EPSS Colloquium fall-2015

Although detailed age models exist for some marine sediment core records of the last glacial cycle (0-150 ka), age models for many other cores rely on the stratigraphic correlation of benthic d18O, which records changes in ice volume and deep ocean temperature. The large amount of data available for the last glacial cycle offers the opportunity to significantly improve upon benthic d18O compilations, such as the "LR04" global stack [Lisiecki and Raymo, 2005]. Not only are the age constraints for the LR04 stack now outdated, but a single global alignment target neglects regional differences of several kiloyears in the timing of benthic d18O change during glacial terminations. Here we present regional stacks that characterize mean benthic d18O change for eight ocean regions and a volume-weighted global stack of data from 263 cores. Age models for these stacks are based on radiocarbon data from 0-40 ka, correlation to a layer-counted Greenland ice from 40-56 ka, and correlation to radiometrically dated speleothems from 56-150 ka. These regional stacks offer better stratigraphic alignment targets than the LR04 global stack and, furthermore, suggest that the LR04 stack is biased 1-2.5 kyr too old throughout the Pleistocene. Finally, we compare global and regional benthic d18O responses with records of sea level and climate change over the last glacial cycle.