GEL 109 Test 2 Complete Questions And Answers Well Elaborated

What kind of rocks make up most of the Earth's crust? - correct answers Igneous What is the importance of Strabo? - correct answers He is the first geographer to observe magma cooling. Define Vicosity - correct answers The resistance to flow. High vicosity - correct answers slower flow Low vicosity - correct answers faster flow Difference between felsic and mafic lava flows/eruptions. - correct answers Mafic lava is hotter and faster moving while felsic lava is explosive and slow moving. Define aphanitic texture - correct answers Fine grained texture caused by fast cooling lava. Define phaneritic texture - correct answers Course grained texture caused by slow cooling magma. What are extrusive rocks and how do they form? - correct answers Rocks formed of volcanic glass that form via rapid cooling at the Earth's surface. What is a pyroclast? - correct answers Broken pieces of lava that are thrown into the air during an eurption. What are intrusive rocks and how do they form? - correct answers Rocks formed deep within the Earth from slow cooling magma. What are different kinds of plutons and how are they differentiated? - correct answers Determined by size; Stock, Batholith, Laccolith(tend to be domed). And Dikes and Sills that are above ground. What is the difference between a dike and a sill? - correct answers Dikes cut across the country rock diagonally while sills are parallel to the layers of country rock. What is a xenolith? - correct answers A piece of country rock that is broken off during magmatic stopping. What is magmatic stopping? - correct answers The ways in which magma makes space for itself as it rises to the surface; wedging, melting the surrounding rock, and breaking off large chunks of rocks. Why are igneous rocks good at recording polarity? - correct answers Because of the iron content in the rock. Define ultramafic rocks. - correct answers Consist of primarily mafic minerals. Define intermediate rocks. - correct answers Rocks that are midway between mafic and felsic rocks. When was the last magnetic reversal? - correct answers 774 thousand years ago. Why are magnetic reversals preserved so well along spreading ridges? - correct answers Because magnetic reversals are recorded during seafloor spreading. What makes pegmatite special? - correct answers It consists of many minerals that are not often found in intrusive igneous rocks. What is tuff? - correct answers Rock formed from the compression of volcanic ash. What does vesicular mean? - correct answers Gas pockets in the rocks. What are sedimentary rocks composed of? - correct answers Sediment What conditions do sedimentary rocks form under? - correct answers When sediments from existing rocks are compacted together. What 2 processes form sediments? - correct answers Mechanical and Chemical weathering. What are 4 kinds of sediment? - correct answers Gravel, Sand, Silt, and Clay. What is marine transgression and regression? - correct answers Transgression occurs when sea levels rise and Regression occurs when sea levels drop. What would a sediment structure containing limestone at the top tell you about its deposition environment? - correct answers That it was formed under water. What is cross bedding? - correct answers Layers deposited at an angle from water or wind. Define fluvian transport. - correct answers Sorting by water. Define eolian transport. - correct answers Sorting by air. How are graded beds formed? - correct answers By currents that larger particles to settle first and then for the smaller particles. How are sediments sorted? - correct answers Sediments are sorted based on grain size by fluvial or eolian processes. What is the difference between asymmetrical and symmetrical ripple marks? - correct answers Asymmetrical ripple marks are caused by a current and only go one way while symmetrical ripple marks are caused by waves and go in both directions. Define erosion. - correct answers The process that loosens soil or rock. Define transportation. - correct answers The movement of eroded material. Define deposition. - correct answers The settling of material. Define burial. - correct answers Accumulated sediment that is overlain with new sediment. Define diagenesis. - correct answers The physical and chemical changes by which sediments are converted to sedimentary rocks. What two processes are usually needed for lithification to occur? - correct answers Compaction and Cementation. How are sedimentary rocks classified? - correct answers Detrial, Chemical, and Biochemical. Name and define 3 main types of sedimentary rocks. - correct answers Carbonate; composed of minerals of carbonate iron. Dolostone; when magnesium replaces calcium in limestone. Evaporates; form from precipitation of minerals from water evaporation. Name three things that can be found in sedimentary rocks or deposits. - correct answers Fossils,