Work

Petrogenesis of Intermediate Rocks in Tethyan Himalaya Igneous Province (SE Tibet): The Role of Source Composition and Fractional Crystallization

Year: 2025

Type: article

Abstract: The origin of intermediate rocks within large igneous provinces (LIPs), which often exhibit a bimodal compositional distribution, remains poorly understood. To investigate the petrogenesis of such intermediate magmas within the Early Cretaceous Tethyan Himalaya igneous province in Tibet, we present a comprehensive study of zircon U–Pb geochronology, whole-rock geochemistry, and Nd isotopes for the tonalites from the Zhegucuo area. Zircon U–Pb dating yields a crystallization age of 130.81 ± 0.55 Ma. The rocks exhibit low Mg# and compatible element contents, indicating significant fractional crystallization of ferromagnesian minerals, plagioclase, and accessory minerals. Their homogeneous, near-chondritic εNd(t) values (−0.34 to +0.01) preclude significant crustal contamination. Based on field relationships, geochemistry, and isotopic evidence, we conclude that the Zhegucuo tonalites were generated by extensive fractional crystallization of basaltic magmas. FC3MS and FCKANTMS systematics reveal a peridotitic component in the mantle source of the Zhegucuo mafic rocks. The exceptionally high values of these proxies of the Zhegucuo tonalites are attributed to extensive fractional crystallization of evolved magmas.

Source: Minerals

DOI: 10.3390/min15121251

Authors: Shengsheng Chen, Haonan Jie

Institutions: China University of Geosciences, China University of Geosciences (Beijing), State Key Laboratory of Geological Processes and Mineral Resources

Language: English

Topic: Geological and Geochemical Analysis

Subfield: Geophysics

Field: Earth and Planetary Sciences

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,896

Funder: National Natural Science Foundation of China