Post on 23-Aug-2020
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Supercontinent - Pangea . . .
(zoom in to view the names of the geologic eras)
Alfred Wegner
Supercontinent - Pangea . . .
PangeaGondwanalandLaurasia
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Geologic Time
Milankovitch Cycles(~ 100,000 years)
Milutin Milankovitch(1879-1958)
Milankovitch Cycles(~ 100,000 years)
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Factors affectingEarth’s Climate
1. Milankovich Cycles(~100,000 years)
2. Pacific Decadal Oscillation(~10 – 15 years)
3. El Nino/La Nina Cycles (annual cycles*)
• Pleistocene Epoch– Ice ages (WIKN) – Humans appear – 1.8 my to 10,000 yr
http://www.museum.state.il.us/exhibits/ice_ages/images/loopglac.gif
Time Scale: The Cenozoic Era“Recent Life”
Stages
Continental Glaciers . . . . .
What is a “nunatak”?
Nebraskan(oldest)
Kansan
Illinoian
Wisconsin(most recent)
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Human Migration
NationalGenographic
Project
Human Migration
Source: www.utexas.edu/features/2007/ancestry/
Continental Glaciers . . . . .
Question: What type of vegetation covered the
landscape immediately south of the continental glaciers?
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Glaciers, Biotic Exchange,and Vegetation Patterns
Vegetation Patternsduring Glacial Periods
North American Glaciers . . . . .
Note the names
and locations
of the refugium
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Glacial Lake Missoula
Glacial Lake Missoula
The name Missoula is derived from a Flathead (Salish) termmeaning “cold, chilling waters”.
Continental Glaciers . . . . .
How did the continental glaciers affect the Willamette
Valley?
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Glacial Lake Missoula
Glacial Lake Missoula
A Sudden Onslaught of Water
The Dalles, Oregon ~ 1,000 feet
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Question.. . . . . . . . .
Question: As the glaciers formed, they locked up water,
how much lower were sea levels then?
Astoria Trench
Pacific Salmon Species
Genus Oncorhynchus – “hooknose”
Pink Salmon (O. gorbuscha)
Chum Salmon (O. keta)
Sockeye Salmon (O. nerka)
Coho Salmon (O. kisutch)
Chinook Salmon (O. tshawytscha)
Steelhead Trout (O. mykiss)
Sea-run Cutthroat Trout (O. clarkii)
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Glacial Lake Missoula
Glacial Erratics
The lake was named after the early explorer, B.L. Bonneville. It was formed about 50,000 years ago and had receded to the current level of the Great Salt Lake by about 10,000 years ago. It was about 560 km (about 350 mi) long and 240 km (150 mi) wide, had a maximum depth of more than 305 m (1000 ft), and was more than 1525 m (5000 ft) above sea level.
Lake Bonneville
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Megafaunal Extinctions
Megafaunal Extinctions
Shasta ground slothNothrotheriops shastensis
The stag-moose(scientific name Cervalces scotti)
Megafaunal Extinctions
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Ancient BisonBison Antiquus
Dwarf PronghornCapromeryx minor
Extinct CamelCamelops hesternus
Megafaunal Extinctions
Columbian Mammoth Mammuthus columbi
American MastodonMammut americanum
Megafaunal Extinctions
Sabertoothed CatSmilodon fatalis
American LionPanthera atrox
Megafaunal Extinctions
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Dire WolfCanis dirusShort-faced Bear
Arctodus simus
Megafaunal Extinctions
Source: http://www.ucmp.berkeley.edu/mammal/artio/irishelk.html
The Misnamed Extinct “Irish Elk”
~ 4 meters
Holocene Ecology
1. Vegetation Patterns2. Ecological Communities3. Species and Populations
Anthropocene?