Geology Terms: Minerals, Rocks, Formation, and Processes, Quizzes of Geology

Download Geology Terms: Minerals, Rocks, Formation, and Processes and more Quizzes Geology in PDF only on Docsity! TERM 1 Mineral DEFINITION 1 Inorganic, naturally occurring solids with a definite chemical composition and crystalline structure TERM 2 Rock DEFINITION 2 Aggregate of one or more mineral crystals TERM 3 Crystal form DEFINITION 3 Geometric shape of a crystal TERM 4 Cleavage DEFINITION 4 Tendency of minerals to break along flat, parallel surfaces TERM 5 Mohs hardness scale DEFINITION 5 Higher numbered minerals on scale will scratch lower numbered minerals-the material that scratches is harder than the one scratched TERM 6 Conchoidal fracture DEFINITION 6 Smooth curved fracture surfaces, like glass TERM 7 Striations DEFINITION 7 Straight grooves on cleavage surface or crystal faces of some minerals TERM 8 Intrusive DEFINITION 8 -Igneous rocks that form deep underground-Slow cooling rates result in large mineral crystals TERM 9 Extrusive DEFINITION 9 -Form near and on Earth's surface-Rapid cooling leads to small or non-existent mineral crystals TERM 10 Phaneritic DEFINITION 10 Igneous rocks made of visible crystals (coarse-grained; crystals 1-10mm) TERM 21 Gneissic banding DEFINITION 21 Alternating layers of light and dark medium to coarse grained minerals-Dark bands usually ferromagnesian-Light bands usually quartz or feldspar TERM 22 Porphyroblasts DEFINITION 22 Arrangement of large crystals set in a finer-grained groundmass-Garnet is common TERM 23 Parent rock DEFINITION 23 The rock type that was metamorphosed TERM 24 Fault DEFINITION 24 Where rocks slide in opposite directions along a crack in the rock TERM 25 Normal fault DEFINITION 25 Caused by tensionTensional stress pulls rocks apart, gravity pulls down hanging wall block TERM 26 Reverse fault DEFINITION 26 Caused by compressionCompressional stress pushes rocks together, one block pushed atop the other TERM 27 Strike-slip (transform) fault DEFINITION 27 Caused by shear stressInvolve horizontal motions of rock TERM 28 Compression DEFINITION 28 Opposing stresses that push and squueze rocks TERM 29 Tension DEFINITION 29 Stresses that pull rocks apart TERM 30 Shear DEFINITION 30 Stresses that cause parts of the body of rock to slide past one another TERM 31 Footwall DEFINITION 31 Bottom surface of the fault TERM 32 Hanging wall DEFINITION 32 Top surface of the fault TERM 33 Lithosphere DEFINITION 33 Brittle upper layer of crust TERM 34 Asthenosphere DEFINITION 34 Ductile lower layer of crust TERM 35 Decompression melting DEFINITION 35 upward movement of the earth's mantle to an area of lower pressure. The reduction in overlying pressure enables the rock tomelt TERM 46 Parent and daughter isotopes DEFINITION 46 Parent isotope: when a mass of atoms of a radioactive isotope is incorporated into the structure of a newly formed crystalDaughter isotope: atoms of the parent isotope that have decayed to a stable form TERM 47 Contour lines DEFINITION 47 Lines that connect all points of equal elevation above sea level on a map TERM 48 Index contours DEFINITION 48 Contour lines with elevations printed on them TERM 49 Relief DEFINITION 49 Difference in elevation between landforms or other landscape features TERM 50 Regional relief DEFINITION 50 Difference in elevation between the highest and lowest points on a topographic map TERM 51 Gradient DEFINITION 51 Measure of the steepness of a slopeUsually determined by dividing relief between two points on a map by the distance between them TERM 52 Benchmark DEFINITION 52 Permanent marker placed by the USGS TERM 53 Hachure marks DEFINITION 53 Short line segments pointing downhillIndicate the presence of a closed depression TERM 54 Strike DEFINITION 54 Compass bearing of a line formed by the intersection of a horizontal plane and an inclined surface TERM 55 Dip DEFINITION 55 Angle between the horizontal plane and an inclined surface, measured perpendicular to strike TERM 56 Structural geology DEFINITION 56 study of the three-dimensional distribution of rock units with respect to their deformational histories. TERM 57 Topographic profile DEFINITION 57 cross sectional view along a line drawn through a portion of atopographicmap TERM 58 Block diagrams DEFINITION 58 An oblique sketch of a block of Earth's lithosphereHas a geologic map on top and a geologic cross section on each visible side TERM 59 Anticlines DEFINITION 59 Upfolds or convex folds with the oldest rocks at the middle TERM 60 Synclines DEFINITION 60 Downfolds or concave folds with the youngest rocks at the middle TERM 71 Cut banks DEFINITION 71 Outer edge of meandersErosion occurring TERM 72 Point bars DEFINITION 72 Deposits of mostly gravel and sand along the inner edge of meanders TERM 73 Oxbow lakes DEFINITION 73 Channel cutting a new path may cut off outer edge of a meander TERM 74 Flood plains DEFINITION 74 Develop when alluvium accumulates landward of the river banks TERM 75 Terraces DEFINITION 75 Level surfaces that are higher than the present floodplainRemnants of older floodplains that have been cut by younger streams TERM 76 Escarpments DEFINITION 76 Steep slopes or cliffs separating relatively horizontal stream terraces TERM 77 Dendritic drainage patterns DEFINITION 77 Resembles branching of a treeWater flow is from branch-like tributaries to the trunk-like main streamCommon where a stream cuts into flat lying layers of rock or sediment TERM 78 Rectangular drainage patterns DEFINITION 78 Network of channels with right-angle bends; form pattern of rectangles and squares TERM 79 Drainage basins DEFINITION 79 Entire area of land that is drained by one stream TERM 80 Divides DEFINITION 80 Linear boundaries that separate one drainage divide from another TERM 81 Mass wastage DEFINITION 81 Downslope movement of rock TERM 82 Submergent coastlines DEFINITION 82 Coastline that is being flooded, eroded back, or otherwise receedingCan occur due to erosion by waves (short term) or also sea level rise (long term) TERM 83 Emergent coastlines DEFINITION 83 Coastline that is advancingCan occur when sediment and reefs build up to sea level, then build seawardCan also occur when global sea level falls or when sea floor rises TERM 84 Jetties DEFINITION 84 Long walls extending from shore at the mouth of harborsUsed to protect harbor entrance from filling with sand TERM 85 Groins DEFINITION 85 Short wall constructed perpendicular to shorelineUsed to trap sand TERM 96 Unconfined aquifer DEFINITION 96 Aquifer that is not confinedGroundwater establishes a water table just beneath land surface TERM 97 Aquitard DEFINITION 97 Impermeable bedrock materials that prevent the flow of water TERM 98 Artesian well DEFINITION 98 Naturally flowing well TERM 99 Cone of depression DEFINITION 99 Cone shaped depression in the water tableResults when water is being with draw from an aquifer faster than it can be replenished TERM 100 Subsidence DEFINITION 100 Withdrawing water reduces water pressure in aquifer; aquifer gradually compacted and ground surface above is gradually lowered TERM 101 Karst topography DEFINITION 101 Dissolution of underlying soluble rock, generally limestone TERM 102 Cryosphere DEFINITION 102 All of Earth's snow and ice TERM 103 Glaciers DEFINITION 103 Large ice masses that form on land areas that are cold enough and have enough snowfall to sustain them year after yearForm wherever winter accumulation of snow exceeds summer ablation TERM 104 Zone of accumulation DEFINITION 104 Accumulation of snow and ice in and beneath snowfields TERM 105 Zone of ablation DEFINITION 105 Where glacier melts or sublimes faster than new ice can form TERM 106 Plucking DEFINITION 106 Glaciers freeze around rocks and rip it from the bedrock TERM 107 Abrasion DEFINITION 107 Extreme weight and downhill movement of glaciers causes them to wear away rock materials that they encounter TERM 108 Crevasses DEFINITION 108 Open fissures that form when the velocity of ice flow is variable TERM 109 Transverse crevasses DEFINITION 109 Perpendicular to the flow direction TERM 110 Longitudinal crevasses DEFINITION 110 Aligned parallel with the direction of flow