Popular in Geology
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Popular in Geology
This 11 page Study Guide was uploaded by Alanna Wight on Monday October 26, 2015. The Study Guide belongs to Geology 101 at Washington State University taught by Wilkie in Fall 2015. Since its upload, it has received 55 views. For similar materials see Geology in Geology at Washington State University.
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Date Created: 10/26/15
Geology Exam 1 Study Guide Understand the workings behind the scientific method What are the different steps and the balances and checks associated with the scientific method Observations Hypothesis Theory and the Scientific Model What is the principle of uniformitarianism and how is it applied by geologists The present is the key to the past everything can be linked to past events Understand the nebular hypothesis and how it applies to the formation of our Solar System sun and planets Nebula An area of space dominated by dust A nebula starts to collapse under its own gravity Stars form at the center The collapse of the nebula causes the nebula to spin faster As the nebula spins faster it flattens out into a disk The dust starts to clump up into larger pieces called Planetesimals The first planets attracted most of the Planetesimals creating solid masses The outer planets got some Planetesimals but absorbed mostly gases How did the Earth39s moon form Why is the Earth39s orbital plane tilted Large Mass hit Earth at an angle Causing the ejection of debris Which Sped up the Earth39s Rotation Tilting of Earth39s orbital plane to 23 degrees Thus forming our Moon The Earth began to differentiate forming a stratified Earth How does density change with depth What are these zones not necessary to memorize depths How are these zones Fig 116 grouped Which one makes up the tectonic plates Which zones are strong and which ones are weak or ductile The zones are the crust mantle and core inner and outer The density changes with depth by that the more into the earth you go the more dense it gets It gets weaker the farther you go in How old is the Earth 453 Billion years old universe although 14 billion sonlv How did Earth39s continents atmosphere and oceans form Earth39s continents formed when the molten lava covering the earth cooled The earth39s atmosphere formed when Planetesimals hit earth and released their gases The Earth39s Ocean formed when gases on the surface cooled and condensed into rain and poured onto the land or came from within from the earth released violtiles from volcanoes Did Mars undergo the same processes that occurred on Earth Yes Mars was once a molten planet but even though it is covered by volcanoes they are not ac ve The Earth has an external heat engine and internal heat engine Why are they important Where did the heat energys originate which powers the internal and external heat engines External Heat Engine The sun solar energy Internal Heat Engines Energy in motion is converted into heat Additional heat is added by decay of radioactive elements like uranium and the energy left over from initial forming Heat causes the Earth to melt and separate into layers of different densities through a process called differentiation What is the theory of plate tectonics What is the driving force behind plate tectonics The theory of plate tectonics is that the plates are moving over the asthenosphere and are constantly broken down and recreated The driving force behind plate tectonics is Convection What is the continental drift hypothesis as advanced by Alfred Wegner What evidence did he use to support his hypothesis With so much evidence why was it not elevated to a theory what were some of the problems What is Pangea When did Pangea form Supercontinent called Pangaea separated into the different continents today Continental Fit Patterns of present day life Fossil Evidence Related Rocks Ancient Climates Wegner lacked a mechanism he had no way to move continents He incorrectly believed that only the continent were moving Continentals are not independent plates plates are often made of both continental and oceanic lithosphere Pangaea was a supercontinent that formed approximately 300 million years ago What evidence was found that supported sea floor spreading What is magnetic stripping How and where does it form Seafloor Spreading New Oceanic Lithosphere is created where particularly molten mantle material rises to fill the gap in the rift What is the quotRing of Firequot What relevance does it have to plate tectonics The Ring of Fire is an area where a large number of earthquakes and volcanic eruptions occur in the basin of the Pacific Ocean What type of plate boundary do earthquakes occur at What type of plate boundary do volcanoes occur at All of the plate boundaries can create earthquakes Convergent and hotspots form Volcanoes What are the three main types of plate tectonic boundaries and any subdivisions of each What are the plate motions relative to each other Divergent Boundaries Plates move apart from each other Convergent Boundaries Plates move towards each other Subduction or Collision Transform Boundaries Plates slide past each other Hot Spots Plates move over them What are the stresses associated with each Are there any features associated with these boundaries midocean ridge trench subduction zone rift volcanoes Divergent Boundaries Tension Decompression melting convection midocean ridge rift Convergent Boundaries Compression Flux Melting subduction deepsea trenches volcanoes accretion Transform Boundaries Shear Stress Hotspots Volcanoes What causes the plates to move 3 possible mechanisms p65 Convection Ridge Push Slab Pull Identify the plate tectonic settings for real world examples of the different type of plate boundaries and hot spots location or mountain range Iceland MidAtlantic Ridge East African Rift Red Sea Cascade Mtn Andes Mtn Himalayas Hawaii Yellowstone Aleutians Island Chain Japan Gulf of California Sea of Cortez San Andreas fault Convergent Cascade Mountain range Andes Himalayas Divergent MidAtlantic Ridge East African Rift Red Sea Transform Gulf of California San Andres Fault Hot Spot Hawaii Yellowstone Where do you find quotblack smokersquot Black smokers are found deep under the sea convection by divergent plate boundaries The oldest ocean crust dates to about 200 my and the oldest continental crust dates to about 4 by Why the big difference Because of subduction oceanic crust is constantly being recycled into the athenosphere since it is less dense than continental crust What determines which plate will subduct What is decompression melting and where would this occur at What type of crust forms there The density determines which plate will subduct Decompression melting forms new oceanic crust at divergent boundaries What is flux melting and where would this occur at boundary type and subdivisions and location in subduction zone What type of crust is destroyed there Is any new crust created there How deep are the plates recycled to Flux Melting is the melting of oceanic crust mixed with water that allows it to melt at lower temperature than usual the magma created forms new continental crust through volcanism They Occur at Convergent plate boundaries that have subduction zones How is continental crust created What type of plate tectonic boundarys is continental crust created at Continental crust is created through Volcanism or Accretion Volcanism is at subduction zones or hotspots Accretion is at subduction zones that have oceanic crust merging the continental crust What are hot spots Where would you find them Do they create or destroy oceanic or continental crust What featurelandform do you find above them Be familiar with how to tell the direction of plate motion using hot spot paths and volcano ages dates Hotspots are stationary surface expression of volcanic activity from thermal plume They form volcanoes that are active until they are too far from the active zone The direction is based on the dates from youngest to oldest What is the fate of California will it fall into the ocean What will happen California will eventually become an island because it is on a transform boundary How fast do plates move General idea cmyr or myr or kmyr The plates move 15 cmyr What is a mineral Naturally Occurring Inorganic No organic carbon Crystalline Solid atoms are arranged in a particular structure cube Specific Chemical Compound contains particular elements is a set ratio What is an isotope How can they be used in geology Atoms that have different numbers of neutrons They can form different types of minerals Understand what chemical bonding is and the difference between ionic and covalent bonding Which bonding type is the strongest Ionic bond Transfer of Electrons weak bond Covalent Bond Sharing of Electrons strong bonds How do minerals form What determines which minerals will form at a given location What conditions cause minerals to form Examples were given in lecture evaporates hydrothermal fluids minerals formed by metamorphism Chemical reactions between elements created minerals bonding Crystallization growth of a solid from a gas or liquid whose constituents come together in the proper chemical proportions and crystalline arrangement Metamorphism Lower the temperature of a liquid below its freezing point ice Evaporates Liquids evaporate from a solution forming a supersaturated solution and results in precipitatesalt mineral Hydrothermal fluids When atoms and ions in a solid become mobile and rearrange themselves at high temperature gt250 Chot water Be familiar with the mineral properties color luster streak cleavage fracture hardness density crystal habit amp specialty properties and how these properties can be used to identify minerals Color Least Reliable depends on presence of certain ions such as iron chromium and cobalt Luster How the surface reflects light Metallic vs Nonmetallic Streak Color of a mineral in powdered state Cleavage The tendency of Minerals to break along planes of weakness Fracture Random Breaks Hardness A minerals resistance to being scratched Based on Moh39s hardness scale Specific Gravity Ratio of weight to equal volume of water Atomic weight of atoms Crystal Structure Crystal Habit Characteristics shape as it grows Atomic Structure also affects how the mineral grows Sell and Taste Sulfur and Halite Fluorescence Some minerals glow under UV light Magnetism Magnetite Effervescence Chemical Reaction from HCL Double Refraction Light is split into 2 2 images What are mineral polymorphs What are the polymorphs of carbon as discussed in class Minerals with the same composition but form different crystal structure Carbon Diamond and Graphite What is the most abundant mineral group in the crust The silicate rock classification is based on their crystal structure Are there other mineral groups besides silicates What are some of them Silicates are the most abundant Silcon Oxygen Other groups include Carbonates Oxides Sulfides Sulfates Native Elements Are all the different mineral included in the group of asbestos minerals carcinogenetic or linked to lung disease No only one of the asbestos is linked to lung disease Chrysolite is the one that is linked to lung disease But all are treated as deadly though What makes a gem What are some of these characteristics Beauty as reflected by color and luster Transparency Brilliance Enhanced by cutting and polishing Durability Based on hardness Rarity or perceived rarity Where do diamonds come from Are they brought up from the mantle to the surface fast or slow How hard is a diamond on Mohs hardness scale Diamonds come from the mantle They travel up at fast speeds or else they would become graphite 10 on the Mohs hardness scale What are the three main rock types and what processes melting weathering metamorphism cause them to form Igneous solidification of molten rock or melt Sedimentary either cementing together fragments of preexisting rocks or by precipitation of minerals crystals out of water solutions at or near the earth39s surface Metamorphic preexisting rocks change character in the solid state as a response to a change in pressure and temperature conditions What is the most abundant rock type in the Earth39s crust What is the most abundant rock type we find on the land surface Igneous is most abundant in the earth39s crust Sedimentary is most abundant at the earth39s surface Understand the rock cycle in a plate tectonic setting in the context of identifying where any particular rock type is likely to be founddeposited Also understand the rock cycle in context of how one rock type can be changed to another Refer to lab material Igneous Lava molten rock freezes to form igneous rocks found near volcanoes Sedimentary Sand formed from grains eroded off the rock cliffs collects on beaches If buried and turned to rock it becomes sandstone such as those making up the cliffs still sedimentary because the fragments grains are cemented together Found near beaches Metamorphic New minerals and textures form such as foliation lines in the rock Found in mountains Rock cycle Sedimentary rocks Sedimentary rocks are formed through erosion and deposition They are formed from the erosion and deposition of igneous rocks metamorphic rocks and sedimentary rocks as well Recycle themselves Metamorphic Rocks 1 Metamorphic rocks are formed from burial and heating from sedimentary rocks igneous rocks and recycled from metamorphic rocks as well 2 They are formed from the burial and heating from sedimentary rocks igneous rock 5 and recycled from metamorphic rocks as well Igneous Rocks 1 Igneous rocks are formed from melting and cooling 2 They are formed from melting and cooling metamorphic rocks as well as recycled igneous rocks as well How are igneous rock formed What are the two types of igneous rock How does the location where they cool affect the speed of cooling and there crystal size Created by magma cooling Extrusive Igneous Rocks from when magma erupts at the earths surface cools rapidly and creates small crystals Intrusive Igneous Rocks forms when magma cools underground cools slowely and creates large crystals Understand and be able to use or recognize in slides the following terms What does each texture indicate about the rate of cooling Plutonic Another word for Intrusive Igneous rocks Volcanic Aphanitic Crystals too fine to be distinguished cooled quickly Phaneritic Large crystals that are distinguishable cooled slowly Porphyritic Both sizes cooled at different temperatures Pegmatitic Extremely Large cooled slowly Glassy No minerals present no crystals fast cooling Vesicular Contains holes from gas release Pyroclastic Fragments of material ejected explosively into the air Where are magmas generated What makes magma How do rocks melt 3 ways Give an example of the plate tectonic setting that corresponds to each way What type of magma is produced in Hawaii Yellowstone Cascades Andes Magma is generated in convergent boundaries Oceanicoceanic Oceaniccontinental Magma is generated from the old heat left over from the planet39s formation as well as new heat produced by the decay of radioactive elements Forms only in places where preexisting solid rock melts Melting Of Rocks Decompression decrease in pressure Takes place when the pressure acting on hot rising rock decreases Addition of Volatiles Chemicals called volatiles such as water and carbon dioxide that evaporate easily and can exist in gaseous forms at the earth39s surface mix with hot mantle rock When they mix they help break chemical bonds Heat transfer from rising magma magma rises from the crust and brings heat with it enough to melt part of the crustal rock How do the factors of partial melting and where the melting takes place affect the composition of the resulting magma Partial Melting Process by which only part of an original rock melts to produce magma Magmas formed by partial melting tend to be more felsic than the original rock from which they were derived Partial melting of an ultramafic rock produces a mafic rock Igneous rocks are classified based on there silica composition What are the four composition groups What is there relative melting temperature order for the compositional groups How do Fe Mg and Si NaK vary in the groups What minerals would you expect to see or not see in rocks created from Mafic and Felsic compositions magma See figure 410 in text Felsic High Silica Low temperature Intermediate Intermediate Silica Intermediate temperature Mafic Low Silica High Temperature Ultramafic Very Low Silica Very High Temperature How does viscosity vary among the compositional groups How is this related to the magma temperature and magma composition Felsic Very High Viscosity Low temperature Intermediate High Viscosity Intermediate temperature Mafic Low Viscosity High Temperature Ultramafic Very Low Viscosity high Temperature From magma to igneous rock What process is involved What is fractional crystallization Why does this change the composition of the remaining magma Igneous Rocks Classification of igneous rocks is based on mineral composition crystal size and texture When magma cools and crystallizes below Earth39s surface intrusive rocks form 0 Lava that cools and crystallizes on Earth39s surface forms extrusive rocks 0 Igneous rocks are classified by their mineral compositions 0 Basaltic mafic rocks are darkcolored have lower silica contents and contain mostly plagioclase and pyroxene 0 Granitic felsic rocks are lightcolored have high silica contents and contain mostly quartz potassium feldspar and plagioclase feldspar 0 Rocks that have a composition of minerals that is somewhere between basaltic and granitic are called intermediate rocks 0 A fourth category called ultrabasic contains the rock peridotite Ultrabasic rocks contain only ironrich minerals such as olivine and pyroxene and are always dark Fractional crystallization a sequential process during which early formed crystals are removed from the melt and do not react with the remaining magma Be able to identify the different forms of intrusions for slides and multiple choice questions Where do they form How does magma make its way to the surface Sill Horizontal intrusions Dike Vertical or angled intrusions Batholith Largest of intrusive igneous rock bodies Be able to discuss any of the following Mt St Helens Columbia River Basalts Mt Rainier and Hawaii in terms of the dominant landform s eruptive style composition of magma lava viscosity of magmalava type of plate boundary and any other special textures or volcanic hazards associated with each Mt St Helens Dominant landforms cascade mountain range ring of fire eruptive style pyroclastic composition of magmalava high in silica intermediate to felsic viscosity of magmalava high type of plate boundary convergent Columbia River Basalts Dominant landforms Cascades ring of fire eruptive style pyroclastic compostion of magmalava intermediate to felsic viscosity of magmalava low type of plate boundary divergent Mt Rainer Dominant landforms Cascades ring of fire eruptive style pyroclastic composition of magmalava intermediate to felsic viscosity of magmalava high type of plate boundary convergent Hawaii Dominant Landforms Caldera eruptive style fissure composition of magmamafic viscosity low type of plate boundary hot spot
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