Late Paleozoic-Early Mesozoic granitic rocks in Eastern Peninsular Mmalaysia: New insights for the subduction and evolution of the Paleo-Tethys

• Main Authors: Yu, Yongqi, Qian, Xin, Mustapha, Khairul Azlan, Sheldrick, Thomas C., Gan, Chengshi, Zhang, Yuzhi, Wang, Yuejun
• Format: Article
• Published: Elsevier 2022
• Subjects: QE Geology
• Online Access: http://eprints.um.edu.my/40876/
• Institution: Universiti Malaya

Well-preserved Late Paleozoic-Early Mesozoic igneous rocks in Peninsular Malaysia are important for investigating the Paleotethyan tectonic evolution. This study presents new zircon U-Pb dating, whole-rock geochemical, and Sr-Nd-Pb-Hf isotopic data for granitoids identified from the East Malaya. By utilizing all available data, the Permian-Middle Triassic granitoids in Eastern Peninsular Malaysia can be divided into three groups. Group A (289-270 Ma) I-type granites have higher epsilon(Nd) (t) values of - 6.6 to - 2.6 and zircon epsilon(Hf) (t) values of - 7.1 to + 4.9 than Group B S-type granites (285-272 Ma) with epsilon(Nd) (t) = - 10.1 and zircon epsilon(Hf) (t) = - 23.1 to + 1.5. Group C (254-244 Ma) with A-type characteristics, has epsilon(Nd) (t) and zircon epsilon(Hf) (t) values ranging from - 7.3 to - 3.8 and - 8.9 to + 2.2, respectively. The Pb isotopic values for three groups are similar with (Pb-206/Pb-20(4))(i) = 18.71-19.43, (Pb-207/Pb-204)(i) = 15.66-15.71 and (Pb-208/Pb-204)(i) = 38.27-39.43. Group A was derived from metaigneous rocks with a juvenile mafic component, while Group B was from metasedimentary rocks. Group C had a mixed source of ``ancient'' meta-mafic rocks with a juvenile mafic component. This study proposes that the Late Paleozoic-Early Mesozoic granitoids were formed in response to the subduction of the Paleotethyan Ocean, and that a tectonic transition from subduction to slab roll-back might occur at similar to 270 Ma. Subduction-related granitoids in East Malaya can northernly extend to the Tachileik Batholith in eastern Myanmar and Jinghong in SW China, and southernly link with W Borneo.