Preliminary result for the Rb-Sr whole-rock age and initial Nd isotope ratios from the Closepet granite in Karnataka, Southern India
The Rb-Sr whole-rock isochron age was determined for granitic rocks from the Closepet granite, southern India. Porphyritic monzogranite, clinopyroxene quartzmonzonite, pink granite and grey granite, four main representative granitic rocks, gave an Rb-Sr age of 2669±125 Ma with an initial ^<87>...
| Main Authors: | , , |
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| Format: | Report |
| Language: | English |
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Department of Natural Environment, Faculty of Human Development, Kobe University
1999
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| Online Access: | https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=3049 http://id.nii.ac.jp/1291/00003049/ https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=3049&item_no=1&attribute_id=18&file_no=1 |
| Summary: | The Rb-Sr whole-rock isochron age was determined for granitic rocks from the Closepet granite, southern India. Porphyritic monzogranite, clinopyroxene quartzmonzonite, pink granite and grey granite, four main representative granitic rocks, gave an Rb-Sr age of 2669±125 Ma with an initial ^<87>Sr/^<86>Sr ratio of 0.70193±0.00088. This Rb-Sr whole-rock isochron age indicates a major period of equilibration of the isotopic system on a whole- rock scale at 2669 Ma. Initial εNd values normalized to 2669 Ma for individual granitic rocks range from -4.4 to -7.2. The large initial εNd values and low Sr initial ratios suggest that the Closepet granite has complicated history such as mixing. |
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