Glaciers Earth Science Chapter 6 p 154 159 168 173 Southern Hemisphere Northern Hemisphere Ice Age Sea Level on North America Valley and Piedmont Glaciers Malaspina Glacier Alaska Crevasse Glacier movement tracked by stakes Glacial Snow Budget Striations and polish Cycle of valley glacier erosion U Shaped Valley with tarns Hanging Valley Arete Cirque Horn Fiord Lateral moraine Lateral and Medial Moraine Moraine deposit Loess Continental Glacial deposits Pleistocene Ice Maximum Upper Midwest End Moraines Coastal moraines of New England Upper Midwest drainage before glaciation Upper Midwest Drainage after glaciation Deranged drainage after ice melts Pluvial Lakes of Southwest Ice Age Sea Level on North America Iceberg Photo Iceberg diagram Bering land bridge http www atmos washington edu dennis Our Changing Climate html Location of 300 MY Continental Glaciation Location of 300 MY Continental Glaciation with continents located 300 mya Elliptical orbit Axial Tilt variation obliquity Precession of axial tilt Milankovitch cycles Northern hemisphere insolation differences due to Milankovitch cycles Oxygen isotope fractionation Temperature record from O 18 Threshold diagram Positive Climate Feedback Loops Ice albedo decreases temperature increases ice Reduced ice increases temperature Ice albedo feedback loop Positive Climate Feedback Loops Ice albedo decreases temperature increases ice Reduced ice increases temperature Glacial periods result in larger arid areas increasing delivery of iron nutrients to sea lowering CO2 levels and temperature Lowering sea level will expose reefs to weathering Reaction consumes CO2 lowering temperature Rising sea level has opposite effect Negative Climate Feedback Loop Forest die out during glacial ages reducing mechanism to remove CO2 from atmosphere increasing temperature Forest cover negative feedback Temperature compared to sulfur aerosol concentration Nutrient cycle Nutrients related to sea level change Past Glacial Ages Pliocene Pleistocene Ice in Antarctica starting about 40 m y a Widespread N Hemisphere ice about 3 mya Advances every 40 000 to 100 000 years Karoo Ice Ages 260 to 350 mya Lasted 90 million years Wegener s evidence of continental movement Past Glacial Ages Andean Saharan Ice Ages 430 to 460 mya Lasted 30 million years Cryogenian 630 to 850 mya Lasted 200 million years Periods of all Earth covered with glacier Huronian Over 2 billion years ago Lasted 300 to 400 million years
View Full Document
Unlocking...