We report the first sensitive high-resolution ion microprobe (SHRIMP) U-Pb zircon ages with geochemical data from metavolcanic rocks in the Lolotoi complex, Timor. The zircon U-Pb ages of two andesitic metavolcanic rocks yield a permissible range of the Middle Jurassic extrusion from 177. Ma to 174. Ma. The geochemical data indicate that the origins of the basaltic and andesitic metavolcanic rocks are products of prolonged oceanic crust and arc magmatism, respectively. They are originated from partial melting of lherzolites, providing an insight into the tectonic evolution of the forearc basements of the Banda volcanic arc. Thus, parts of the Banda forearc basement are pieces of allochthonous oceanic basalts and Jurassic arc-related andesites accreted to the Sundaland during the closure of Mesotethys, and are incorporated later into the Great Indonesian Volcanic Arc system along the southeastern margin of the Sundaland.
Bibliographical noteFunding Information:
We thank anonymous reviewer, Prof. K. Sajeev and Prof. Yungpeng Dong for constructive reviews and valuable comments. This work was supported as a Basic Research Project (GP2012-012; Tectonic evolution of the western Gyeonggi Block and construction of geologic DB system) of the Korea Institute of Geoscience and Mineral Resources (KIGAM), funded by the Ministry of Knowledge Economy , South Korea. This research was also supported by Korea International Cooperation Agency (KOICA) of South Korea and Democratic Republic of Timor-Leste Secretariat of State for Natural Resources.
All Science Journal Classification (ASJC) codes
- Earth-Surface Processes