GEOL 102 1st Edition Lecture 9 Outline of Last Lecture I. Relationship Between Slope Thickness for Glacial Dynamics II. Glacial Budget III. Glacial Erosion and Landforms IV. Ice Ages V. Consequences of GlaciationOutline of Current Lecture I. Ice AgesII. Rivers and FloodsCurrent LectureI. Ice AgesWe’ve had 5-6 ice ages, which account for less than 10% of Earth’s historyThe ace ages are 10-100 million years longWhat do the ice ages have in common?There is lots of land near the polesOcean circulation patterns can deliver snow to the land areasMountains with high elevationIce ages are hard to get out of because snow’s albedo keeps temperatures lowAdvance/retreat within ice ages100,000 year cycles of glacial integrationOscillations within ice age are due toEccentricity in Earth’s orbit: more elliptical or loss elliptical 100-1000 year fluctuations are due to unknown reasons: possibly biota, humans, deforestation, volcanic activitiesThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Recent climate event: Little Ice Age 1300-1850 ADColder, snowier, more icebergsGlaciers advanced and overran villages in the AlpsWarming since 1850. . . why?Recent increase in CO2 in the atmosphereHas increased 25% since 1850Fossil fuel burningDeforestation2-4*C predicted warmingSea level has risen 20cm since 1900II. Rivers and FloodsDischarge = Volume/TimePractical issues: water supply, flooding, erosion, biological activity and habitat, damsOnly 0.001% of global water is in rivers, but more than 10% passes through rivers each yearWatershed: hydrologic unit, drainage divideHeadward erosion occurs via intense scouring where sheetflow enters the uppermost part of a channelDendritic basins are the most ‘classic’ drainage basinsRadial drainage develops around a point of uplifTrellis drainage develops in deformed strataParallel drainage develops on a surface with uniform
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