冲绳海槽高分辨率层序地层研究

冲绳海槽为西太平洋内弧盆体系中一个典型的弧后盆地,其形成和发展与太平洋板块、欧亚板块和菲律宾板块活动有关,为海底扩张的结果,具有高的热流值和活火山的岩浆活动。中新世以来的太平洋活化区,沉积物包括海洋的生源物质和陆源碎屑物质,地层中记录了古海洋环境和大陆古气候变化的有关信息,对该区进行高分辨率层序地层研究和计算沉积速率显得尤为重要。在小波变换的基础上建立高分辨率的层序地层格架,以米兰科维奇思想对测井曲线和天文周期进行频谱分析,从而求得地层的沉积速率是沉积时限,另外对测井曲线和天文周期曲线运行调谐,建立起地层的天文年代标尺,从而对地层进行精确的定年。

HIGH RESOLUTION SEQUENCE STRATIGRAPHY OF THE OKINAWA TROUGH

The Okinawa Trough is a typical back-arc basin of the west Pacific arc-basin system resulted from the joint action of the Pacific plate, Eurasian plate and Philippine Sea plate. It is located in the Pacific activation zone since Miocene. Owing to the seafloor spreading, there occur high heat flow values and active volcanic activities in the trough. Sediments are coming from marine biogenic materials and terrigenous debris, which contains rich formation of the paleo-environment and the climate change. Therefore, the study of high resolution sequence stratigraphy and sedimentation rate is critical important. In this paper, the high resolution sequence stratigraphy of the trough is established based on the wavelet transform and logging curve interpretation. Milankovitch and astronomical cycle are used for spectrum analysis. Sedimentation rate and the duration are calculated, in addition to tuning logging and astronomical cycle curves. Finally, a sequence on astronomical scale with accurate time is established.