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A review of the geochronology and geochemistry of Late Yanshanian (Cretaceous) plutons along the Fujian coastal area of southeastern China: Implications for magma evolution related to slab break-off and rollback in the Cretaceous
The Cretaceous plutonic suites in the Fujian coastal area include abundant I-type and A-type granitoids and lesser gabbroids. They are important components of the Late Yanshanian magmatic belt along the southeastern coast of China, and define a linear NNE–SSW-trending belt of magmatism. Geochronolog...
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Published in: | Earth-science reviews 2014-01, Vol.128, p.232-248 |
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Main Authors: | , , |
Format: | Article |
Language: | English |
Subjects: | |
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Online Access: | Get full text |
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Summary: | The Cretaceous plutonic suites in the Fujian coastal area include abundant I-type and A-type granitoids and lesser gabbroids. They are important components of the Late Yanshanian magmatic belt along the southeastern coast of China, and define a linear NNE–SSW-trending belt of magmatism. Geochronological, geochemical and geological data from thirty intrusions are summarised in this paper, and the data provide distinct magmatic, geochemical and tectonic patterns in the area. A compilation of geochronological data for these intrusive rocks indicates emplacement mainly from around 125 to 90Ma, with a major peak from 115 to 90Ma, and a subordinate peak from 125 to 115Ma. Besides their temporal and spatial coexistence, all these intrusive rocks have similar geochemical patterns which point to involvement of components from a depleted asthenospheric mantle source for the parental magmas, most probably by magma mixing. The first appearance of sparse I-type granitoids with post-collisional extensional granite affinities, and the emplacement of the Baijuhuajian and Suzhou A-type granites, mark the beginning of extension during the Early Cretaceous at ca. 125 to 119Ma. The subsequent development of bimodal magmatism at 115 to 90Ma, with numerous arc-related mafic gabbros and I-type granites, together with some A-type granites, suggests that this major igneous event took place as a response to back-arc extension. On the basis of petrology, geochronology, tectonics, and elemental and isotopic geochemistry, we speculate that break-off and rollback of the subducting Palaeo-Pacific Plate during the Cretaceous were responsible for the Late Yanshanian regional tectono-magmatic evolution in the area. We suggest that this process facilitated a strong and rapid linear upwelling of the asthenospheric mantle beneath the coastal area of southeastern China, with consequential extension of the overlying continental lithosphere, and ultimately the large-scale Late Yanshanian magmatism of the study area. |
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ISSN: | 0012-8252 1872-6828 |
DOI: | 10.1016/j.earscirev.2013.09.007 |