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Luigi Jovane 1,2 , Kenneth L. Verosub 1 , Fabio Florindo 2 and Gary Acton 1

First Evidence for Milankovitch Forcing of Antarctic Climate in the Ross Sea Sector during the Quaternary. Luigi Jovane 1,2 , Kenneth L. Verosub 1 , Fabio Florindo 2 and Gary Acton 1 1 Geology Department, University of California, Davis, USA

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Luigi Jovane 1,2 , Kenneth L. Verosub 1 , Fabio Florindo 2 and Gary Acton 1

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  1. First Evidence for Milankovitch Forcing of Antarctic Climate in the Ross Sea Sector during the Quaternary Luigi Jovane1,2, Kenneth L. Verosub1, Fabio Florindo2 and Gary Acton1 1Geology Department, University of California, Davis, USA 2Istituto Nazionale di Geofisica e Vulcanologia, Roma, Italy

  2. New Paleomagnetic Studies of Old Cores from the Ross Sea Sector USNS Eltanin (1960s) USCGC Glacier (1970s) R/V Polar Duke (1980s) Nathaniel B. Palmer (1990-present) Glomar Challenger (DSDP Leg 28)

  3. Eltanin Cruise 27 Core 21 (1968) Water Depth 3456 meters Length 16 m First studied by Jim Kennett & Norm Watkins

  4. Eltanin 27-21 Ross Sea Ross Ice Shelf 682 samples in plastic boxes Sampling Site Cape Adare Victoria Land

  5. Ross Sea with other coring sites

  6. Zijderveld Plots Eltanin 27-21

  7. Eltanin 27-21 Paleomagnetic record 682 samples

  8. Correlation of Elt-27-21 with MPTS

  9. Eltanin 27-21 ODP Site 1101

  10. Tangent Cylinder Hypothesis

  11. Environmental Magnetic Parameters

  12. Mid-Pleistocene Transition “100 kyr world” “40 kyr world” Environmental Magnetic Parameters

  13. 19 28 31 35 63 74 81 MIS Stage MIS Stages at Magnetic Boundaries

  14. This suggests, but does not prove, that the peaks in environmental magnetic record represent interglacial periods. And is consistent with ARM/IRM data because higher values of ARM/IRM are usually interpreted as finer magnetic grains.

  15. Sediment versus Magnetic Grain Sizes

  16. Output of Laser Granulometer

  17. Environmental Magnetic Parameters

  18. Normalized NRM Intensity

  19. SINT-800 Global Paleointensity Stack

  20. Because we have a • a magnetostratigraphic record • an orbital parameter record • a paleointensity record Eltanin 27-21 could be the Rosetta Stone for other studies of old cores from the Ross Sea sector.

  21. CONCLUSIONS Environmental magnetic data from 40-year old Eltanin core 27-17 clearly show that paleoclimatic processes were dominated by ~40 kyr cyclicity prior to the mid-Pleistocene transition and by ~100 kyr cyclicity afterward. We don’t fully understand the nature of the signal but our working hypothesis is that peaks in the environmental magnetic record correspond to interglacials. (For funding agencies.) If a 40-year old core can still produce exciting science so can a scientist after a 40-year career. So don’t throw out your old cores or your old scientists.

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