Paper No. 242-6
Presentation Time: 11:15 AM
NEW MAGNETOSTRATIGRAPHIC INSIGHTS FROM ICEBERG ALLEY ON THE RHYTHMS OF ANTARCTIC CLIMATE DURING THE PLIO-PLEISTOCENE (Invited Presentation)
REILLY, Brendan1, TAUXE, Lisa2, BRACHFELD, Stefanie3, HATFIELD, Robert G.4, STONER, Joseph4, RAYMO, Maureen E.5, BAILEY, Ian6, HEMMING, Sidney7, WEBER, Michael E.8, WILLIAMS, Trevor9, GARCIA, Marga10, GUITARD, Michelle11, MARTOS, Yasmina12, PÉREZ, Lara13, ZHENG, Xufeng14, ARMBRECHT, Linda15, CARDILLO, Fabricio16, DU, Zhiheng17, FAUTH, Gerson18, GLUEDER, Anna19, GUTJAHR, Marcus20, HERNANDEZ-ALMEIDA, Ivan21, HOEM, Frida22, HWANG, Ji-Hwan23, IIZUKA, Mutsumi24, KATO, Yuji25, KENLEE, Bridget26, O'CONNELL, Suzanne27, PECK, Victoria L.28, RONGE, Thomas29, SEKI, Osamu30, TRIPATHI, Shubham31 and WARNOCK, Jonathan P.32, (1)Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093-0220, (2)Scripps Institution of Oceanography, La Jolla, CA 92093-0220, (3)Earth and Environmental Studies, Montclair State University, Montclair, NJ 07043, (4)College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, (5)Lamont-Doherty Earth Observatory, Columbia U., 61 ROUTE 9W, Palisades, NY 10964, (6)Camborne School of Mines, University of Exeter, Penryn Campus, Cornwall, TR10 9FE, United Kingdom, (7)Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, (8)Steinmann-Institute, University of Bonn, Poppelsdorfer Schloss, Bonn, 53115, Germany, (9)International Ocean Discovery program, Texas A&M University, College Station, TX 77843, (10)Oceanographic Center of Cadiz, Spanish Institute of Oceanography (IEO), Cádiz, 11006, Spain, (11)College of Marine Science, University of South Florida, St. Petersburg, FL 33701, (12)Department of Astronomy, University of Maryland College Park, College Park, MD 20742, (13)British Antarctic Survey, Cambridge, United Kingdom, (14)Chinese Academy of Sciences, China Sea Institute of Oceanology, 164 West Xingang Road, Guangzhou, 510301, China, (15)Australian Centre for Ancient DNA (ACAD), University of Adelaide, South Australia, Australia, (16)Departamento Oceanografía, Servicio de Hidrografía Naval, Buenos Aires, Argentina, (17)State Key Laboratory of Cryospheric Sciences, Chinese Academy of Sciences, Lanzhou Gansu, China, (18)University of Vale do Rio dos Sinos (UNISINOS), San Leopoldo, Brazil, (19)College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, (20)Helmholtz Centre for Ocean Research Kiel, Christian-Albrechts-University of Kiel, Kiel, Germany, (21)Federal Technical University-Centre, Zurich, Switzerland, (22)Utrecht University, Utrecht, Netherlands, (23)Korea Basic Science Institute, Chungbuk Cheongju, Korea, Republic of (South), (24)Tokyo City University, Tokyo, Japan, (25)Kochi University, Kochi, Japan, (26)Department of Earth Sciences, University of California, Riverside, Riverside, CA 92521, (27)Wesleyan University, 265 Church St, Middletown, CT 06459, (28)British Antarctic Survey, High Cross, Madingley Rd, Cambridge, CB30ET, United Kingdom, (29)Department for Marine Geology, Alfred Wegener Institute, Bremerhaven, Germany, (30)Hokkaido University, Sapporo Hokkaido, Japan, (31)National Centre for Antarctic and Ocean Research (NCAOR), Vasco Da Gama, India, (32)Department of Geoscience, Indiana University of Pennsylvania, Weyandt Hall 137, Indiana, PA 15705
International Ocean Discovery Program (IODP) Expedition 382 in the Scotia Sea’s “Iceberg Alley” recovered among the most continuous and highest resolution stratigraphic records in the Southern Ocean near Antarctica spanning the last 3.3 Myr. Sites drilled in Dove Basin (U1536/U1537) have well-resolved magnetostratigraphy and a strong imprint of orbital forcing in their lithostratigraphy. All magnetic reversals of the last 3.3 Myr are identified, providing a robust age model independent of orbital tuning. In this presentation, we discuss the alternation of warmer (diatom-rich) versus cooler (silty clays) Dove Basin lithologies in comparison to the LR04 benthic δ18O stack using an ensemble of possible age models constrained by the magnetic reversals. To account for limitation in the age model resolution, we begin by comparing the amplitude modulation of the eccentricity, obliquity, and precession frequency bands for different age-depth model possibilities. Then we compare the position of the magnetic reversals relative to local facies changes in Dove Basin and the same magnetic reversals relative to benthic δ18O at North Atlantic IODP Site U1308. Finally, to establish a higher resolution age model in the latest Pliocene and early Pleistocene, we explore the possibility of interhemispheric stratigraphic correlation between North Atlantic IODP sites and Dove Basin using Relative Paleointensity (RPI). We demonstrate Dove Basin facies change at different times than benthic δ18O during intervals between ~3-1 Ma. These differences are consistent with precession phase shifts and suggests climate signals with a Southern Hemisphere summer insolation phase were recorded around Antarctica. If Dove Basin lithology reflects local Antarctic ice volume changes, these signals could represent ice sheet precession variations not captured in benthic δ18O during the 41-kyr world.
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