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Definition
| promote downslope movement. The main driving force is gravity Slope angle, climate, matierial and water contribute as well. |
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Definition
| deter movement. Shear strength of rock which is a function of sohesion and internal friction. Water reduces cohesion. |
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Definition
The relative magnitude of driving and resisting forces on slopes of differant angles where:
W= Weight at center of the mass
D= Vector of W parallel to potential mvmnt (which is a driving force)
and N= Vector of W normal to slip plane( resisting force). |
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Term
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Definition
| Slumps or rotational slides occur in homogenous material with no potential slip planes. Slips or translational slides occur in planes of weakness. |
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| Climate and vegetations effect on slope |
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Definition
| controls water content which lowers resistance and adds to driving forces. Vegetation adds weight and does the same. But roots add cohesion. |
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Term
| Human activity and slopes |
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Definition
| causes 90% of mass wasting .1.) Artificial evacuations during road constructions. 2.) projects that increase slopes. 3.) Adding water (eg. irrigation or ditches) |
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Term
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Definition
| drainage control, slope dewatering (installing surface and subsurface drains), slope reduction and stabilizing structures. |
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Definition
| sinking of a mass of earth material below the surrounding ground level. Results from removal of the ground support from below by removal of solid material or withdraw of groundwater. |
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Definition
| when water soluble rocks (like limestone) disolve by chemical weathering it produces void spaces ranging from very small to cavernously large. |
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Term
| fluid extraction and subsidence |
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Definition
| results from compaction of grains due to the lowering of pore fluid pressure. Irreversible. |
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Definition
| exploding to create small scale avalanches, or engineering diversion structures. |
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Definition
| all forms of snow and ice |
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Term
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Definition
| the lower boundary of perennial snow on a mountain. A function of both temp and precipitation. high precipitation leads to lower snow lines. |
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Definition
| permanent bodies of ice that move downslope or outward under the stress of their own weight. |
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Term
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Definition
| 1.) excess snow accumulates 2.) snow recrystallizes to produce smaller, rounder and denser crystals 3.) pore spaces are closed off, the pressure of gravity is a tremendous weight which pushes down and out. |
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Definition
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Term
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Definition
| in mountainous regions, shape and flow centered around area topography. |
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Definition
| in bowl shaped depressions on mountainsides formed by glacial erosion. |
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Term
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Definition
| in mountain vallys and may extend 100's of km from cirque headwalls. |
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Term
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Definition
| valley glaciers that emerge from confining valleys and spread laterally to form fan shaped lobes. |
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Term
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Definition
| cover highland areas and flow outward from a central dome |
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Term
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Definition
| cover large sections of a continent. Cureently ice sheets cover greenland, antarctica etc |
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Term
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Definition
| floating margins of an ice cap or ice sheet that extend into the sea. |
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Term
| warm or temperate glaciers |
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Definition
| contain liquid water for two reasons: experience of above freezing temps during summer or the ice is so thick that its above melting point at the bed, producing a layer of melt water |
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Term
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Definition
| @ below freezing throughout and are frozen to their bed. |
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Term
| internal deformation/plastic creep |
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Definition
| all glaciers move by this force which involves individual crystal planes gliding past eachother in response to gravitational stress on a large body of ice. |
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Term
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Definition
| a layer of meltwater at the glacial bed provides lubrication allowing slide. Only in warm/temperate glaciers. |
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Term
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Definition
| because of frictional resistance, glaciers moves the fastest in the middle and this causes crevasses to open and close amidst the surface to accomodate differant flow rates within the glacier. |
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Term
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Definition
| likely result from basalt sliding due to a change in subglacial draining conditions. The reduced friction is caused by a surge in water on the bedrock. |
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Definition
| glaciers that reach the sea |
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Term
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Definition
| a process which takes mass from icebergs from their terminus which often forms a near vertical ice cliff. |
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Term
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Definition
| difference between mass added to glaciers by accumulation and mass lost by ablation (ie mass bal= accum-loss) |
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Definition
| all mass additions by snowfall or avalanche by adjacent walls or rock fall. |
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Definition
| loss caused by melting or calving |
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Definition
| more accum than loss causing an expansion in thickness |
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Definition
| less accum, so glacier retreats in thickness and area. |
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Term
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Definition
| the portion of the glacier with net gain of mass. |
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Term
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Definition
| portion of the galcier with net loss of mass. |
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Term
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Definition
| the boundary between the accumulation and ablation areas. |
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Term
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Definition
| sea water freezes, ice is excluded. This makes fresh water. This changes the salinity and density of sea surface water |
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Term
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Definition
| breaking off of large chunks of rock from down glacier (lee) side of rock outcrops along pre-existing joints or fractures |
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Term
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Definition
| the crushing and grinding of rock into fine particles called glacial flour. |
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Definition
| long parallel scratches in bedrock produced as glacier ice drags rock fragments across a bedrock surface. |
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Definition
| very large striations. Striations and grooves indicate which direction the ice was flowing |
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Term
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Definition
| the smoothing of bedrock surfaces by the abrasive action of ice containing rock flour, producing a smooth, reflective surface. |
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Term
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Definition
| alpine lakes partially filling the bowl shaped depression at the bottom of a cirque |
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Term
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Definition
| a narrow knife edge ridge that is left standing in nearly sheer relief as glaciers erode from opposite sides of a mountain ridge. |
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Term
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Definition
| where glaciers cut through a ridge and create a u shaped notch |
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Term
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Definition
| a pyramid shaped mountain peak left by cirque glaciers cutting into three or more sides of a mountain (eg matterhorn) |
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Term
| glacial trough/ u-shaped valley |
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Definition
| a straight, wide valley is a straight wide valley with steep sides and flat bottom |
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Term
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Definition
| where smaller tributary glaciers join main trunk of a glacier a hanging valley is formed high above the valley floor bc of the less corrosive power of small tributaries |
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Definition
| a U shaped valley partially drowned by sea water |
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Definition
| glacial deposits, usually poorly sorted material. |
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Term
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Definition
| piles of till that accumulate at the edge of a glacier when it remains in one place for some time. |
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Term
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Definition
| deposited alongside of a glacier |
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Term
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Definition
| deposit at the end of a glacier |
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Term
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Definition
| when one glacier flows into another turning two lateral moraines into one single medial moraine. |
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Term
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Definition
| when till is shaped into a streamlined hill underneath continental ice sheets |
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Term
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Definition
| slender sinuous ridges caused by deposited glacial sediment that form tunnels beneath continental icesheets |
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Term
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Definition
| Glacial ice buried in sediment can melt to produce small depressions called kettles |
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Term
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Definition
| form in areas beyond the limit of glaciers. Low temps and frost action are important factors in landscape development in these areas |
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Term
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Definition
| permanantley frozen ground found at high altitudes or latitudes |
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Term
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Definition
| masses of loose rock material held together by ice so that it behaves and flows as a mass |
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Term
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Definition
| mechanisms that cause climate change. many forcings produce climate change by altering Earth's radiation budget. |
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Term
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Definition
| Intial climate forcing leads to initial climate response and this response is amplified by the climate system. The ic-albedo feedback eg |
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Term
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Definition
| stabalizing changes made to the climate system such as chemical weathering of rocks which takes out CO2 |
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Term
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Definition
| the study of past climates by the indices of geologic matter surrounding us like tree rings and rock assortment and organization |
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Term
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Definition
| dramatic period of climate change with cyclical periods of growth and retreat of glaciers and ice sheets worldwide |
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Term
| Evidence for glacial advance and retreat using marine sediment |
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Definition
| The isotopic composition in sea water shows the decay and growth of the calcium carbon shells of foraminiferma in marine sediment. Therefore, marine carbonate sediments provide a record of global ice on hand |
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Term
| Ice Core paleoclimatology |
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Definition
| preserves record of atmospheric comp including trace gasses and aerosols. |
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Term
| results from Vostok station |
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Definition
| glacail-interglacial cycles are paced by Milankovitch orbital variations and amplified by changes in atmospheric CO2 and methane |
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Term
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Definition
| three separate, periodic changes in the Earth's orbit around the sun causes regular variations in the total amount and spatial distribution of solar radiation recieved by the Earth. These variations cause periodic changes in the size of icesheets. |
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Term
| the 3 milankovitch cycles |
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Definition
| Eccentricity (shape of orbit), Obliquity (tilt of axis), and Precession (wobble of axis) |
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Term
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Definition
| change in standard orbit every 100,000 years. High Eccentricity is farther away from the sun and is thus less exposed to radiation |
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Term
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Definition
| change in tilt of axis every 41,000 years and affects seasonality. The less the tilt, the lesser the differance between seasons. |
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Term
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Definition
| wobble of earths rotational axis and affects seasonality by canging the timing of winter an summer relative to the position of the Earth's rotation around the sun. |
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Term
| Milankovitch orbital cycle effects on climate |
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Definition
| Amount of solar radiation and seasonality: summer is melt season so when summers are cooler glaciers advance and vice versa. Cool summers and ice growth are best in low obliquity (small tilt) and N. Hemi summer is far from the sun |
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Term
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Definition
| breaking of rocks into smaller fragments with no change in their chemical properties |
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Term
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Definition
| decomposition of rocks and minerals into new forms by solution, oxidation or hydration. physical weathering promotes chemical weathering by increasing the surface area of geologic matter |
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Term
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Definition
O- decomp leaves brown
A-zone of leaching
B encriched from leeching; zone ofaccum
C- weathered
R-unweathered rock |
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Term
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Definition
| proportion of clay silt and sand sized particles |
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Term
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Definition
| Plasticity, strength, cohesion, sensitivity, compressibiltiy, erodability, permeability |
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Term
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Definition
| down slope movement of sediment or rocks in response to the force of gravity |
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Term
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Definition
| very slow flow involving alternation of expansion and contraction of slope material |
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Term
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Definition
| occurs in homogenous material aka rotational slides bc they move on curved, concave-upward surfaces causing the block to tilt in the upslope direction. |
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Term
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Definition
| move along planes of weakness (slip planes |
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