Details Title: Earth10: Geologic Principles [FINAL] Description: N/A Total Flash Cards: 92 Created: 06/08/2009 21:03:59		New Users: To study from this flashcard set, or to create your own your own study flash cards, REGISTER HERE. Existing Users: CLICK HERE. Additional Geology Flashcards
Cards in this set: Term Basin Definition a fold or depression shaped like a right-side-up bowl Term Drainage Network Definition an array of interconnecting streams that together drain an area Term Catchment Definition drainage network Term Sheetwash Definition a film of water less than a few millimeters thick that covers the ground surface during heavy rains Term Dentritic Drainage Network Definition like veins on a leaf or branches on a tree, gentle slopes, uniform rock type Term Radial Drainage Network Definition flows out from central location, common around volcanoes or other conical features Term Rectangular Drainage Network Definition streams join together at right angle because of a rectangular grid of fractures that breaks up the ground and localizes channels Term Trellis Drainage Network Definition drainage network that forms over valley-and-ridge sequences Term Headwaters Definition the beginning point of a stream Term Channel Definition a trough dug into the ground surface by flooding water Term Floodplain Definition the flat land on either side of a stream that becomes covered with water during a flood Term Terraces Definition the elevated surface of an older floodplain into which a younger floodplain had cut down Term Thalwag Definition the deepest part of a stream’s channel Term Meandering Streams Definition a reach of stream containing many meanders (snake-like curves) Term Braided Streams Definition a sediment-choked stream consisting of entwined subchannels Term Bedrock Streams Definition streams made of rocks still attached to the Earth’s crust Term Superposed Definition stream channels cut down through resistant rock, can end up with channels having a shape based on rocks that are now eroded away Term Antecedent Definition topography comes up around stream, which can erode at the same rate Term Turbulent Definition chaotic twisting and swirling motion in flowing fluid Term Laminar Definition when a fluid flows in parallel layers, with no disruption between the layers Term Bed Load Definition large particles, such as sand, pebbles, or cobbles that bounce or roll across a stream bed Term Suspended Load Definition tiny solid grains carried along by a stream without settling to the floor of the channel Term Dissolved Load Definition ions dissolved in a stream’s water Term Fluvial Deposits Definition sediments transported and deposited by streams Term Alluvium Definition sediment transported by flowing water that is dropped when there is a sudden loss in water capacity, reduction in velocity Term Flood Definition an event during which the volume of water in a stream becomes so great that is covers areas outside the stream’s normal channel Term Hotspot Definition a location at the base of the lithosphere, at the top of a mantle plume, where temperatures can cause melting Term Sea-Floor Spreading Definition the gradual widening of an ocean basin as new oceanic crust forms at a mid-ocean ridge axis and then moves away from the axis Term Seamounts Definition an isolated submarine mountain Term Carbonate Compensation Depth Definition line below which CaCO3 dissolves Term Shallow Currents Definition driven mainly by wind and modified by the corriolis effect Term Deep Currents Definition driven mainly by gravity and the corriolis effect Term Gyres Definition subcircular current systems, in which water flows in a circular pattern Term Centrifugal Force Definition the force due to Earth’s rotation about the center of the Earth-Moon system Term Spring Tides Definition Sun, Moon, & Earth are aligned (highest, high tides) Term Neap Tides Definition Sun & Moon form 90 degree angle with the Earth (lowest, high tides) Term Berm Definition a deposit of sand and gravel at the edge of the swash zone Term Swash Definition the upward surge of water that flows up a beach slope when breakers crash onto the shore Term Wave-Cut Bench Definition a platform of rock, cut by wave erosion, at the low-tide line that was left behind a retreating cliff Term Wave-Cut Bench Definition a platform of rock, cut by wave erosion, at the low-tide line that was left behind a retreating cliff Term Wave-Cut Notch Definition a notch in a coastal cliff cut out by wave erosion Term Wave-Cut Cliff Definition a coastal cliff that is cut by wave erosion Term Ground Water Definition subsurface water that occurs below the water table within geologic formations that are saturated (pore spaces filled). This is not the same as soil moisture - there is often water trapped between grains of soil, but generally it will not flow to a well (held by capillary forces) Term Infiltration Definition water passing through ground surface Term Recharge Definition water reaching the water table, level of water than can be produced from wells Term Porosity Definition the volume fraction of open spaces in a rock or soil Term Hydraulic Conductivity Definition ease of ground water flow Term Aquifer Definition geologic unit that is completely saturated by water, that stores and transmits water in usable quantities Term Confining Layer Definition geological unit with much lower transmissive properties than surrounding formation (aquiclude versus aquitard) Term Aquiclude Definition sediment or rock that transmits no water Term Aquitard Definition sediment or rock that does not transmit water easily and therefore retards the motion of the water Term Unconfined Aquifer Definition one in which the upper surface of the aquifer is defined by the water table Term Perched Aquifer Definition an aquifer of limited lateral and vertical extent that is underlain by a confining layer Term Confined Aquifer Definition one in which the level to which water in the aquifer would rise in a pipe, emplaced in the ground and open at the bottom, is higher than where the top of the aquifer meets the overlying confining layer Term Capillary Fringe Definition a region above the water table that is also saturated, but within this zone water is held in place by suction Term vadose zone Definition the region above the saturated zone Term Hydraulic Head Definition elevation of water table that tells you how much energy is available to drive flow Term Adiabatic Definition the abrupt rise or fall of air, without gaining or losing heat Term Sensible Heat Definition heat you can feel Term Latent Heat Definition hidden heat Term Weather Definition short-term conditions, wind speed, temperature, humidity, precipitation, etc. Term Climate Definition long-term conditions, seasonality, variability, average conditions, etc. Term Albedo Definition the reflectivity of an object Term Monsoons Definition seasonal reversals in winds, leading to very wet and very dry seasons Term El Niño Definition trade winds die, water moves back to east, gets very warm offshore west US and SA, little or no upwelling Term Sabkhas Definition deserts near the ocean Term Glacier Definition streams or sheets of recrystallized ice/snow that last through warm season, move under the influence of gravity Term Mountain Glaciers Definition found in or near mountains, shape controlled by mountain topography, flow from high elevation to low elevation Term Continental Glaciers Definition cover vast expanses of continental areas, flow outward toward margins Term Temperate Glaciers Definition most ice is close to melting, moves mainly by sliding at the bed Term Polar Glaciers Definition ice is well below melting point, frozen to underlying ground under most of the glacier, move mainly by internal deformation Term Three Conditions For Glacier Formation Definition (1) local climate must be cold (2) enough snowfall for accumulation (3) gentle enough slope to avoid removal by sliding Term Erratics Definition rocks that are out of place, carried by glaciers Term Earthquake Definition the abrupt release of energy due to slipping of rock masses (usually along a fault), leading to shaking of the ground Term Seismicity Definition a measure of the amount of energy released Term Elastic Strain Definition reversible. release the stress and the strain vanishes. Term Ductile and Brittle Strains Definition not reversible. release the stress and strain stops accumulating, but the rock does not return to its original shape. Term Aftershocks Definition smaller earthquakes that follow any large earthquake Term Body Waves Definition (1) P-waves (primary, primus, "push") (2) S-waves (secondary, "side-to-side", slower) Term Surface Waves Definition (1) Rayleigh waves - up and down (kind of like waves on the ocean) (2) Love waves - side to side Term P Waves Definition a wave that propagates as a series of compressional and expansional vibrations is known as a compressional wave Term Bulk Modulus Definition a measure of how difficult a solid (or fluid) is to compress Term Shear Modulus Definition a measure of how difficult a solid is to shear Term S Waves Definition shear waves. travel slower than P waves and arrive later. Term Surface Waves Definition seismic surface waves propagate only along the surface of the planet, they do not pass through the planet Term Love Waves Definition create vibrations somewhat like those of S waves. makes rocks near the surface vibrate horizontally back and forth perpendicular to the direction of wave propagation Term Rayleigh Waves Definition create vibrations that trace out circular paths aligned with wave propagation. resemble ocean waves with one major exception: the orbits rotate in the opposite direction. Term Divergent Boundaries Definition lots of little, shallow earthquakes Term Transform Faults Definition strike slip, somewhat larger, rarer earthquakes, also generally shallow, sometimes intermediate Term Convergent Boundaries Definition complex, many kinds of earthquakes normal faults, shallow quakes where plate is flexed Term Seismographs Definition sensitive instruments designed to record the vibratory motion (strains) of passing seismic waves Term Greenhouse Effect Definition long-wave radiation becomes trapped within Earth's atmosphere, helping to increase the heat stored