GEOG 4014 Study Guide - Uniformitarianism, Paleoclimatology, Silt
Document Summary
Techniques utilize the principle of uniformitarianism: geologic evidence. Look for evidence of glacier"s advance or retreat (landforms) Look for plankton that prefer cold or warm water, or are sensitive to salinity changes. Look at the ratio of two different oxygen isotopes in the hard parts microscopic oceanic plankton. Drill deep holes in ice sheets to examine variations in oxygen-isotope ratios in ice layers. Also works for determining the amount of co2 in the atmosphere. Advantages/disadvantages: varves -- annual layers of silt and clay deposited on the bottoms of lakes and ponds that freeze in winter and thaw in summer, dendroclimatology. Characteristics of a tree"s annual rings can give clues about the climate during the year when that ring was produced. When climate is cooling, treeline moves southward and downslope. When climate is warming, treeline moves northward and upslope. Look for pollen or spores and attribute their presence to climate. Weather phenomena per se (frosts, snowfall totals, etc. )
