The relationship between petrology and Nd isotopes as evidence for contrasting anorogenic granite genesis; example of the Corsican Province (SE France)

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Authors:Poitrasson, Franck; Duthou, Jean-Louis; Pin, Christian
Author Affiliations:Primary:
Université Blaise Pascal, Département des Sciences de la Terre, Clermont-Ferrand, France
Volume Title:Journal of Petrology
Source:Journal of Petrology, 36(5), p.1251-1274. Publisher: Clarendon Press, Oxford, United Kingdom. ISSN: 0022-3530
Publication Date:1995
Note:In English. 90 refs.; illus., incl. 3 tables, geol. sketch maps
Summary:This study shows that within a single anorogenic igneous province three types of granite can be recognized: 1) aluminous subsolvus (AS), 2) peralkaline (P) and 3) aluminous hypersolvus (AH). The close correlation between granite petrology and Nd isotope characteristics shows that different granitic types originated from contrasting source materials and/or have subsequently undergone variable petrogenetic processes. It seems that the Nd isotopic characteristics were acquired in the deep crust. As granites were probably generated by partial melting in the lower crust of a protolith heterogeneous and unradiogenic in terms of its Nd isotopes. In contrast, P and AH granites are mantle-derived magmas contaminated by mixing with deep crustal components. Compared with P types, the less radiogenic Nd isotopic signatures and the lower agpaitic indices of AH granites are the result of larger amounts of crustal components. The close correlation between εNd(i) values of AS or AH granites and the presence of slightly older mafic rocks in the local crust strongly suggest that the lower-crustal component involved in the genesis of the granites is mainly mafic. This hypothesis is also supported by other petrological and geochemical observations. Mixing calculations show that a significant amount of crust has been involved in the petrogenesis of both AH and P granites. [R.E.S.]
Subjects:A-type granites; Absolute age; Dates; Fractional crystallization; Geochemistry; Granites; Igneous rocks; Isotopes; Magma contamination; Magmas; Mesozoic; Metals; Nd-144/Nd-143; Neodymium; Plutonic rocks; Rare earths; Sm/Nd; Stable isotopes; Triassic; Corsica; Europe; France; Western Europe
Coordinates:N411500 N430000 E0093000 E0083000
Abstract Numbers:96M/1877
Record ID:1996025892
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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