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House, Martha A; Rea, David K; Janecek, Thomas R (1991): Grain size record of Oligocene to Pleistocene sediments from Broken Ridge [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.759769, Supplement to: House, MA et al. (1991): Grain-size record of ocean current winnowing in Oligocene to Pleistocene ooze, Broken Ridge, southeastern Indian Ocean. In: Weissel, J; Peirce, J; Taylor, E; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 121, 211-218, https://doi.org/10.2973/odp.proc.sr.121.133.1991

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Abstract:
At Ocean Drilling Program Sites 752 and 754, located on Broken Ridge in the eastern Indian Ocean, we recovered a sequence of shallow-water pelagic sediments that span the past 90 m.y. The Oligocene to Pleistocene portion of these sediments are unconsolidated carbonate oozes that display a coherent variation in bulk grain size. We believe these sediments to be winnowed, and suggest that their grain size is a measure of that winnowing energy. The largest increase in grain size, interpreted to represent an enhancement in the energy of ocean currents, occurs in the earliest late Miocene. This increase occurs about 20 m upcore from the oxygen isotope indication of ice-volume increase about 13 Ma, and is about 3 m.y. younger. If this distinct temporal separation between proxy indicators of ice volume and of current intensity observed in the Broken Ridge cores is correct, the general impression of paleoclimatologists that the planetary temperature gradient and therefore atmospheric and oceanic circulation intensity varies directly with ice volume needs to be reconsidered.
Project(s):
Ocean Drilling Program (ODP)
Coverage:
Median Latitude: -30.916000 * Median Longitude: 93.572250 * South-bound Latitude: -30.941000 * West-bound Longitude: 93.566500 * North-bound Latitude: -30.891000 * East-bound Longitude: 93.578000
Date/Time Start: 1988-05-10T03:15:00 * Date/Time End: 1988-05-15T05:15:00
Event(s):
121-752A * Latitude: -30.891000 * Longitude: 93.578000 * Date/Time Start: 1988-05-10T03:15:00 * Date/Time End: 1988-05-12T13:55:00 * Elevation: -1097.0 m * Penetration: 317.6 m * Recovery: 217.32 m * Location: South Indian Ridge, South Indian Ocean * Campaign: Leg121 * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 34 cores; 317.6 m cored; 0 m drilled; 68.4 % recovery
121-754A * Latitude: -30.941000 * Longitude: 93.566500 * Date/Time Start: 1988-05-13T18:30:00 * Date/Time End: 1988-05-15T05:15:00 * Elevation: -1075.0 m * Penetration: 172.1 m * Recovery: 128.27 m * Location: South Indian Ridge, South Indian Ocean * Campaign: Leg121 * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 23 cores; 170 m cored; 0 m drilled; 75.5 % recovery
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
2 datasets

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Datasets listed in this publication series

  1. House, MA; Rea, DK; Janecek, TR (1991): (Table 1) Grain-size distribution in ODP Hole 121-752A. https://doi.org/10.1594/PANGAEA.759767
  2. House, MA; Rea, DK; Janecek, TR (1991): (Table 2) Grain-size distribution in ODP Hole 121-754A. https://doi.org/10.1594/PANGAEA.759768