SEDIMENTARY CHARACTERISTICS AND DEPOSITIONAL EVOLUTION OF LITTORAL-TIDAL FLAT SYSTEM OF SILURIAN ROCKS IN THE TABEI AREA, TARIM BASIN, NW CHINA

The marine clastic rock of the Silurian in the Tabei Area is a favorable reservoir. Based on an analysis of geological data such as core, logging, and seismic information, this study investigated the characteristics and differences of the Silurian rocks in the Tabei area main sedimentary system types. Both tidal flat and littoral have been meticulously depicted. In addition, the paleogeographic environment and depositional evolution features of the Silurian rocks in this area have been remodeled. The obtained results show that: (1) according to the difference in sedimentary environment, tidal flat facies have been subdivided into shallow tidal flat and bay tidal flat. (2) During the Early Silurian stage, the center-western region of the study area developed an incised channel with curved characteristics, which was associated with the coastal plain. (3) The whole Silurian deposition was significantly controlled by tectonic movement. Consequently, under the background of Late Caledonian orogeny, the Tabei area was gradually uplifted, and its depocenter constantly migrated southward. This resulted in the vertical transformation of sedimentary types from an incised channel-coastal plain-shallow tidal flat system to a littoral-bay tidal flat system. Moreover, Backshore and supratidal zone were generally denuded due to uplifting at a later stage.