Evaluating the evolution of the Red River system based on in situ U‐Pb dating and Hf isotope analysis of zircons

Abstract

[1] The Red River originates from SW China and SE Tibet and has a total length >1000 km. In this study, we present new U-Pb dating and Hf isotopic analysis of zircon grains, from both modern and paleoriver sands in order to constrain the provenance of the modern river and to decipher drainage evolution through time. Our data show that the Yangtze and Songpan Garze blocks are the most important sources for sediment, although this material is mostly reworked via younger sedimentary rocks in the upper reaches of the Red River. Sands in the Da River and to a lesser extent the Lo River have zircon ages indicating that they are minor contributors to the net flow, consistent with rock uplift, which is strongest in the upper reaches of the Red River, rather than precipitation being the primary control on erosion. Sediments eroded from the metamorphic rocks along the Red River Fault Zone appear to have made a greater contribution during the Miocene. Zircon ages suggest that the Red River flowed north of the Day Nui Con Voi in the Middle-Late Miocene. The Red River appears to have had a largely stable provenance since at least the Late Miocene. Upper Miocene sedimentary rocks NE of the Red River indicate the presence of a separate, large river in the Late Miocene. Hf isotope data indicate that the Irrawaddy River was never part of the Red River system. Although we do not exclude the Salween, Mekong, and Yangtze rivers from having been part of the Red River, any connection must have been pre-Middle Miocene.

Zircon U-Pb geochronology and heavy mineral composition constraints on the provenance of the middle Miocene deep-water reservoir sedimentary rocks in the Yinggehai-Song Hong Basin, South China Sea

“…253e250 Ma and 423e421 Ma, with subordinate Neoproterozoic and Paleoproterozoic ages (1100e500 Ma and 1900e1500 Ma, respectively). U-Pb detrital zircon ages of these two samples compare favorably with published geochronological data from the modern Red River (Bodet and Sch€ arer, 2000;Hoang et al, 2009) (Fig. 9), and could be mainly from the southern Yangtze Block, or recycled via Triassic sedimentary basins (Hoang et al, 2009).…”

“…U-Pb detrital zircon ages of these two samples compare favorably with published geochronological data from the modern Red River (Bodet and Sch€ arer, 2000;Hoang et al, 2009) (Fig. 9), and could be mainly from the southern Yangtze Block, or recycled via Triassic sedimentary basins (Hoang et al, 2009). The heavy mineral assemblages are magnetite, hematite, tourmaline, zircon and garnet (Fig.…”

“…Overall, it is reasonable to infer that the four samples have similar source that mainly derived from southern Yangtze delivered by Red River during the middle Miocene. The detritus could also have been transported from more distant sources, including Songpan-Garze, Qiangtang and Sibumasu blocks, by the Red River (Hoang et al, 2009).…”

“…Data for Indochina Block are from Carter and Moss (1999), Carter et al (2001), Carter and Bristow (2003), Roger et al (2007), Liu et al (2012) and Kamvong et al (2014). Data for Red River are from and Hoang et al (2009). Data for rivers in central Vietnam are from Usuki et al (2013) and Wang (2016).…”

“…The search for hydrocarbons in the strata has been hampered by a poor understanding of the sediment sources. Recently, the studies of river sediments and rocks in the potential source regions around the basin suggest that detrital zircon populations derived from the Red River are fundamentally different to those derived from central Vietnam and Hainan Island (Bodet and Sch€ arer, 2000;Hoang et al, 2009;Wang et al, 2014bWang et al, , 2015aWang et al, , 2015bJiang et al, 2015). Therefore, detrital zircon U-Pb studies could constrain the provenance of the Meishan Formation in this basin.…”