論文

2021年5月

Structural and geochemical evidence for a failed rift crustal evolution model in Western Dharwar Craton, South India

Lithos
  • Lakshmanan Sreehari
  • ,
  • Tsuyoshi Toyoshima
  • ,
  • Madhusoodhan Satish-Kumar
  • ,
  • Toshiro Takahashi
  • ,
  • Hayato Ueda

388-389
開始ページ
106020
終了ページ
106020
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1016/j.lithos.2021.106020
出版者・発行元
Elsevier BV

Detailed geological mapping along with structural and geochemical analysis were carried out in the Kibbanahalli Schist Belt (KSB) of the Bababudan Group in the Western Dharwar Craton (WDC). Repeated sequences of sedimentary rocks and volcanic rocks with conformable contact relations are the major lithological association in KSB. Sedimentary structures and field relations indicate that the Bababudan Group begins with basal conglomerate composed of debris (talus) and alluvial fan deposits or fluvial deposits. Volcanic rocks preserve features of explosive volcanism in an aqueous environment.Based on the field and microstructural observations five stages of deformations (D-0, D-1, D-2, D-3, and D-4) are characterized from the study area. Among these deformation events, D-2 is the major regional-scale event. East dipping NW-SE trending thrust faults and F-2 parallel folds that are upright and isoclinal mark the D-2 event. These F-2 folds are sandwiched between D-2 thrust faults. D-2 structures suggest the temporal evolution of a fold-and thrust belt by inversion of an intracratonic basin.Trace element geochemical analysis of the mafic to intermediate rocks from KSB and Chitradurga Schist Belt (CSB) shows three types of patterns. Type 1 has Nb-Ta negative anomalies, Type 2 is relatively flat trend and Type 3 has Zr-Hf positive anomalies. Type 1 has slightly enriched LREE trend while relatively flat LREE trend in Type 2 and 3. HREE trend is relatively flat in all samples, except for one sample from Type 3. The geochemical variations are related to the degree of crustal contamination experienced during their eruption in connection with the intracratonic extension.A pair of thrust faults and folded sequences of volcanic, volcanoclastic and sedimentary rocks summarize the major structural association in the study area. This association is identical to an inverted failed rift structure. Geochemical evidence also points to an intracratonic mafic to intermediate volcanism. Our study thus provides a well-preserved example of Archean failed rift. We thus propose the post-3.0 Ga crustal growth throughout the Western Dharwar Craton is therefore initiated by similar failed rifting events. (C) 2021 Elsevier B.V. All rights reserved.

リンク情報
DOI
https://doi.org/10.1016/j.lithos.2021.106020
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000636175000005&DestApp=WOS_CPL
ID情報
  • DOI : 10.1016/j.lithos.2021.106020
  • ISSN : 0024-4937
  • eISSN : 1872-6143
  • Web of Science ID : WOS:000636175000005

エクスポート
BibTeX RIS