Wang, M.A., Liu, Yingchao, Yang, Zhusen, Huizenga, Jan-Marten, Li, Zhenqing, Yue, Longlong, and Zhao, Sibo (2024) Geochronology and Petrogenesis of Late Carboniferous to Early Permian Basalts in the Central Lhasa Subterrane, Southern Tibet: Implications for the Evolution of the Sumdo Paleo‐Tethys Ocean. Acta Geologica Sinica, 98 (4). pp. 955-968.

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Abstract

Basalts from the Late Carboniferous to Early Permian are extensively developed in the central Lhasa subterrane, southern Tibet. Studying the petrogenesis of these rocks may have implications for the late Paleozoic arc magmatism along the central Lhasa subterrane uncovering more of the evolution of the Sumdo Paleo-Tethys Ocean and its dynamic mechanism. Basalt samples from the Luobadui Formation in the Leqingla area, NW of Linzhou City in the central Lhasa subterrane, southern Tibet exhibit arc-like geochemical signatures in a subduction-zone tectonic setting characterized by high Al2O3 and low TiO2 contents, fractionated REE patterns with low Nb/La ratios and high LREE concentrations, and negative HFSE anomalies. Based on their higher Th/Ce, Nb/Zr, and lower Ba/Th, Pb/Nd ratios, slightly negative to positive εNd(t) values, and the relatively high Sr-Pb isotopic compositions, these samples were probably derived from partial melting of a depleted mantle source of garnet + spinel lherzolite, metasomatized by subducted sediments around 297 Ma. Modeling of the trace elements indicates that these basalts experienced fractional crystallization of olivine, clinopyroxene and minor plagioclase during magma ascent and eruption. It is proposed that these Late Carboniferous–Early Permian basalts are associated with the northward subduction of the Sumdo Paleo-Tethys Ocean seafloor along the southern margin of the central Lhasa subterrane.

Item ID:	83729
Item Type:	Article (Research - C1)
ISSN:	1755-6724
Keywords:	geochemistry, northward subduction, Sumdo Paleo-Tethys Ocean, Lhasa terrane, Tibet
Copyright Information:	© 2024 Geological Society of China
Date Deposited:	23 Oct 2024 02:40
FoR Codes:	37 EARTH SCIENCES > 3703 Geochemistry > 370303 Isotope geochemistry @ 35% 37 EARTH SCIENCES > 3703 Geochemistry > 370302 Inorganic geochemistry @ 35% 37 EARTH SCIENCES > 3705 Geology > 370511 Structural geology and tectonics @ 30%
SEO Codes:	28 EXPANDING KNOWLEDGE > 2801 Expanding knowledge > 280107 Expanding knowledge in the earth sciences @ 100%
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