Fossils are almost always found in sedimentary rock strata. Sedimentary rocks are the most abundant type on the surface of the Earth, and they are the only type that forms under conditions that are likely to preserve organic artifacts.Continue Reading
Non-sedimentary rocks are either unable to collect fossils or likely to destroy them during their formation. Igneous rock pours out from the molten region of the Earth's crust and cools at or near the surface. Surface igneous rocks, such as obsidian and pumice, erupt from volcanoes and cool before they can take up organic remains. Any bone, tooth or plant matter they come into contact with while they are still malleable is burned completely, leaving no trace to fossilize. Substrate igneous formations, such as plutonic granite, rise in a hot bolus to a point just beneath the surface and cool in place, which prevents biological material from entering the rock at any point.
The third rock type, metamorphic, is occasionally found with fossils embedded in it, but this is unusual. Metamorphic rock usually begins as a sediment, such as limestone, but undergoes a process of reformation under conditions of extreme heat and pressure. Metamorphic conditions often destroy fossils, and the resulting rock, such as marble, rarely has any remaining trace of biological entities.Learn more about Geology
Shale is a sedimentary type of rock. Sedimentary rock is formed when tiny particles of sand, pebbles or other fragments of material gather in layers, hardening over time.Full Answer >
Bauxite ore is formed when the surrounding soil or rock is dissolved by natural weathering processes until it forms a new type of rock that is usually rich in aluminum ore. Though both types are used for aluminum production, the most valuable type of bauxite ore is lateritic ore.Full Answer >
Pumice is a type of rock that can actually float. It is an igneous rock formed by explosive volcanic eruptions, and is so porous that it floats until the pores fill and become waterlogged.Full Answer >
The specific type of rock that forms when magma cools at the Earth's surface is extrusive igneous rock. Igneous rock forms when magma cools, but where the magma cools determines the type of igneous rock that forms. Igneous rock gets its name from the Greek word for fire and is so called due to the extremely hot liquid from which the rocks originate.Full Answer >