Wilkes Land Paleogene - a cyclostratigraphic approach
Zusammenfassung der Projektergebnisse
IODP Expedition 318 acquired an important early Paleogene record in the high latitudes that are still characterized by scarcity of field data. The retrieval of Hole U1356A sediments, although in a single hole and with only low to moderate core recovery and therefore at times more bumpy than straight research progress, provided the opportunity to contribute to improved understanding of the stability of Paleogene climate at high latitudes by carefully analyzing early Eocene and Oligocene sediments. The main scientific objective of the project was to investigate the presence and nature of sedimentary cycles and their relation to orbital forcing. Site U1356 is located at the transition between the continental rise and the abyssal plain. The moderately to strongly bioturbated claystones and calcareous claystones of Eocene and Oligocene age characterize a typical hemipelagic sedimentation with variable bottom current and gravity flow influence. The Paleogene section is characterized by a superb magnetostratigraphy and also got a robust biostratigraphic age control (dinocysts/pollen/partly calcareous nannofossils). Data and resulting implications of the project are part of several publications: the compilation of the initial chronostratigraphic framework was the necessity for all following and more detailed investigations. The identification of 100 kyr cycles validates that the early Eocene sediments of this Antarctic margin are indeed influenced by orbital forcing, provided a robust estimate on their detailed age – the early Eocene record starts at 53.6 Ma and is about 1.3 Myr long, and for the first time identified hyperthermal layers H2, I1, I2, and J in the high southern latitudes. Here, palynological and geochemical proxies yield seasonal temperature reconstructions for the early Eocene greenhouse world. XRF core scanning based records of chemical alteration, clay mineralogy and distribution of dinocysts indicate a prominent weathering regime turnover in the context of the earliest Oligocene cooling, ice-sheet expansion, and subsequent sea-ice formation. The geochemical composition of the siliciclastic sediments assisted in extracting a precipitation and temperature record for the Eocene through mid-Miocene. 3D-images from CT scanning provide detailed information on the development of the Antarctic margin at Wilkes Land through high-resolution evidence for ice-rafting. Although potential ties between Hole U1356A and ODP Site 1218 exist, the detailed integration to Leg 199 and 189 sites for the Oligocene interval is still work in progress. The reasons are manifold: initially the (early) Eocene interval of Hole U1356A was in focus of all Exp. 318 Paleogene studies, no nannoplankton expert was invited to sail on the expedition resulting into to incomplete definition of biozones, and the core recovery gaps in this single hole did not allow retrieving a complete record from the beginning, as the more than 400-m long Oligocene section is quite elaborative for acquiring a variety of proxies other than non-destructive core scanning. However, recently new strategies were agreed on to now focus on two shorter intervals with moderate recovery and pronounced cyclicity where several investigators will contribute to acquire a suite of parameters incl. palynology, geochemistry, clay mineralogy, and grain size.
Projektbezogene Publikationen (Auswahl)
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(2012) Chronostratigraphic framework for the IODP Expedition 318 cores from the Wilkes Land Margin: Constraints for paleoceanographic reconstruction. Paleoceanography, 27. PA2214
Tauxe, L, Stickley, CE, Sugisaki, S, Bijl, PK, Bohaty, SM, Brinkhuis, H, Escutia, C, Flores, JA, Houben, AJP, Iwai, M, Jiménez-Espejo, FJ, McKay, R, Passchier, S, Pross, J, Riesselman, C, Röhl, U, Sangiorgi, F, Welsh, K, Klaus, A, Fehr, A, Bendle, JA, Dunbar, R, Gonzales, J, Hayden, T, Katsuki, K, Olney, MP, Pekar, SF, Shrivastva, PK, van de Flierdt, T, Williams, T and Yamane, M
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(2012) Persistent near-tropical warmth on the Antarctic continent during the early Eocene epoch. Nature, 488(7409), 73-77
Pross, J, Contreras, L, Bijl, PK, Greenwood, DR, Bohaty, SM, Schouten, S, Bendle, JA, Röhl, U, Tauxe, L, Raine, JI, Huck, CE, van de Flierdt, T, Jamieson, SSR, Stickley, CE, van de Schootbrugge, B, Escutia, C, Brinkhuis, H and IODP Expedition 318 Scientists
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(2013) Dynamic behaviour of the East Antarctic ice sheet during Pliocene warmth. Nature Geoscience, 6. 765-769
Cook, CP, van de Flierdt, T, Williams, T, Hemming, SR, Iwai, M, Kobayashi, M, Jiménez-Espejo, FJ, Escutia, C, González, JJ, Khim, BK, McKay, RM, Passchier, S, Bohaty, SM, Riesselman, CR, Tauxe, L, Sugisaki, S, Galindo, AL, Patterson, MO, Sangiorgi, F, Pierce, EL, Brinkhuis, H, Klaus, A, Fehr, A, Bendle, JAP, Bijl, PK, Carr, SA, Dunbar, RB, Flores, JA, Hayden, TG, Katsuki, K, Kong, GS, Nakai, M, Olney, MP, Pekar, SF, Pross, J, Röhl, U, Sakai, T, Shrivastava, PK, Stickley, CE, Tuo, S, Welsh, K and Yamane, M
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(2013) Early Eocene to middle Miocene cooling and aridification of East Antarctica. Geochemistry Geophysics Geosystems, 14
Passchier, S, Bohaty, SM, Jiménez-Espejo, FJ, Pross, J, Röhl, U, van de Flierdt, T, Escutia, C and Brinkhuis, H
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(2013) Eocene cooling linked to early flow across the Tasmanian Gateway. Proceedings of the National Academy of Sciences of the United States of America, 110(24). 9645-9650
Bijl, PK, Bendle, JA, Bohaty, SM, Pross, J, Schouten, S, Tauxe, L, Stickley, CE, McKay, R, Röhl, U, Olney, M, Sluijs, A, Escutia, C, Brinkhuis, H and Expedition 318 Scientists
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(2013) Relative sea-level rise around East Antarctica during Oligocene glaciation. Nature Geoscience, 6(5). 380-384
Stocchi, P, Escutia, C, Houben, AJP, Vermeesen, BLA, Bijl, PK, Brinkhuis, H, DeConto, RM, Galeotti, S, Passchier, S, Pollard, D, Klaus, A, Fehr, A, Williams, T, Bendle, JA, Bohaty, SM, Carr, SA, Dunbar, RB, Flores, JA, Gonzàlez, JJ, Hayden, TG, Iwai, M, Jiménez-Espejo, FJ, Katsuki, K, Kong, GS, McKay, RM, Nakai, M, Olney, MP, Pekar, SF, Pross, J, Riesselman, C, Röhl, U, Sakai, T, Shrivastava, PK, Stickley, CE, Sugisaki, S, Tauxe, L, Tuo, S, van de Flierdt, T, Welsh, K and Yamane, M
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(2013) Reorganization of Southern Ocean plankton ecosystem at the onset of Antarctic glaciation. Science, 340(6130). 341-344
Houben, AJP, Bijl, PK, Pross, J, Bohaty, SM, Passchier, S, Stickley, CE, Röhl, U, Sugisaki, S, Tauxe, L, van de Flierdt, T, Olney, M, Sangiorgi, F, Sluijs, A, Escutia, C, Brinkhuis, H and Sawyer, DS
