Geochronology and geochemistry of mafic igneous rocks in the Zhegu area of southern Tibet

The Zhegu region, located in southern Tibet, is positioned within the central and eastern segments of the Tethys Himalayan tectonic belt. In this area, mafic igneous rocks are predominantly intrusion into Jurassic strata, occurring as vein-like bodies. This study presents zircon U-Pb age determinati...

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Main Authors: Ming Cheng, Saijun Sun, Yuanlin Lou, Yingzi Min, Yao Tang, Xinyue Li, Ming Zhang, Xuming Hu, Tianyong Wan, Hao Zou, Kaihong Xu, Chao Chen, Junjie Zhang, Wei Guo
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-07-01
Series:Frontiers in Earth Science
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Online Access:https://www.frontiersin.org/articles/10.3389/feart.2025.1513583/full
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author Ming Cheng
Saijun Sun
Saijun Sun
Yuanlin Lou
Yuanlin Lou
Yuanlin Lou
Yingzi Min
Yao Tang
Xinyue Li
Ming Zhang
Xuming Hu
Tianyong Wan
Hao Zou
Kaihong Xu
Chao Chen
Junjie Zhang
Junjie Zhang
Wei Guo
author_facet Ming Cheng
Saijun Sun
Saijun Sun
Yuanlin Lou
Yuanlin Lou
Yuanlin Lou
Yingzi Min
Yao Tang
Xinyue Li
Ming Zhang
Xuming Hu
Tianyong Wan
Hao Zou
Kaihong Xu
Chao Chen
Junjie Zhang
Junjie Zhang
Wei Guo
author_sort Ming Cheng
collection DOAJ
description The Zhegu region, located in southern Tibet, is positioned within the central and eastern segments of the Tethys Himalayan tectonic belt. In this area, mafic igneous rocks are predominantly intrusion into Jurassic strata, occurring as vein-like bodies. This study presents zircon U-Pb age determinations and whole-rock geochemical analyses of diabase and gabbro samples from the region, aimed at elucidating their petrogenesis and geodynamic background. The zircon U-Pb ages yield crystallization ages of 130.7 ± 1.5 Ma for diabase and 131.6 ± 2.5 Ma for gabbro, both of which are consistent with the crystallization ages of ocean island basalt (OIB)-type mafic rocks in the Comei Large Igneous Province (130–136 Ma). Geochemical data reveal that these mafic rocks are characterized by elevated TiO2, FeOT, and P2O5 contents, alongside relatively low MgO content, indicative of tholeiitic affinities. They exhibit enrichment in light rare earth elements (LREEs) and high field strength elements (HFSEs) such as Nb, Hf and Y, resembling OIB signatures. These rocks show evidence of fractional crystallization without significant crustal contamination. Melting models suggest that the magmas originated from partial melting of a garnet-lherzolite mantle source. The petrogenetic characteristics of these rocks reflect interactions between the Kerguelen mantle plume and the overlying lithospheric mantle.
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spelling doaj-art-8ac15908fe6f4086b10dee09f1f254f42025-08-20T03:17:51ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632025-07-011310.3389/feart.2025.15135831513583Geochronology and geochemistry of mafic igneous rocks in the Zhegu area of southern TibetMing Cheng0Saijun Sun1Saijun Sun2Yuanlin Lou3Yuanlin Lou4Yuanlin Lou5Yingzi Min6Yao Tang7Xinyue Li8Ming Zhang9Xuming Hu10Tianyong Wan11Hao Zou12Kaihong Xu13Chao Chen14Junjie Zhang15Junjie Zhang16Wei Guo17Changsha Natural Resources Comprehensive Survey Center, China Geological Survey, Changsha, ChinaLaboratory for Marine Geology, Qingdao Marine Science and Technology Center, Qingdao, ChinaCenter of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, ChinaChangsha Natural Resources Comprehensive Survey Center, China Geological Survey, Changsha, ChinaInstitute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing, ChinaChina University of Geosciences, Beijing, ChinaChangsha Natural Resources Comprehensive Survey Center, China Geological Survey, Changsha, ChinaChangsha Natural Resources Comprehensive Survey Center, China Geological Survey, Changsha, ChinaChangsha Natural Resources Comprehensive Survey Center, China Geological Survey, Changsha, ChinaChangsha Natural Resources Comprehensive Survey Center, China Geological Survey, Changsha, ChinaChangsha Natural Resources Comprehensive Survey Center, China Geological Survey, Changsha, ChinaChangsha Natural Resources Comprehensive Survey Center, China Geological Survey, Changsha, ChinaChangsha Natural Resources Comprehensive Survey Center, China Geological Survey, Changsha, ChinaChangsha Natural Resources Comprehensive Survey Center, China Geological Survey, Changsha, ChinaKunming General Survey of Natural Resources Center, China Geological Survey, Changsha, ChinaLaboratory for Marine Geology, Qingdao Marine Science and Technology Center, Qingdao, ChinaCenter of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, ChinaChangsha Natural Resources Comprehensive Survey Center, China Geological Survey, Changsha, ChinaThe Zhegu region, located in southern Tibet, is positioned within the central and eastern segments of the Tethys Himalayan tectonic belt. In this area, mafic igneous rocks are predominantly intrusion into Jurassic strata, occurring as vein-like bodies. This study presents zircon U-Pb age determinations and whole-rock geochemical analyses of diabase and gabbro samples from the region, aimed at elucidating their petrogenesis and geodynamic background. The zircon U-Pb ages yield crystallization ages of 130.7 ± 1.5 Ma for diabase and 131.6 ± 2.5 Ma for gabbro, both of which are consistent with the crystallization ages of ocean island basalt (OIB)-type mafic rocks in the Comei Large Igneous Province (130–136 Ma). Geochemical data reveal that these mafic rocks are characterized by elevated TiO2, FeOT, and P2O5 contents, alongside relatively low MgO content, indicative of tholeiitic affinities. They exhibit enrichment in light rare earth elements (LREEs) and high field strength elements (HFSEs) such as Nb, Hf and Y, resembling OIB signatures. These rocks show evidence of fractional crystallization without significant crustal contamination. Melting models suggest that the magmas originated from partial melting of a garnet-lherzolite mantle source. The petrogenetic characteristics of these rocks reflect interactions between the Kerguelen mantle plume and the overlying lithospheric mantle.https://www.frontiersin.org/articles/10.3389/feart.2025.1513583/fullzircon U-Pb agewhole-rock geochemistryOIB-like type mafic rocksKerguelen mantle plumesouthern Tibet
spellingShingle Ming Cheng
Saijun Sun
Saijun Sun
Yuanlin Lou
Yuanlin Lou
Yuanlin Lou
Yingzi Min
Yao Tang
Xinyue Li
Ming Zhang
Xuming Hu
Tianyong Wan
Hao Zou
Kaihong Xu
Chao Chen
Junjie Zhang
Junjie Zhang
Wei Guo
Geochronology and geochemistry of mafic igneous rocks in the Zhegu area of southern Tibet
Frontiers in Earth Science
zircon U-Pb age
whole-rock geochemistry
OIB-like type mafic rocks
Kerguelen mantle plume
southern Tibet
title Geochronology and geochemistry of mafic igneous rocks in the Zhegu area of southern Tibet
title_full Geochronology and geochemistry of mafic igneous rocks in the Zhegu area of southern Tibet
title_fullStr Geochronology and geochemistry of mafic igneous rocks in the Zhegu area of southern Tibet
title_full_unstemmed Geochronology and geochemistry of mafic igneous rocks in the Zhegu area of southern Tibet
title_short Geochronology and geochemistry of mafic igneous rocks in the Zhegu area of southern Tibet
title_sort geochronology and geochemistry of mafic igneous rocks in the zhegu area of southern tibet
topic zircon U-Pb age
whole-rock geochemistry
OIB-like type mafic rocks
Kerguelen mantle plume
southern Tibet
url https://www.frontiersin.org/articles/10.3389/feart.2025.1513583/full
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