古第三紀における気候変動 : 近年の研究動向

概要

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Climatic and environmental changes through the Paleogene are characterized by some unusual sedimentological and astronomical events. LPTM (Latest Paleocene Thermal Maximum) event is thought to have been produced by an abrupt dissociation of marine sedimentary hydrates along ocean mareins. The abrupt warming that took place 55.5 Ma is one of the pronounced climatic events in the geohistory. Sudden climate cooling event at the Eocene-01igocene boundary might have been caused by multiple or continuous impacts of extraterretrial materials. EXtraordinarily warm climate during the Eocene may have been brought by either vigorous erosion and oxidation of organic carbons exhumed from the early Himalayan orogeny, or by voluminous metamorohic C0_2 degassing due to the regional metaraorphism. Although the first two events (LPTM and E-O boundary event) certainly affected some environmental changes during each geologic time, a longer-term effect of global plate tectonics, particularly the Himalayan orogeny, is of paramount causal importance throughout the Paleogene. I summarize these views of cause and effect for circumstantial changes on the earth surface and duiscuss about them.
静岡大学の論文