Glaciers:  blob of ice on land moving downhill/downslope; NOT sea ice = frozen seawater
        (a) valley/alpine glaciers; in narrow valleys, typical of mountain ranges (high altitude)
        (b) continental glaciers/ice caps/ice sheets; spread out over large area, polar regions (high latitude)
    snowfall, avalanches onto glacier converts to ice in a few years; rest melts
    glacial features:  shape of glaciers, head, snout, sub-glacial streams, crevasses, ice-falls

Dynamics of Glaciers: glaciers move downhill/downslope by two different mechanisms
        (1) flow within glaciers; glacial ice as a hot gooey solid oozing downslope
        (2) sliding along the muddy base aided by pressure melting around obstacles
            glaciers can move at speeds: inches/month (winter) to 100's of feet/day (surging glaciers)
    advance (growth) and retreat (shrink) of glaciers related to changes in glacial budget
        more snowfall/less melting = growth/advance, less snowfall/more melting = shrink
        features of advance and retreat:  trim lines and recessional moraines

Glacial Erosion: glaciers are very efficient at eroding both loose and solid materials
    plucking of floor and walls using freeze-thaw ; abrasion by transported debris in ice
        features of erosion: polished bedrock, striations, roche moutonée/stoss and lee
            rock steps, rock basin lakes/paternoster lakes, tarns; cirques, horns, aretes
            U-shaped valleys, hanging valleys, truncated spurs/facets
    Channeled Scablands of WA produced by glacial outburst floods

Glacial Transport of Sediment:  glaciers can carry any size, as well as large volumes
    indicators of transport direction:  striations, roche moutonée, drumlins, rock trains, etc.

Glacial Deposits:  classified based on location in relation to the glacier.
    in front of glacier (pro-glacial): rivers and lakes often found in front of glacier
        lakes: glacial lake deposits, rock flour, varved clays, deltas
        rivers: outwash fans, braided stream deposits
        terminus: moraines, kettles and kames, dead ice topography, Mima Mounds of WA
    at bottom of glacier (basal): glaciers lay down a slug track of deposits underneath
        ground moraine and till, till types; drumlins; eskers
    at sides of glacier (lateral): rivers and lakes often found along sides of glaciers
        lateral moraines, kames, ice marginal streams/lakes/deltas

Glaciation in the Past: glaciers have covered continents many times in the past
    reconstructing past glaciers using erosional and depositional features
    ancient glaciers in North America; history of  Olympic and Cascade glaciers
    past glacial epochs, worldwide glacial periods, paleoclimate data
    glaciers and climate; causes of glaciation (excessive growth of glaciers)
        --decreased solar output--dim sun (colder climate, more snow, less melting)
        --block sunlight with volcanic dust/ash in upper atmosphere (Krakatoa, Pinatubo)
        --change pattern of precipitation with changing ocean currents (e.g.)--no T change
        --earth wobble--tilt the earth's axis away from the sun (Milankovitch cycles)
        --reflection feedback--ice reflects sun, less heat, more ice, more reflection, etc.
        --all of the above--why should there be one single cause of a common phenomenon?
 

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