Glaciations Flashcards
Period within the Climatic Optimum or Hypsithermal from about 7500 -4000 B.P when the climate was warmer than at the present
Altithermal
Period in the Holocene from about 9000 to 2500 B.P when mean annual temperatures were higher than at the present day.
Climatic Optimum/ Hypsithermal
Postglacial rise of sea level that has occured since the end of the Pleistocene
Flandrian glaciation
Widespread Climatic episode as interpreted from Quaternary successions; eg., glaciations, interglacials, stades etc.
Geologic Climate Unit
Typically an upland area to which cold climate species of animals and plants retreated as continental ice sheets withdrew and the post glacial climate ameliorated.
Glacial refiugium
Informal geologic climate unit, usually accorded the status of a stage, as that term is used in quaternary stratigraphy.
Glaciation
Informal geologic climatic unit, usually accorded the status of a stage, as that therm is used in Quaternary stratigraphy.
Glaciations
Substage of a glacial stage when a climatic cooling caused a brief readvance of the ice.
Stade
In quaternary stratigraphy, its a glacial or interglacial episode.
stage
Fluvioglacial deposits laid down by meltwater streams issuing from glaciers
Outwash deposits
Accumulation of unsorted, unstratified till deposited by a glacier.
Moraine
Refers to sea level when it is below the shelf edge
lowstand
Graph showing relative areas of the earth’s surface at different elevations above and below sea level.
Hypsometric curve
Time between two glacial advances
Interglacial
Short lived recessions of the ice during a period of glacial advance, a warm stage
Interstade
Refers to the sea level when it is above the edge of the continental shelf
High stand
Studies of the cored drills show that glacial - interglacial cycles have occured about every
100,000 years
How many cycles of cooling and warming were identified for the span of ice age?
20 cycles
sinuous ridge that are largely composed of sand and gravel that were once occupied by glaciers, either deposited by meltwater rivers or covered beneath a mass of motionless stagnant ice, that was revealed after melting.
Esker
are streamlined assymetrical hills composed of till, where the steep sife of the hill faces the direction from which the ice advanced whereas the gentler slopes points in the direction where the ice moved.
Drumlins
are steep sided hills that like eskers, are composed of sand and gravel glacial which originate from glacial meltwater that washed sediment into openings and depressions in the stagnant wasting terminus of a glacier. When the ice is melted, the stratified drift is left behind as mounds or hills
Kame
Deposits that are not directly deposited by glaciers but rather reflect the sorting activity of glacial meltwater
stratified drift
an all embracing term for sediments of glacial origin, no matter how, where or in what form they were deposited.
Glacial drift
Glacier drift deposited directly by glaciers
till
glacial drift laid down by glacial meltwater
stratified drift
