GEOG 3105 Lecture Notes - Lecture 7: Milankovitch Cycles, Biological Pump, Last Glacial Maximum
5 Mar 2018
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Document Summary
When looking at climate graphs, we must be aware of: the timescale, direction of time axis, amplitude of change, rate of change, what region is represented. Climate proxy: sources of climate information from natural archives such as tree rings, ice cores, corals, lake and ocean sediments; using climate proxies is dependent on: preservation of proxy, chronology, signal, resolution, timescale. The earth is either in an icehouse or hothouse phase. Icehouse phase: cold period; ice sheets are on earth. Hothouse: war(cid:373) period; (cid:374)o i(cid:272)e sheets are prese(cid:374)t; (cid:373)ost of earth"s history. An ice age is a time when ice sheets are present on earth. The current ice age (quaternary glaciation) began 2. 58 mya and is still occurring. Air bubbles trapped in the ice can be measured and dated. Volcanic ash in the ice core indicates volcanic eruptions. Isotopes of ice: melt layers show summer warmth, dust, pollen, sulphates.
