North Atlantic (DSDP 607) Geochemistry Data and BWT Reconstruction during the Mid-Pleistocene Transition Ford, H.L.; Sosdian, S.M.; Rosenthal, Y.; Raymo, M.E. Ford, H.L. Sosdian, S.M. Rosenthal, Y. Raymo, M.E. earth science/paleoclimate/paleoceanography (depth,null,null,meter,null,paleoceanography,composited,null,N,null) earth science/paleoclimate/paleoceanography (delta 18O,benthic foraminifer,null,per mil PDB,null,paleoceanography,corrected,null,N,adjusted to Uvigerina sp. comparable values) earth science/paleoclimate/paleoceanography (titanium/calcium,Uvigerina sp.,null,micromole per mole,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (notes,null,null,null,null,paleoceanography,null,null,C,null) earth science/paleoclimate/paleoceanography (age,null,null,calendar kiloyear before present,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (iron/calcium,Uvigerina sp.,null,micromole per mole,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (sample identification,null,null,null,null,paleoceanography,null,null,C,null) earth science/paleoclimate/paleoceanography (aluminum/calcium,Uvigerina sp.,null,micromole per mole,null,paleoceanography,null,null,N,null) earth science/paleoclimate/climate reconstructions|paleoceanography (sea water temperature,magnesium/calcium,null,degree Celsius,null,climate reconstructions|paleoceanography,null,null,N,deepwater temperature using Uvigerina spp.) earth science/paleoclimate/climate reconstructions|paleoceanography (delta 18O,delta 18O|magnesium/calcium|sea water,null,per mil SMOW,null,climate reconstructions|paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (magnesium/calcium,Uvigerina sp.,null,millimole per mole,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (manganese/calcium,Uvigerina sp.,null,micromole per mole,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleocean earth science/paleoclimate/paleocean earth science/paleoclimate/paleocean (DSDP 607>LATITUDE 41.000019>LONGITUDE -32.950122) During the Mid-Pleistocene Transition (MPT), the dominant glacial-interglacial cyclicity as inferred from the marine d18O records of benthic foraminifera (d18Obenthic) changed from 41 kyr to 100 kyr years in the absence of a comparable change in orbital forcing. Currently, only two Mg/Ca-derived, high-resolution bottom water temperature (BWT) records exist that can be used with d18Obenthic records to separate temperature and ice volume signals over the Pleistocene. However, these two BWT records suggest a different pattern of climate change occurred over the MPTda record from North Atlantic DSDP Site 607 suggests BWT decreased with no long-term trend in ice volume over the MPT, while South Pacific ODP Site 1123 suggests that BWT has been relatively stable over the last 1.5 Myr but that there was an abrupt increase in ice volume at ~900 kyr. In this paper we attempt to reconcile these two views of climate change across the MPT. Specifically, we investigated the suggestion that the secular BWT trend obtained from Mg/Ca measurements on Cibicidoides wuellerstorfi and Oridorsalis umbonatus species from N. Atlantic Site 607 is biased by the possible influence of D[CO3 2_] on Mg/Ca values in these species by generating a low-resolution BWT record using Uvigerina spp., a genus whose Mg/Ca values are not thought to be influenced by D[CO3 2_]. We find a long-term BWT cooling of ~2e3_C occurred from 1500 to ~500 kyr in the N. Atlantic, consistent with the previously generated C. wuellerstorfi and O. umbonatus BWT record. We also find that changes in ocean circulation likely influenced d18Obenthic, BWT, and d18Oseawater records across the MPT. N. Atlantic BWT cooling starting at ~1.2 Ma, presumably driven by high-latitude cooling, may have been a necessary precursor to a threshold response in climate-ice sheet behavior at ~900 ka. At that point, a modest increase in ice volume and thermohaline reorganization may have caused enhanced sensitivity to the 100 kyr orbital cycle. STUDY NOTES: DSDP 607 minor element and derived d18Oseawater records from Uvigerina spp. Provided Keywords: Mid-Pleistocene Transition, Mg/Ca, Uvigerina spp. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Ford, H.L. Investigator : Sosdian, S.M. Investigator : Rosenthal, Y. Investigator : Raymo, M.E. 2016-08-24 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/20439 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/ford2016/ford2016.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/ford2016/ford2016.txt English https://www.ncdc.noaa.gov/paleo/study/20439 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/ford2016/ford2016.txt Ford, H.L., S.M. Sosdian, Y. Rosenthal, and M.E. Raymo2016Gradual and abrupt changes during the Mid-Pleistocene TransitionQuaternary Science Reviews148222-23310.1016/j.quascirev.2016.07.005 START YEAR: 1500000 cal yr BP * END YEAR: 500000 cal yr BP -32.950122 41.000019 -32.950122 41.000019