Basement Lithology and Distribution of Lishui Jiaojiang Cenozoic Sag in East China Sea

Abstract:

The lithology and distribution characteristics of the basement in Lishui Jiaojiang Cenozoic Sag were studied according to 2D seismic profiles and borehole data. As a result, metamorphic, granite, volcanic, sedimentary and volcanic sedimentary interbedded rocks basement units were qualitatively differentiated. The metamorphic rocks basement generally surrounds the central parts of the West Lishui Sub sag and Jiaojiang Sag with discontinuous, low frequency and moderate to weak amplitude seismic reflectors. However, in the northeast regions of the Lishui and Jiaojiang sags dominantly site the granite and volcanic rocks basement, in which the former appears to be mounded geometries with chaotic and weak amplitude internal reflections, whereas the latter represents a good stratification with moderate to continuous, low frequency and strong amplitude reflectors. Besides, the sedimentary rocks basement scattersl mainly in the Lishui Sag with moderate to continuous and strong amplitude reflectors, whereas the volcanic sedimentary interbedded rocks basement largely covers the central area of the Lishui Jiaojiang Sag with the continuity, frequency and amplitude varying violently in spatial.