| Nanpu Sag is located in the north of Huanghua Depression, is a double half graben basin whose north side is faulted and south side overlapped. In this paper, based on measurement of core, logging data, seismic and lots of testing data, guided by the theory of sedimentology, a systematic research of provenance system and sedimentary system of palaeogene in Nanpu sag was carried on.Nanpu sag got multiple provenance systems in Palaeogene. Combining with the results of previous studies on palaeohighs around the basin,through Dickinson graphic,clastic particles, heavy minerals, sand and conglomerate percentage isoline, seismic clinoform reflection and landforms of basin margin analysis that, there are three main provenance systems in Nanpu sag, northern orogenic belt provenance system, southern stable land block provenance system and mix ing-character provenance system. All three main provenance systems had inheritance development feature in palaeogene entire time. Northern provenance system gives priority to igneous rock cuttings in detrital composition. In the aspect of heavy mineral, higher iron oxide content is a typical trait. At the same time, unstable heavy mineral components fall over time. In Dickinson graphics, accumulation area transite from undissected arc to basement uplift. All that represents northern provenance system had a transition from unstable to stable orogenic belts geotectonic background. Metamorphic debris and igneous debris plays a vital role in Southern provenance system. Transparent and stable heavy minerals are the important part of heavy minerals combination. Southern provenance accumulation area in Dickinson graphics has no big change. All of which exemplifies Southern provenance has a strong stability background. Eastern provenance system has the mixed characteristic and varies considerably. Combined with the ancient uplift analysis we reach the conclusion that eastern provenance system has various types of parent rocks and steady supply fragmentary material.Nanpu sag develops a variety of types of deposional systems, including meandering river delta, braided river delta, fan delta, beach bar and fluxoterbidite. In Es3 slope-break zone of Nanpu sag, sedimentary and subsidence center is located in Gaoshangpu- Liuzan area. There are many fan delta sand body developed in downdropped block of boundary fault. In gentle slope belt, continuous development of the braided river delta was the do minant phase. In later period, structure uplift cause southern part denudated. During Es2~Es1, due to previous tectonic elevation, north-east part of the basin develop alluvial fan which was transformed by fan delta. In Es1 x water body is shallow and tecto nic activity is weak, in this context, beach and bar sandbody was developed well in Beipu area. Later, water deepening, in deep end of the basin developed contains turbidity deposit. In Ed, lake expand again, at gentle slope belt translate braided river de lta into meandering river delta. Due to the tilting of Gaoliu fault, north-east part of the basin was no longer accepted deposit and got erosion. Boundary fault downthrow side successive develop fan delta and in deep lake area had a lot of turbidite deposit. Untile Ed1, the lake basin tended to be filled, gentle slope belt deposit large area meandering river delta sand body. O n the whole, on second grade sequence boundary develop large area of sand body deposition, on secondary sequence maximum flooding sur face develop turbidity sand deposit.As a whole, Nanpu Sag provenance system had three system of northen,southern, eastern in plane. Three stage of sedimentary sequence controlled by tectonic evolution stages in vertical. Sedimentary faceis zone had a clear distinction between each other due to provenance system. The sedimentary facies types had inheritance characteristic but also had mutual evolution expression. |
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