Imprints of ancient recycled oceanic lithosphere in heterogeneous Indian Ocean mantle: Evidence from petrogenesis of Carlsberg ridge basalts from Northwest Indian Ocean

被引：14

作者：

Saha, Abhishek ^{[1
]}

Sensarma, Simontini ^{[1
,2
]}

Hazra, Arghya ^{[1
,3
]}

Ganguly, Sohini ^{[3
]}

Peketi, Aditya ^{[1
]}

Doley, Bhagyashree ^{[1
,4
]}

Mudholkar, Abhay V. ^{[1
]}

机构：

[1] CSIR Natl Inst Oceanog, Panaji 403004, Goa, India

[2] Indian Inst Sci, Ctr Earth Sci, Bengaluru 560012, India

[3] Goa Univ, Sch Earth Ocean & Atmospher Sci, Taleigao Plateau 403206, Goa, India

[4] Acad Sci & Innovat Res, Ghaziabad, Uttar Pradesh, India

来源：

GONDWANA RESEARCH | 2020年 / 86卷

关键词：

Carlsberg Ridge Basalts; HIMU source; Oceanic lithosphere; Indian Ocean mantle; Gondwana Supercontinent; GEOCHEMICAL CONSTRAINTS; CHEMICAL CLASSIFICATION; ISOTOPE SYSTEMATICS; TRIPLE JUNCTION; VOLCANIC-ROCKS; MARIANA TROUGH; FLOOD BASALTS; SW CHINA; EVOLUTION; ND;

D O I：

10.1016/j.gr.2020.05.003

中图分类号：

P [天文学、地球科学];

学科分类号：

07 ;

摘要：

This paper reports new petrological, geochemical and isotopic data for Carlsberg Ridge Basalts (CRB) of northwest Indian Ocean and evaluates their petrogenetic aspects in the context of the geochemical and tectonic evolution of the Indian Ocean mantle. The CRB samples exhibit tholeiitic to transitional composition of precursor melts derived by high degree, shallow level partial melting of a spinel peridotite mantle source. CRB reflects distinct E-MORB affinity with selective enrichment in incompatible trace elements. Higher values of Zr/Hf (33.8-47.3) and Zr/Sm (24.9-36.4) in conjunction with lower Nb/Ta (1.7-7.3) ratio corroborate their origin from an enriched mantle source. Negative Nb anomalies with lower Nb/Y (0.04-0.11) and Zr/Y (2.5-3.5) conform to a non-plume origin of these basalts. Higher Zr/Nb (25.5-71.5) and Th/Nb (0.6-0.42) compared to OIB substantiate contributions from recycled subduction-processed components in the source mantle. Lower Nb/U (6.2-37.9) values with higher Ba/Nb (6.1-21.9), Ba/Th (27.7-147.5), Zr/Nb (25.5-71.5) and Th/Nb (0.6-0.42) compared to OIB and N-MORB attest to role of a metasomatized oceanic lithosphere that recycled into the depleted upper mantle attributing to the source heterogeneity. Sr-Nd isotopic signatures (Sr-87/Sr-86: 0.702668 to 0.702841 and Nd-143/Nd-144: 0.512972 to 0.513068) of CRB suggest a HIMU source component preserved in the northwest Indian Ocean Ridge mantle. The compositional diversity of the Indian Ocean mantle can be translated in terms of periodic refertilization of depleted N-MORB type mantle through delamination and recycling of oceanic (HIMU component) and continental lithosphere (EM I component) concurrent with NeoproterozoicPalaeozoic amalgamation and Jurassic dispersal of Gondwana Supercontinent respectively. This study complies with the derivation of CRB from a geochemically heterogeneous Indian Ocean mantle that experienced a protracted residence beneath the Gondwana Supercontinent prior to the opening of Indian Ocean and trapped recycled metasomatized oceanic lithosphere genetically linked with multiple stages of paleo-ocean closure and continental convergence during Gondwana assembly. (C) 2020 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

引用

页码：60 / 82

页数：23

共 124 条

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