Geology: Classification of Rocks and Minerals Based on Chemical Compositions and Formation, Quizzes of Geology

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TERM 1 plate tectonics DEFINITION 1 unifying theory of geology can explain rock types and fuel rock cycle explain: dist. of earthquakes and volcanoes, origin of continents and ocean basins, dist. of fossil plants and animals, genesis and destruction of mtn chains, continental drift TERM 2 2 types of lithosphere DEFINITION 2 continental-granitic, thicker, lighter(less dense), more buoyant (floats higher) oceanic-basaltic-thinner, heavier (more dense), less buoyant (sinks lower) one plate can contain both kinds of crust oceanic ALWAYS subducts (more dense) TERM 3 divergent plate boundary DEFINITION 3 spreading centers, two plates moving apart process driving it: sea floor spreading (new ocean floor is formed by lava erupting from a rift, pushing existent floor outward from the rift) TERM 4 stages of sea floor spreading DEFINITION 4 early: before substantial widening of ocean, forms long thin ocean basin with young oceanic crust. Ex) red sea mid: continents move further apart, new seafloor added at ridge. Ex) greenland and north atlantic late: mature wide ocean basin, linear increase in age with distance from central ridge. Ex) atlantic ocean TERM 5 characteristic features of divergent plate boundaries DEFINITION 5 formation of mid ocean ridges and valley rifts earthquake activity at fracture zones along mid ocean ridges volcanic activity formation of hydrothermal vents TERM 6 convergent boundary DEFINITION 6 to plates move toward each other 2 types: subduction and collision TERM 7 subduction DEFINITION 7 part of convergent boundary recycles oceanic lithosphere balanced by SFS associated with trenches, accretionary prisms, volcanic arcs, and back-arc basins TERM 8 accretionary prisms DEFINITION 8 subduction feature deformed sediment wedges sediments scraped off subducting plates are smeared and welded onto overriding plates these contorted sediments can be pushed above sea TERM 9 volcanic arc DEFINITION 9 subduction feature volcanic belt on overriding plate descending plate partially melts at 150 km magmas burn upward, fueling volcanic eruptions a curved earth dictates that volcanic belts are curved arc type depends on overriding plate: continental crust=continental arc. oceanic crust=island arc TERM 10 ocean-ocean convergent DEFINITION 10 features: deep sea trench bordering continent, volcanic arcs along coast of the continents, earthquakes EX) andes mtns TERM 21 continental margins DEFINITION 21 where land meets ocean margins near plate boundaries are "active" margins far from plate boundaries are "passive" TERM 22 matter DEFINITION 22 the substance of which any physical object is composed anything that has mass and volume (takes up space!) TERM 23 states of matter DEFINITION 23 solid (gold) (low temp, high pressure) liquid (mercury) (med temp, med pressure) gas (oxygen) (high temp, low pressure) plasma (highest temp, lowest pressure) controlled by pressure and temperature TERM 24 phase diagram DEFINITION 24 shows solid liquid gas triple point-where all 3 phases come together critical point- always separates liquid and gas shows relationship btw states of matter with variables of temp and pressure TERM 25 atoms DEFINITION 25 stuff that builds elements the smallest particle that uniquely defines an element TERM 26 atomis structure DEFINITION 26 protons: positive charge neutrons: no charge electrons: negative charge nucleus=protons + neutrons orbitals/energy-level shells = layers of electrons that orbit around the nucleus TERM 27 atomic number DEFINITION 27 # of protons TERM 28 mass number DEFINITION 28 # protons + # neutrons atoms of the same element can have different mass numbers-called isotopes (Ex: carbon- C12, C13, C14) TERM 29 atomic weight DEFINITION 29 # protons + average # neutrons TERM 30 cations DEFINITION 30 a LOSS of electrons resulting in a POSITIVE charge Ex: Na + TERM 31 anions DEFINITION 31 a GAIN of electrons resulting in a NEGATIVE charge Ex: Cl - larger than cations bc take on electrons TERM 32 important ions in common minerals DEFINITION 32 anions: O (-2), Cl (-1) cations: Si (+4), K (+1), Ca (+2), Na (+1), Al (+3), Mg (+2), Fe (+2 or 3) most abundant minerals in earths crust are cations (non metals) TERM 33 compounds DEFINITION 33 a chemical compound consists of elements that combine in a specific ratio. Ex) NaCl, H2O the smallest quantity of a compound is called a molecule molecules are held together by chemical bonding TERM 34 chemical bonding DEFINITION 34 formation of a compound by combining 2 or more elements manner in which electrons are distributed among atoms in bonded atoms, electrons may be lost, gained, or shared TERM 35 ionic bonding DEFINITION 35 electrons are transferred btw atoms forming attracting ions (ex: NaCl) orderly arrangement of oppositely charged ions bonds are moderately strong second strongest TERM 46 how do scientists identify minerals? DEFINITION 46 physical properties (determined by crystalline structure and chemical composition) - color, luster, hardness, crystal shape, cleavage/fracture, specific gravity, special properties TERM 47 color DEFINITION 47 most obvious but oftentimes misleading diff colors may result from impurities and elemental substitution streak - color of a mineral in powdered form (used for metallic minerals) obtained by scratching of a mineral on a piece of unglazed porcelain TERM 48 luster DEFINITION 48 how a mineral surface reflects light 2 major types metallic and non-metallic TERM 49 hardness DEFINITION 49 how easy is it to scratch a mineral with another mineral TERM 50 mohs scale DEFINITION 50 of relative hardness consists of 10 minerals, ranked 1 (softest) to 10 (hardest) TERM 51 crystal shape (or habit) DEFINITION 51 external expression of a minerals internal atomic structure planar surfaces are called crystal faces angles btw crystal faces are constant for any particular mineral TERM 52 atomic scale of mineral cleavage DEFINITION 52 brown atoms bonded with blue atoms into flat sheets (strong bonds) sheets joined by long bonds btw sheets (break along weakest bonds) cleave into sheets TERM 53 bonds with same strength DEFINITION 53 minerals can break along 3 sets of planes without passing through an atom in other arrangements, mineral breaks in nearly any direction so it will fracture TERM 54 fracture DEFINITION 54 minerals that dont exhibit cleavage smooth curved surfaces when minerals break in a glass- like manner = conchoidal fracture TERM 55 special properties DEFINITION 55 reaction with hydrochloric acid (calcite fizzes) taste (halite tastes salty) feel (talc feels soapy, graphite feels greasy) magnetism (magnetite attracts a magnet) TERM 56 how do scientists classify minerals? DEFINITION 56 chemical compositions economic vs rock forming TERM 57 chemical compositions DEFINITION 57 minerals can be classified into groups according to their chemical compositions mineral groups are named for the dominant anion (negative charge) TERM 58 2 major mineral groups DEFINITION 58 silicates (most abundant) (90% of earths crust) non-silicates (5-8% of earths crust) ex: oxides (O-2), carbonates (CO3-2), sulfides (S-2), sulfates (SO4-2), halides (Cl-, F-, Br-), native elements (single elements: ex: Au) TERM 59 silicates DEFINITION 59 SiO4 -4 the building block of all silicates=tetrahedron (4 oxygen ions surrounding a much smaller silicon ion) form thru the solidification of melt (magma) TERM 60 types of silicate structures DEFINITION 60 independent tetrahedron single chain double chain sheet 3-D framework TERM 71 economic vs rock forming DEFINITION 71 economic minerals are minerals that are mined for profit - commonly referred to as ore(s). less prevalent minerals. rock forming minerals are the MOST COMMON minerals - economically not worth as much TERM 72 rock definition DEFINITION 72 an aggregate of any combo of minerals, elements (Au- gold, S-sulfur), solid organic material (coal), and/or pieces of other rocks rock=minerals + elements + solid organics + other rocks TERM 73 where are rocks found on earth? DEFINITION 73 the CRUST which contains the most diverse variety of rocks the MANTLE which contains molten rocks that are seldom seen on the surface and are largely the same composition TERM 74 how do we classify rocks? DEFINITION 74 rocks are classified by how they were formed, their COMPOSITION, TEXTURE, and color texture=the size, shape, and arrangement of its grains TERM 75 igneous rocks DEFINITION 75 any rock that is formed by the cooling and hardening (CRYSTALLIZATION) of hot, molten rock TERM 76 sedimentary rocks DEFINITION 76 any rock formed by compaction and cementing (LITHIFICATION) of layers of sediments sediment=rock fragments, plant and animal remains, and minerals that settle out of solution onto stream, lake, or ocean bottoms TERM 77 metamorphic rocks DEFINITION 77 any rock that is formed by the effect of heat and pressure (METAMORPHISM) on a pre-existing rock TERM 78 what is the rock cycle? DEFINITION 78 the repeating series of events by which a rock gradually and continually changes from one type to another it involves processes on the earth's surface as well as the earths interior it connects the HYDROLOGIC CYCLE with the TECTONIC CYCLE TERM 79 what drives the rock cycle? DEFINITION 79 earths internal energy (heat energy) and radioactive decay earths gravity solar radiation from sun TERM 80 the role of pressure in magma formation DEFINITION 80 all other things being equal, the greater the pressure, the les likely materials are to melt explains liquid outer core and solid inner core decompression (removing pressure) melting has to happen rapidly to turn solid to liquid TERM 81 decompression melting DEFINITION 81 the melting of hot mantle rocks due to decrease of pressure during migration toward earth's surface through convection from solid to liquid melting along divergent boundary (MOR)-solid asthenosphere rises. magma=mafic due to partial melting of ultramafic mantle TERM 82 role of comp. change (addition of volatiles) in magma formation DEFINITION 82 adding volatiles LOWERS the melting temp melting in ocean-ocean convergent boundary (subduct. zone)-partial and total melting of ocean crust produces intermediate and mafic eruptions at lower temps-felsic at higher temps-mafic TERM 83 how does water get into a subduction zone? DEFINITION 83 hot water circulates in ridge; added in pores and in minerals here and also at trench TERM 84 4 major types of magma DEFINITION 84 classified according to the amount of silica each magma contains felsic, intermediate, mafic, ultramafic TERM 85 felsic magma DEFINITION 85 high silica content contains light colored minerals (feldspar and quartz) low crystallization temp low density high viscosity (resistance to flow) (honey=high and water=low) ex: granite, rhyolite TERM 96 location of formation of igneous rocks DEFINITION 96 extrusive=fine grained igneous rocks that cool quickly on the earths surface intrusive=coarse grained igneous rocks that cool slowly inside the earth TERM 97 texture of igneous rocks DEFINITION 97 a function of grain packing and size packing: grain relationships =crystalline (interlocking grains), clastic (cemented grains), glass (no grains). majority of igneous rocks =crystalline. TERM 98 phaneritic DEFINITION 98 (coarse grained) grains visible to naked eye, intrusive rocks. slow cooling =large grains TERM 99 aphanitic DEFINITION 99 (fine grained) grains visible with magnification, extrusive rocks. fast cooling=small grains, very fast cooling=glassy TERM 100 porphyritic DEFINITION 100 (mixed grain size) phenocrysts in matrix, forms from 2 stage cooling, usually extrusive TERM 101 pegmatitic DEFINITION 101 very large grain size, result of slow cooling, usually intrusive rocks TERM 102 fragmental (pyroclastics) DEFINITION 102 explosive volcanic eruptions appear porphyritic with visible crystals-crystals show breakage or distortion matrix dominated by glassy fragments-hot fragments may "weld" together TERM 103 mineral composition in igneous rocks DEFINITION 103 classified according to the individual minerals that make up a rock felsic, intermediate, mafic, ultramafic TERM 104 felsic igneous rocks DEFINITION 104 made of mostl light colored minerals and have a high silica content ex: granite TERM 105 intermediate igneous rocks DEFINITION 105 made of both light and dark colored minerals ex: diorite TERM 106 mafic igneous rocks DEFINITION 106 made of mostly dark colored minerals and have a low silica content ex: basalt, gabbro (found under ocean) mafic lava spreads out rapidly silica (felsic)=thick ans sticky (explosive eruptions) TERM 107 ultramafic igneous rocks DEFINITION 107 made of extremely dark colored minerals and have a very low silica content ex: peridotite TERM 108 extrusive igneous structures DEFINITION 108 not all volcanic eruptions are the same so not all extrusive rocks are the same! non-explosive explosive eruption, explosive explosive eruption TERM 109 nonexplosive explosive eruption DEFINITION 109 ex: hawaiian islands lava sheets, dome pillow basalts-form along MOR-outside instantly cools to form blobs but inside stays hot for 1000s of yrs. outside acts as insulator TERM 110 explosive explosive eruption DEFINITION 110 produce ash and pyroclastics that become welded together to form fragmental igneous rocks ex: andocite, rhyolite intermediate to felsic-lots of gas involved TERM 121 physical and chemical weathering in concert DEFINITION 121 both forms occur simultaneously in real world phys. weathering INC chem. weathering chem. weathering INC phys. weathering TERM 122 differential weathering DEFINITION 122 diff rocks form in diff locations, under diff conditions, and are exposed to diff minerals TERM 123 mineralogy as a weathering control factor DEFINITION 123 the resistance of a silicate mineral to weathering is a function of the chem. composition and the acidity of the water from which the mineral reacts. acidity INC weathering halite, calcite, olivine=fastest to weather/least stable clay, orthoclase, biotite=slowest to weather/most stable the higher the quartz content, the more resistant to weathering the rock is TERM 124 adjacent rock type and structure as a weathering control factor DEFINITION 124 diffs in composition and structure of adjacent rock units can lead to contrasting rates of weathering and to landscapes that reflect such differential weathering TERM 125 slope angle as a weathering control factor DEFINITION 125 on a steep slope, solid products of weathering move quickly away continually exposing fresh bedrock to renewed attack on gentle slopes, weathering products are not easily washed away and in places may accumulate to depths of 50m or more TERM 126 climate as a weathering control factor DEFINITION 126 moisture and heat promote chemical reactions therefore, weathering is more intense and generally extends to greater depths in a warm, moist climate than in a cold, dry one hot and wet=chemical weathering cold and dry=mechanical weathering limestone/marble highly susceptible to chem. weathering in moist climate and commonly form on low, gentle landscapes in dry climate, same rocks form bold cliffs bc little carbonic acid is present to dissolve carbonate minerals TERM 127 time as a weathering control factor DEFINITION 127 100,000s yrs needed for a hard, quartz-rich igneous rock to decompose rate of weathering tends to decrease with time as the weathering profile, or a weathering rind, thickens the weathering rind slows weathering rate-protects fresh rock the thicker the rind, the slower the weathering rate TERM 128 how do sediments move? DEFINITION 128 moved from one location to another by running water, wind, or ice TERM 129 erosion DEFINITION 129 process of carrying away sediments means that it no longer weathering! weathering ALWAYS happens first TERM 130 what determines how far a sediment can be moved? DEFINITION 130 the size of the sediment mass more energy to move large sediment TERM 131 controls on size, shape, and sorting DEFINITION 131 farther from source means rounder and smaller high velocity stream can carry boulders low velocity=silt/clay/sand rounding-angular/partially/rounded(travel furthest from source) sorting-poorly/moderately/well TERM 132 soil DEFINITION 132 the solid material on earths surface that results from the interaction of weathering and biological activity on the parent material and underlying bedrock (hard rock) soil is one type of regolith, which is term used to describe any unconsolidated material that covers bedrock the #1 reason why rocks are impt to us. 2nd only to water as main reasons for human existence TERM 133 processes of soil formation DEFINITION 133 bedrock begins to disintegrate organic materials facilitate disintegration horizons form (humus) developed soil supports thick vegetation TERM 134 development of a soil profile DEFINITION 134 OABC (Only A Boy Can) O (organic) horizon- humus A horizon-like a coffee filter B horizon-zone of accumulation C horizon-partially decomposed parent material (breaking up rocks) organic layer needed to grow crops-need A,B, and C to support organic layer TERM 135 soil erosion DEFINITION 135 the removal of soil by water or wind increased by deforestation, poor farming practices, periods of drought (takes 10,000 yrs to make 1 in of soil) (SLOW regeneration process) TERM 146 maturity (sed rocks) DEFINITION 146 a measure of the degree of "processing" textural maturity=degree of roundness + sorting mineral maturity=degree of unstable mineral removal time and transport causes sediment evolution-texture-avg grain size decreases roundness and sorting increases. composition-unstable minerals increases stable minerals increases maturity is used to reconstruct depositional conditions alluvial fan=less distance/less mature. river=med/med. beach=most distance/most mature TERM 147 clastic sed rocks (coarse grained) DEFINITION 147 coarse clastics=gravel sized clasts breccia=comprised of angular clasts. indicates lack of transport processing. deposited close to source conglomerate=comprised of rounded clasts. indicates processing by transport. deposited away from source area both poorly sorted and immature TERM 148 clastic sed rocks (med grained) DEFINITION 148 sandstone-made of sand sized particles. forms in many depositional settings. texture and composition permit historic interpretation. quartz is by far the dominant mineral in sandstone. there are MANY sandstone varieties. pinkish color means there is feldspar in it (immature). gray=mature TERM 149 clastic sed rocks (fine grained) DEFINITION 149 composed of silt and clay siltstone=made of silt sized particles shale=made of clay sized particles (smallest size). only deposited in low energy environments (clam). looks crumbly. fine clastics are only deposited in non-agitated water-common in deep water basins. organic rich shales are the source of petroleum TERM 150 biochemical sed rocks DEFINITION 150 sediments derived form living organisms biochemical limestone=made from clcite shell remains. carbonate grains accumulate in the "carbonate factory". warm (tropical and subtropical), normal salinity marine water, wave agitated, oxygenated, shallow, clear. fossils found here! coquina=a limestone made of carbonate shells and shell hash. loosely held together biochemical chert=formed from silica skeletons. silica added to bottom sediments dissolves. silica pore fluids solidifies to form chert nodules. dissolved shells of microorganisms TERM 151 organic sed rocks DEFINITION 151 made from organic carbon coal=altered remains of fossil vegetation. accumulates in tropical swamp settings. requires deposition in the absence of oxygen. oil shales=shale with heat altered organics TERM 152 chemical sed rocks DEFINITION 152 comprised of minerals precipitated from water solution created from evaporated seawater-evap triggers deposition of chemical precipitates (halite-more salt content, gypsum) precipitated from interaction of groundwater-travertine=high concentrations of dissolved calcium ion and bicarbonate ion. CO2 is expelled in contact with air.this causes the CaCO3 to precipitate(thermal hot springs/caves) (stalagmites/stalactites) replacement chert=nonbiogenic. many varieties:flint (black/gray),jasper(red/yellow),petrified wood(preserved by silica).takes something already existing and replaces w/ new mineral TERM 153 sedimentary structures DEFINITION 153 distinctive arrangements of particles and layers within a sed rock indicators of the sed environment in which the rock formed, and processes responsible TERM 154 bedding (sed structures) DEFINITION 154 sed rocks usually layered or "stratified" arranged in planar horiz, beds bedding is often laterally continuous for long distances beds are often similar in comp., color, and texture caused by changing conditions during deposition. can be changes in energy conditions or disturbance by organisms bedding may also reflect non-dep. erosion TERM 155 bedforms (sed structures) DEFINITION 155 water and wind flowing over loose sediment creates bedforms they are linked to flow velocity and sediment size TERM 156 ripples (bedforms sed rocks) DEFINITION 156 cm scale ridgles and troughs that can indicate flow direction. commonly preserved in sed rocks. asymmetric=unidirectional flow (short steep down current slip face and long gentle up current ramp) (river). symmetric=wave oscillation (sharp ridges and concave up troughs (ocean beach envir.) TERM 157 dunes (bedforms sed rocks) DEFINITION 157 similar to ripples but on much larger scale associated with wind asymmetrical bc wind direction changes frequently TERM 158 cross bedding (bedforms sed rocks) DEFINITION 158 created by ripple and dune migration sediment moves up the gentle slope and piles up, then slips down the steep face. the slip face continually moves downstream. added sediment forms sloping "cross- bedded" layers TERM 159 graded beds (beforms sed rocks) DEFINITION 159 bedding layers that fine upward transition from coarse to med to fine grain sizes base of coarse sand and gravel mid level sands a fine silt and clay cap abrupt contact with overlying coarse base TERM 160 mudcracks (sed bed surface marking) DEFINITION 160 polygonal desiccation indicate alternating wet/dry conditions necessitate deposition in a terrestrial setting clay dries up + shrinks apart and when wet, swells ex: a lake that dried up TERM 171 terrestrial sed environment-swamp DEFINITION 171 coal found here! hot and wet anaerobic-low oxygen heat and pressure TERM 172 terrestrial sed environment-desert DEFINITION 172 wind-blown piles of quartz-rich well-sorted sand dunes move according to the prevailing winds result in uniform sandstones with gigantic crossbeds sandstone found here! asymmetrical TERM 173 terrestrial sed environment-coastal beaches DEFINITION 173 form in the surf zone sediments constantly being processed by wave attack well-sorted well-rounded med sand beach sandstones may preserve oscillation symmetrical TERM 174 marine sed environment-reef DEFINITION 174 shallow water carbonates-tropical climate skeletons of marine invertebrates born in the carbonate factory warm, clear, shallow, normal salinity marine water fossiliferous limestone and coquina found here! TERM 175 marine sed environment-shallow marine DEFINITION 175 accumulation of finer version of beach sediment biologically active LIMESTONE fossils and trace fossils found here! TERM 176 marine sed environment-deep marine DEFINITION 176 fines predominate far from land sources skeletons of planktonic organisms make biochemical chert fine silt and clays turn to SHALE TERM 177 where do basins form? DEFINITION 177 basins=where sed rocks form rift basins foreland basins intercontinental basins passive continental margins TERM 178 rift basin DEFINITION 178 crust thins by stretching and rotational normal faulting thinned crust subsides sediment fills the down-dropped basin TERM 179 foreland basin DEFINITION 179 craton side of a collisional mtn belt flexture of the crust from loading creates a down-warp fills with debris eroded off of the mtn form basin in front of mtn convergent boundary TERM 180 intercontinental basin DEFINITION 180 interiors far from continental margins result from diff thermal subsidence may be linked to failed crustal rifts TERM 181 passive continental margin DEFINITION 181 non-plate boundary continental edge underlain by crust thinned by previous rifting thinned crust subsides as it cools oceanic crust TERM 182 sea level changes (sed rocks) DEFINITION 182 sed deposition strongly linked to sea level changes in sea level are commonplace geologically depositional belts shift landward or seaward in response layers of strata record deepening or shallowing upward transgression=flooding due to sea level RISE (shale, limestone, sandstone, conglomerate) youngest to oldest regression=when sea level RECEDES. exposure-depositional belts shift seaward. tied to erosion (conglomerate, sandstone, limestone, shale) youngest to oldest TERM 183 diagenesis DEFINITION 183 physical, chemical, and biological changes to sediment bioturbation (animal influence mixing up sediment) lithification (compaction) dissolution (chemical weathering break apart minerals) mineral precipitation (how chem sed rocks are made) the entire history of a rock TERM 184 metamorphic rock DEFINITION 184 changed from original parent rocks called "proliths" can occur in any prolith ANY rock can be metamorphosed causes od metamorphism=burial, tectonic stresses, heating by magma, fluid alteration TERM 185 what is metamorphosis/metamorphic process? DEFINITION 185 change is slow and in solid state melting is not considered metamorphosis!!! recrystallization=minerals change size and shape phase change=diff minerals form with same chemical formula and different crystal structure (polymorphs!) pressure solution=mineral grains partially dissolve plastic deformation=mineral grains soften and deform neocrystalization=new minerals form with press/temp changes. initial minerals become unstable, change to new minerals