North Atlantic Globorotalia truncatulinoides Data During the Mid-Pleistocene Kaiser, E.A.; Caldwell, A.; Billups, K. Kaiser, E.A. Caldwell, A. Billups, K. earth science/paleoclimate/paleocean (DSDP 607>LATITUDE 41.000019>LONGITUDE -32.950122) (ODP 1058>LATITUDE 31.69>LONGITUDE -75.43) (DSDP 552A>LATITUDE 56.042667>LONGITUDE -23.231333) (ODP 925B>LATITUDE 4.204133>LONGITUDE -43.48915) We use the coiling direction of planktic foraminifer Globorotalia truncatulinoides from four sites in the North Atlantic Ocean to assess spatial changes in upper-ocean hydrography during the mid-Pleistocene climate transition. Core top sediments indicate that the left-coiling (sinistral) variety dominates regions characterized by a deep permanent thermocline as is characteristic of the subtropical gyre (Ocean Drilling Program Sites 1058 and Deep Sea Drilling Project Site 607) while right-coiling (dextral) tests dominate the tropical (Ocean Drilling Program Site 925) and subpolar site (Deep Sea Drilling Project Site 552). We observe pronounced changes in the dominant coiling direction at the three subtropical to subpolar sites during the first of the more extreme glacial to interglacial transitions of the mid-Pleistocene climate transition, Marine Isotope Stages (MISs) 22 to 21. We interpret these observations to reflect an increase in poleward warm water advection. The time interval between MIS 21 and MIS 15 is marked by a pronounced absence of sinistral tests. Because G. truncatulinoides (sinistral) is a deep dwelling species, their absence may be related to a decrease in dissolved oxygen during warm interglacial intervals. At the tropical site, precessional-scale variations dominate changes in the coiling direction until midpoint interglacial MIS 23. Occurrences in the sinistral variety at this locale must be linked to cross-equatorial water transport in the North Brazil Current, and precessional-scale variations provide evidence for the sensitivity of the tropical regions to precessional forcing, at least until MIS 23 when this morphotype disappears in agreement with observation at other sites in the Atlantic Ocean. STUDY NOTES: Provided Keywords: mid-Pleistocene transition, Globorotalia truncatulinoides, subtropical gyre, subpolar North Atlantic, cross-equatorial heat transport, precession NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Kaiser, E.A. Investigator : Caldwell, A. Investigator : Billups, K. 2019-05-03 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/26711 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/kaiser2019/kaiser2019-dsdp607.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/kaiser2019/kaiser2019-odp925.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/kaiser2019/kaiser2019-dsdp552.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/kaiser2019/kaiser2019-odp1058.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/kaiser2019/kaiser2019-dsdp607.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/kaiser2019/kaiser2019-odp925.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/kaiser2019/kaiser2019-dsdp552.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/kaiser2019/kaiser2019-odp1058.txt English https://www.ncdc.noaa.gov/paleo/study/26711 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/kaiser2019/kaiser2019-dsdp607.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/kaiser2019/kaiser2019-odp925.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/kaiser2019/kaiser2019-dsdp552.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/kaiser2019/kaiser2019-odp1058.txt Kaiser, E.A., Caldwell, A., and Billups, K.2019North Atlantic Upper-Ocean Hydrography During the Mid-Pleistocene Transition Evidenced by Globorotalia truncatulinoides Coiling RatiosPaleoceanography and Paleoclimatology10.1029/2018PA003502 START YEAR: 1220000 cal yr BP * END YEAR: 411000 cal yr BP -75.43 4.204133 -23.231333 56.042667