Geology Midterm Review

Introduction to Geology GEOL-101 Midterm 1 check into Based on the textbook perceptiveness country, 6th Edition, by Grotzinger and Press CH 1 earth governance epitome The gentlemans gentleman creative process, field and lab observations, and experiments coope send geoscientists exerciseu modern testable hypotheses ( forms) for how the mankind works and its history. A assumption is a tentative exposition focusing attention on believable features and relationships of a working sham. If a testable hypothesis is confirmed by a salient body of data, it whitethorn be exalted to a theory. Theories atomic number 18 aband singled when ensuant investigations show them to be false. arrogance grows in those theories that halt repeated tests and successfully predict the forces of tonic experiments. A set of hypothesis and theories may become the tail of a scientific model that represents an entire system likewise complicated to replicate in the laboratory. a great deal mode ls atomic number 18 tested and revised in a series of computer simulations. Confidence in such a model grows as it successfully predicts the behavior of the system. The elevations of land topography averages 12 kilometers above ocean level for land features and 45 kilometers below sea level for features of the muddy marine.The principle of uniformitarianism atomic number 18as that geological processes involve worked in the same way through turn up time. pedestals interior is divided into coaxial layers (crust, blanket, centre) of sharply different chemic authorship and density. The layered art object of the Earth is goaded by sombreness. Only eight of the light speed or so particles account for 99 percent of Earths mass. The lightest element (oxygen) is close to abundant in the spring up crust and cover, while the densest ( atomic number 26) makes up most of what is found duncish in the snapper. Earths study interacting systems argon the temper system, the weighing machine archi tectonic system, and the geodynamic system.The climate system involves interactions among the atmosphere, hydrosphere, and biosphere. The place tectonic system involves interactions among the lithosphere, asthenosphere, and deep mantle. The geodynamic system involves interactions at heart the central core that produce occasional reversals of Earths magnetic field. As the Earth cooled, an satellite relatively rigid shell, called the lithosphere, organize. Dynamic processes dictated by passionateness transfer, density differences, and gravity broke the outer shell into headquarterss that send outside around the Earth at evaluate of centimeters per year.Major comp adeptnts (atmosphere, hydrosphere, biosphere) of Earths surface systems are driven mostly by solar energy. Earths ind stronging heat energizes the lithosphere, asthenosphere, deep mantle, and outer and inner core. terms and Concepts Asthenosphere Convection Core Continental lithosphere Continental crust Earth systems Geology Inner core Lithosphere Mantle Oceanic lithosphere Oceanic crust Plate tectonic system Principle of uniformitarianism Scientific order Topography CH 2 dwelling tectonics synopsis For over the last century near geologists have argued for the concept of continental course base on he jigsaw-puzzle aspect of the coasts on both sides of the Atlantic the geological similarities in tilt ages and trends in geologic social organizations on opposite sides of the Atlantic dodo register suggesting that continents were joined at one time the distribution of glacial deposits as well as otherwise paleoclimatic evidence In the last half of the 20th century the major elements of the menage tectonic theory were formulated. Starting in the mid-forties (WWII), maritime floor mapping began to let out major geologic features on the ocean floor.Then, the match between magnetic anomalousness patterns on the seafloor with the paleomagnetic time scale r evealed that the ocean floor had a young geologic age and was systematically older away from the oceanic ridge systems. The concepts for seafloor spreading, subduction, and transform faulting evolved out of these and other observations. According to the theory of scale of measurement tectonics, the Earths lithosphere is blue into a dozen abject plates. The plates sliding board over a partially break away down, bl separatelyed asthenosphere, and the continents, implant in some of the moving plates, are carried along. at that place are three major types of boundaries between lithospheric plates divergent boundaries, where plates move apart oblique boundaries, where plates move together and one plate often subducts beneath the other transform boundaries, where plates slide past all(prenominal) other Vol ignoreoes, earthquakes, and crustal deformation are difficult along the active plate boundaries. lucks typically form along convergent- and transform-plate boundaries. Where divergent-plate boundaries are assailable on land, lessen washbowls and mafic volcanism are typical.Various methods have been employ to estimate and measure the rate and direction of plate movements. Today seafloor-spreading rank vary between a hardly a(prenominal) to 24 cm per year. Seafloor isochrons pull up stakes the basis for rebuilding plate motions for active the last cc cardinal years. Distinct assemblages of excites characterize eachtype of plate confines. Using diagnostic joggle assemblages embedded in continents and paleo-environmental data recorded by fossils and depositoryary lists, geologists have been able to reconstruct ancient plate tectonic events and plate configurations.Driven by Earths internal heat, convection of hot and cold matter inside the mantle, the force of gravity and the existence of an asthenosphere are substantial factors in any model for the driving mechanism of plate tectonics. shortly studies of the plate-driving forces focus on discovering the exact record of the mantle convection. Questions being addressed take Where do the plate driving forces explicate? At what depth does recycling go past? What is the nature of rising Convection Currents? The assembly and ensuant break up of Pangaea represent a striking example of the effects of plate tectonics acting over geologic time.The story begins with the breakup of the ancient supercontinent of Rodinia 750 million years agone. Plate tectonic processes disperse the fragments of Rodinia forming a system of ancient continents that existed from the late Proterozoic through much of the Paleozoic. continue tectonic movement eventually resulted in a set of continental collisions and renewal of the ancient continents into Pangaea. Assembly was completed during the beforehand(predicate) Triasic, about 240 million years ago. Then, about 200 million years ago the rift that would evolve into the Atlantic ridge began to open and the separation of Pangaea was under way.By the beginning of the Cenezoic, India was well on its way to Asia, and the Tethys sea that had separated Africa from Eurasia began to close into the modern midland sea that we know as the Mediterranean. move changes during the Cenozoic produced our modern world and its geography. price and Concepts Continental drift Continent-continent convergent marches Convergent boundary Divergent boundary Island arc Isochron Lithospheric plates magnetised anomaly Magnetic time scale Mid-ocean ridge Mountain range Ocean-ocean convergent boundary Ocean-continent convergent boundary Pangaea Plate tectonicsSeafloor spreading spreadhead center Subduction Transform boundary Wegeners hypothesis CH 3 earth materials sum-up minerals are naturally bechancering inorganic hards with a specific crystallizing structure and chemic composition. Minerals form when atoms or ions chemicly stay put and come together in an orderly, 3-dimensional geometric arraya crystal structure. chemical bond ing may occur both as a result of simple electrostatic attraction (ionic bond) or electron sharing (covalent bond). The strength of the chemical bonds and the luculent structure determine more of the physiological properties, e. . , hardness, cleavage of minerals. Silicate minerals are the most abundant class of minerals in the Earths crust and mantle. Common silicate minerals are polymorphs of silicon ions arranged in either isolated tetrahedral (olivine), single chains (pyroxene), stunt man chains (amphibole), sheets (mica), or three-dimensional frameworks (feldspar). There are three grievous groups of silicates ferromagnesium silicates, e. g. , olivine and pyroxene commonalty in the mantle feldspar and watch crystalcommon in the crust form mineralcommonly produced by chemical weatheringOther common mineral classes include carbonates, oxides, sulfates, sulfides, halides, and indispensable metals. A thrill is a naturally occurring solid aggregate of minerals. A few didde rs consist of only one mineral and a few others consist of non-mineral matter. The properties of brandishs and rock music names are determined by mineral satiate (the kinds and proportions of minerals that make up the rock) and texture (the size, shapes, and spatial arrangement of crystals or perforates. There are three major rock types Igneous rocks solidify from molten liquid (magma) crystal size at heart perfervid rocks is largely determined by the cooling rate of the magma body. depositaryary rocks are make of sediments organize from the weathering and erosion of any preexistent rock deposition, burial and lithification (compaction and cementation) transform emancipate sediments into sedimentary rocks. Metamorphic rocks are formed by an alteration in the solid state of any preexisting rock by high temperatures and twitch. Terms and Concepts Anion atomic mass Atomic number change Cation Cleavage Covalent bond crystal Crystallization negatron sharing Electron transf er Isotope Magma Mineral Polymorph Precipitate stir CH 4 torrid rocks succinctIgneous rocks can be divided into two broad textual classes coarsely crystalline rocks, which are curious (plutonic) and therefore cooled slowly finely crystalline rocks, which are extrusive (volcanic) and cooled rapidly. Within each of these broad textual classes, the rocks are subdivided accord to their composition. General compositional classes of igneous rocks are felsic, intermediate, mafic and ultramafic, in decreasing silica and increase iron and magnesium content. physical bodys 4. 1, 4. 2, 4. 3 and dishearten 4. 1 summarize common minerals and composition of igneous rocks.The lower crust and pep pill mantle are typical places where physical conditions begin rock to melt. Temperature, closet, rock composition, and the presenceof irrigate all affect the melting temperature of the rock Increase temperature not all minerals melt at the same temperature refer to Figures 4. 6 and 4. 7, which explain how fractional crystal results from Bowens reaction series. The mineral composition of the rock affects the melting temperature. Felsic rocks with higher silica content melt at lower temperatures than mafic rocks which curtail slight silica and more iron/magnesium.Lower the contain pressure a diminution in pressure can induce a hot rock to melt. A reduction in confining pressure on the hot upper mantle is opinion to generate the basaltic magmas which intrude into the oceanic ridge system to form ocean crust refer to Figure 4. 15. Add piss the presence of water in a rock can lower its melting temperatures up to a few hundred degrees. Water released from rocks subducting into the mantle along convergent plate boundaries is thought to be an all-important(a) factor in magma generation at convergent plate boundaries.As subduction begins water trapped in the rock is subjected to increasing temperature and pressure. Eventually the water is released into sedimentary layers a bove where it melts parts of the overlying plate refer to Figure 4. 16. Terms and Concepts Andesite Basalt pluton Bomb Concordant intrusion verdant rock Decompression melting dekameter Discordant intrusion Diorite Extrusive igneous rock Felsic rock Fractional crystallization Gabbro Granite Granodiorite Intermediate rock Intrusive igneous rock Lava Mafic rock Magma chamber Magmatic speciality Partial melting Pegmatite Peridotite Pluton Rhyolite PorphyryPumice Pyroclast Rhyolite Sill Ultramafic rock Volcanic ash xenolith CH5 sedimentary rocks Summary Plate tectonic processes play an important role in producing depressions (basins) in which sediments accumulate. Sedimentary basins result from rifting, thermal sag, and flexure of the lithosphere. The sedimentary stages of the rock cycle involve the imbrication processes of weathering, erosion, transportation, deposition, burial, and diagenesis. Weathering and erosion produce the clastic particles and fade out ions that compose sed iment. Water, wind, and ice transport the sediment downhill to where it is deposited. entombment and diagenesis harden sediments into sedimentary rocks via pressure, heat, and chemical reactions. The two major types of sediments are clastic and chemical/biochemical. Clastic sediments are formed from rock particles and mineral fragments. Chemical and biochemical sediments originate from the ions dissolved in water. Chemical and biochemical reactions precipitate these dissolved ions from solution. understanding the characteristics of sediments and modern sedimentary environments provides a basis for reconstructing past environmental conditions using the rock record.Sedimentary structures like bedding, ripple marks, and mud cracks, provide important clues about the sedimentary environment. Diagenesis transforms sediment into sedimentary rock. Burial promotes this transformation by subjecting sediments to increasing heat and pressure. Cementation is especially important in the lithific ation of clastic sediments. The classification of clastic sediments and sedimentary rocks is based primarily on the size of the grains inside the rock. The name of chemical and biochemical sediments and sedimentary rock is based primarily on their composition. Terms and Concepts carbonate rockCarbonate sediment Cementation Chemical weathering Compaction foregather Cross-bedding Crude oil Diagenesis Evaporite rock Flexural basin Foraminifera Graded bedding get Limestone Lithification Physical weathering Porosity Ripple salt Sandstone Sedimentary basin Sedimentary structure Shale Siliciclastic sediments Sorting Subsidence Thermal remit basin CH 6 Metamorphic rocks Summary Metamorphism is the alteration in the solid state of preexisting rocks, including older metamorphic rocks. Increases in temperature and pressure and reactions with chemicalbearing fluids stupefy metamorphism.Metamorphism typically involves a rearrangement (recrystallization) of the chemical components at bottom the parent rock. Rearrangement of components within minerals is facilitated by higher temperatures, which increase ion mobility within the solid state higher confining pressure compacts the rock directed pressure associated with tectonic activity can cause the rock to shear (smear), which orients mineral grains and generates a foliation and chemical reactions with migrating fluids may suppress or add materials and induce the appendage of new minerals.The two major types of metamorphism are regional metamorphism, associated with orogenic processes that build mountains, contact metamorphism, caused by the heat from an intruding body of magma, and seafloor metamorphism, in addition known as metasomatism. Other less common kinds of metamorphism are burial metamorphism, associated with subsiding regions on continents, high-pressure metamorphism, occurring deep within subduction zones and upper mantle, and shock metamorphism due to meteor impact refer to Figure 6. 4.Metamorphic rocks die into two major textural classes the foliated (displaying a preferred orientation of minerals, analogous to the grain within wood) and granoblastic (granular). The composition of the parent rock and the grade of metamorphism are the most important factors controlling the mineralogy of the metamorphic rock. etamorphism usually causes precise to no change in the volume composition of the rock. The kinds of minerals and their orientation do change. Mineral assemblages within metamorphic rocks are used by geoscientists as a bunk to the original composition of the parent rock and the conditions during metamorphism.Metamorphic rocks are characteristically formed in subduction zones, continental collisions, oceanic spreading centers, and deep subsiding regions on the continents. Terms and Concepts Amphibolite Burial metamorphism Contact metamorphism Eclogite Foliation Gneiss Granoblastic rock marble Metasomatism Migmatite Phyllite Porphroblast Quartzite Regional metamorphism Schis t Seafloor metamorphism Shock metamorphism Slate fitted for the GEOL101 course by Alfonso Benavides (2012)