Spatial-temporal distribution and tectonic setting of Mesozoic W-mineralized granitoids in the Xing-Meng Orogenic Belt, NE China

ABSTRACT

The Xing-Meng Orogenic Belt is characterized by intense and widespread Mesozoic granitic magmatism related to large-scale W mineralization. Three periods of W-mineralized granitic magmatism can be distinguished: Early Triassic, Early–Middle Jurassic, and Late Jurassic–Early Cretaceous. Early Mesozoic W-mineralized granitoids are I-type granites with metaluminous to weakly peraluminous characteristics, with higher Rb concentrations and lower K/Rb ratios than coeval W-barren granitoids. Late Mesozoic W-mineralized granitoids belong to highly fractionated A-type granites, enriched in Rb, Th, and U, and depleted in Ba, Sr, P, Ti, and Eu. They have higher Rb/Sr and U/Th ratios, and lower (La/Yb)_N, LREE/HREE, Eu/Eu*, K/Rb, Zr/Hf, Nb/Ta, and Y/Ho ratios than contemporary W-barren granitoids. Mesozoic W-mineralized granitoids mainly originated from the partial melting of juvenile lower crust, whereas Early Mesozoic W-mineralized granitoids encompassed minor reworked ancient crustal material. Triassic W-mineralized granitoids formed in a syn- and/or post-collision setting related to the closure of Paleo-Asian Ocean. Early–Middle Jurassic W-mineralized granitoids formed in a compressional setting created by the subduction of Paleo-Pacific Ocean plate in the east and the closure of Mongol-Okhotsk Ocean in the west. Late Mesozoic W-mineralized granitoids formed in a post-orogenic extensional setting controlled by the MOO and PPO tectonic regimes.

KEYWORDS:

• Xing-Meng orogenic belt
• NE China
• W-mineralized granitoids
• W-barren granitoids
• Mesozoic
• W mineralization

Highlights

1. Three periods of W-mineralized granitoids were distinguished: Early Triassic, Early–Middle Jurassic, and Late Jurassic–Early Cretaceous.

2. Early Mesozoic W-mineralized granitoids are I-type granites, whereas Late Mesozoic W-mineralized granitoids belong to highly fractionated A-type granites.

3. Mesozoic W-mineralized granitoids mainly originated from the partial melting of juvenile lower crust.

4. (La/Yb)_N and (LREE/HREE) vs. δEu, U/Th, Nb/Ta, Zr/Hf, K/Rb, and Y/Ho vs. Rb/Sr, and Nb/Ta vs. Zr/Hf diagrams can be used for discrimination of Late Mesozoic W-mineralized and W-barren granitoids.

Acknowledgments

We are grateful to the Prof. Robert Stern for his constructive comments which greatly help in improving our paper. We would like to thank three anonymous reviewers for their thoughtful suggestions that have helped to improve the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

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Additional information

Funding

This study was financially supported by the National Natural Science Foundation of China (Grand No. 91962104)