Multiple stages of continental rifting in Eastern Peninsular Malaysia: new insights from Jurassic–Cretaceous granitoids

Abstract

Mesozoic granitoids in Peninsular Malaysia provide crucial information on the temporal–spatial relationship between the Tethyan and Palaeo-Pacific domains. This paper presents new ages and geochemical data for newly identified Jurassic–Cretaceous granites and meta-granites from East Malaya. These granitoids can be divided into three groups. Group 1 consists of high-K calc-alkaline granites and granodiorites (171–162 Ma) with variable εNd(t) values of −7.4–+0.5, zircon εHf(t) values of −7.4–+8.6, and high initial ratios for206Pb/204Pb (20.04–20.65),207Pb/204Pb (15.73–15.79) and208Pb/204Pb (39.80–40.20). The melting of metasedimentary rocks with a juvenile mafic component formed Group 1 samples. Group 2 granite porphyries (c. 131 Ma) with A-type affinities and Group 3 granitic gneisses (c. 130 Ma) with I-type affinities share similar εNd(t) values (−7.2 to −5.5), zircon εHf(t) values (−10.1–+6.5), and initial ratios for206Pb/204Pb (18.81–19.02),207Pb/204Pb (15.71–15.77) and208Pb/204Pb (38.95–39.59). Although Group 2 and 3 samples were derived from an ‘ancient’ meta-mafic source region, Group 2 shows evidence for the involvement of a juvenile mafic component. All these granitoids are akin to the Permian–Triassic igneous rocks in East Malaya. The Jurassic–Cretaceous igneous rocks in Eastern Peninsular Malaysia were formed during multiple stages of continental rifting in response to Palaeo-Pacific slab rollback pulses rather than by Tethyan evolutionary processes.