Salt-related structure and deformation mechanism of the Middle-Lower Cambrian in the middle-west parts of the Central Uplift and adjacent areas of the Tarim Basin

Abstract

The salt beds of the Middle-Lower Cambrian are widespread in the middle-west parts of the Central Uplift and adjacent areas, the Tarim Basin. This paper presents the results of seismic interpretation and drilling data analysis, which discovered that the salt beds were formed in an old geologic age, deeply buried, with relatively small scaled flowing and gathering and uneven distribution. As the regional detachment layers, the salt sequences considerably control the structural deformation of the up-salt Paleozoic, forming a series of hydrocarbon traps. In due course, the salt beds of the Middle-Lower Cambrian provide excellent cap rocks and trap conditions; thus the value of exploring hydrocabon reservoir in the target strata of the sub-salt Sinian-Cambrian is greatly increased. Research has shown that the salt-related structures of the Middle-Lower Cambrian in the area mainly exist in the form of salt pillow, salt roller, up-salt anticline, salt diapir, assemblage of the salt arch and up-salt fault-block, assemblage of basement fault and salt anticline, assemblage of the basement fault-block and salt dome, assemblage of salt detachment and fault-related fold, and assemblage of basement fault-block, salt arch and up-salt imbricated thrusts. The evolution and deformation mechanisms of the salt-related structures are controlled largely by basement faulting, compressional shortening, plastic flowing and gathering, superstratum gravitation, and up-salt faulting and detaching. They are distributed in rows or belts along basement faults or fault block belts.