chapter 17 glacial and periglacial processes and landforms
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Chapter 17 Glacial and Periglacial Processes and Landforms. Geosystems 6e An Introduction to Physical Geography. Robert W. Christopherson Charles E. Thomsen. The Pleistocene Ice Age Epoch . Changes in the Landscape Lowered Sea Levels and Temperatures Paleolakes . - PowerPoint PPT PresentationTRANSCRIPT
Chapter 17Glacial and Periglacial
Processes and Landforms
Geosystems 6eAn Introduction to Physical Geography
Robert W. ChristophersonCharles E. Thomsen
The Pleistocene Ice Age Epoch Changes in the Landscape Lowered Sea Levels and Temperatures Paleolakes
Ice age – extended period of cold that occur at intervals of 40,000 to 100,000 years
Pleistocene Epoch
Glacial periods are separated by shorter interglacials
Holocene Epoch
The Pleistocene Ice Age Epoch
Temperature Record of the Past 2 Million Years
Figure 17.26
Pleistocene Glaciation
Figure 17.27
Pleistocene Glaciation
Figure 17.27
18,000 years ago 9500 years ago
Evolution of the Great Lakes
Figure 17.28
Sea Level18,000 years ago, sea level was 330 ft lower than today
Paleolakes – dry lake beds that were filled during the last glacial period
Lake Bonneville
Polar jet stream
Paleolakes
Figure 17.29Sevier Dry Lake
Mechanisms of Climate Fluctuation
Milankovitch Theory – describes astronomical factors that may affect broad climatic cycles
Earth’s elliptical orbit
Earth’s axis – timing of seasons
Earth’s tilt
Solar Output
Plate tectonics
Volcanic eruptions
Oceanic Circulation
Astronomical Factors
Figure 17.31
Vostok Ice Core Record
Figure 17.32
Present level at 480 ppm (2004)
Greenland and Dome C Ice Cores
Figure FS 17.1.1 Figure FS 17.1.3
End of Chapter 17
Geosystems 6eAn Introduction to Physical Geography
Robert W. ChristophersonCharles E. Thomsen
Chapter 18The Geography of Soils
Geosystems 6eAn Introduction to Physical Geography
Robert W. ChristophersonCharles E. Thomsen
Geography of SoilsSoil – dynamic natural material composed of fine particles in which plants grow that contains mineral fragments and organic matter
Agricultural Extension Service
Soil CharacteristicsSoil horizon – the zone of soil that extends from the surface to the bedrock
O horizon – top layerHumus – mixture of decomposed and synthesized organic materials
A horizon – humus and clay particlesE horizon – coarse sand, silt, mineralsB horizon – clays, aluminum, ironA, E, and B – true soil
Soil CharacteristicsC horizon – weathered bedrock
Plant roots and soil microorganisms rare
R horizon - rock
End of Chapter 18
Geosystems 6eAn Introduction to Physical Geography
Robert W. ChristophersonCharles E. Thomsen