Plio-Pleistocene Ice Volume, Antarctic Climate, and the Global 18O Record

M. E. Raymo
2006 Science  
We propose that from È3 to 1 million years ago, ice volume changes occurred in both the Northern and Southern Hemispheres, each controlled by local summer insolation. Because Earth's orbital precession is out of phase between hemispheres, 23,000-year changes in ice volume in each hemisphere cancel out in globally integrated proxies such as ocean d 18 O or sea level, leaving the in-phase obliquity (41,000 years) component of insolation to dominate those records. Only a modest ice mass change in
more » ... ntarctica is required to effectively cancel out a much larger northern ice volume signal. At the mid-Pleistocene transition, we propose that marine-based ice sheet margins replaced terrestrial ice margins around the perimeter of East Antarctica, resulting in a shift to in-phase behavior of northern and southern ice sheets as well as the strengthening of 23,000-year cyclicity in the marine d 18 O record.
doi:10.1126/science.1123296 pmid:16794038 fatcat:wfqj57emufeo3lypsuhg4k7c7i