorate, Hubbard was appointed a research scientist at the Lawrence Berkeley National Laboratory. She was made Division Director of the Earth Sciences Division at Berkeley Lab in 2013 and Associate Lab Director of the Earth & Environmental Sciences Area in 2015. In her leadership role as an Associate Director of Berkeley lab, Hubbard has been committed to bolstering efforts to increase diversity and foster inclusion and respect for women and members of underrepresented minorities in the Earth and Environmental Sciences. Her research looks to advance the use of geophysics for subsurface characterisation, using integrated datasets to understand the environment. In particular, Hubbard attempts to quantify the dynamics of terrestrial systems. She specialises in hydrogeophysics, in particular making measurements of hydraulic conductivity, lithology and moisture movement. She has extended and advanced concepts used by the petroleum industry to better understand shallow environmental systems. Hubbard has served as Head of the Berkeley Laboratory Environmental Remediation and Water Resources Program.
She is currently involved with monitoring watershed systems, imaging of permafrost and agricultural systems and monitoring of biogeochemical processes using surface geophysical data. To characterise the permafrost, Hubbard travelled around the Arctic using a ground-penetrating radar device pulled on skis. These observations help to establish how permafrost impacts carbon cycles and the balance of energy in the polar regions of Earth. Hubbard visits the same places throughout the year to understand seasonal changes to permafrost, and attempt to understand how climate change will influence its future. Within the permafrost there is a thin surface layer (the "active layer") that freezes and thaws, resulting in a dynamic habitat for microbes.
Personal life.
Alongside her academic research, Hubbard is involved with winemaking. In 2009 she earned a Professional Certificate in Winemaking at the University of California, Davis. Her viniculture is inspired by her understanding of geophysics, using experimental research to improve the yield of grapes whilst reducing the use of water and fertiliser. She has studied the wine of the "Mila Family" vineyard using soil-pit samples, ground-penetrating radar and neutron probe analysis.


Melanosome (geology)

In geology, a melanosome is a dark, mafic mineral band formed in migmatite which is melting into a eutaxitic texture ; often, this leads to the formation of granite. The melanosomes form bands with leucosomes, and in that context may be described as "schlieren" or "migmatitic".


Wax Lake

Wax Lake was a lake in St. Mary Parish, Louisiana that was converted into an outlet channel, the Wax Lake outlet, to divert water from the Atchafalaya River to the Gulf of Mexico.
History.
The history of the Wax Lake Outlet, as well as the 20,000 cfs "Charenton Drainage and Navigation Canal", the Avoca Island Cutoff (Avoca Island-Cutoff Bayou drainage channel), and to a lesser extent the Chene, Boeuf, and Black navigation channel, was to provide flood relief to the lower Atchafalaya Basin and Morgan City.
Wax Lake outlet.
The Wax Lake outlet is an artificial channel that was created by the United States Army Corps of Engineers in 1942 to divert 30 percent of the flow from the Atchafalaya River to the Gulf of Mexico and reduce flood stages at Morgan City, Louisiana. The project design flood flow capacity for the outlet is .
Construction.
In a reversal of normal building procedures construction of the bridges began first, as well as the Bayou Teche floodgates at Calumet. Including the elevated roadways across the flood basin, and the Southern Pacific Railroad swing bridge in Baldwin as well as the three span K-truss bridge in Calumet, a total six bridges were built on dry land between Baldwin and Calumet. The dredging of the approximately of Wax Lake Outlet, that begins at Six Mile Lake (Yellow Bayou), and the "Charenton Drainage and Navigation Canal", that began at Bayou Teche in Baldwin, both started in 1941 and was completed in 1942.
Wax Lake Delta.
The Wax Lake Delta is a river delta in Louisiana that was formed by rapid deposition of sediment following the creation of a canal through Wax Lake off of the Atchafalaya River in 1942. It is roughly 20 miles (32 km) southwest of Morgan City adjacent to the Atchafalaya delta.
It receives 34 million tons of sediment per year. In the 64 years between 1941 and 2005, Wax Lake was completely filled with sediment, and the delta prograded approximately 8 km into the sea.
The Wax Lake Delta's distributary channels form via deposition of mouth bars. The first branch to the west is "Campground Pass" and further south there are the three main branches, "East Pass", "Greg Pass" and "Main Pass". The mid-channel is eroded and deposited downstream at the mouth of the river (usually during a period of higher water flow), which will create a new path of flow around it. There is then an added deposition upstream, thus causing the river to bifurcate. This results in the familiar dendritic pattern.
Because it was entirely created during an observable period and, other than the creation of the canal, was not altered by humans, it has often been in studies of deltaic formation. In the time since Hurricane Katrina, it has also served and as a model for delta regrowth in the Mississippi River Delta region in order to restore habitat and protect against storm surge.


Shonkinite

Shonkinite is an intrusive igneous rock found in few places in the world. It is unique in having low silica, feldspathoid minerals, and large blocky crystals of black augite. It makes up much of the hard dark grey rock comprising certain mountains and buttes in Montana that are remnants of laccoliths and stocks, such as the Highwood mountains.
Composition.
Shonkinite is an intrusive igneous rock. More specifically, it is a mafic foidal (feldspathoid bearing) syenite, a holocrystalline (completely crystalline) intrusive rock which, , is composed of potassic feldspar in the form of sanidine, nepheline, augite, biotite, and olivine. Shonkinite is also used for mafic nepheline syenite with aegerine-augite as the pyroxene, and with the addition of plagioclase (andesine to labradorite). Nepheline in shonkinite from the is largely altered to natrolite and stilbite.
The close view of the rocks in the Adel mountains show large glossy crystals of augite in a dark grey matrix made up of small crystals of augite and feldspar. This is unusual as augite is usually dull.
Formation.
In central Montana buttes of shonkinite are capped with white layers of syenite. There appear round globes of syenite at the boundary which suggest that the less dense syenite float up to the top of molten shonkinite as the mass cooled.
Etymology.
The rock gets its name from the type locality at Shonkin Sag in the Highwood Mountains of north-central Montana.


Pulak Sengupta

Pulak Sengupta (born 1963) is an Indian petrologist and a professor and head of the Department of Geological Sciences of Jadavpur University. He is known for his studies on grain-scale reaction mechanism and ultra-high temperature regional scale metamorphism and his studies have been documented in several peer-reviewed articles; ResearchGate and Google Scholar, online repositories of scientific articles, have listed 31 and 60 of them respectively. Besides, he has contributed chapters to many books published by others. He has also mentored doctoral scholars in their studies.
Sengupta, born on 5 December 1963 in the Indian state of West Bengal did his master's studies at Jadavpur University and subsequently secured a PhD from the same institution before joining his alma mater as a member of faculty. He is an elected fellow of Indian Academy of Sciences, and the Indian National Science Academy. The Council of Scientific and Industrial Research, the apex agency of the Government of India for scientific research, awarded him the Shanti Swarup Bhatnagar Prize for Science and Technology, one of the highest Indian science awards for his contributions to Earth, Atmosphere, Ocean and Planetary Sciences in 2006.


Kahlberg Formation

The Kahlberg Formation is a geologic formation in Germany.
Geological Period.
It preserves fossils dating back to the Devonian period.


Yongsong Huang

Yongsong Huang is a Chinese-American organic geochemist, biogeochemist and astrobiologist, and is a professor of Earth, Environmental, and Planetary Sciences at Brown University. He researches the development of lipid biomarkers and their isotopic ratios as quantitative proxies for paleoclimate and paleoenviromental studies and subsequent application of these proxies to study mechanisms controlling climate change and environmental response to climate change at a variety of time scales.
Education.
Huang received a B.Sc. in Geochemistry from University of Science and Technology of China in 1984, then received a M.S. in Analytical Chemistry from Sichuan University. He earned his first Ph.D. in Petroleum Geochemistry from the Chinese Academy of Sciences in 1990, and earned a second Ph.D. in Organic Geochemistry from the University of Bristol in 1997, as a student of Geoffrey Eglinton.
Career and research.
Huang is an organic geochemist, biogeochemist and astrobiologist. After graduating from the University of Bristol, he joined the lab of Katherine H. Freeman at Pennsylvania State University as a postdoctoral research associate. He periodically worked as a guest investigator with Timothy Eglinton at the Woods Hole Oceanographic Institution during his postdoc. In 2000, Huang joined the faculty of Brown University, where he was awarded tenure in 2012.
Huang's primary fields are organic geochemistry, geochemistry, and paleoclimatology. He is particularly well known for his work developing organic geochemical proxies of climate change and reconstructing climates sediments.
According to Scopus, he has published 187 research articles so far with 9681 citations and has an H-index of 55.


Andouille Formation

The Andouille Formation is a geologic formation in France. It preserves fossils dating back to the Ordovician period.


Joseph Dwyer

Joseph R. Dwyer (born 1963) is an American physicist known for his lightning research. He is a Professor of Physics at the University of New Hampshire. Dwyer received his Ph.D. in Physics from the University of Chicago in 1994 and worked on cosmic-ray physics and gamma-ray astronomy as a research scientist at Columbia University and the University of Maryland before joining the faculty at the Florida Institute of Technology in 2000. After moving to Melbourne, Florida, Dwyer became interested in lightning physics and his research now focuses on high-energy radiation production from thunderstorms and lightning. In 2002, Dwyer and collaborators discovered that rocket-triggered lightning produced large quantities of x-rays, allowing for first the time detailed studies of an atmospheric phenomenon known as runaway breakdown. In 2014, Dwyer left the Florida Institute of Technology and joined the University of New Hampshire.
Research.
In 2002 Dwyer, along with colleagues from Florida Institute of Technology and the University of Florida, launched rockets during thunderstorms at a facility now known as the UF/Florida Tech International Center for Lightning Research and Testing (ICLRT) at Camp Blanding, Florida. Using a heavily shielded instrument containing a scintillation detector, built by Dwyer and his students, they found that lightning does indeed produce x-rays and that x-ray emission is common for lightning. This research was published in Science (Dwyer et al. 2003). Since that time, Dwyer and his collaborators have established many key properties of the x-ray emissions from lightning, including the fact that the x-ray emission is produced during the lightning stepping process, has energies up to approximately 1 MeV and the x-rays are produced in the high field regions generated by the leader as it propagates. In 2005 TERA (Thunderstorm Energetic Radiation Array), a 24 detector array, was built to continue measuring x-rays and gamma-rays from lightning and to further study the x-ray characteristics that are associated with thunderstorms. Also, in 2005, Dwyer and collaborators made the surprising discovery that long laboratory sparks in air also generate x-rays similar to lightning, which has since motivated many groups around the world to study the x-ray emissions from sparks. Most recently, Dwyer and his team have built and deployed an x-ray camera at the ICLRT and have made the world's first x-ray images of lightning. Dwyer also has made several important theoretical contributions to the newly developing field of High Energy Atmospheric Physics, including work on runaway electron or runaway breakdown physics, gamma-ray and radio frequency emissions or atmospheric noise, and lightning initiation. In 2003, he introduced the Relativistic Feedback Mechanism of relativistic-runaway-electron avalanches, a new discharge mechanism in air, which explains how thunderclouds may generate very large flashes of gamma-rays called terrestrial gamma-ray flashes (TGFs). This work also showed the importance of positrons (anti-electrons) for thundercloud electrodynamics. Working with David Smith from UCSC he also helped establish that TGFs originate from deep within our atmosphere and not at high altitudes as had been previously assumed. Indeed, Dwyer and his team observed a ground level TGF at Camp Blanding in 2004. Finally, using BATSE data from the Compton Gamma-ray Observatory, Dwyer and collaborators discovered Terrestrial Electron Beams (TEBs) in the inner magnetosphere, which are generated by the high energy emissions from thunderstorms.
Achievements.
Dwyer has written and/or co-authored over 100 scientific research papers, more than 40 of them on lightning, terrestrial gamma-ray flashes, and x-rays from lightning. He has provided content to the PBS/NOVA website on lightning. He has spoken at many university colloquia, conferences, and workshops on his work. His work has also appeared on multiple documentaries, including Nova ScienceNow, Discovery Channel, the weather channel and BBC. Dwyer is the director of the Geospace Physics Lab at Florida Institute of Technology, advisor of graduate students, a member of the American Geophysical Union, and helps Florida Institute of Technology jointly operate the International Center for Lightning Research and Testing with the University of Florida lightning research group.
Dwyer was named a Fellow of the American Geophysical Union in 2019.


Jean Morrison (professor)

Jean Morrison (born May 19, 1958) is an American university academic. She is provost, chief academic officer and professor of earth and environment at Boston University; she is the first woman to be appointed provost of the university. She was formerly executive vice provost for academic affairs and graduate programs at the University of Southern California.
Biography.
Morrison is a metamorphic petrologist by training, whose research explores the evolution of the Earth’s crust. A native of Pawling, New York, she received her BA from Colgate University, an MS from the University of Georgia, and a PhD from the University of Wisconsin–Madison.
Morrison joined the faculty of USC in 1988 as assistant professor. She served as a member of USC's earth sciences faculty for 22 years before taking the role of provost at Boston University. While at USC, Morrison became the inaugural director of the university's Women in Science and Engineering Program and served as vice provost for academic affairs and graduate programs. She was also director of the university's graduate school for six years. Morrison has served on several National Science Foundation panels, as an editor of the "Journal of Metamorphic Geology", and as an associate editor of "American Mineralogist" and the "Geological Society of America Bulletin". In 2000, she was named Sigma Chi Professor of the Year, and she received Sigma Gamma Epsilon’s Excellence in Teaching Award. She also received USC's Associates Award for Excellence in Teaching, the university's highest teaching award.
In January 2011, Morrison joined Boston University as its second highest ranking officer and the first woman provost in its history, succeeding previous provost David Campbell.
Work as provost.
As provost, Morrison has overseen several efforts designed to enhance BU’s academic quality and global competitiveness, including the launch of the , a university-wide general education program for all undergraduates; a university-wide arts initiative; new divisions in digital learning, diversity, and graduate education; and initiatives to expand BU's footprint in the data sciences and opportunities for women in the STEM fields.
Boston University's progress has been acknowledged in many ways under Morrison's tenure, including improved academic rankings. Most notably, in 2012, Boston University was admitted to the Association of American Universities (AAU), the group of premier public and private research universities in the United States and Canada. The university has also launched two new colleges during this time: the Arvind and Chandan Nandlal Kilachand Honors College, a residential honors college for Boston University undergraduates, which was dedicated in 2011; and the Frederick S. Pardee School of Global Studies, established in 2014, which combines traditional international relations with faculty in the humanities and social sciences interested in global students, as well as the traditional area studies centers.
Research and teaching.
Morrison’s research in stable isotope geochemistry focuses on understanding the evolution and properties of the Earth's deep crust, with particular emphasis on the physiochemical characteristics in earthquake fault systems and the origins of rocks and minerals. She has received numerous National Science Foundation grants supporting her research and published dozens of articles in leading scientific journals, including "Science", "Geology", and "International Geology Review". Her teaching at the collegiate level has explored geology, mineralogy, petrology, and the process of change in science.
Personal.
Morrison lives in Brookline, Massachusetts, with her husband, Lawford Anderson, who works at Boston University as a professor of earth and environment. They have two grown children.


Falls of the Ohio National Wildlife Conservation Area

The Falls of the Ohio National Wildlife Conservation Area is a national, bi-state area on the Ohio River near Louisville, Kentucky in the United States, administered by the U.S. Army Corps of Engineers. Federal status was awarded in 1981. The falls were designated a National Natural Landmark in 1966.
Overview.
The area is located at the Falls of the Ohio, which was the only navigational barrier on the river in earlier times. The falls were a series of rapids formed by the relatively recent erosion of the Ohio River operating on 386-million-year-old Devonian hard limestone rock shelves. Louisville, Kentucky, and the associated Indiana communities—Jeffersonville, Clarksville, and New Albany—all owe their existence as communities to the falls, as the navigational obstacles the falls presented meant that late-18th-century and early- to late-19th-century river traffic could benefit from local expertise in navigating the drop made by the river over a distance of two miles (3 km). In its original form, the falls could be characterized more as rapids extending over a length of the river, than as a point-like discontinuity in a river such as Niagara Falls. Still, the falls provided a singular, dramatic and daunting obstacle to navigation on this important inland waterway.
The first locks on the river, the Louisville and Portland Canal completed in 1830, were built within a bypass canal constructed to provide year-round navigation of the river. The falls were later largely covered by the McAlpine Locks and Dam, built by the Army Corps of Engineers. The taming of the Ohio River at the falls, with the attendant reduction in local flow velocity has of late led to the covering over of the fossil beds by large and increasing quantities of low-velocity effluvia: although an impediment to viewing of the fossils, this action serves to protect the portions of the falls covered over by sediment and therefore temporarily immune to direct weathering. However, a significant area of the fossil-rich Devonian limestone rock is still left exposed, and is accessible to visitors today. The best time for visitation is during the low water season of the Ohio River between August and October. Removal of fossils is prohibited.
The shallowness of the falls provided a favored crossing point for bison in pre-settlement times and, later, an easy crossing for Native Americans.
In 1990, a section of the area in Indiana became the Falls of the Ohio State Park. An interpretive center is open throughout the year.
Size and sound.
Prior to modification for industrial and navigational purposes, the Falls of the Ohio spanned the entire width of the Ohio River. Native Americans and early European explorers heard the crisp roar of the Ohio River crashing down the cascade falls more than 10 miles away.
Geology.
The rock unit in which the falls are formed is referred to as the Jeffersonville limestone. The limestone formed approximately 387 to 380 million years ago during the Emsian Age (in the latest part of the Early Devonian Period) and the Eifelian Age (Middle Devonian). The exposure is unique—large and diverse tabulate corals and rugose corals are exposed in lifelike positions. Brachiopods and bryozoans are also present, as are gastropods (snails).
During the Devonian Period, the region lay at the bottom of a shallow inland sea about ten degrees north of the equator in the supercontinent of Euramerica.


Flinz Limestone

The Flinz Limestone is a geologic formation in Germany. It preserves fossils dating back to the Devonian period.


Black Rock Formation

The Black Rock Formation is a geologic formation in England. It preserves fossils dating back to the Carboniferous period.


Teredolites

Teredolites is an ichnogenus of trace fossil, characterized by borings in substrates such as wood or amber.
Club-shaped structures rimming mid-Cretaceous Burmese amber were formerly identified as the fungal sporocarps "Palaeoclavaria burmitis". a 2018 study re-identified the structures as domichnia (crypts) bored in the amber nodules by bivales of the pholadid subfamily Martesiinae. The borings are comparable with "Teredolites clavatus" and "Gastrochaenolites lapidicus" . Due to the substrate of the Myanmar borings being amber, the term Amberground was coined.


Phenotype (igneous petrology)

In igneous petrology, a phenotype is an aphanitic igneous rock which is identified and classified according to the mineralogy of its phenocrysts, when it is impossible to determine the mineralogy of the groundmass.
Because phenocrysts represent the earlier part of crystallisation, and a melt may have evolved somewhat in between stages of cooling, they cannot be used to accurately describe the rock's true mineralogy or chemistry, but do provide an approximate estimation. As a result of this potential for error, phenotypes are identified using the prefix "pheno-".


Observatory Group

The Observatory Group is a geologic group in Scotland. It preserves fossils dating back to the Devonian period.


Douglas Canyon Formation

The Douglas Canyon Formation is a geologic formation in Washington (state). It preserves fossils dating back to the Neogene period.


Ghaghara

Ghaghara, also called Karnali (; "Ghāghrā" [ˈɡʱɑːɡrɑː]; ; "Karṇālī" [kʌrˈnɑːliː]; ; "Jiāgélāhé" [t͡ɕi̯ákɤ̌láxɤ̌]) is a perennial trans-boundary river originating on the Tibetan Plateau near Lake Manasarovar. It cuts through the Himalayas in Nepal and joins the Sharda River at Brahmaghat in India. Together they form the Ghaghara River, a major left bank tributary of the Ganges. With a length of it is the longest river in Nepal. The total length of Ghaghara River up to its confluence with the Ganges at Revelganj in Bihar is . It is the largest tributary of the Ganges by volume and the second longest tributary of the Ganges by length after Yamuna.
Lower Ghaghara is also known as Sarayu river and finds mention in Ramayana. Ayodhya is situated on its right bank. The Ghaghara was also the site of the battle between Amin Khan Aitigin and Tughral Tughan Khan.
Course.
It rises in the southern slopes of the Himalayas in Tibet, in the glaciers of Mapchachungo, at an elevation of about above sea level. The river flows south through one of the most remote and least explored areas of Nepal as the Karnali River. The Seti River drains the western part of the catchment and joins the Karnali River in Doti District north of Dundras hill. Another tributary, the long Bheri, rises in the western part of Dhaulagiri Himalaya and drains the eastern part of the catchment, meeting the Karnali near Kuineghat in Surkhet.
Cutting southward across the Siwalik Hills, it splits into two branches, the Geruwa on the left and Kauriala on the right near Chisapani to rejoin south of the Indian border and form the proper Ghaghara. Other tributaries originating in Nepal are the West Rapti, the Kali (or Mahakali) and the little Gandak. It flows southeast through Uttar Pradesh and Bihar states to join the Ganges downstream of the town of Chhapra, after a course of . Sarayu river is stated to be synonymous with the modern Ghaghara river or as a tributary of it.
Karnali River exposes the oldest part of the Sivalik Hills of Nepal. The remnant magnetization of siltstones and sandstones in this group suggests a depositional age of between 16 million and 5.2 million years.
Basin.
The Karnali River Basin lies between the mountain ranges of Dhaulagiri in Nepal and Nanda Devi in Uttarakhand. Dhaulagiri II, elevation , is the highest point of the entire basin. In the north, it lies in the rain shadow of the Himalayas. The basin formed by the river has a total catchment area of , of which 45 percent is in India. The population of the Basin districts in Nepal increased from 1.9 million in 1971 to 4.7 million people in 2001, almost a 250% increase over three decades. The average population density of the Basin area increased from 53 persons/km2 in 1981 to 87 persons/km2 in 2001. There is a steady growth in the economically active population in the basin districts. The average literacy rate has increased from a mere 7.5% in 1971 to 45% in 2001. The social status of the permanent households increased from 24% in 1991 to 31% in 2001. The basin has a total road length of , but the pace of road development is slow.
Tributaries.
Chhoti Gandak is a groundwater-fed meandering river originating near Dhesopool, Maharajganj district of Uttar Pradesh. It travels a distance of about and joins Ghaghara near Guthani, Siwan district of Bihar. The Chhoti Gandak River Basin is located between 26°00' to 27°20' N latitude and 83°30' to 84°15' E longitude. Right bank tributaries are Khekhra, Hirna, Jethan, Maun, Duhari, Kanchi and Koilar rivers; Khanua river joins from the left bank. The discharge of Chhoti Gandak is mainly controlled by rain, which is very high during the monsoon season and low during the summers. It has been observed that whenever precipitation is high in the catchment areas, there is flood in the downstream part of the Chhoti Gandak River Basin. The region exhibits upland terrace surface, river valley terrace surface, present-day river channel with narrow flood plains, natural levee, and point-bar deposits. All these geomorphic features are depositional in nature and made up of alluvium of different ages.
The main tributaries of the Karnali are: the Seti, the Bheri.
Administrative zones and districts.
In Nepal, Karnali Zone is the largest zone with about area. Its administrative center is Jumla. The zone is divided into the five districts of Dolpa, Humla, Jumla, Kalikot and Mugu.
The Karnali zone has the lowest population density in Nepal. There are no large settlements on the banks of the river, which is only crossed near Chisapani by the Mahendra Highway. This region is now connected by karnali highway and now due to various hydro electricity projects this area is being developed. Now a 900 MW project is going to be constructed in this river
In India, the administrative districts in the Ghaghra catchment are Ambedkar Nagar, Faizabad, Ayodhya, Azamgarh, Barabanki, Basti, Ballia, Bahraich, Deoria, Gonda, Gorakhpur, Sant Kabir Nagar, Lakhimpur Kheri, Mau, Sitapur of Uttar Pradesh and Siwan district in Bihar.
Important towns in India include Akabarpur, twin towns of Ayodhya and Faizabad, Bahraich, Barabanki, Basti, Deoria, Barhalganj, Gonda, Gorakhpur, Sitapur, Siddharthnagar, Saint Kabir Nagar, Kamhariya, Rajesultanpur and Tanda in Uttar Pradesh and Chapra, Siwan, and Sonepur in Bihar.
The Ghaghra River is locally known as the legendary "Sarayu River" in the holy city of Ayodhya.
Protected areas.
Bardia National Park is the largest and most undisturbed protected area in the Karnali River basin, covering on the southern slopes of the Sivalik Hills. It is bordered in the south by the Babai River, and to the west by the Girwa River, a tributary of the Karnali. At Chisapani Gorge, the swift-flowing Karnali River emerges from the Shiwalik Range onto the broad plain and flows purposefully through the semi-tropical jungle. The park is famous for two Asian elephant herds, several deer species, gaur, nilgai, Himalayan tahr, serow and goral. The Karnali supports the endangered mugger crocodile, the gharial, a few remaining South Asian river dolphins and the golden mahseer.
Other protected areas include Katarniaghat Wildlife Sanctuary.
Endangered species.
The Karnali provides the upper range for the Gangetic river dolphin ("Platanista gangetica"), the largest freshwater mammals found on the Indian subcontinent. They are considered vulnerable species under CITES Appendix 1 and are classified as endangered on the IUCN Red List (IUCN, 2004). The river dolphins are legally protected animals in Nepal as endangered mammal and fall under Schedule I of the protected list of National Parks and Wildlife Conservation Act, 1973. Living at the upstream range limit, dolphins in the Karnali River are particularly vulnerable to threats from habitat degradation. Dolphins need deep pools of water. They are often found in places where human activities are most intense and they are sometimes accidentally caught by the local people who live in the lower Karnali basin. The Karnali River supports the last potentially viable population of the Ganges river dolphin in Nepal. These dolphins are at their farthest upstream range and isolated by the Girijapur Barrage (a low gated dam), located about downstream of the Nepal–India border.
A high dam has been planned for some time just upstream of the dolphins' current (or at least recent) range in the Karnali River, Nepal. If built, this structure would almost certainly eliminate the small amount of dolphin habitat in Nepal's last river with a potentially viable dolphin population. Disturbance and environmental degradation associated with geotechnical feasibility studies and bridge and road construction for the dam already may have contributed to a decline in the number and range of dolphins or "susu" above the Nepal-India border. The Ghaghara is the furthest upstream in the dolphin range.
Other important protected areas and their biological and religious significance are a) Khaptad NP at , 1984 - oak, fir, conifer, musk deer, leopard, black bear. Ashram of late Khaptad Baba (sage), Shiva shrine, Khaptad daha - a shallow lake; b) Dhorpatan HR at , 1987- fir, hemlock, spruce, birch, junipers, grassland. Game hunting reserve; and c) Royal Suklaphanta - WR (1976) at Kanchanpur at in the Terai Sal, acacia, sisso, extensive grassland, elephant, swamp deer, tiger, hispid hare, Bengal florican.
Development projects.
In Nepal
The Karnali basin is the first to arouse keen interest in Nepal's vast hydropower development study. There are several attractive sites for the generation of cheap hydroelectric energy in this basin.
The Master Plan Study for Water Resource Development of the Upper Karnali River and Mahakali River Basins (1993) identified 32 potential hydropower projects in the Karnali Basin. Despite the high potential of hydropower development (32,000 MW) in the Basin, only 2,245 kW capacities (from eight micro hydel schemes) has been developed so far.
Considering the pace of hydropower development in Nepal (Out of 83,000 MW potential, only 705 MW hydropower has been generated throughout the country till the end of 12th national plan viz. 2009/10-2011-12) in general and in the Karnali Basin in particular, harnessing the total hydropower potential of the Basin is envisaged to take a long time. Based on recent water resources development planning and project progress, the likely large scale hydropower projects that will be operational in the Basin by 2025 are predicted to be: West Seti HEP (750 MW); Upper Karnali HEP (300 MW); Bheri-Babai Multipurpose Project (48 MW); and Lohore Khola HEP (58 MW).
West Seti HEP (750 MW)
The proposed West Seti HEP is located on the Seti River in the Far-Western Development Region of Nepal. The West Seti HEP catchment covers the upper of the Seti River Basin. The West Seti HEP is a large storage project with a rated capacity of 750 MW. The power station is located approximately upstream of the Seti River confluence with the Karnali River, with the dam site located a further upstream. All project sites, excluding the reservoir area and transmission line corridor, are located in either Doti and/or Dadeldhura Districts. The reservoir area is located in Doti, Dadeldhura, Baitadi and Bajhang Districts. The transmission line corridor is located in Doti, Dadeldhura, Kailali and Kanchanpur Districts. The project has been allocated for development as BOOT project under private sector.
Upper Karnali HEP (900 MW)
The proposed Upper Karnali HEP is located on the main course of the Karnali River and has a catchment area of . This project is one of Nepal's most economically attractive runoff- river diversion schemes (900 MW), with daily peaking capacity and high firm energy. Project facilities will be located in three districts: Surkhet, Dailekh and Achham. Project hydrology is based on data from station 240 at Asaraghat. The river is snow fed and the mean annual estimated flow at the headworks is . The project has been allocated to GMR of India for development on BOOT basis.
Bheri-Babai Multipurpose Project (48 MW)
The Bheri-Babai Multipurpose Project is an inter-Basin water transfer project prioritised for the development of irrigation in Bardia District . The intake of the Bheri-Babai (BR-1) diversion scheme lies on the Bheri River upstream of the confluence with the Karnali River. The tailrace outlet is located in the Babai River upstream of the existing Babai irrigation project diversion weir. The Bheri-Babai project aims to generate electricity and supply additional water to the Babai Irrigation Scheme in the Terai by diverting of water from the Bheri River into the Babai River. The project is yet to undergo a feasibility study.
Lohore Khola HEP (LR-1) – (58 MW)
The Lohore Khola HEP is a proposed reservoir storage project situated on the Lohore Khola, a tributary of the Karnali River in Dailekh District. The project is located a few kilometers downstream from the confluence with Chham River and upstream of Dungeshowr. The catchment area of the Lohore River at the reservoir site is . Based on the isohyetal map of the Karnali River Basin, average annual rainfall for the basin is estimated to be . As there is no stream gauge on the Lohore River, its flow was estimated using data from Station 240 (1963–2000) located on the Karnali River at Asaraghat with a catchment area of . The sediment flow into the river is estimated to be 2.4 million tonnes per year. As the economic internal rate of return (EIRR) for the project is highest for the draft rate of 0.7, the flow for power generation was estimated for this draft rate. The riparian flow was assumed to be 10 percent of the monthly minimum flow; i.e., .
Karnali (Chisapani) Multipurpose Project (10,800 MW)
The site of the Karnali Multipurpose Project, also Chisapani Dam Project, is located in the Karnali Gorge, immediately upstream of the Terai. The project has a catchment area of , covering nearly 30 percent of Nepal. The long-term average river flow is , with an average dry season flow (November–May) of and an average wet season flow (June–October) of .
The Karnali (Chisapani) Multipurpose Project is a potential mega multipurpose storage project on the Karnali River at Chisapani, envisaging a high dam, with reservoir area of , with power station operating under a design head of to operate 18 units of 620 MW capacity each ( 10,800 MW installed capacity) and with a re-regulating weir downstream with power plant of 84 MW capacity operating under a head of . A large-scale irrigation development is also envisaged— in Nepal and in India. Project planning commenced in 1960, although the feasibility study for the project was only completed in 1989. Before this project is developed a number of significant underlying issues have to be resolved. These issues include: Nepal and India reaching a bilateral agreement on the downstream benefits of regulated river flows; the resettlement of over 60,000 people; the impact on and restoration of habitat within Bardia National Park; and, above all, the financial arrangements for project funding. Accordingly, it is predicted that the chances of this project being implemented before 2025 are very slim, although increasing international pressure on reducing greenhouse gas (GHG) emissions from the energy generation sector may assist project initiation. While the likelihood of this project being developed by 2025 is low, Nepal and India could cooperate to develop this project to meet India's growing energy demand from renewable resources.
Irrigation.
Nepal.
The major existing river use by volume in the Karnali Basin is irrigation. Three areas on the Nepal Terai and two areas in India are irrigated from the Karnali River. Within Nepal, two areas are irrigated in Bardiya District, , and a single site is irrigated in Kailali District, . The total demand for irrigation water from the Karnali River by these three areas represents a very small proportion of existing total annual river flows, amounting to a mean annual rate of . This is equivalent to 3.9 percent of the mean annual Karnali River flow into India.
India.
In India, water is diverted from the Karnali River at the Girija Barrage into the Sarda Sahayak Irrigation Scheme and the Saryu Nahar Irrigation Scheme, which have command areas of and respectively. The combined annual irrigation demand of these two schemes is approximately .
The Sarda Sahayak Irrigation Project uses the combined flows from the rivers Ghaghara and Sarda in the Girija Barrage built across the Ghaghara river below a catchment area of . This barrage is situated about downstream of Khatria Ghat Rly station and from the international border to Nepal in Bahraich district. It is linked to the Lower Sarda Barrage (built across the Sarda river, with a catchment area of , about northeast of Lakhimpur Kheri Rly station in Lakhimpur Kheri district) via a link canal from Girija Barrage to the Lower Sarda Barrage which is long and is designed to divert a discharge of from Gandak to Sarda river.
The feeder channel taking off from the Lower Sarda Barrage is long, feeds the five branches of Dariyabad, Barabani, Haideganj, RaeBareil and Purva, and is designed to carry a discharge of . The Sarda Sahayak feeder channel meets the Haidergarh branch at and Raibareli branch at . The entire canal system is considered the largest in Asia and designed to provide irrigation to a Culturalable Command Area (CCA) of covering 14 districts in 168 blocks with a gross command area of .
On account of high silt flows during the flood season, Sarda Sahayak supplies (from Karnali) are suspended for 100 days between June and October, when the Lower Sarda Canal (feeder canal) draws water from the Sarda River, which is then flooded.
Navigation.
In the past the Karnali River was considered to be attractive for the development of navigation right from the Indo–Nepal border till the confluence of this river and the Ganges. The lower reach of this river—called the Ghaghra in India—was used in the past for navigation by steamers. Apart from in the foothills of the Himalayas where most of the streams were simply fast-moving water throughout the greater part of the year and not navigable when flowing rapidly, most of the rivers with steadier currents had boats on them. The Ganges, the Ghaghra, the Yamuna, the Gomti, the Sharda and the Rapti were the most important navigable rivers in the Northwestern provinces and Oudh.
Many trade items such as timber, food grains, sugar, indigo, cotton seed, poppy seed and mustard seed were transported by boats. April, May and June were the most suitable months and were a busy trading period. Different kinds of cargo boats were used on the Ganges, the smaller ones were known as , while the larger ones were known as .
In the latter half of the 19th century when the railways came into existence, the significance of waterways as inland trade routes declined, as the railways were faster and safer. With the exception of eastern parts of Bengal where abundance of water in the natural network of channels sustained and continued to provide a suitable mode of transport of goods and people, the railways had almost entirely replaced the waterways as communication lines throughout the country by the end of the 19th century.
The possibilities for further extension of the steamer services to the north had also been explored in the past. The Central Water and Power Commission of the Government of India had carried out hydrographical survey of the Karnali River from the Bahramghat to the confluence of this river and the Ganges a distance of . This survey was done in the years 1943–53 to explore the possibility of improvement and extension of navigation on this river by powered crafts. These surveys revealed that there were only 5 shoals under at low water between Burhaj and Bahramghat a distance of about . The minimum depth was . These depths were available without any river conservancy works. All other conditions of navigable channel such as the width and current of flow etc. were also found to be very favourable. The low water stage in this river is only for a short duration. There is a great urgency to carry out detailed study of the Karnali river to develop modern inland waterway by applying various channel improvement technologies.


Haverford Formation

The Haverford Formation is a geologic formation in Wales. It preserves fossils dating back to the Ordovician period.


Fosters Point Formation

The Fosters Point Formation is a Cambrian limestone geologic formation in Nova Scotia and Newfoundland. It preserves fossils.


Chase Formation

The Chase Formation is a geologic formation in Nebraska. It preserves fossils dating back to the Carboniferous period.


Pavlova Corona

Pavlova Corona is a corona found on the planet Venus, at , Mead Quadrangle. It is named after Anna Pavlova, a Russian ballerina (1881-1931).
Geography and geology.
Pavlova Corona covers a circular area of around 400 km in diameter. Pavlova Corona is one of the four major coronae of eastern Eistla Regio (Didilia, Pavlova, Ninmah, and Isong). These coronae have relatively similar structure: an uplifted concentric feature with a central dome and surrounded by a relatively flat interior floor.


Enid Formation

The Enid Formation is a geologic formation in Oklahoma. It preserves fossils dating back to the Permian period.


Killey Bridge Formation

The Killey Bridge Formation is a geologic formation in Northern Ireland. It preserves fossils dating back to the Ordovician period.


Derfel Limestone

The Derfel Limestone is a geologic formation in Wales. It preserves fossils dating back to the Ordovician period.


Chatham Group

The Chatham Group is a Triassic-age geologic group in the eastern United States. It is one of the most fossiliferous sections of the Newark Supergroup, preserving much of the Late Triassic up until the Triassic-Jurassic mass extinction. The group was originally named to refer to Triassic rocks (the Pekin, Cumnock, and Sanford formations) specifically within the Deep River Basin of North Carolina. Later studies have utilized it to encompass Late Triassic strata in most other sedimentary basins in the Newark Supergroup.


Lava delta

Lava deltas, similar to river deltas form wherever sufficient sub-aerial flows of lava enter standing bodies of water. The lava cools and breaks up as it encounters the water, with the resulting fragments filling in the adjacent seabed topography such that the flow can move further offshore sub-aerially. Lava deltas are generally associated with large-scale, effusive type basaltic volcanism.
Occurrence.
Lava deltas are found mainly associated with volcanic islands, particularly those formed at hotspots as they produce the necessary effusive basaltic flows.
The largest lava delta systems known are associated with formation of volcanic type passive margins. Just prior to break-up along the northern Atlantic in the late Paleocene, massive eruptions occurred along the eventual line of break-up. This volcanism, part of the North Atlantic Igneous Province, led to the formation of two extensive lava escarpments, interpreted as deltas, extending from the Faeroes onto the More Margin (the Faeroe-Shetland escarpment) and the Vøring escarpment on the Vøring margin, a combined distance of approximately . As these deltas were prograding into water of relatively constant depth, they were able to extend as much as from their original vents.
Formation.
When a sub-aerial lava flow reaches the ocean (or other large body of water), contact with the water causes both rapid cooling of the lava and steam explosions that fragment it. The glassy fragments that are formed, known as hyaloclastites, fall down to the seabed forming foresets. As the seabed topography becomes infilled, the subaerial flow is able to build out. The process continues as long as the lava supply is maintained, creating a lava bench. A lava bench is a volcanic landform with a horizontal surface raised above the level of the surrounding area. The Hawaiian islands are an example of land that was formed this way, and the Big Island is currently still expanding due to lava benches. The Kilauea Volcano releases lava that flows down the slope of the volcano and eventually encounters the ocean; this lava flow hardens when it comes into contact with the significantly cooler water of the ocean and forms an unstable lava bench. Eventually, when the material beneath the lava bench stabilizes, it becomes stable land that has been added to the island.
Most lava deltas are formed by relatively low viscosity Pahoehoe type flows and the lava reaches the sea via a system of small lava tubes, their entry into the water being marked by a series of steam plumes.
Hazards.
Collapse of the frontal part of lava deltas is common during their formation, representing a hazard for any people that are watching from a solidified part of the delta and such areas are normally marked as dangerous. If a newly formed lava bench rests on sediments, it may pose hazards due to its extremely unstable structure. Oftentimes, these benches are so unstable that they collapse into the sea, exposing the water to the hot lava on the interior of the bench and releasing acres of land into the ocean. When the hot lava hits the water, violent explosions of steam can shoot large rocks and molten lava up to inland. These collapses are extremely dangerous because they can happen without warning, and anyone or anything on the bench will be caught in the collapse. For safety, people are advised not to walk on lava benches because of their unstable nature, and they must maintain a safe distance from the lava bench.
People standing too close to the edge of an active delta are not only at risk from being thrown in the water but from the steam explosions and the accompanying acidic clouds ("laze") that result from the collapse as seawater comes into contact with the active lava tube system.
Uses.
On steep-sided volcanic islands, lava deltas make attractive sites for building and many villages and towns are located on old lava deltas, such as Garachico on Tenerife.


Jenny Clack

Jennifer Alice Clack, ("née" Agnew; 3 November 1947 – 26 March 2020) was an English palaeontologist and evolutionary biologist. She specialised in the early evolution of tetrapods, specifically studying the "fish to tetrapod" transition: the origin, evolutionary development and radiation of early tetrapods and their relatives among the lobe-finned fishes. She is best known for her book "Gaining Ground: the Origin and Early Evolution of Tetrapods", published in 2002 (second edition, 2012) and written with the layperson in mind.
Clack was curator at the Museum of Zoology and Professor of Vertebrate Palaeontology at the University of Cambridge, where she devoted her career to studying the early development of tetrapods, the "four-legged" animals said to have evolved from Devonian lobe-finned fishes and colonised the freshwater swamps of the Carboniferous period.
Early life and education.
Clack was born on 3 November 1947 to Ernest and Alice Agnew. She was brought up in Manchester, England. She was educated at Bolton School (Girls' Division), an independent school in Bolton, Lancashire. She received a B.Sc. in Zoology from the University of Newcastle upon Tyne in 1970, and a Ph.D. from the University in 1984, where she studied under Alec Panchen. She also held a Graduate Certificate in Museum Studies from the University of Leicester and an MA from the University of Cambridge. On 9 December 2000, she was awarded a Doctor of Science (ScD) degree by the University of Cambridge.
Academic career.
In 1981, Clack joined the University Museum of Zoology, University of Cambridge, as an Assistant Curator. She was promoted to Senior Assistant Curator in 1995. Since 2005, she has been Curator in Vertebrate Palaeontology at the museum. In 2006, she was awarded a personal chair by the University of Cambridge, and took the title Professor of Vertebrate Palaeontology. She retired in 2015 and became Emeritus Professor of Vertebrate Palaeontology at the museum. In 1997, Clack was elected a Fellow of Darwin College, Cambridge; since 1 October 2015, she has been an Emeritus Fellow. From 2000 to 2005, she was Reader in Vertebrate Palaeontology at the University of Cambridge. On 1 October 2006, Clack was awarded a personal chair by Cambridge, taking the title Professor of Vertebrate Palaeontology.
Clack is best known for her extensive body of work on early tetrapods, much of which redefined how paleontologists conceived of the evolution of limbs and other features associated with tetrapods' transition from other lobe-finned fishes. She began her career working primarily on the ear of early tetrapods and later expanded to more broadly addressing the osteology and evolution of tetrapods. Together with Michael Coates (University of Chicago), Clack defined what is known as "Romer's Gap," a major gap in the fossil record of early tetrapods and one that she subsequently began to fill in collaboration with other paleontologists. Clack also undertook extensive fieldwork expeditions in order to search for further remains of early tetrapods. In 1987, during an expedition to East Greenland, Clack and her team discovered the remains of the Devonian tetrapods "Acanthostega" and "Ichthyostega," following up on field notes of researchers who had collected material of "Acanthostega" in 1970. Additional surveys in 1998 led to the collection of substantial new material, including what is now recognized as "Ymeria." Most recently, she led a major consortium project (TW:eed) investigating some exciting new fossils from Northumberland and the Borders Region of Scotland which date from the Tournaisian stage of the earliest Carboniferous period; this project has produced numerous publications furthering the understanding of early tetrapod evolution.
Over the course of her lengthy career, Clack published in some of the most notable scientific journals, including Nature, Science, and Proceedings of the National Academy of Sciences and is one of the most published vertebrate paleontologists in Nature, arguably the leading scientific journal in the world, with over 15 papers in that journal alone. In addition to her "Gaining Ground" book, Clack also co-authored a volume of the Handbuch der Paläoherpetologie series on early tetrapods with Andrew Milner in 2015 and co-edited a volume on the evolution of hearing in 2016.
Clack supervised many graduate students who went on to pursue successful careers in paleontology and evolutionary biology, including Per Ahlberg (Uppsala University), Paul Upchurch (University College London), Michael Lee (Flinders University), and Matthew Friedman (University of Michigan). In April 2012 she was featured in an episode of the BBC television series "Beautiful Minds", a set of documentaries about scientists who have made important discoveries. Clack was honored by her peers with a festschrift published in 2019.
Death.
Clack died on 26 March 2020 at the age of 72.
Honours.
In 2008, Clack was awarded the Daniel Giraud Elliot Medal from the U.S. National Academy of Sciences, the first woman to achieve the honor.
In 2009, Clack was elected a Fellow of the Royal Society, the first female vertebrate paleontologist to achieve the honor. She has also been elected a Foreign Honorary Member of the American Academy of Arts and Sciences.
On 15 June 2013, Clack was awarded an honorary Doctor of Science (DSc) degree by the University of Chicago. The university described her as "an internationally preeminent palaeontologist whose research has profoundly changed the understanding of the origin of terrestrial vertebrate life." Also in 2013, she was awarded the T Neville George Medal by the Geological Society of Glasgow.
On 17 July 2014, she was awarded an honorary Doctor of Science degree by the University of Leicester. Also in 2014, she was made an Honorary Foreign Member of the Royal Swedish Academy of Sciences.
In 2018, she won the Palaeontological Association's most prestigious award, the Lapworth Medal.


Harpers Formation

The Harpers Formation is a geologic formation in Maryland, Pennsylvania, Virginia, and West Virginia, consisting of schist, phyllite, and shale. It dates back to the early Cambrian period. It is considered part of the Chilhowee Group.
Notable exposures.
The type section is in gorges of the Potomac River and the Shenandoah River at Harpers Ferry.


Rheid

In geology, a rheid is a substance whose temperature is below the melting point and whose deformation by viscous flow during the time of observation is at least three orders of magnitude (1,000×) greater than the elastic deformation under the given conditions. A material is a rheid by virtue of the time of observation. The term, coined by S. Warren Carey in 1953, has the same Greek root as rheology, the science of viscoelasticity and nonlinear flow.
Types of rheids.
Almost any type of rock can behave as a rheid under appropriate conditions of temperature and pressure. For example, the Earth's mantle undergoes convection over long time-scales. As the mantle supports the propagation of shear waves, it may be deduced that it is a solid and, therefore, behaving as a rheid when it undergoes said convection. Granite has a measured viscosity at standard temperature and pressure of about 4.5×1019 Pa·s
so it should be considered a rheid. Similarly halite, the mineral form of table salt, is a geological material that behaves as a rheid over relatively short time-periods. As salt is buried by other types of sediments, it will often flow laterally towards regions of less-confining stress. Through this mechanism, salt domes and other structures may form. In some areas, such as the Gulf of Mexico, these structures often serve as traps for petroleum and natural gas.


Hay River Formation

The Hay River Formation is a geologic formation in Northwest Territories. It preserves fossils dating back to the Devonian period.


Booley Bay Formation

The Booley Bay Formation is a geologic formation in Ireland. It preserves fossils dating back to the Cambrian period.