A Preliminary Discussion Of The Development Characteristics Of The Palaeogene Gully In Huanghekou Sag

The research is based on the instruction of sequence stratigraphy, sedimentologyand seismic geomorphology, using the well logging and seismic data, combined withresults of previous studies, especially studied on the development characteristics ofthe Paleogene gully and its control on the sedimentary system of distribution inHuanghekou Sag.In accordance with the previous studies, make full use of three-dimensionalseismic data, especially the new-acquired three-dimensional seismic data of southwestslopes BZ31-32, and well drilling, well logging data, the various levels of threesequence boundaries were divided to recognize, summarizes the characteristics of theinterface by a single well analysis, compared the analysis of signal well withassociated wells, wells and seismic methods, then built the Paleogene sequencestratigraphic framework of Huanghekou Sag, three second-order sequences, eightthird-order sequences and nine three-order sequence interfaces were identified.Combined with seismic, tectonic and stratigraphic thickness map,palaeolandform map, because of geometric shape features, the gully are divided intothree types, they are U-shaped valley, V-shaped gully and W-shaped gully; accordingto the feature of causes can divided into sedimentary origin type and tectonic origintype, tectonic origin has5types including signal groove, double-break groove,structure hub zone, multi-level faults and strike-slip faults. With the combination ofthe movement of the tectonic evolution of the work area, we can clarify the causes ofthese two types and genetic mechanism of the entire study area at differentdevelopmental stages of the sequence.Based on the former studies, this paper also studied the role of the HuanghekouSag control gully on provenance transportation and distribution of depositional system.Considering the causes of deposition type gully can supply source during denudation,and it is also the place of deposition sites during depositing; tectonic origin type gullymainly exists as a communication source area and depositional center channel, it canalso be used as a small deposition area. In examining the impact of the development on the gully sedimentary systems in different developmental stages, we can learn thatnorth and south has the different characteristics of the terrain, the developments ofsedimentary systems are also different. and in the northern steep slope zone,sediments passed the gully fast and most of them develop into fan delta; while theslope in southern is gentle, sediments were flew with a lot of water along the directionof the gully, then most of them develop into braided river delta.