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Orbital and CO 2 forcing of late Paleozoic continental ice sheets
Author(s) -
Horton Daniel E.,
Poulsen Christopher J.,
Pollard David
Publication year - 2007
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2007gl031188
Subject(s) - paleozoic , geology , orbital forcing , ice sheet , gondwana , paleontology , ice age , cryosphere , climatology , sea ice , geomorphology , structural basin , glacial period
Contrasting views of the size, duration, and history of the Gondwanan continental ice sheets have been proposed from late Paleozoic glaciological and sedimentological evidence. To evaluate these differing views, a coupled ice sheet‐climate model is used to simulate continental ice sheets under a wide range of late Paleozoic orbital and pCO 2 conditions. The model experiments indicate that orbital variations at pCO 2 concentrations below 2X pre‐industrial atmospheric levels (PAL; 280 ppm) produce large changes in late Paleozoic ice volume (∼1.3 × 10 8 km 3 ) and sea level (∼20 to 245 m). Between 2 and 8X PAL Gondwana continental ice is simulated only under the most extreme Southern Hemisphere cold summer orbit, but still produces significant ice volumes (∼8–12 × 10 7 km 3 ). Our results highlight the important role of atmospheric CO 2 in determining the distribution, volume, and stability of late Paleozoic ice sheets, factors that ultimately impacted sea level, cyclothem deposition, and global climate, and reconcile disparate views of the Late Paleozoic Ice Age.