资源环境科技发展态势分析平台

Cenozoic sedimentary strata of the continental margin are well preserved in ocean basins and offer an important geological window for studying source-to-sink relationships between potential source areas and sedimentary basins over time. We conducted coupled U-Pb dating and Lu-Hf isotope analysis of detrital zircon in fluvial sediments along northern and central Vietnam and sediment core in the western Yinggehai-Song Hong Basin in order to characterize the potential sources, investigate the sedimentary provenance, and decipher the crustal evolution processes of the source areas. The detrital zircons from the fluvial sediments reveal marked spatial changes in their age signatures that correlate with changing basement characteristics. The Red River system generally has multiple zircon age populations with peaks at ca. 30-25 Ma, 247-239 Ma, 441-414 Ma, 751-743 Ma, 1876-1742 Ma, and 2700-2200 Ma, in contrast to the sediments from central Vietnam, which commonly exhibit markedly different age patterns with well-defined Silurian and Triassic peaks (ca. 244-234 Ma and 438-419 Ma). The source-to-sink study demonstrates that both the Red River and central Vietnam materials have made important provenance contributions to the western Yinggehai-Song Hong Basin since the middle Miocene. The western basin has had constantly changing provenance since the middle Miocene because the contributions from these two source areas vary temporally. This integrated study also indicates that the southern Yangtze block and eastern Indochina block had a significantly different tectonic evolution history, as manifested by the age populations of major tectonic-magmatic events. Juvenile crustal growth occurred in the southern Yangtze block during the Neoproterozoic and late Paleozoic to Mesozoic, while the eastern Indochina block is characterized by prominent crustal additions in the Paleoproterozoic.