Geology 109 Exam Questions and Answers (Already Passed)

Geology 109 Exam Questions and Answers (Already Passed) Metamorphic Rocks - Answers Form at depths under the earth when preexisting rocks are placed high degrees of heat and stress. Occurs mountain building his happening. Sedimentary Rocks - Answers Produced on earths surface. Made up of pieces of old rocks. When rocks are exposed on the surface they are whethered and eroded. Theses pieces of rock fragments are deposited where they pile up and eventually turn into sedimentary rocks. Ingenous Rocks - Answers Formed by cooling of molten magma. When magma cools slowly under the earths surface it allows large crystals to form. Ex. common Granite Minerals that from are very small or glasses are produced. Strike - Answers Direction of the intersection of rock layer with horizontal surface Dip - Answers Amount of tilting of the rock measured at 90* from the strike. How rocks are deformed? - Answers 1.) Compressive forces 2.) Tensional forces 3.) Shearing Forces Fault - Answers Brittle structure break occurs under low temperature and pressure near the surface. Fold - Answers Ductile material occurs under high temp and pressures when rocks buried at depth. Plate Tectonics - Answers The crust is broken into pieces called plates that are constantly moving. Contiental Drift - Answers Early Theory on the motion of the continents. Alfred Wegener in 1915 popularized book. Contiental Evidence Contiental Drift - Answers If you removed the Atlantic Ocean Africa and South America would make a good fit like puzzle pieces. Glaciation. Fossil Evidence. Similar fossils found in Africa and South America. First reactions very hostile, primarily because continents move. Wegener suggests that the continents moved by tidal influences of the moon, which is clearly impossible. Paleomagnetism - Answers When molten rocks cool down, iron in them points toward the north pole ( like small magnets). The temperature in which this happens is called the Currie Point. This allows geologists to figure out where the North Pole was in the past Hot Spots - Answers These are chains of volcanoes formed as plates move over stationary hot spots. Earthquake Patterns - Answers Earthquakes occur primarily on late margins.At convergent margins earthquakes get deeper as the plate is subducted. Convection the driving Force - Answers It is believed (although there are competing theories) that convection currents in the mantle push the plates of crust along. Divergent Margins - Answers This is where new oceanic crust is produced.Causes plates to spread apart, and oceans to widen. Convergent Margins - Answers This is where two plates collide.What happens depends on the type of plates colliding.Can be Ocean-Ocean, Ocean-Continent or Continent-Continent. Preservation - Answers Most organisms are completely destroyed after death. Because of this fossilization (the formation of a fossil) is incredibly rare Most organisms are eaten, decay or destroyed by geologic processes long before they have a chance to enter the fossil record. The chances of being fossilized are largely controlled by the makeup of the organism and where it lives. Animals with hard mineralized shells have a much better chance of being fossilized than those without. Where the animals lives is important because the chances of being fossilized increase greatly if the body is quickly covered in sediment. Tapthonomy - Answers Study of everything that happens to an organism from the time it dies until it is fossilized. Permineralization - Answers Occurs when minerals are deposited in pores or other voids in a shell or bone. Makes the material stronger improving chances of preservation. Most common method of fossilizing bone. Replacement - Answers Replacement is when minerals in the original shell or bone are replaced by new ones. Very detailed. Pyrite. Carbonization - Answers Is when thin layers of tissue are preserved as films of carbon. Leaves and tissues of soft-bodied organisms often preserved this way. Molds - Answers Sometimes the after burial the original shell material is dissolved. This leaves a void where the shell used to be. Can be either internal or external molds. Molds can also be filled at a later time forming a cast. Soft tissue Preservation - Answers Soft tissues an be preserved in rare occasions. Most likely to occur if the animal is buried quickly with little or no oxygen present. Ichnology - Answers Sometimes you also find evidence of an organisms tracks, trails, borings or burrows. Can tell you a lot about the animal that made them. Can tell how it walked, how fast it could run and in some cases information about its environment. Systematics - Answers The science of classifying things is known as taxonomy (laws of order in Greek). Any named grouping of organisms is called a taxon (plural is taxa). Linnaean Classification - Answers Every species name has 2 parts consisting of the genus name and the trivial name. These species are then grouped into genera, then the genera into increasingly higher groups. Important features of this system is that it is hierarchical, with each rank is grouped into larger ranks. Cladistics - Answers Base their classifications directly from the branching order on cladograms. Always naming only monophyletic groups. Synapomorphies - Answers is a character that is an evolutionary novelty that is then passed on to its descendants . Sponges - Answers Cambrian- Recent The poriferans (sponges) are characterized by cell groups that are independent o