Mesozoic paleogeography and tectonic evolution of South China Sea and adjacent areas in the context of Tethyan and Paleo‐Pacific interconnections

Abstract

During the Mesozoic era, the South China Sea and its environs were located at the south-eastern margin of the Eurasian continent. There has been hot debate on the influences of Tethyan and Paleo-Pacific tectonics to the Mesozoic evolution of the area. This paper compiles lithofacies maps of six time slices and discusses the paleogeographic and tectonic evolution of the area based on this compilation and other data on structural deformation and magmatism. In the Early Triassic, the Paleotethys Ocean extended eastward to the study area through the Song Da passage. Then a significant east-west differential evolution began. In the Late Triassic, the western area uplifted as a result of the collision between the Indosinian and South China blocks during the Indosinian orogeny, and the Song Da passage has closed since then. Meanwhile, a transgression of Paleo-Pacific waters occurred in the eastern and south-eastern portions of the area, forming the 'East Guangdong-North-west Borneo Sea'. In the Early Jurassic, seawater transgression was even more pronounced, resulting into the connection of this sea with the Mesotethys Ocean to the west. Large quantities of Tethyan water carrying Tethyan organisms entered the area. In the Middle Jurassic, a short-lived transgression occurred in the eastern Mesotethys and resulted in the formation of the 'Yunnan-Burma Sea'. The Late Jurassic to Early Cretaceous was the climax of the subduction of both the Mesotethys and PaleoPacific towards the Eurasian continent. This led to the formation of the great 'Circum South-east Asia Subduction-Accretion Zone' in the Middle or Late Cretaceous. This paper also presents various lines of evidence for a newly recognized segment of this Mesozoic subduction-accretion zone buried under Cenozoic sediments in the north-eastern South China Sea.The deep-sea basin of the South China Sea (SCS) was formed by seafloor spreading in the Late Oligocene to Early Miocene (Holloway 1982;Taylor & Hayes 1983;Briais et al. 1993). The shelves and slopes of the SCS are floored mainly by Cenozoic sediments. While great attention has been paid to the geology and evolution of the SCS and its Cenozoic sedimentary basins, there has been little study on the pre-Cenozoic geology and evolution of the area. This has changed recently, stimulated by the urgent demand to know the pre-Cenozoic hydrocarbon potential of the region (e.g. Su et al.

Structural inversion in the northern South China Sea continental margin and its tectonic implications

“…Seismic reflections are correlated with well data from MZ-1-1 (Hao et al 2001;Yan and Liu 2004;Yan et al 2014;Fig. 3) and interpretations of nearby seismic profiles by Zhou et al (1995Zhou et al ( , 2006Zhou et al ( , 2008 and Zhu et al (1999). Drilling and logging data of well MZ-1-1 were acquired by industrial standards and are provided by TCPOC.…”

“…The distribution of middle to late Mesozoic (150 -90 Ma) granites in the northern SCS continental margin is well documented and indicates that granitic magmatism was active form the Jurassic to Cretaceous periods at a convergent setting (e.g., Li 2000; Chen et al 2008Chen et al , 2010Li et al 2012). Meanwhile, Chen et al (2010) reported a series of volcanic rocks including rhyolite, dacite, and andesite dated from 100 -55 Ma along the SE coastal range of China.…”

“…The published seismic profiles from the northern SCS (Zhou et al 1995(Zhou et al , 2006(Zhou et al , 2008 indicate that the Mesozoic basement and the Cenozoic sediment and formation were separated by seismic reflection T g (~66 Ma; Table 1). For the geological evolution of the SCS margin in the Cenozoic, the seismic reflector T 7 (~30 Ma) separated the syn-rift stage from the post-rift stage around the middle Oligocene.…”

“…This is critical to the tectonics of this region but has not been discussed until the drilling of well MZ-1-1 (Yan and Liu 2004;Shi and Li 2012;Yan et al 2014). Therefore, in this study, we have focused on the western Dongsha-Penghu Uplift area and tried to decipher the Mesozoic tectonic history of the northern Ru and Pigott (1986), Clift and Lin (2001), Shi et al (2005), Zhou et al (2008), and seismic profiles in this study. See Fig.…”

Cenozoic sedimentary evolution of deepwater sags in the Pearl River Mouth Basin, northern South China Sea

“…1), namely from the north to the south, the northern terrace, the northern depression zone consists of Zhu 3 and Zhu1 depressions, the central uplift zone consists of Shenhu, Panyu, and Dongsha uplifts, the southern depression zone consists of the Zhu 2 and Chaoshan depressions, and the southern uplift zone along the margin of the deep-sea basin. The basement of the Pearl River Mouth Basin consists of Cretaceous and Jurassic granites in its central and northern portions, Mesozoic unmetamorphosed sedimentary rocks in the east, and Paleozoic quartzite and other metamorphic rocks in the west (Zhou et al 2008b). The crust underlain the basin thins from *30 km near the coast in the north to *11 km near the deep-sea basin in the south (Huang 2005;Kido et al 2001;Nissen et al 1995).…”