The late Mesozoic–Cenozoic tectonic evolution of the South China Sea: A petrologic perspective

Abstract

Interpretations of seismic, gravity and magnetic anomalies and structural data on the coastal zone of southern part of Central Viet Nam (SCVN) and the adjacent Tertiary basins suggest several phases in the tectonic evolution of the study region since the Late Cretaceous to Quaternary. In this paper, we try to clarify the tectonic evolution of SCVN and the adjacent continental margin. The Cretaceous -Paleocene tectonic phase commenced after cessation of the West Pacific plutonic magmatic activity that produced numerous diabases and aplite dykes of mainly submeridian orientation. It was characterized by N-S compression and E-W extension. The geomorphology and geology of SE Asia were considerably changed during the Neotectonic phases caused by collision between the Indian plate and the Eurasian continent. Two tectonic phases -Early and Late Neotectonic -are separated by a regional unconformity represented by a boundary surface between below strongly deformed strata (synrift) and above less deformed formations (post-rift). The Early Neotectonic phase was related to the left-lateral movement of the Red River Fault Zone (RRFZ) and includes two tectonic sub-phases: Eocene -Oligocene (NW-SE compression), and Oligocene -Miocene (E-W compression). Activity in the Oligocene-Miocene sub-phase gave birth to rift basins in the continental margin of the SCVN. The Late Neotectonic phase began since the RRFZ stopped left-lateral movement and the East Viet Nam (or South China) Sea stopped spreading. The Late Neotectonic phase is also divided into two tectonic sub-phases: Late Early Miocene (sub-meridian compression), and Late Miocene -Pliocene (NE-SW compression). The Late Miocene -Pliocene sub-phase is characterized by vertical movements that caused episodic uplifting of the onland terrains, and subsidence of the offshore Phu Khanh basin. Besides, Miocene -Pliocene-Quarternary basaltic eruptions were widespread all over the southern Indosinian terrain and the continental margin.

The role of rifting in the development of the continental margins of the southwest subbasin, South China Sea: Insights from an OBS experiment

“…There are several basement high features around the SWSB, including the Macclesfield Bank, Reed Bank, Zhongjian Massif and Zhenghe Massif. Their Precambrian metamorphic basements (Yan and Liu 2004) suggested that they deformed little and remained as rigid blocks during the progressive continental lithosphere rifting, and have a continental origin from the South China Block (Yan et al 2014). They acted as a sharpener during the breakup of the continent until the advent of seafloor spreading of the SWSB (Ding and Li 2016).…”

New isotope–geochemical and mineralogical data on the ultramafic xenoliths in the volcanic rocks of the Kamchatka–Koryak region: Two types of mantle protolith in the modern island-arc system

“…The pyroxenites-andesitesbasanites trend of the rocks of the Valovayam River is also significantly displaced toward the enriched EM-II component, where mantle metasomatism is best expressed. The displacement of some data points toward an increasing radiogenic lead component Δ208/204 and Δ207/204 toward the EM-II component may indicate the contribution of the asthenospheric mantle reservoir [38] to the formation of this type of xenoliths. The localities of the "within-plate" xenoliths are confined to the large Sr-isotope anomalies of Central Kamchatka (Bakening volcano) and the Bering Sea region (Valovayam River and Cape Navarin), thus reflecting traces of penetration of asthenospheric diapirs into the lower lithosphere [11].…”

Upper mantle and transition zone structure beneath Leizhou–Hainan region: Seismic evidence for a lower-mantle origin of the Hainan plume

“…Those models, however, are in contradiction with a few observations including the amount and the precise age of motion of Red River fault, as well as the kinematic evolution of the SCS spreading (Searle, 2006). Those models completely overlooked the possible presence of a deep mantle upwelling whose initiation likely coincided with the SCS opening (Yan et al, 2014).…”

“…However, with a history of extensive riftings and possible presences of deep mantle upwelling (Wang et al, 2013) as well as a late Mesozoic subduction zone (Yan et al, 2014), the mantle structure beneath Leiqiong is of course a complex 3-D structure. As shown in Fig.…”