非洲Lake Chad盆地上白垩统层序地层及沉积特征

UPPER CRETACEOUS SEQUENCE STRATIGRAPHIC AND SEDIMENTARY FEATURES OF AFRICAN LAKE CHAD BASIN

综合利用测井、录井和地震资料对非洲乍得的LakeChad盆地上白垩统进行了三级层序划分，在此基础上对层序’内部体系域沉积相类型及其特征进行了研究。LakeChad盆地的上白垩统可划分为2个地层组，对应3个三级层序、6个体系域，但只有下部的层序1发育较为完整，主要为河流相、三角洲相和滨一浅海相沉积，沉积物源主要来自于盆地东部、南部和西部的古隆起。

By comprehensive using the data of the well logging, mud logging and seismic results, third-order se- quences are divided in the Upper Cretaceous strata of Lake Chad Basin in African Chad. On the basis of the above, the sedimentary faeieses and their characteristics of the system tracts within the sequences are researched in detail. The strata have been classified into 2 formation groups that are correspondent to 3 third-order sequences and 6 sys- tem tracts. But only the Lower sequence I is comparatively well-developed, which is characterized by fluvial faci- es, delta facies and littoral facies sedimentations. The sources of the sediments are from the eastern, southern and western parts of the ancient uplifts.