Zinc concentrations in benthic foraminifera reflect seawater chemistryPaleoceanography - Tập 15 Số 3 - Trang 299-306 - 2000
Thomas M. Marchitto, William B Curry, Delia W Oppo
We have measured Zn/Ca ratios in two taxa of Holocene‐aged benthic foraminifera from throughout the world's oceans. Zn/Ca is controlled by bottom water dissolved Zn concentration and, like Cd/Ca and Ba/Ca, by bottom water saturation state with respect to calcite. Measurements on “live‐collected” foraminifera suggest that the saturation effect occurs during growth and is not a postdepositio...... hiện toàn bộ
High‐amplitude variations in North Atlantic sea surface temperature during the early Pliocene warm periodPaleoceanography - Tập 24 Số 2 - 2009
K. T. Lawrence, Timothy D. Herbert, Catherine Brown, Maureen E. Raymo, Alan M. Haywood
We provide the first continuous, orbital‐resolution sea surface temperature (SST) record from the high‐latitude North Atlantic, a region critical to understanding the origin of the Plio‐Pleistocene ice ages and proximal to regions that became frequently glaciated after ∼2.7 Ma. We analyzed sediments from Ocean Drilling Program Site 982 over the last 4 Ma for their alkenone unsaturation ind...... hiện toàn bộ
The 41 kyr world: Milankovitch's other unsolved mysteryPaleoceanography - Tập 18 Số 1 - 2003
Maureen E. Raymo, Kerim H. Nisancioglu
For most of the Northern Hemisphere Ice Ages, from ∼3.0 to 0.8 m.y., global ice volume varied predominantly at the 41,000 year period of Earth's orbital obliquity. However, summer (or summer caloric half year) insolation at high latitudes, which is widely believed to be the major influence on high‐latitude climate and ice volume, is dominated by the 23,000 year precessional period. Thus th...... hiện toàn bộ
Role of tropics in changing the response to Milankovich forcing some three million years agoPaleoceanography - Tập 18 Số 2 - 2003
S. George Philander, Alexey V. Fedorov
Throughout the Cenozoic the Earth experienced global cooling that led to the appearance of continental glaciers in high northern latitudes around 3 Ma ago. At approximately the same time, cold surface waters first appeared in regions that today have intense oceanic upwelling: the eastern equatorial Pacific and the coastal zones of southwestern Africa and California. There was furthermore a...... hiện toàn bộ
The timing of major climate terminationsPaleoceanography - Tập 12 Số 4 - Trang 577-585 - 1997
Maureen E. Raymo
A simple, untuned “constant sedimentation rate” timescale developed using three radiometric age constraints and eleven δ18O records longer than 0.8 Myr provides strong support for the validity of the SPECMAP timescale of the late Quaternary [Imbrie et al., 1984]. In particular, the present study independently confirms the link between major d...... hiện toàn bộ
A core top assessment of proxies for the ocean carbonate system in surface‐dwelling foraminifersPaleoceanography - Tập 22 Số 3 - 2007
Yunyan Ni, Gavin L. Foster, T. R. Bailey, Tim Elliott, Daniela N. Schmidt, Paul N. Pearson, Brian A. Haley, Christopher D. Coath
We have assessed the reliability of several foraminifer‐hosted proxies of the ocean carbonate system (δ11B, B/Ca, and U/Ca) using Holocene samples from the Atlantic and Pacific oceans. We examined chemical variability over a range of test sizes for two surface‐dwelling foraminifers (Globigerinoides sacculifer and ... hiện toàn bộ