Where are Fossils Found?
Fossils are typically found in sedimentary rock, almost all of which were originally deposited as sediments by moving water. Subsequent processes hardened them into sedimentary rock, as overlying pressure squeezed the water out and the grains were cemented together. Often plants and animals were trapped, being buried in the sediments. As the sediments hardened into sedimentary rock, the dead things hardened into fossils. The vast majority of visible fossils are marine invertebrates, animals that live in the sea and have no backbone, mostly animals with a hard outer shell. This would include clams, coral, brachiopods, ammonites, and other animals familiar to us, as well as extinct animals like trilobites and crinoids. In some locations the deposits are dominated by fish fossils and more rarely insects. Interestingly enough, while sedimentary rocks are found in most places, fossils are not so easy to find. Lots of sedimentary rocks contain no recognizable fossils at all, other than micro
Fossils are most often found in sediments and sedimentary rocks. Igneous rocks, which form from molten rock, almost never contain fossils (some exceptions include fossil-bearing boulders encased in lava, but not completely melted and fossils preserved in ash layers and clastic debris flows produced by volcanoes). A significant number of fossils have also been recovered from metamorphosed sedimentary rocks. Metamorphic rocks have been subjected to extreme temperature and pressures that at times produce significant distortion and deformation of the rock unit. In areas where the metamorphism is weak, identifiable fossils have often survived, although they may show some of the wear and tear of these stresses. A look at Maine’s bedrock map shows the areas most influenced by intense metamorphism and igneous activity and explains why most of Maine’s fossil bearing units occur in the northern and eastern parts of the state. Certain types of sedimentary communities are better represented in the
Both body and trace fossils are commonly found buried in sedimentary rocks. There are major sediment deposits in such places as the mouths of rivers or at the bottom of sea and lake beds. Because rock layers are laid down oldest at the bottom and youngest at the top, fossils can provide an important clue to the Earth’s history. (See info on the Fossil Record.) Fossils can be found in more unusual places as well, such as inside amber or tar pits. Fossils can be found in many places around the world provided the conditions are right. What does fossilization tell us about the fossil record? The fossil record does not represent all of the living things once found on Earth. The reason for this is because not all organisms have correct properties that allow for fossilization. Some organisms may have decayed before fossilization could begin. Organisms that live on land or have soft body parts are less likely to fossilize than those that live in water or have hard body parts. Therefore, the fo
Fossils can be found in road cuttings, quarries, cliff faces, river valleys and seashores-even in such places as building sites. Palaeontologists (and other fossil hunters) can recognise sedimentary rocks that are likely to contain fossils of a particular period. Background research plays a large part in knowing where to look, but luck plays a major role as well. When a site has been identified as being a possible site for fossils, and perhaps excavated with some success, similar rock formations may be sought in other localities.
