Pb–Pb zircon ages of Archaean metasediments and gneisses from the Dharwar craton, southern India: Implications for the antiquity of the eastern Dharwar craton

Journal of Earth system science

B Maibam1 2¹  J N Goswami1¹  R Srinivasan3² 

[1] Physical Research Laboratory, Ahmedabad 380 009, India.$$;Geomysore Services (India) Pvt. Ltd., Bangalore 560 028, India.$$

关键词: Archaean;    craton;    geochronology;    zircon;    ion microprobe;    Dharwar.;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

207Pb–206Pb ages of zircons in samples of metasediments as well as ortho- and para-gneisses from both the western and the eastern parts of the Dharwar craton have been determined using an ion microprobe. Detrital zircons in metasedimentary rocks from both yielded ages ranging from 3.2 to 3.5 Ga. Zircons from orthogneisses from the two parts also yielded similar ages. Imprints of younger events have been discerned in the ages of overgrowths on older zircon cores in samples collected throughout the craton. Our data show that the evolution of the southwestern part of eastern Dharwar craton involved a significant amount of older crust (< 3.0 Ga). This would suggest that crust formation in both the western and eastern parts of the Dharwar craton took place over similar time interval starting in the Mesoarchaean at ca. 3.5 Ga and continuing until 2.5 Ga. Our data coupled with geological features and geodynamic setting of the Dharwar craton tend to suggest that the eastern Dharwar craton and the western Dharwar craton formed part of a single terrane.

【 授权许可】

Unknown