Cretaceous Granitic Magmatism in South-Central Vietnam: Constraints from Zircon U–Pb Geochronology

Abstrakt

South-central Vietnam abundantly presents magmatic rocks with larger volumes of
Cretaceous granitic rocks. In this study, zircon U–Pb geochronology of granite samples from the Deoca,
Ankroet, and Dinhquan complexes in south-central Vietnam are utilized to investigate Cretaceous
granitic magmatism. According to U–Pb analysis results, zircon ages of granitic rocks display the Deoca
at ~113–92 Ma, the Ankroet at ~103–98 Ma, and the Dinhquan at ~97–113 Ma. The range of ages is
narrow from 113 to 92 Ma, with most common ages date at ~100 Ma. Published data and our results
display that Cretaceous granitic magmatism was active between ~87–118 Ma and most active at ~100
Ma in south-central Vietnam. Additionally, the Deoca and Dinhquan complexes show inherited ages in
Triassic followed by Proterozoic and Carboniferous to Ordovician. The obtained ages indicate that Itype
granitic rocks could be derived from melting of basement rocks. Our study suggests that I-type
granitic rocks in south-central Vietnam were significantly intruded around 100 Ma.