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Petrogenesis and tectonic significance of the Early Cretaceous Xizhelimu diorite in Keyouzhongqi, Inner Mongolia, China.

Authors :
Tian, Li
Sun, Deyou
Gou, Jun
He, Zhonghua
Zhang, Duo
Source :
Canadian Journal of Earth Sciences; Oct2023, Vol. 60 Issue 10, p1428-1442, 15p
Publication Year :
2023

Abstract

To determine the emplacement age, petrogenesis, and geodynamic setting of the Xizhelimu diorite in Keyouzhongqi, Inner Mongolia of northeastern China, a detailed study of the petrography, geochronology, and whole-rock geochemistry has been conducted. Geological and petrographic studies show that the Xizhelimu diorite is zoned: the central lithofacies zone is composed of medium-fine-grained monzodiorite and quartz diorite, and the marginal lithofacies zone is fine-grained diorite. The zircon U–Pb dating results show that the ages of the central and marginal facies are 133.5 ± 1.9 and 133.4 ± 1.4 Ma, respectively. The whole-rock rare earth and trace element characteristics of the Xizhelimu diorite show an O-type adakite affinity. Combining the analysis of zircon Hf isotope composition (ε<subscript>Hf(t)</subscript> values of +7.7 to +10.0), the geochemical features of whole rock, and the results of partial melting modeling, we suggest that the parental magma of the Xizhelimu diorite was derived from the partial melting of altered oceanic crust mixing with subducting sediments at shallow depths. In the early stage of early Cretaceous, the Xizhelimu diorite originated in an extensional setting, mainly related to the closure of the western part of the Mongol–Okhotsk Ocean. The upwelling asthenospheric flow in this extensional setting induced partial melting of the paleo-oceanic crust to form the parental magma of the Xizhelimu diorite. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00084077
Volume :
60
Issue :
10
Database :
Complementary Index
Journal :
Canadian Journal of Earth Sciences
Publication Type :
Academic Journal
Accession number :
172433038
Full Text :
https://doi.org/10.1139/cjes-2022-0094