Grobe, Hannes; Fütterer, Dieter K; Spieß, Volkhard (1990): Sedimentological and paleomagnetic investigations on two gravity cores and ODP sites 113-690 and 693 off Kapp Norvegia, Antarctic continental margin. doi:10.1594/PANGAEA.552177, Supplement to: Grobe, H et al. (1990): Oligocene to Quaternary sedimentation processes on the Antarctic continental margin, ODP Leg 113, Site 693. In: Barker, PF; Kennett, JP; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 113, 121-131, doi:10.2973/odp.proc.sr.113.193.1990
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Oligocene to Quaternary sediments were recovered from the Antarctic continental margin in the eastern Weddell Sea during ODP Leg 113 and Polarstern expedition ANT-VI. Clay mineral composition and grain size distribution patterns are useful for distinguishing sediments that have been transported by ocean currents from those that were ice-rafted. This, in turn, has assisted in providing insights about the changing late Paleogene to Neogene sedimentary environment as the cryosphere developed in Antarctica.
During the middle Oligocene, increasing glacial conditions on the continent are indicated by the presence of glauconite sands, that are interpreted to have formed on the shelf and then transported down the continental slope by advancing glaciers or as a result of sea-level lowering. The dominance of illite and a relatively high content of chlorite suggest predominantly physical weathering conditions on the continent. The high content of biogenic opal from the late Miocene to the late Pliocene resulted from increased upwelling processes at the continental margin due to increased wind strength related to global cooling. Partial melting of the ice-sheet occurred during an early Pliocene climate optimum as is shown by an increasing supply of predominantly current-derived sediment with a low mean grain size and peak values of smectite.
Primary productivity decreased at ~ 3 Ma due to the development of a permanent sea-ice cover close to the continent. Late Pleistocene sediments are characterized by planktonic foraminifers and biogenic opal, concentrated in distinct horizons reflecting climatic cycles. Isotopic analysis of AT. pachyderma produced a stratigraphy which resulted in a calculated sedimentation rate of 1 cm/k.y. during the Pleistocene. Primary productivity was highest during the last three interglacial maxima and decreased during glacial episodes as a result of increasing sea-ice coverage.
Median Latitude: -70.023595 * Median Longitude: -12.039914 * South-bound Latitude: -70.835333 * West-bound Longitude: -14.574400 * North-bound Latitude: -65.161000 * East-bound Longitude: 1.204900
Date/Time Start: 1987-01-20T03:15:00 * Date/Time End: 1988-01-18T13:40:00
113-690B * Latitude: -65.161000 * Longitude: 1.204900 * Date/Time Start: 1987-01-20T03:15:00 * Date/Time End: 1987-01-21T07:00:00 * Elevation: -2925.0 m * Penetration: 213.4 m * Recovery: 214.75 m * Location: South Atlantic Ocean * Campaign: Leg113 * Basis: Joides Resolution * Device: Drilling/drill rig (DRILL) * Comment: 25 cores; 213.4 m cored; 0 m drilled; 100.6 % recovery
113-693B * Latitude: -70.832000 * Longitude: -14.574400 * Date/Time Start: 1987-02-05T03:15:00 * Date/Time End: 1987-02-07T21:00:00 * Elevation: -2371.0 m * Penetration: 401.2 m * Recovery: 92.16 m * Location: Weddell Sea * Campaign: Leg113 * Basis: Joides Resolution * Device: Drilling/drill rig (DRILL) * Comment: 18 cores; 167.4 m cored; 0 m drilled; 55.1 % recovery
PS1481-3 (PS10/694) * Latitude: -70.835330 * Longitude: -13.927000 * Date/Time: 1987-01-26T12:57:00 * Elevation: -2505.0 m * Penetration: 12 m * Recovery: 10.76 m * Location: Kapp Norvegia * Campaign: ANT-V/4 (PS10) * Basis: Polarstern * Device: Gravity corer (Kiel type) (SL) * Comment: 11 core sections: 0-0.8, 0.8-1.8, 1.8-2.8, 2.8-3.8, 3.8-4.8, 4.8-5.8, 5.8-6.8, 6.8-7.8, 7.8-8.8, 8.8-9.8, 9.8-10.76 m