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Pliocene–Quaternary evolution of the continental shelf of central Vietnam based on high resolution seismic data

2013; Elsevier BV; Volume: 79; Linguagem: Inglês

10.1016/j.jseaes.2013.08.001

1878-5786

Mai Thành Tân, Lê Van Dung, Le Duy Bach, Nguyen Bieu, Tran Nghi, Hoang Van Long, Phan Thien Huong,

earthquake and tectonic studies

The continental shelf of central Vietnam is characterized by complex geological structures in a strike-slip setting and thus by unique morphology compared to other parts of the Vietnam shelf. Studying the Pliocene–Quaternary sediments in this area allows the processes that control the stratigraphic evolution to be highlighted. In this paper, we present new results derived from high resolution seismic data that reveal the geological evolution of the continental shelf of central Vietnam during the Pliocene–Quaternary. Our results demonstrate that the continental shelf of central Vietnam is narrow relatively to other parts of the Vietnam shelf. The evolution of the shelf during the Pliocene–Quaternary was controlled by the pre-Pliocene rifting process. However, fault systems below the present shelf were not strongly active during the Pliocene–Quaternary period, except for several listric faults in the slope. Nonetheless, Quaternary volcanic activities occurred widely both offshore and onshore, especially near the major faults. The Pliocene–Quaternary sedimentary deposits were subdivided into 7 units based on unconformities as result of marine regression corresponding to glacial cycles. Sedimentary environments during this period consist of coastal plain, fluvial, nearshore and shelf environments. Most of the Holocene sediments were trapped nearshore while the outer shelf is characterized by abundant lag gravels as a result of rapid sea level rise between ∼20 and 8 ka.