Detrital zircon U–Pb geochronology, Lu–Hf isotopes and REE geochemistry constrains on the provenance and tectonic setting of Indochina Block in the Paleozoic

Abstract

In situ U–Pb geochronology, Lu–Hf isotopes and REE geochemical analyses of detrital zircons from Cambrian–Devonian sandstones in the Truong Son Belt, central Vietnam, are used to provide the information of provenance and tectonic evolution of the Indochina Block. The combined detrital zircon age spectra of all of the samples ranges from 3699Ma to 443Ma and shows with dominant age peaks at ca. 445Ma and 964Ma, along with a number of age populations at 618–532Ma, 1160–1076Ma, 1454Ma, 1728Ma and 2516Ma. The zircon age populations are similar to those from time equivalent sedimentary sequences in continental blocks disintegrated from the East Gondwana during the Phanerozoic. The younger zircon grains with age peaks at ca. 445Ma were apparently derived from middle Ordovician–Silurian igneous and metamorphic rocks in Indochina. Zircons with ages older than about 600Ma were derived from other Gondwana terrains or recycled from the Precambrian basement of the Indochina Block. Similarities in the detrital zircon U–Pb ages suggest that Paleozoic strata in the Indochina, Yangtze, Cathaysia and Tethyan Himalayas has similar provenance. This is consistent with other geological constrains indicating that the Indochina Block was located close to Tethyan Himalaya, northern margin of the India, and northwestern Australia in Gondwana.