Origin of continental components in Indian Ocean basalts: Evidence from Elan Bank (Kerguelen Plateau, ODP Leg 183, Site 1137)

Weis, Dominique; Ingle, Stéphanie; Damasceno, Dimitri; Frey, Frederick A.; Nicolaysen, K. P.; Barling, Jane; Party, Leg Shipboard Scientific

doi:10.1130/0091-7613(2001)029<0147:ooccii>2.0.co;2

Cited by 65 publications

(47 citation statements)

References 31 publications

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“…The Indian margin basins comprise a cratonic phase containing continental and marine rift-phase sediments of Jurassic and Early Cretaceous age, and a post-rift mainly marine section of Late Cretaceous and Cainozoic age (Prabhakar and Zutshi, 1993). Geological and geochemical evidence from the Ocean Drilling Program (ODP) Leg 183 Site 1137 show that Elan Bank, a west-protruding salient on the Kerguelen Plateau, is at least partly of continental origin (Coffin et al, 2000;Nicolaysen et al, 2001;Weis et al, 2001). However, little detail is known of the pre-breakup geology of Elan Bank (and any other continental fragments incorporated into the Kerguelen Plateau) and its precise fit between India and Enderby Land.…”

Section: Geologymentioning

confidence: 99%

Geology of the Continental Margin of Enderby and Mac. Robertson Lands, East Antarctica: Insights from a Regional Data Set

et al. 2004

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In 2001 and 2002, Australia acquired an integrated geophysical data set over the deep-water continental margin of East Antarctica from west of Enderby Land to offshore from Prydz Bay. The data include approximately 7700 km of high-quality, deep-seismic data with coincident gravity, magnetic and bathymetry data, and 37 non-reversed refraction stations using expendable sonobuoys. Integration of these data with similar quality data recorded by Japan in 1999 allows a new regional interpretation of this sector of the Antarctic margin. This part of the Antarctic continental margin formed during the breakup of the eastern margin of India and East Antarctica, which culminated with the onset of seafloor spreading in the Valanginian. The geology of the Antarctic margin and the adjacent oceanic crust can be divided into distinct east and west sectors by an interpreted crustal boundary at approximately 58°E. Across this boundary, the continent-ocean boundary (COB), defined as the inboard edge of unequivocal oceanic crust, steps outboard from west to east by about 100 km. Structure in the sector west of 58°E is largely controlled by the mixed rift-transform setting. The edge of the onshore ArchaeanProterozoic Napier Complex is downfaulted oceanwards near the shelf edge by at least 6 km and these rocks are interpreted to underlie a rift basin beneath the continental slope. The thickness of rift and pre-rift rocks cannot be accurately determined with the available data, but they appear to be relatively thin. The margin is overlain by a blanket of post-rift sedimentary rocks that are up to 6 km thick beneath the lower continental slope. The COB in this sector is interpreted from the seismic reflection data and potential field modelling to coincide with the base of a basement depression at 8.0-8.5 s two-way time, approximately 170 km oceanwards of the shelf-edge bounding fault system. Oceanic crust in this sector is highly variable in character, from rugged with a relief of more than 1 km over distances of 10-20 km, to rugose with low-amplitude relief set on a long-wavelength undulating basement. The crustal velocity profile appears unusual, with velocities of 7.6-7.95 km s )1 being recorded at several stations at a depth that gives a thickness of crust of only 4 km. If these velocities are from mantle, then the thin crust may be due to the presence of fracture zones. Alternatively, the velocities may be coming from a lower crust that has been heavily altered by the intrusion of mantle rocks. The sector east of 58°E has formed in a normal rifted margin setting, with complexities in the east from the underlying structure of the N-S trending Palaeozoic Lambert Graben. The Napier Complex is downfaulted to depths of 8-10 km beneath the upper continental slope, and the margin rift basin is more than 300 km wide. As in the western sector, the riftstage rocks are probably relatively thin. This part of the margin is blanketed by post-rift sediments that are up to about 8 km thick. The interpreted COB in the eastern sector is the...

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Section: Geologymentioning

confidence: 99%

Geology of the Continental Margin of Enderby and Mac. Robertson Lands, East Antarctica: Insights from a Regional Data Set

et al. 2004

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“…Important features are (a) emanating from the field defined by Kerguelen archipelago flood basalt, samples from Site 1139, Site 1137, Unit 6 of Site 1142, Site 738, and dredges from eastern Broken Ridge (BR) define a positive trend. The highest values, data for lavas from eastern Broken Ridge, Sites 738 and 1137, are interpreted to reflect a component derived from continental crust (Mahoney et al, 1995;Weis et al, 2001;Ingle et al, 2002b). Note that such a component is absent from Cenozoic basalt at Site 1140 and the flood basalt of the Kerguelen archipelago.…”

Section: Fa Frey Et Al Leg 183 Synthesis: a Large Igneous Province 27mentioning

confidence: 90%

Leg 183 Synthesis: Kerguelen Plateau–Broken Ridge—A Large Igneous Province

Frey¹,

Coffin²,

Wallace³

et al. 2003

Proceedings of the Ocean Drilling Program

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The Kerguelen Plateau and Broken Ridge form a large igneous province (LIP) in the southern Indian Ocean. The main objectives of Ocean Drilling Program Leg 183 were to understand the origin and evolution of this LIP and the impact of its formation on the environment. Igneous basement (33 to 233 m of penetration) has been recovered from 11 drill sites on the LIP, and 7 are Leg 183 sites. Studies of the basement and sediment cores lead to the following conclusions. Although an important caveat is that we have access only to uppermost basement of a thick (~20 km) igneous crust, these results are inconsistent with massive volcanism associated with a single plume head and continental breakup. 2. The uppermost igneous basement is dominantly tholeiitic basalt. Based on the physical characteristics of the lava flows, which indicate subaerial eruption, and the occurrence of overlying terrestrially derived sediments containing wood fragments, fern remains, and terrestrial palynoflora, much of the LIP was above sea level when magmatic output was high. 3. The geochemical characteristics of basalt forming the LIP are unlike mid-ocean-ridge basalt (MORB). There are, however,

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“…Alternatively, the early reservoir could (Kramers and Tolstikhin, 1997 ). Basalt data are from Eiler et al (1995) ; Eisele et al (2002) ; Gast et al (1964) ; Ingle et al (2002) ; Regelous et al (2009) ;Richardson et al (1982) ; Weis et al (2001) and Woodhead and McCulloch (1989) . (b) The same data in thorogenic Pb -isotope space.…”

Section: Enriched Mantle Reservoirs and Their Connection To Continentmentioning

confidence: 99%

“…The similarity between lower continental crust and certain EM -1 ocean island basalts in Pb -isotope composition and pertinent trace element geochemical signatures also has led to the proposal that there might be recycled lower continental crust in the shallow astenosphere (e.g. Weis et al 2001 ) and that it might be the source of at least the South Atlantic EM -1 signature (e.g. Willbold and Stracke 2006 ;Regelous et al 2009 ).…”

Section: Enriched Mantle Reservoirs and Their Connection To Continentmentioning

confidence: 99%

“…Proterozoic granulite xenoliths have been recovered in Kerguelen Plateau boreholes (e.g. Weis et al 2001 ), proving that entrainment of granulite facies continental crust is feasible, at least in that particular setting. It was further suggested that such crust could have affected the radiogenic isotope, and particularly the Pb -isotope, systematics of the entire Indian Ocean basin mantle (e.g.…”

Section: Enriched Mantle Reservoirs and Their Connection To Continentmentioning

confidence: 99%

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Geochemistry and Secular Geochemical Evolution of the Earth's Mantle and Lower Crust

Kamber

2011

Frontiers in Geochemistry

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Origin of continental components in Indian Ocean basalts: Evidence from Elan Bank (Kerguelen Plateau, ODP Leg 183, Site 1137)

Cited by 65 publications

References 31 publications

Geology of the Continental Margin of Enderby and Mac. Robertson Lands, East Antarctica: Insights from a Regional Data Set

Geology of the Continental Margin of Enderby and Mac. Robertson Lands, East Antarctica: Insights from a Regional Data Set

Leg 183 Synthesis: Kerguelen Plateau–Broken Ridge—A Large Igneous Province

Geochemistry and Secular Geochemical Evolution of the Earth's Mantle and Lower Crust

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