Subspecies. 1  H. c. charithonia, Ecuador. 2  H. c. simulator, Jamaica. 3  H. c. bassleri, Colombia. 4  H. c. churchi, Haiti. 5  H. c. tuckeri, Florida. 6  H. c. vazquezae, Mexico. 7  H. c. ramsdeni, Cuba. 8  H. c. antiquus, St. Kitts, Antigua.
This is the cell, a current develops as hot liquid rises and cooler liquid sinks. All liquids do this weather air, water, or molten rock. In a pot, the liquid is water, the heat source is the stove burner. In the earth the mantle is the liquid, the heat source is the core.Cells develop in different areas due to variations in the mantle.here cool material is sinking between two cells you have a subduction margin form, the asthenosphere is dragged down and with it the plate forming subduction zones. In the odd occasion you might have a hot spot. I describe this as somethng like a welding torch burning through a plate of steel.
Pumice is a common product of explosive eruptions (plinian and ignimbrite-forming) and commonly forms zones in upper parts of silicic lavas. Pumice has an average porosity of 90%, and initially floats on water. Scoria differs from pumice in being denser.With larger vesicles and thicker vesicle walls, it sinks rapidly.coria is another vesicular volcanic rock that differs from pumice in having larger vesicles, thicker vesicle walls and being dark colored and denser. Pumice is created when super-heated, highly pressurized rock is violently ejected from a volcano.