کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6434455 | 1637149 | 2016 | 12 صفحه PDF | دانلود رایگان |
- A geological model of point bar is established and the method to identify paleocurrent direction is proposed.
- Two types of delta were recognized in Yaojia Formation of Songliao Basin.
- Large-scale turbidity current systems have been found in the TST of k2n1 Formation.
- Fourteen sub-lacustrine fans in different sizes were formed by turbidity current flowing from the delta to the lake.
- The sedimentary model provides a guiding significance and a new technological means for the optimization of exploration targets.
With the aid of seismic geomorphology method, depositional systems such as fluvial-delta and turbidity current of the Cretaceous Quantou-Nenjiang Formations in Sangliao Basin were studied in detail as well as the morphology, dimension, depositional structures and boundaries of these sedimentary bodies. A geological model of a point bar in a fluvial system and the method to identify paleocurrent direction were proposed. The delta of Yaojia Formation with a gentle slope less than 1.4â° in trangressive system tract (TST) was controlled by lake waves. Subaqueous distributary channels were widely developed in large-scale delta front with a width more than 16Â km. Fluvial-dominated deltas with leaf and bird's foot shapes were widespread in highstand system tract (HST) of Qinshankou and Nengjiang Formation with moderately high slope gradients of 4â° and 6.7â°.The width of the leaf-like and bird's foot delta front ranges from 1Â km to 4Â km and 3Â km-5Â km respectively. The mouth bar were well preserved due to the poorly developed widely distributed subaqueous distributary channels and the delta plains having widths of 9Â km-15Â km, 16Â km-25Â km respectively. Many turbidity current systems were recognized in the TST of the first member of Nengjiang Formation and the distribution area is about 10,000Â km2. Fourteen sublacustrine fans with different dimension were formed by ten fluvial-delta systems extending 30Â km-70Â km toward the lake from the west and south. With the application of seismic geomorphology, the analysis of fluvial system, delta system and turbidity current system could switch from approximation to quantitative analysis. Sedimentary model proposed for point bars and the quantitative analysis of delta system could provide new technical support for exploration and drilling plan. The research on turbidity current systems will also be beneficial for new exploration targets.
Journal: Marine and Petroleum Geology - Volume 78, December 2016, Pages 836-847