Holmes, Mary Anne (1992): Mineralogy of southern Kerguelen Plateau sediments [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.758558, Supplement to: Holmes, MA (1992): Cretaceous subtropical weathering followed by cooling at 60°S latitude: the mineral composition of southern Kerguelen Plateau sediment, Leg 120. In: Wise, SW; Schlich, R; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 120, 99-111, https://doi.org/10.2973/odp.proc.sr.120.140.1992
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Abstract:
Kaolinite, goethite, minor hematite, and gibbsite were found in fluvial upper Lower Cretaceous basal sediment from the Southern Kerguelen Plateau, Sites 748 and 750, 55°S latitude. This mineral assemblage, derived from the weathering of basalt, indicates near-tropical weathering conditions with high orographic rainfall, at least 100 cm per year. The climate deteriorated by the Turonian or Coniacian, as indicated by the decline in kaolinite content of this sediment.
The Upper Cretaceous sediment at Site 748 consists of 200 m of millimeter-laminated, sparsely fossiliferous, wood-bearing glauconitic siltstone and clay stone with siderite concretions deposited on a shelf below wave base. Some graded and cross beds indicate that storms swept over the shelf and reworked the sediment. Overlying this unit is 300 m of intermittently partly silicified, bryozoan-inoceramid-echinoderm-rich glauconitic packstones, grainstones, and wackestones. The dominant clay mineral in both units is identical to the mineral composition of the glauconite pellets: randomly interstratified smectite-mica. The clay fraction has a higher percent of expandable layers than the mineral of the glauconite pellets, and the clay of the underlying subunit has a higher percentage of expandable layers than the clay of the carbonate subunit. Potassium levels mirror these mineral variations, with higher K levels in minerals that have a lower percentage of expandable layers. The decrease in expandability of the mineral in the upper subunit is attributed to diagenesis, the result of higher porosity.
Project(s):
Ocean Drilling Program (ODP)
Coverage:
Median Latitude: -58.016500 * Median Longitude: 80.118800 * South-bound Latitude: -58.441000 * West-bound Longitude: 78.998100 * North-bound Latitude: -57.592000 * East-bound Longitude: 81.239500
Date/Time Start: 1988-03-15T11:00:00 * Date/Time End: 1988-04-23T04:00:00
Event(s):
120-748C * Latitude: -58.441000 * Longitude: 78.998100 * Date/Time Start: 1988-03-15T11:00:00 * Date/Time End: 1988-03-23T22:54:00 * Elevation: -1301.0 m * Penetration: 935 m * Recovery: 185.88 m * Location: South Indian Ridge, South Indian Ocean * Campaign: Leg120 * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 87 cores; 760 m cored; 0 m drilled; 24.5 % recovery
120-750B * Latitude: -57.592000 * Longitude: 81.239500 * Date/Time Start: 1988-04-20T05:00:00 * Date/Time End: 1988-04-23T04:00:00 * Elevation: -2041.0 m * Penetration: 709.7 m * Recovery: 24.6 m * Location: South Indian Ridge, South Indian Ocean * Campaign: Leg120 * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 6 cores; 57.4 m cored; 0 m drilled; 42.9 % recovery
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
2 datasets
Download Data
Datasets listed in this publication series
- Holmes, MA (1992): (Table 1) Chemical composition of the fine clay fraction of ODP Hole 120-748C. https://doi.org/10.1594/PANGAEA.758554
- Holmes, MA (1992): (Table 2) Mineral composition of ODP Hole 120-750B samples. https://doi.org/10.1594/PANGAEA.758555