LA-MC-ICP-MS dating of zircon from chromitite of the Archean Bangur Gabbro Complex, Orissa, India : ambiguities and constraints
Sunder-Raju, P. V. (National Geophysical Research Institute (CSIR) (Telangana, Índia))
Hanski, E. (University of Oulu (Finlàndia). Oulu Mining School)
Lahaye, Y. (Geological Survey of Finland)

Date:	2015
Abstract:	The Mesoarchean chromitites in the Singhbhum craton provide the main source of chromium in India. We report here results of dating zircon grains that were found in the chromitite of ultramafic rocks belonging to the southern part of the Archean Baula Complex. The chromite-bearing ultramafic rocks are cut by a gabbronorite intrusion, which had earlier been dated by SHRIMP at 3. 12Ga. We have performed isotopic analysis of the zircon grains by Laser Ablation Multicollector Inductively Coupled Plasma Mass Spectrometry (LA-MC-ICP-MS) and obtained an age of 2. 84Ga, which is inconsistent with the previous age reported for the gabbronorite. We have also determined the Pb isotopic composition of galena found in the chromitite and found out it was highly radiogenic given the Archean age of its host rock. We discuss the potential reasons for these results, such as later Neoarchean or even Proterozoic tectono-magmatic/hydrothermal events, and stress the importance of future detailed petrographic, mineralogical and isotopic studies to solve the dilemmas.
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, sempre i quan aquestes es distribueixin sota la mateixa llicència que regula l'obra original i es reconegui l'autoria.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Chromitite ; Zircon ; Galena ; U-Pb isotopes ; Pb-Pb isotopes ; Archean ; Orissa (India)
Published in:	Geologica acta, Vol. 13 Núm. 4 (December 2015) , p. 325-334 (Articles) , ISSN 1696-5728

Adreça alternativa: https://raco.cat/index.php/GeologicaActa/article/view/302722
Adreça alternativa: https://revistes.ub.edu/index.php/GEOACTA/article/view/GeologicaActa2015.13.4.5
DOI: 10.1344/GeologicaActa2015.13.4.5

10 p, 1.9 MB

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