lecture 05: pleistocene epoch of quaternary period Flashcards

1
Q

pleistocene epoch time period

A

2.58 Ma to 11.7 Ka

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2
Q

milankovitch cycles

A

‘canon of the earth’s insolation’: characterizes the climates of all the plants
explanation of earth’s long-term climate changes caused by changes in the position of the earth in comparison to the sun

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3
Q

what are the 3 milankovitch orbital cycles

A

eccentricity, obliquity, precession

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4
Q

beringia

A

areas free of ice, much of asia, siberia to yukon (some areas up to 1 Ma)

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5
Q

last glacial maximum

A

ice sheet and glacial coverage peaked

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6
Q

the 2 ice sheets

A

cordilleran and larentide (divided into keewatin and labrador)

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7
Q

driftless area

A

glaciers missed one region of the midwest USA leaving an unglacieted region surrounded by glaciated landscapes.
great lakes likely deflected or redirected the glaciers since it’s more sloped and hilly

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8
Q

remaining continental glaciers as of today

A

antarctic and greenland ice sheets

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9
Q

post-glacial isostatic adjustment

A

uplift of the land surface following ice melt

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10
Q

north american ice-free corridor

A

~13.8ka
coast + yukon –> alberta

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11
Q

proglacial lakes

A

would form at the margins of large glacial lakes created by receding glaciers

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12
Q

misfit streams

A

forms in the hollow valley of divides or ice dams

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13
Q

glacial lake agassiz

A

largest proglacial lake in Manitoba and parts of saskatchewan, ontario, n. dakota and minnesota

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14
Q

alberta’s connection to lake aggasiz mega-flood

A

clearwater to athabasca to arctic ocean
cut the clearwater gorge
sent massive deposits of delta sand down river

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15
Q

potholes

A

formed from extreme vortexes in the water

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16
Q

catastrophism vs uniformitarianism

A

competing geological theories

17
Q

younger dryas

A

12.9 Ka - 11.7 Ka
considered end of ice age
named after arctic plant (dryas octopetala)
showing up in europe’s paleo-vegetation at this time

18
Q

microspherules

A

form at >2200C
inconsistent with anthropogenic and volcanic materials, perhaps molten iron droplets

19
Q

carolina bays

A

inferred to be ‘ejecta’ craters (secondary impacts by ice)

20
Q

ice-margin

A

interface between ice and the glacier foreland or pro-glacial zone

21
Q

subglacial

A

situated or occurring underneath a glacier or ice sheet

22
Q

moraines

A

push moraines, dump moraines, ablation moraines

23
Q

drumlins

A

low oval mound or small hill, typically one of a group, consisting of compacted boulder clay molded by past glacial action

24
Q

outwash fans/plains

A

fan-shaped body of sediments deposited by braised streams from a melting glacier

25
Q

kames

A

glacial landform, irregularly shaped made of sand or gravel. can be deposited at or near the terminus of a glacier

26
Q

kame-kettle topography

A

locataed on end moraines where sediment accumulates at the end of the glacier. kettles are depressions formed by ice being trapped under

27
Q

glacial erratic

A

large rocks from elsewhere

28
Q

glaciolacustrine

A

glacial lake deposits

29
Q

glaciofluvial

A

glacial river deposits

30
Q

surficial geology

A

refers to the unconsolidated geologic materials lying on top of the bedrock. subsequent soil development is highly dependent on these original source materials

31
Q

eolian deposits

A

sand

32
Q

stagnant ice moraine

A

collapsed and slumping of debris near ice margin

33
Q

what is a feature of stagnant ice

A

doughnuts

34
Q

ice-thrust moraine

A

formed by displacement of blocks or ‘rafts’ that are left more or less intact

35
Q

major meltwater channel

A

massive river drainage during melting of glacier and possible major break in glacial lake