論文

筆頭著者
2021年5月

Sr-Nd isotopic study of dolerite dykes in the Western Dharwar craton, southern India: Implications for the evolution of the subcontinental lithospheric mantle in late Archean

Lithos
  • Ammini Sasidharan Silpa
  • ,
  • Madhusoodhan Satish-Kumar
  • ,
  • Toshiro Takahashi

388-389
開始ページ
106023
終了ページ
106023
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1016/j.lithos.2021.106023
出版者・発行元
Elsevier BV

Mafic dyke swarms are one of the major geologic features that represent crustal extension and rifting episodes which result in the transfer of large volumes of mantle materials to the crust. The rapid emplacement of dykes within a short span of time helps to preserve the composition of subcontinental lithospheric mantle (SCLM) and understand its evolution over time. Here we report major and trace element geochemistry and Sr-Nd isotopic characteristics of dykes from the Tiptur area in the late Archean Western Dharwar craton of southern India. The studied mafic dykes are un-metamorphosed and preserve pristine igneous textures and mineralogy. Three different groups of dykes were identified and categorized as olivine dolerites, dolerites and REE enriched dolerites, based on the distinct petrographical and geochemical characteristics. Olivine dolerites are having a high Mg# suggesting a lower degree of fractionation and is indicative of a less evolved magma. Dolerites have comparatively lower Mg# than the olivine dolerites indicating that the former have undergone significant fractional crystallization as confirmed by the higher Ni contents. The low initial Sr isotopic ratio for olivine dolerites (Sr-87/Sr-86 = 0.70088) with negative epsilon Nd values are suggesting a late Archean enriched subcontinental lithospheric mantle (SCLM) in the source region. The dolerites (Sr-87/Sr-86 = 0.70132 to 0.70327) and REE enriched dolerites (Sr-87/Sr-86 = 0.70405 to 0.70653) show signatures of a more enriched source. The evolution of SCLM from a DMM source enriched by the subduction of the mafic oceanic crust in the late Archean to a mantle enriched by continent-derived sediments towards the early Proterozoic are reflected in the dolerite and REE enriched dykes. (C) 2021 Elsevier B.V. All rights reserved.

Web of Science ® 被引用回数 : 2

リンク情報
DOI
https://doi.org/10.1016/j.lithos.2021.106023
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000636175000002&DestApp=WOS_CPL
ID情報
  • DOI : 10.1016/j.lithos.2021.106023
  • ISSN : 0024-4937
  • eISSN : 1872-6143
  • Web of Science ID : WOS:000636175000002

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