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Geochemical evolution of Indian Ocean basaltic magmatism


Sushchevskaya, NM and Kamenetsky, VS and Belyatsky, BV and Artamonov, AV, Geochemical evolution of Indian Ocean basaltic magmatism, Geochemistry International, 51, (8) pp. 599-622. ISSN 0016-7029 (2013) [Refereed Article]

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Copyright 2013 Pleiades Publishing

DOI: doi:10.1134/S0016702913070057


A comparison of new and published geochemical characteristics of magmatism in the western and eastern Indian Ocean at the initial and recent stages of its evolution revealed several important differences between the mantle sources of basaltic melts from this ocean. 1. The sources of basalts, from ancient rises and from flanks of the modern Central Indian Ridge within the western Indian Ocean contain an enriched component similar in composition to the source of the Reunion basalts (with radiogenic Pb and Sr and unradiogenic Nd), except for basalts from the Comores Islands, which exhibit a contribution from an enriched HIMU-like component. 2. The modern rift lavas of spreading ridges display generally similar geochemical compositions. Several local isotopic anomalies are characterized by the presence of an EM2-like component. However, two anomalous areas with distinctly different enriched mantle sources were recognized in the westernmost part of the Southwestern Indian Ridge (SWIR). The enriched mantle source of the western SWIR tholeiites in the vicinity of the Bouvet Triple Junction has the isotopic ratios indicating a mixture of HIMU + EM2 in the source. The rift anomaly distinguished at 40 E displays the EM1 signature in the mantle source, which is characterized by relatively low 206Pb/204Pb (up to 17.0) and high 207Pb/204Pb, 208Pb/204Pb and 87Sr/86Sr. This source may be due to mixing with material from the continental lithosphere of the ancient continent Gondwana. The material from this source can be distinguished in magmas related to the Mesozoic plume activity in Antarctica, as well as in basalts from the eastern Indian Ocean rises, which were formed by the Kerguelen plume at 100-90 Ma. 3. The geochemical heterogeneities identified in the ancient and present-day magmatic products from the western and eastern Indian Ocean are thought to reflect the geodynamic evolution of the region. In the eastern part of the ocean, the interaction of the evolving Kerguelen plume with the rift zones produced magmas with specific geochemical characteristics during the early opening of the ocean; such a dispersion of magma composition was not recognized in the western part of the ocean.

Item Details

Item Type:Refereed Article
Keywords:plume-related magmatism, geochemistry of mantle sources, Indian Ocean
Research Division:Earth Sciences
Research Group:Geology
Research Field:Igneous and metamorphic petrology
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the earth sciences
UTAS Author:Kamenetsky, VS (Professor Vadim Kamenetsky)
ID Code:86332
Year Published:2013
Web of Science® Times Cited:5
Deposited By:Centre for Ore Deposit Research - CODES CoE
Deposited On:2013-09-06
Last Modified:2014-06-05

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