Genesis and evolution of a Paleoproterozoic basement inlier within West Gondwana addressed by Sm-Nd isotopic geochemistry and Zr saturation thermometry
Abstract
This paper presents new isotopic Sm-Nd ID-TIMS data and applies the Zr saturation thermometry on orthogneisses of the Quirino Complex to address the mechanisms of magma genesis, evolution and tectonic setting. Quirino Complex is considered a Paleoproterozoic basement inlier within a Neoproterozoic belt, comprised of two distinct calcalkaline magmatic suites: a Siderian to Rhyacian high-K suite (2.30-2.19 Ga); and a Rhyacian medium-K suite (2.17-2.16 Ga). High zircon solubility and ɛNd(t) values (+2.7 to -5.8) indicate that the protoliths of the high-K suite gneisses can be related to high-temperature (TZr = ca. 810 °C) I-type granites. The gneisses of the medium-K suite display isotopic signature for crustal residence (ɛNd(t) = -17.9 and -8.1). Their protoliths, rich in inherited zircons (ca. 3.0 Ga) and other restitic/refractory components (hornblende clots and mafic enclaves), were derived from partial melting of Archean crust at relatively low temperature (TZr = ca. 750 °C) within a collisional tectonic setting.
- Publication:
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Journal of South American Earth Sciences
- Pub Date:
- December 2017
- DOI:
- 10.1016/j.jsames.2017.09.005
- Bibcode:
- 2017JSAES..80...95V