Upper cretaceous and paleogene sediments from the Northern Kerguelen Plateau

Earth and Planetary Science Letters

et al. 2000

214

142

Oceanic plateaus form by mantle processes distinct from those forming oceanic crust at divergent plate boundaries. Eleven drillsites into igneous basement of Kerguelen Plateau and Broken Ridge, including seven from the recent Ocean Drilling Program Leg 183 (1998^99) and four from Legs 119 and 120 (1987^88), show that the dominant rocks are basalts with geochemical characteristics distinct from those of mid-ocean ridge basalts. Moreover, the physical characteristics of the lava flows and the presence of wood fragments, charcoal, pollen, spores and seeds in the shallow water sediments overlying the igneous basement show that the growth rate of the plateau was sufficient to form subaerial landmasses. Most of the southern Kerguelen Plateau formed at V110 Ma, but the uppermost submarine lavas in the northern Kerguelen Plateau erupted during Cenozoic time. These results are consistent with derivation of the plateau by partial melting of the Kerguelen plume. Leg 183 provided two new major observations about the final growth stages of the Kerguelen Plateau. 1: At several locations, volcanism ended with explosive eruptions of volatilerich, felsic magmas; although the total volume of felsic volcanic rocks is poorly constrained, the explosive nature of the eruptions may have resulted in globally significant effects on climate and atmospheric chemistry during the late-stage, subaerial growth of the Kerguelen Plateau. 2: At one drillsite, clasts of garnet^biotite gneiss, a continental rock, occur in a fluvial conglomerate intercalated within basaltic flows. Previously, geochemical and geophysical evidence has been used to infer continental lithospheric components within this large igneous province. A continental geochemical signature in an oceanic setting may represent deeply recycled crust incorporated into the Kerguelen plume or continental fragments dispersed during initial formation of the Indian Ocean during breakup of Gondwana. The clasts of garnet^biotite gneiss are the first unequivocal evidence of continental crust in this oceanic plateau. We propose that during initial breakup between India and Antarctica, the spreading center jumped northwards transferring slivers of the continental Indian plate to oceanic portions of the Antarctic plate. ß

Section: Summary Of Age Variationmentioning

confidence: 73%

“…Also, piston coring of sediments on the northeast £ank of the CKP between the Kerguelen Archipelago and Heard Island (MD35-510 in Fig. 1) recovered cherts and calcareous oozes of probable Santonian age (83.5^85.5 Ma) [29]. Site 1138 basalts from the CKP are overlain by CenomanianT uronian (V94 Ma) sandstone (Fig.…”

Section: Summary Of Age Variationmentioning

confidence: 97%

Origin and evolution of a submarine large igneous province: the Kerguelen Plateau and Broken Ridge, southern Indian Ocean

Frey

Coffin

Earth and Planetary Science Letters

et al. 2000

214

142

“…Also, piston coring of sediments on the northeast flank of the CKP between the Kerguelen Archipelago and Heard Island (MD35-510 in Fig. 4) recovered cherts and calcareous oozes of probable Santonian age (Fröhlich and Wicquart, 1989). In summary, we have very few high-quality age data for the 2.3 x 10 6 km 2 (equivalent to approximately eight Icelandic plateaus) of the Kerguelen Plateau-Broken Ridge LIP.…”

Section: Previous Sampling Of Igneous Basement: Ages and Geochemical mentioning

confidence: 84%

Kerguelen Plateau-Broken Ridge: A Large Igneous Province

Coffin¹,

Frey²,

1999

ODP Preliminary Report

This informal report was prepared from the shipboard files by the scientists who participated in the cruise. The report was assembled under time constraints and is not considered to be a formal publication which incorporates final works or conclusions of the participating scientists. The material contained herein is privileged proprietary information and cannot be used for publication or quotation.

“…Also, piston coring of sediments on the northeast flank of the plateau between the Kerguelen Archipelago and Heard Island (Fig. 4) recovered Upper Cretaceous cherts and calcareous oozes of probable Santonian age (Fröhlich and Wicquart, 1989).…”

Section: Previous Sampling Of Igneous Basementmentioning

confidence: 98%

Kerguelen Plateau-Broken Ridge: A Large Igneous Province

Coffin¹,

Frey²,

ODP Scientific Prospectus

1998

This Scientific Prospectus is based on precruise JOIDES panel discussions and scientific input from the designated Co-Chief Scientists on behalf of the drilling proponents. The operational plans within reflect JOIDES Planning Committee and thematic panel priorities. During the course of the cruise, actual site operations may indicate to the Co-Chief Scientists and the Operations Manager that it would be scientifically or operationally advantageous to amend the plan detailed in this prospectus. It should be understood that any proposed changes to the plan presented here are contingent upon approval of the Director of the Ocean Drilling Program in consultation with the Science and Operations Committees (successors to the Planning Committee) and the Pollution Prevention and Safety Panel.