15. Data Report: Bulk Sediment Parameters (CaCO3, TOC, and >63m) of Sites 1095, 1096, and 1101, and Coarse-Fraction Analysis of Site 1095 (ODP Leg 178, Western Antarctic Peninsula)1

Thomas C.W. Wolf-Welling,2 Tobias Moerz,3
Claus-Dieter Hillenbrand,4 Carol J. Pudsey,5 and Ellen A. Cowan6


The area west of the Antarctic Peninsula is a key region for studying and understanding the history of glaciation in the southern high latitudes during the Neogene with respect to variations of the western Antarctic continental ice sheet, variable sea-ice cover, induced eustatic sea level change, as well as consequences for the global climatic system (Barker, Camerlenghi, Acton, et al., 1999). Sites 1095, 1096, and 1101 were drilled on sediment drifts forming the continental rise to examine the nature and composition of sediments deposited under the influence of the Antarctic Peninsula ice sheet, which has repeatedly advanced to the shelf edge and subsequently released glacially eroded material on the continental shelf and slope (Barker et al., 1999). Mass gravity processes on the slope are responsible for downslope sediment transport by turbidity currents within a channel system between the drifts. Furthermore, bottom currents redistribute the sediments, which leads to final build up of drift bodies (Rebesco et al., 1998). The high-resolution sedimentary sequences on the continental rise can be used to document the variability of continental glaciation and, therefore, allow us to assess the main factors that control the sediment transport and the depositional processes during glaciation periods and their relationship to glacio-eustatic sea level changes.

Site 1095 lies in 3840 m of water in a distal position on the northwestern lower flank of Drift 7, whereas Site 1096 lies in 3152 m of water in a more proximal position within Drift 7. Site 1101 is located at 3509 m water depth on the northwestern flank of Drift 4. All three sites have high sedimentation rates. The oldest sediments were recovered at Site 1095 (late Miocene; 9.7 Ma), whereas sediments of Pliocene age were recovered at Site 1096 (4.7 Ma) and at Site 1101 (3.5 Ma).

The purpose of this work is to provide a data set of bulk sediment parameters such as CaCO3, total organic carbon (TOC), and coarse-fraction mass percentage (>63 m) measured on the sediments collected from the continental rise of the western Antarctic Peninsula (Holes 1095A, 1095B, 1096A, 1096B, 1096C, and 1101A). This information can be used to understand the complex depositional processes and their implication for variations in the climatic system of the western Pacific Antarctic margin since 9.7 Ma (late Miocene). Coarse-fraction particles (125-500 m) from the late Pliocene and Pleistocene (4.0 Ma to recent) sediments recovered from Hole 1095A were microscopically analyzed to gather more detailed information about their variability and composition through time. These data can yield information about changes in potential source regions of the glacially eroded material that has been transported during repeated periods of ice-sheet movements on the shelf.

1Wolf-Welling, T.C.W., Moerz, T., Hillenbrand, C.-D., Pudsey, C.J., and Cowan, E.A., 2001. Data report: Bulk sediment parameters (CaCO3, TOC, and >63 m) of Sites 1095, 1096, and 1101, and coarse-fraction analysis of Site 1095 (ODP Leg 178, western Antarctic Peninsula). In Barker, P.F., Camerlenghi, A., Acton, G.D., and Ramsay, A.T.S. (Eds.), Proc. ODP, Sci. Results, 178 [Online]. Available from World Wide Web: <http://www-odp.tamu.edu/publications/178_SR/chap_15/chap_15.htm>. [Cited YYYY-MM-DD]

2Christian Albrechts University Kiel, Institute for Geosciences, Olshausenstrasse 40, D-24118 Kiel, Federal Republic of Germany. twolf@geomar.de

3GEOMAR Research Center for Marine Geosciences, Wischhofstrasse 1-3, C4, 24148 Kiel, Federal Republic of Germany.

4Alfred Wegener Institute for Polar and Marine Research, Columbusstrasse, 27568 Bremerhaven, Federal Republic of Germany.

5British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, United Kingdom.

6Department of Geology, Appalachian State University, Boone NC 28608, USA.

Initial receipt: 11 October 2000
Acceptance: 1 June 2001
Web publication: 24 October 2001
Ms 178SR-223