Metacarbonatite or marble? - the case of the carbonate, pyroxenite, calcite-apatite rock complex at Borra, Eastern Ghats, India
DSpace at IIT Bombay
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Title |
Metacarbonatite or marble? - the case of the carbonate, pyroxenite, calcite-apatite rock complex at Borra, Eastern Ghats, India
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Creator |
LE BAS, MJ
SUBBARAO, KV WALSH, JN |
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Subject |
tamil-nadu
grenville province upper-mantle metamorphism granulites limestones mineralogy ontario magmas earth carbonatite metacarbonatite marble pyroxenite trace elements al-pyroxene |
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Description |
Carbonatites are often of economic importance, which raises the problem of distinguishing carbonatites from limestones when either are metamorphosed to high-grade marbles. They can be of similar appearance, particularly those from the Proterozoic and Archaean of the Indian Subcontinent. This study also contributes to solving the problem of determining the frequency of alkaline and carbonatitic magmatism during the early history of the Earth. The mineral assemblage of apatite-magnetite-phlogopite-calcite is common to marbles of both carbonatite and limestone origin. If pyrochlore is present that identifies the rock as carbonatite, if anorthite, fassaite, scapolite or spinel then it was formerly a limestone. If these minerals are absent. then trace element analysis can supply the critical Sr and REE data, which are both normally high in carbonatitic rocks and low in former limestones. These distinguishing factors are applied to the metamorphic carbonate, pyroxenite, calcite-apatite rock complex at Borra, Eastern Ghats, India, which has been variously interpreted as formerly a carbonatite and as a limestone. The evidence shows that the Borra rocks are meta-sedimentary. (C) 2002 . .
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Publisher |
PERGAMON-ELSEVIER SCIENCE LTD
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Date |
2011-08-25T12:44:51Z
2011-12-26T12:57:04Z 2011-12-27T05:46:48Z 2011-08-25T12:44:51Z 2011-12-26T12:57:04Z 2011-12-27T05:46:48Z 2002 |
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Type |
Article
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Identifier |
JOURNAL OF ASIAN EARTH SCIENCES, 20(2), 127-140
1367-9120 http://dx.doi.org/10.1016/S1367-9120(01)00030-X http://dspace.library.iitb.ac.in/xmlui/handle/10054/11021 http://hdl.handle.net/10054/11021 |
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Language |
en
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