南海北部陆坡区深水水道沉积体系研究

IOCAS-IR > 海洋环流与波动重点实验室

	南海北部陆坡区深水水道沉积体系研究
其他题名	SEDIMENTARY SYSTEM OF DEEPWATER CHANNEL，THE SLOPE AREA OF NORTHERN SOUTH CHINA SEA
	袁圣强
学位类型	博士
	2009-05-16
学位授予单位	中国科学院海洋研究所
学位授予地点	海洋研究所
关键词	南海北部陆坡深水区深水水道浊流深水油气
摘要	被动陆缘陆坡深水区因蕴藏大量的油气及天然气水合物资源而受到石油行业的关注。峡谷水道作为重力流沉积物从陆缘向陆坡盆区搬运的主要通道，是现今海洋科学研究的热点，是“由源到汇”研究的重要内容。峡谷水道可以作为粗粒沉积物的最终沉积场所，已被钻探证实可作为良好的油气储集体。本文选择陆坡水道为研究目标具有科学和实际意义。本文借助1979年至2007年采集的2D（部分）、3D地震数据，参考部分钻井资料，以层序地层分析为基础，以多种地球物理属性为手段，以南海北部深水陆坡区为研究区，进行层序地层分析，并对陆坡水道的发育进行研究。层序特征分析发现琼东南南部陆坡具有不同于北部陆坡的物源供给模式，断陷期以北部华南地块和西南方向中南半岛为主要物源，也有部分来自西沙隆起的物源；拗陷期西南方向的中南半岛为主要物源区。通过大量2D地震资料研究，本文首次系统地研究了发育在南海北部陆坡的大型水道，该水道起源于莺歌海盆地东部、横跨琼东南盆地、西沙海槽，终结于南海西北次海盆西部，我们把该水道命名为“琼东南中央水道”。琼东南中央水道长约570km，宽4－8km不等，发育在上新统地层中，该水道的产生与中新世以来红河对莺歌海盆地充足的物源供给，中新世末的海平面下降以及5Ma左右红河断裂带的反转诱发的滑塌有关。基于新采集的3D地震资料和地球物理技术，本文首次在琼东南盆地南部陆坡深水区识别出深水水道，该期水道发育在更新统地层中，形态各异，有类似曲流河的曲流水道，也有典型的低弯曲侧向迁移水道。振幅特征显示该期水道主要以弱振幅细粒泥质充填为主，部分位置有强振充填反射，可能为粗粒充填。根据地震剖面和相干时间切片时空分析，认为该水道主要有3期侵蚀和3期充填过程。从展布特征来看，该期水道的形成与更新世（中）末次盛冰期海平面的下降，地震诱发中南半岛中部小型山脉河流的复苏对南海西部的供给有关。
其他摘要	The oil industry is interested in the deepwater slope area of passive margin because of its contained large scale of oil & gas and gas hydrate resources.Submarine canyons and deepwater submarine channels act as the primary conduits for sediment transported by gravity (turbidity) currents into the deep slope and basin area, and also can be the repositories for coarse-grained sediment, which is the important study content of “Source to sink”. Canyon and channel can be good reservoir of hydrocarbon have been proved by the well drilling on passive continental margin basins. So study of deepwater slope channel (canyon) has scientific and actual siginificance. Based on the 2D, 3D seismic data (acquired from 1979 to 2007) and well data, used 3D geophysical interpretation technologies (such as coherence time slice, RMS and 3D visualization) and sequence stratigrapy analysis, analysed the slope sequence and study the development of channel on the slope area of northern South China Sea. The south part of Qiongdongnan slope area has different provenance supply model compared to the north area. The provenance supply in rifting period was mainly from the southern Xisha Uplift and the SW mid-south peninsula and northern South China Block; whereas the provenance supply in post-rifting period was mainly from the mid-south peninsula. Trough the study of large scale of 2D seismic data, this dissertation discussed the extent and formation mechanism of the Qiongdongnan deep sea channel wholly first time. The Qiongdongnan deep sea channel is a large incised channel which extends from the east boundary of the Yinggehai Basin，through the whole Qiongdongnan and the Xisha trough, and terminates in the western part of the Northwest Subbasin of South China Sea. It is more than 570 km long, 4～8 km wide and developed in Pliocene strata. The channel formed as a complex result of global sea level drop during early Pliocene, large scale of sediment supply of the Yinggehai Basin, and the inversion event of the Red River strike-slip fault at 5.0 Ma induced slumps. Based on 3D seismic data and coherence time slice, RMS and 3D visualization, a series of deepwater channels were recognized on the slope that probably developed in the late Quaternary period. These channels trend SW-NE to W-E and show bifurcations, levees, meander loops and avulsions. Most of the detected channels are characterized by low-amplitude reflections and is likely to be dominated by mudstones with interbedded thin sandstones. These channels are formed by turbidity currents originated from the SW direction and were probably accompanied by a relative sea level drop, which related with the feed to west South China Sea by little scale of mountain river of the mid-south peninsula induced by earthquakes at that period.
页数	136
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/1213
专题	海洋环流与波动重点实验室
推荐引用方式 GB/T 7714	袁圣强. 南海北部陆坡区深水水道沉积体系研究[D]. 海洋研究所. 中国科学院海洋研究所,2009.

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