Sequence Stratigraphy of Carboniferous Donghe Sandstone in Tazhong Area,Tarim Basin
- Rev Recd Date: 1996-02-12
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Key words:
- Sequence stratigraphy /
- Sedimentary system /
- Donghe Sandstone,Tazhong /
- Area
Abstract: Donghe Sandstone in Iarim Basin is a set of fine elastic reservoir rocks which deposited on the regional unconformity of early Hercy progeny. The origional basin where the Donghe Sandstone deposited is an intracratonic depressional basin. The basin with the characterstiris of shallow water and low slope was formed by the compression between the north and south plates.basin.The Tazhong area located in the east part is one of the components in the origional The sequence stratigraphy of longhe Sandstone within a depressional basin was depicted in this paper on the basis of study of seismic data,well logging 70-120 m,while and drilling materials. The thickness of Donghe Sandstone vanes between the maximum thickness is more than 165 m,it overlaped eastward and on the buried hill. The Donghe Sandstone is a standard type 1 sequence,including lowstand system tract,transgressive system tract and highstand system tract. It is analogous to the stratigraphyic unit formed by the third order cu-static fluctuation. Compared to the passive continental margin sequence stratigraphic model, the lowstand tract of this sequence only developed the fluvial deposits on land and lacked the early submarine fan,slope wedge,progradational complex and incised valleys which developed on shelf. There is no condensed sections in the transgressive system tract owing to the plenty of source materials and adjacent to the source area. Because of the transgression,the delta and estuary are the main depositional system which formed in the different locations and periods from the east to the west. The parasequences have the stackingg patterns from slight retrogra elation to aggradation. The highstand system tract which is mainly littoral depositional system is widely distributed,its parasequences have the progradational stacking pattern. During the late stage of highstand system tract,the infiiling of deposits and falling of sealevel lead to the basinward movement of estuary line and equlibrium point, which accounts for new land accom-mondation and developed the fluvial and alluvial deposits.
Citation: | Guo Jiianhua, Zeng Yunfu, Zhai Yanghong, Liu Shengguo. Sequence Stratigraphy of Carboniferous Donghe Sandstone in Tazhong Area,Tarim Basin[J]. Acta Sedimentologica Sinica, 1996, 14(2): 56-65. |