GEOL 102 1st Edition Lecture 6 Outline of Last Lecture I. The Hydrologic CycleII. Soils and WeatheringOutline of Current Lecture I. Climate ChangeII. Historical Context of GlaciersIII. Glacial Extent IV. How do you make a glacier?Current LectureI. Climate ChangeAverage temperatures rise 3.2 to 7.8 degrees F by 2100, sea level rise by 7 inches to 23 inchesUSA is leading emitter (25%) but China/India are on the riseSince last IPCC report (2001), we’ve experienced 7 of the 10 warmest years on recordCurrent warming trend is unique in last 1300 yearsWarming would continue if CO2II. Historical Context of GlaciersObservations of drift (Europe 1820s)Found far from sourcesLarge boulders hindered cultivationFound in wide valleysThese 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.Unsorted deposits (unlike river sediments)ErraticsInterpretations of glacial drift1. Great Deluge (flood)2. Glacial originLouis Agassiz (paleontologist) notes that glaciers can carry large boulders, does not sort sediment, melt and leave depositsDeems “a great ice age” during glacial origin, evidence was widely found and gained acceptance in the 1860sIII. Glacial ExtentCurrent- 10% of landmass is covered12.5 million km^2 in South Polar region2.1 million km^2 in North Polar regionIV. How do you make a glacier?Ice crystalsMinerals: solid, inorganic, defined structure and compositionTransformation to glacial ice1. Accumulation and compaction2. Initial snow- 90% air3. Ends blunted by melting or sublimation- 50% air4. With overburden, pressure melting5. Firm snow, packed- 25% air6. Water recrystallizes in voids- 20%
View Full Document
Unlocking...