Instrument data from three buoys in Lake Superior provide a reliable record of water temperatures since about 1980, and the information also shows that, with water temperatures running in the mid-to-upper 60s (and even warmer closer to shore), âwe are at record temperatures for this time of year,â according to Austin.
The talc is formed by the alteration of sedimentary magnesium carbonate rocks (dolomite and magnesite) at elevated temperature and pressure below the earth's surface. While the magnesium is fixed in situ, the silica is transported by silica-containing hot fluids to react with the Magnesium- bearing carbonates to form talc. These altered rocks are then talc-rich dolomites or magnesites. This type of deposits usually deliver the massive talcs accompanied by carbonates, chlorite and some quartz.
Talcum powder is made from talc, a mineral made up mainly of the elements magnesium, silicon, and oxygen. As a powder, it absorbs moisture well and helps cut down on friction, making it useful for keeping skin dry and helping to prevent rashes.n its natural form, some talc contains asbestos, a substance known to cause cancers in and around the lungs when inhaled (see our document Asbestos). All talcum products used in homes in the United States have been asbestos-free since the 1970s.