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Seismic Geomorphology of Early Miocene Multi-Stage Shallow-Water Turbidite System, Yinggehai Basin, China
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 80th EAGE Conference and Exhibition 2018, Jun 2018, Volume 2018, p.1 - 3
Abstract
The multi-stage shallow-water turbidite system is identified in Dongfang (DF) block of the Yinggehai basin on the northern margin of South China Sea at the early Miocene. The heavy mineral assemblage shows Blue River delta (western Vietnam) feed the turbidite shelf fan in two DF blocks (DF-a and DF-b). The facies architectures such as the channel fill, overbank deposit, and lobes are identified through seismic geomorphology approaches. Four stages of shallow-water turbidity system are recognized based on the stratal stacking patterns via seismic slice, which indicated the spatial and temporal difference of characteristics of the channels and lobes between two studied blocks. DF-a block distributed multi-stacked and isolated lobes, whereas DF-b block mainly established deeply incised and elongated channels. Regarding of lithology, DF-a block mainly developed as muddy lobes, which comprise fine sandstone with deformation structures and parallel bedding and reflected low hydrodynamic power. But DF-b block contained sandy turbidite channels and complex cross-bedding structure. In terms of syndepositional topography, the DF-a block has a relatively low gradient, in contrast to DF-b block of a steeper slope. Topographic variations in two block make gradient increase from the DF-a block to the DF-b block, which might force channels deeply incised.