Triassic felsic magmatism in SE Peninsular Malaysia: Petrogenesis and geodynamic implications for the Eastern Paleotethyan tectonic transition
Document Type
Article
Publication Date
12-1-2023
Abstract
Middle-Late Triassic volcanism and contemporary granitoids in East Malaya provide significant insights into the magmatic evolution and geodynamic processes of the Paleotethyan Ocean in SE Asia. This paper presents new zircon ages and whole-rock geochemical data including Sr-Nd-Pb-Hf isotopic analyses for newly identified felsic volcanic rocks and granites in SE Peninsular Malaysia. Zircon geochronological data constrain their formation time at 238-235 Ma. All samples have relatively high SiO2 contents with enrichment in light rare earth elements but have negative anomalies at Nb, Ta, Ti, and Eu on spidergrams. Calculated zircon saturation temperatures are between 840 degrees C and 957 degrees C. Samples have (Sr-87/Sr-86)i ratios between 0.70501 and 0.71014 and epsilon(Nd) (t) values ranging from -6.6 to -5.9, with (Pb-206/Pb-204)(i) = 18.45-18.77, (Pb-207/Pb-204)(i) = 15.68-15.71, and (Pb-208/Pb-204)(i) = 38.88-38.97. The zircon in-situ epsilon(Hf) (t) values and T-DM2 ages range from -5.6 to +4.5 and 1.62 Ga to 0.98 Ga, respectively. The primary melting source which produced these felsic volcanic rocks and granites was Proterozoic crustal rocks with a juvenile middle-lower crustal component. Triassic volcanism in SE Peninsular Malaysia northerly correlates with synchronous volcanic rocks in the Lancangjiang and Chiang Khong-Lampang-Tak volcanic zones. Our data, along with regional observations, indicate that these volcanic rocks and granites formed in a localized extensional setting in response to the Paleotethyan slab breakoff. While the initial collision of Sibumasu with East Malaya may have occurred at similar to 237 Ma.
Keywords
Felsic magmatism, Zircon U-Pb dating, Elements and Sr-Nd-Pb-Hf isotopes, Slab breakoff, Eastern Paleotethyan Ocean, Peninsular Malaysia
Divisions
GEOLOGY
Funders
National Natural Science Foundation of China (NSFC) (42330302) ; (42072256) ; (41972235),Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) (311022010),Fundamental Research Funds for the Central Universities (22lgqb14)
Publication Title
Lithos
Volume
462
Publisher
Elsevier
Publisher Location
RADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS