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利用广州海洋地质调查局在神狐海域采集的高分辨率地震数据,结合2007年第一次水合物钻探航次(GMGS01)获取的岩心资料,从地震反射结构和岩心粒度特征两个方面对GMGS01区块内残留在峡谷群脊部的细粒浊积体进行了识别和特征刻画。过水合物钻探站位的准3D地震剖面显示,GMGS01区块似海底反射(bottom simulating reflectors,BSR)之上的沉积体表现为2套特征迥异的反射单元:位于下部的薄层透镜状的杂乱反射单元,位于上部的厚层波状起伏形态的连续性中—强振幅反射单元。实际钻获岩心的粒度分析结果表明,沉积物的粒度为4~63μm,为细粒的粉砂或粉砂质泥。自下而上,沉积物的岩性和粒度特征没有发生大的变化,较为相似。但通过粒度CM图,可以发现,含水合物层段与不含水合物层段的沉积物表现为不同的特征,含水合物层段沉积物的结果近似与C=M基线平行,暗示了细粒浊积体的存在。结合神狐海域区域性覆盖的2D地震资料,研究认为发育在神狐海域北部的一系列小型水道,将会侵蚀下部地层的沉积物,使其沿着陆坡坡降的方向发生自北向南的再次搬运,在中—下陆坡的位置以细粒浊积体的形式再次沉积下来。神狐海域细粒浊积体的识别,将为从深水沉积的角度探讨GMGS01区块内水合物的不均匀性分布提供依据,从而有助于进一步揭示该区域水合物的成藏机制和富集规律。
Based on the high-resolution seismic data acquired by the Guangzhou Marine Geological Survey in Shenhu sea area and the core data obtained from the first hydrate-drilling voyage in 2007 (GMGS01), the GMGS01 area The fine-grained turbidites remaining in the ridges of the canyon in the block were identified and characterized. The quasi-3D seismic section of the perhydrate hydrate drilling station shows that the sediments above the GMGS01 block-bottom simulating reflectors (BSRs) are characterized by two sets of distinctly distinct units of reflection: a thin lenticular mess at the lower part Reflective unit, located in the upper part of the thick layer undulating continuity of medium - strong amplitude reflection unit. Particle size analysis of the actual core drilled shows that the sediment has a particle size of 4 ~ 63μm and is fine-grained silty or silty mud. Bottom-up, the lithology and grain size characteristics of the sediments did not change much, much like that. However, by means of the CM map, it can be seen that the sediments with hydrate intervals and hydrate-free intervals show different characteristics. The results of hydrate-bearing sediments are approximately parallel to the C = M baseline, suggesting that fine The presence of granular aggregates. Combined with the 2D seismic data of Shenhu sea area, it is considered that a series of small watercourses developed in the north of Shenhu sea area will erode the sediments of the lower strata and make them occur again from north to south in the direction of slope downhill Moving, the sediments were re-deposited in the form of fine-grained turbidites at the mid-lower slope. The identification of fine-grained turbidites in Shenhu sea area will provide a basis for exploring the inhomogeneity distribution of hydrate in the GMGS01 block from the point of deep-water sediment, which will be helpful to further reveal the accumulation mechanism and enrichment of hydrate in this area law.