MSCI 112 Final Exam Questions And Answers Latest Top Score.

MSCI 112 Final Exam Questions And Answers Latest Top Score. An igneous rock was formed with 8000 radioactive (parent) atoms but contains only 1000 radioactive (parent) atoms today. If the half-life for the radioactive element is 10 million years, the rock is ___ million years old. - correct answer. 30 Which of the common components of siliciclastic sediment are likely to have been formed from the original sediment source rock through chemical weathering? - correct answer. clays Which is the largest division of geologic time? - correct answer. eons Which process causes subsidence in a sedimentary basin? - correct answer. both deposition of sediments and regional downfaulting What is a nonconformity? - correct answer. a gap in the geologic record bounded below by metamorphic or igneous rocks and bounded above by sedimentary rocks The study of the history of ancient life based on the fossil record is called: - correct answer. Paleontology The remains of algae, bacteria, and other organic material may accumulate as organic matter on the seafloor that can be transformed into: - correct answer. oil and gas Why does mechanical weathering of an exposed rock cause chemical weathering to take place more quickly? - correct answer. broken rock fragments have more exposed surface area Which of the following is a clastic sedimentary environment? - correct answer. alluvial Which is the most common type of chemical or biological sedimentary environment? - correct answer. carbonate environment The half-life of a radioactive material depends on: - correct answer. the half-life is constant for any one material The Precambrian represents about what fraction of the age of Earth? - correct answer. 90% What is the geologic time scale? - correct answer. a division of Earth's history into time intervals beginning and ending at times when fossils changed significantly What is NOT an example of physical weathering? - correct answer. dissolution of some minerals in a rock, causing it to weaken Why does most of our information on geologic history come from continental rock? - correct answer. oceanic crust older than 200,000,000 years has been recycled by subduction What type of event might lead to the development of an unconformity? - correct answer. sea level drops Cross-bedding forms on ___ of a sand dune - correct answer. the downwind side How do most carbonate sediments and rocks in shallow environments form? - correct answer. they are bioclastic materials Coal is formed from: - correct answer. peat What process must occur before an intrusive igneous rock can be weathered? - correct answer. uplift Which class of rock-forming minerals is the most common in Earth's crust? - correct answer. silicates The lead-zinc province of the Upper Mississippi Valley in the mid-western United States is an example of a _________ deposit - correct answer. disseminated hydrothermal The hardness of a mineral depends on the: - correct answer. strength of chemical bonds Minerals form by which of the following processes? - correct answer. both crystallization and precipitation Which of the following is a good estimate of the melting temperature of a typical crustal rock? - correct answer. 700°C How do plate tectonics and the climate system of Earth interact? - correct answer. 1. Mountain ranges divert air flow and alter precipitation patterns 2. Volcanic eruptions eject rock material into the atmosphere 3. Weathering and erosion transfer rock material to the ocean where they are subducted Which of the following is an example of an igneous rock? - correct answer. granite What type of chemical bonding holds the Na and Cl atoms together in table salt (NaCl)? - correct answer. ionic bonds Which of the following minerals is commonly found only in metamorphic rocks? - correct answer. staurolite What Earth system is NOT involved in the rock cycle? - correct answer. geodynamo system What is the difference between pyroxene and amphibole? - correct answer. different chemical composition If a geologist wants to determine whether an igneous rock sample cooled within Earth or on its surface after an eruption, what property or feature would the geologist want to examine? - correct answer. texture Metamorphism causes changes in which properties of an existing rock? - correct answer. mineralogy, chemical composition, and texture Increases in temperature will normally cause rock density to ______, while increase in pressure cause density to _____________ - correct answer. decrease; increase What is a vein deposit of an economically important mineral? - correct answer. a sheetlike deposit of minerals precipitated from rapidly cooling hydrothermal solutions What is NOT an example of a silicate mineral structure? - correct answer. triple chain Which minerals is an example of a carbonate? - correct answer. calcite A mineral is usually inorganic; which of the following can be considered a mineral? - correct answer. calcite formed from shells of oysters T/F: a mineral must always have exactly the same chemical composition - correct answer. false An igneous intrusion whose boundaries lie parallel to the layering in the surrounding country rock is considered to be: - correct answer. concordant A large igneous body formed at depth in Earth's crust is a: - correct answer. pluton What evidence led Hutton to conclude that granite formed by solidification of magma deep inside Earth? - correct answer. 1. alteration of sedimentary rock by heat next to granite 2. volumes of granite fractured existing sedimentary rock 3. granite is composed of coarse, interlocking crystals Most magmas form at what types of plate boundaries? - correct answer. subduction zones and mid-ocean ridges Which list would you expect to list correctly a set of rocks in order of increasing density? - correct answer. granite, andesite, gabbro If a geologist examines a thick lava flow that solidified after flowing away from a volcanic vent, where would she expect to find the coarsest texture in the flow? - correct answer. in the center of the flow At which type of plate boundary would you expect fluid-induced melting associated with added water content to be most important? - correct answer. subduction zones What statement correctly describes an ophiolite? - correct answer. it is a set of deep-sea sediments, basalt rock, and mafic intrusions found on land The process of magmatic differentiation explains how: - correct answer. rocks of varying composition can arise from the same parent magma Fractional crystallization is the process by which: - correct answer. crystals formed in a cooling magma are removed from the remaining magma Igneous rocks with crystals too small to be seen without a microscope are: - correct answer. fine grained In the general theory of plate tectonics, at which particular settings do igneous rocks form? - correct answer. convergent/divergent boundaries and hot spots The most plentiful minerals in peridotite are: - correct answer. pyroxene and olivine Which process is most important for causing the formation of magma associated with mantle plumes (hot spots)? - correct answer. decompression melting What does the viscosity of a liquid measure? - correct answer. the resistance of a liquid to flow At which type of plate boundary would you expect fluid-induced melting associated with addition of water to rock to be most important? - correct answer. subduction zone