noaa-ocean-24090 Biogenic Silica Data from the Indian Ocean sector of the Southern Ocean during the mid-Pleistocene climate transition Billups, K.; York, K.; Bradtmiller, L.I. Biogenic Silica Data from the Indian Ocean sector of the Southern Ocean during the mid-Pleistocene climate transition 2018-05-16 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/24090 Investigator K. Billups Investigator K. York Investigator L.I. Bradtmiller earth science paleoclimate paleoceanography depth,null,null,meter,null,paleoceanography,null,null,N,below sea floor earth science paleoclimate paleoceanography age,null,null,million years ago,null,paleoceanography,null,null,N,based on magnetostratigraphy using the ages of Ogg et al. (2012) earth science paleoclimate paleoceanography depth at sample end,null,null,centimeter,null,paleoceanography,null,null,N,depth at bottom of core section earth science paleoclimate paleoceanography sample identification,null,null,null,null,paleoceanography,null,null,C,core earth science paleoclimate paleoceanography sample identification,null,null,null,null,paleoceanography,null,null,N,section earth science paleoclimate paleoceanography sample identification,null,null,null,null,paleoceanography,null,null,C,hole earth science paleoclimate paleoceanography age,null,null,million years ago,null,paleoceanography,null,null,N,based on tuning of the biogenic silica to the d18O stack of Lisiecki and Raymo (2005) earth science paleoclimate paleoceanography biogenic silica,sediment,null,percent,null,paleoceanography,null,spectrophotometry,N,null earth science paleoclimate paleoceanography depth at sample start,null,null,centimeter,null,paleoceanography,null,null,N,depth at top of core section earth science paleoclimate paleoceanography sample identification,null,null,null,null,paleoceanography,null,null,N,site earth science paleoclimate paleocean geochemistry geoscientificInformation 1093000 cal yr BP 643000 cal yr BP Complete -59.616667 -59.616667 86.866667 86.866667 -4802 -4802 Ocean Indian Ocean ODP 745B>LATITUDE -59.616667>LONGITUDE 86.866667 None Please cite original publication, online resource, dataset and publication DOIs (where available), and date accessed when using downloaded data. If there is no publication information, please cite investigator, title, online resource, and date accessed. The appearance of external links associated with a dataset does not constitute endorsement by the Department of Commerce/National Oceanic and Atmospheric Administration of external Web sites or the information, products or services contained therein. For other than authorized activities, the Department of Commerce/NOAA does not exercise any editorial control over the information you may find at these locations. These links are provided consistent with the stated purpose of this Department of Commerce/NOAA Web site. English DOC/NOAA/NESDIS/NCEI National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce https://www.ncdc.noaa.gov/data-access/paleoclimatology-data DATA Center Contact Bruce Bauer bruce.a.bauer@noaa.gov paleo@noaa.gov 303-497-6280 303-497-6513

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Boulder CO 80305-3328 USA online ASCII Billups, K., K. York, and L.I. Bradtmiller 2018 Paleoceanography and Paleoclimatology 33 10.1029/2018PA003327

We use biogenic silica (opal) mass accumulating rates (MARs) at Ocean Drilling Program Site 745B to infer upwelling, and by extension upper water column stratification, on glacial to interglacial time scales during the mid-Pleistocene climate transition (MPT; 1.2–0.6 Ma). Distinct variations in the percent biogenic silica content of the sediments parallel the global benthic foraminiferal d18O stack affording the derivation of an orbital-scale age model. Opal MARs confirm that silica production/preservation was indeed at a minimum at each of the glacial maxima during the entire MPT consistent with the late Pleistocene model that links upwelling of dissolved silica with water column stratification. A unique relationship between opal MARs and benthic foraminiferal d13C values in the South Atlantic suggests that during the midpoint of the MPT stratification may also be causally related to deep water circulation. However, there is no evidence that cooling during the MPT and the evolution of the 100 kyr climate cycle are linked to changes in water column stratification. Terrigenous sediment MARs, on the other hand, which can be inferred from the proportion of biogenic silica in the sediments at this particular site, provide evidence for increased glacial activity on Antarctica beginning with the onset of the MPT and culminating in a maximum during its midpoint (Marine Isotope Stage 22, 0.9 Ma). Thereafter, glacial activity decreases and we speculate that the evolution of the 100 kyr cycle is associated with a thickening ice sheet after reaching maximum extent somewhat analogous to the processes proposed for Northern Hemisphere ice sheets.

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/billups2018/billups2018-745b.txt NOAA Template File; ODP 745B Biogenic Silica Data USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11