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Phys Unit 2
| Term | Definition |
|---|---|
| External Forces | -the external forces create various processes that grind and wear the Earth's surface downward. -sun, atmosphere, life |
| Denudation | -the overall lowering of continental surfaces: -Weathering, mass wasting, erosion |
| Weathering | -the disintegration, decomposition, and/or alteration of rocks and minerals at/or near the surface of the earth as a result of physical and chemical processes |
| Disintigration | to break apart, or break into smaller pieces (NaCL= smaller pieces of NaCl) |
| Decomposition | break it down into its constituent elements (NaCl= Na+Cl) |
| Alteration | to change the chemical and/or crystalline structure to produce a different substance (non reversable) |
| 2 types of weathering | mechanical and chemical |
| mechanical | the physical disintegration of rock materials. |
| chemical | the decomposition or alternation of rock materials. |
| mechanical weathering | frost wedging (shattering) and decompression/sheeting and exfoliation dome |
| frost wedging (shattering) | when water enters a joint or smaller crack in rock, it freezes, and splits the rock through expansion |
| decompression/sheeting | when the weight and thus comprehensive force of overlying rock is removed and the underlying rock expands and forms joints |
| joint | a crack or breakage in the rock that develops through stress. |
| Importance of Mechanical Weathering | it creates landforms and sediment -it increases the exposed surface area of rocks where chemical weathering can begin |
| chemical weathering | -when the chemical composition and/or crystalline structure of the rock or mineral is changed and something new is created |
| three main types of chemical weathering | oxidation, hydrolysis, dissolution (carbonation) |
| oxydation | -when metallic ions combine with oxygen to form carious oxides -MgO, MnO, Al2O3 -your car gets scratched |
| Hydrolysis | -the chemical combination of water and some mineral to produce a new material -hydrogen ions (H+) in water replace other elements in the mineral. |
| Dissolution | -when rocks are decomposed by water |
| Carbonation | -a special type of dissolution of limestone and other carbonate rocks and minerals -it is one of the most common, and important types of dissolution -extremely important in landscapes composed of limestone (caves) |
| Differential weathering + erosion | -materials that are less resistant's will be weathered and eroded preferentially. -slate is very resistant to weathering |
| Hydrologic cycle | evaporation, precipitation, runoff |
| The Water Table | the boundary between the saturated zone and the unsaturated zone |
| saturated zone | all pore spaces in sediment, or fractures in rock, are filled with water |
| unsaturated zone | -pore spaces filled with water and air -generally mirrors the land surface. |
| perosity | the percentage of the total volume of rock or sediment that is pore spaces |
| permeability | the ability of rock or sediment that can store and transmit water |
| aquitard | impermeable layers that prevent, or hinder the movement of water |
| perched water table | a shallow, local zone of saturation above the regional water table |
| spring | a place where the groundwater table intersects the land surface |
| geyser | an intermittent foundation of water and steam that is ejected upward. |
| drawdown | when the water table around a well is lowered, or "drawn down" by water removal. |
| cone of depression | the conical shaped lowering of the water table near a well |
| environmental issues | depletion, ground subsidence, contamination |
| karst | topography and land forms that result from underground dissolution and precipitation |
| precipitation | -when the dissolved ions combine to form solid rock and mineral material |
| cavern (cave) | -large open areas created by under ground dissolution along bedding plains or joints -usually related to changes in depth to the underwater table |
| sinkhole | -rounded depressions caused by the dissolution of surface carbonate rocks -typically associated with joint intersections |
| solution sinkhole | a broad depression created by dissolution and widening from the surface downward. |
| collapse sinkhole | when the ground surface collapses into a solution cavity |
| valley bottom | the low area where stream flow is clearly established |
| valley sides | the steeper slopes that rise above the valley bottom on either side |
| interfluve | the higher land above the valley sides that separates small, adjacent valleys |
| drainage basin | -all of the area that contributes water and sediment to a stream -it is also called watershed |
| divide | the higher land that separates adjacent drainage basins |
| fluvial chain of events | -rainfall or snow melt creates runoff -erosion -transportation -deposition -runoff |
| erosion | when soil and rock material is initially dislodged and removed by water |
| fluvial erosion | begins when particles are dislodged by rain-splash erosion- and carried downslope by overland flow (the rock must be softened first) |
| transportation | -when rock material is "dropped off" by water -sediment and material carried by a stream as: dissolved load, suspended load, bed load |
| dissolved load | dissolved minerals carried in solution |
| suspended load | sediment that is "suspended" or floating along |
| bed load | larger particles that bounce, slide or roll along the bottom of the stream, |
| Stream Capacity | -the amount of solid material a stream is capable of carrying -it is controlled by velocity, discharge, etc. |
| stream competence | -the diameter of the largest particle a stream can carry -it is controlled by velocity, as velocity increases, ________ increases rapidly |
| runoff | when water flows or runs off the land surface |
| deposition | when rock material is "dropped off" or set down by water |
| fluvial deposition | -when flow velocity decreases and the stream can no longer carry its full load- it begins to drop it off, or deposit the excess sediment. - stream discharge changes -stream enters a standing body of water -stream gradient becomes lower |
| channel patterns | the actual shape of an individual stream channel |
| straight | channel moves down a relatively straight smooth course. |
| meandering | smooth curves and tight loops alternating with relatively straight portions. very intricate patterns |
| braided | many interwoven and interconnected channels separated by sand and gravel deposits |
| cutbanks | the eroding, outside portion of a meandering bend. it typically has steep bends |
| pointbar | the gently sloping inside of the meander where deposition is occurring/taking place |
| meander neck | a narrow strip of land between two merging meanders |
| meander cutoff (chute) | a new, shorter channel cut through the neck |
| flood plain | -the relatively flat land adjoining the river channel. commonly known as "bottom lands" -note that the ______ is genetically related to the to the river- the river creates it _____ |
| flood plain 2 | ___ ___ are created by 3 general processes: valley deepening, valley widening, and deposition |
| entrenched stream | -when a stream establishes a "stable" course then slow regional uplift occurs- -the stream retains its channel pattern and erodes downward -__ __ can create canyons that are 100s and even 1000s of feet thick -__ __ usually have a meandering pattern |
| entrenched meander | a meander bend which has cut downward, rather than laterally |
| stream terrace | a former flood plain that now stands above the modern river channel and is no longer genetically related to the modern stream |
| valley lengthening | when the stream finds a way to make its valley longer and hence lengthen its channel network |
| headward erosion | increases the length of the upper tributaries by eroding back into the uplands |
| delta creation | when streams enter a standing body of water, they deposit sediment rapidly |
| delta | the land surface created when a river enters a standing body of water |
| glacier | a mass of ice and granular snow lying largely on land and showing evidence of past and/or present movement |
| accumulation | yearly snowfall is greater than yearly loss |
| ablation | -net yearly loss of mass due to melting sublimation, calving -glacier form when accumulation>ablation |
| where do glaciers form? | high latitudes and elevations |
| abrasion | underlying bedrock is worn down by rock debris within the glacier |
| glacial transportion | glaciers are an extremely viscous fluid thus they have huge competence and capacity |
| till | poorly-sorted rock debris deposited directly by glacial ice |
| glacial erratics | large rocks transported from afar and deposited by glaciers |
| big blue marble | 71% of earths surface covered by oceans and seas -northern hemisphere- the "land hemisphere" -southern hemisphere- the water hemisphere" |
| oceans | -four main ocean basins - pacific Atlantic, Indian, arctic |
| southern ocean | the portion of the pacific, Atlantic and instant ocean near Antarctica where currents from each ocean converge |
| salinity | -the total amount of material dissolved in water -typically expressed in parts per thousand (%) -average ___ of ocean water is 35% -major constituent is NaCl |
| terrigenous | mineral grains that were weathered and transported from the continents |
| biogenous | microscopic shells and skeletons of marine animals and algae that settle to the ocean floor. |
| the ocean floor | -continental margins -deep ocean basins -mid ocean ridges |
| deep ocean trenches | -long, narrow valleys at subduction zones -challenger deep= 30,070 feet deep |
| abyssal plains | deep incredibly flat surfaces on the deep ocean floor |
| volcanic features | seamounts, guyots, oceanic palates |
| seamount | undersea volcanoes |
| guyot | volcanic island that was eroded away and now sits below sea level |
| oceanic plateaus | large, sea flood basalt flood |
| ocean currents | -masses of water that flow horizontally from one place to another |
| gyres | - large, roughly circular currents within ocean basins -they are created by: global atmospheric circulation, distribution of continents, earths rotation and Coriolis effect |
| oceanic circulation and climate | -warm currents transfer heat energy from the tropics to the polar regions -cold currents bring cold water to middle latitude and tropical areas -warm and cold currents can warm/chill the air |
| waves | a waves is the transfer of energy (through water) in a cylindrical rising and falling motion |
| breaker | when a wave tumbles foreword to frictional slowing of its base |
| swash | turbulent water from a "broken" wave that rushes toward the shore or up the beach |
| backwash | water that drains back off of the beach or shoreline |
| rip currents | -narrow currents in he surf xone that flow straight out to sea -they return large volumes of water to the sea, that waves have pushed ashore -THEY ARE VARY DANGEROUS |
| refraction | when waves are bent and their energy is either concentrated or dispersed |
| longshore current | an ocean current that moves roughly parallel to the shoreline, or "along the shore" -they are created by winds and waves that srije the shore at a low angle -they are important as they transport large amounts of sediment |
Created by:
emilywinter318
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