Basalt and peridotite recovered from Murray Ridge: Are they of supra-subduction origin?
Burgath, K.-P.; von Rad, U.; van der Linden, W.; De Block, M.; Khan, A.A.; Roeser, H.A.; Weiss, W. (2002). Basalt and peridotite recovered from Murray Ridge: Are they of supra-subduction origin?, in: Clift, P.D. et al. The tectonic and climatic evolution of the Arabian Sea region. Geological Society Special Publication, 195: pp. 117-135. https://dx.doi.org/10.1144/GSL.SP.2002.195.01.08 In: Clift, P.D. et al. (2002). The tectonic and climatic evolution of the Arabian Sea region. Geological Society Special Publication, 195. The Geological Society: London. e-ISBN 9781862394438. VI, 525 pp. https://dx.doi.org/10.1144/GSL.SP.2002.195, more In: Hartley, A.J. et al. (Ed.) Geological Society Special Publication. Geological Society of London: Oxford; London; Edinburgh; Boston, Mass.; Carlton, Vic.. ISSN 0305-8719; e-ISSN 2041-4927, more |
| Keywords | Chemistry > Geochemistry
Petrography
Rocks > Igneous rocks > Ultramafic rocks > Peridotite
Rocks > Igneous rocks > Volcanic rocks > Basalts
Subduction
Topographic features > Submarine features > Ridges > Submarine ridges > Mid-ocean ridges
ISW, Arabian Sea [Marine Regions]
Marine/Coastal |
| Authors | | Top | - Burgath, K.-P.
- von Rad, U.
- van der Linden, W., more
- De Block, M., more
| - Khan, A.A.
- Roeser, H.A.
- Weiss, W.
| |
| Abstract | Petrographic and geochemical data for new basalt and peridotite samples recovered from sampling sites at the Southern Murray Ridge help to constrain models for the evolution of the Owen-Murray Ridge system, which forms the northwestern boundary of the Indian plate. Trace elements immobile during alteration (Ti, Zr, Nb, Y and rare earth elements) suggest that the altered microphyric metabasalt has affinities to magmatism of active margins (island-arc tholeiite sensu lato). It is distinctly different from mid-ocean ridge basalt, back-arc-basin basalt, or intra-plate Deccan Trap basalt. The sampled serpentinized harzburgite or clinopyroxene-poor lherzolite was deformed under mantle conditions and is similar to the mantle section of nearby ophiolite sequences. This association of rocks suggests that an ophiolite mélange was sampled. However, results from sampling station 462 NIOP indicate that the Murray Ridge complex also contains igneous rocks with Deccan Trap affinity. For the emplacement of the island-arc tholeiite we assume an origin in a convergent supra-subduction setting, related to the closing of a Late Cretaceous Neo-Tethyan ocean basin between the Arabian and Indian plates to the south and the Eurasian plate to the north. Since Neogene time, the Murray Ridge-Dalrymple Trough has been underlain by attenuated (?)continental crust and characterized by extensional rift tectonics. |
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