Sedimentary Response Of Tanyuan Fault Basin To The Uplifting History Of Provenances In The Paleogene

Yishu graben is a northeastern spreadable graben which transects the northeastern of our country. It is a branch of northern extending of the famous Tan-Lu fault and is considered the intricate structure characteristics of the northeastern basin with oil and gas. Tuanyuan fault basin is the most northern subordinate tectonic part of the Yishu graben. The boundaries of Tangyuan fault basin are controlled by the two northeastren parallel deep faults (F1 and F2). Inside of the Tangyuan fault basin, faults developed very much, they dissected the basin to many parts. In the other hand, the mountain around the fault basin with a complex structure development, so coupling systems between the Tangyuan fault basin and the surrounding mountain are very intricate.Through the sedimentary response of Tangyuan fault basin to the Xiao-xing-an-ling and Hua-nan and Tai-ping-gou upheaval, the author discussed the coupling system of Tangyuan fault basin and mountain in the Paleogene. In this paper, the objects are Paleogene Wuyun formation, Xinancun formation, Dalianhe formation and Baoquanling formation which lie in Tangyuan fault basin. Conjoining the study of paleocurrent direction, the distribution of heavy minerals and the distribution of sedimentary faces, the author study the orientation of the provenances. As a result, there are three orientations of the provenances, which are western provenance, northeastern provenance and eastern provenance. The western provenance was the main provenance of the Tangyuan fault basin when Wuyun formation deposited. In the Xinancun formation Eastern provenance became the main provenance and in the Dalianhe formation, western provenance and northeastern provenance played important part of the provenances. At last,northeast provenance was the main provenances when Baoquanling formation deposited.The statistic analysis of lithology of conglomerate, component of light mineral and lithology in Tangyuan fault basin reflect that mother rocks of Eastern provenance are granite and middle-low degree metamorphosed rock which match with the lithology of Tai-ping-gou and Hua-nan upheaval near to F1. The mother rocks of western provenance maybe in the main of granite and contain few of middle-low degree metamorphosed rock. Western and northeastern provenances with the same type of lithology match with the rocks of Xiao-xing-an-ling which distributes greatly in the west of Tangyuan fault basin. At the same time, veracity of the orientation of the provenances are proved. Different provenances have different component and configuration of sedimentary rock and content of different steady heavy minerals and unsteady minerals, which can respond exhumation or tectonic movement of provenance. Using the different sedimentary period configuration and component variety of clastic rocks near the controlled basin boundary fault (F1), the author interprets dextral strike-slip of F1 fault in the Paleogene. On the basis of heavy mineral weathering index and jointing unannealed zircon fission track age and reversal development of unannealed apatite fission track, the author discuss uplift history of different provenances and conform that western provenance and northeast provenance intensively thrashed in 61.9 Ma and rapid upheaved before 40 Ma. The east provenance of Tai-ping-gou and Hua-nan upheaval thrashed in the Late Cretaceous period and quickly upheaved in the Xinancun period.Erosion quantity of sedimentary interruption in Tangyuan fault basin discovers that there is erosion in the end of Xinancun formation and Baoquanling formation. Erosion quantity of Xinancun formation is 200m. We can not count the erosion quantity of Baoquanling formation because of the quality of data. But the section of earth quack discovers it is true that it is unconformity between the Baoquanlingand upper formation. At the same time, the calculated results of total sedimentation rate and structure sedimentation rate testify that in the Wuyun period structure sedimentation rate and total sedimentation rate are 38.4 m/Ma and 100.2 m/Ma, in the Xinancun period structure sedimentation rate and total sedimentation rate are 36.3 m/Ma and 94.7m/Ma, the structure sedimentation rate and total sedimentation rate of the Dalinhe period are 16.7 m/Ma and 43.4m/Ma, the structure sedimentation rate and total sedimentation rate of the Baoquanling period are 23.3 m/Ma and 60.7m/Ma. In the Wuyun and Xinancun period the rates of structure sedimentation and total sedimentation were very high. On the contrary, total sedimentation rate and structure sedimentation rate were low in the Dalianhe and Baoquanling period, especially in the Dalianhe period they were the lowest. Jointing the uplift history of mountain and sedimentation rate of basin, the author sums up Tangyuan fault basin-mountain and mountain's coupling system.There are three types relationship between Tangyuan fault basin and Xiao-xin-an-ling. The first type is quick uplift of mountain and quick sedimentation of basin. The example is Wuyun period. In the Xinancun and Baoquanling period, the basin and mountain's coupling is slow exhumation of mountain and rapid sedimentation of basin. And the third type which developed in the Dalianhe period is slow uplift of mountain and slow sedimentation of basin. Between Tai-ping-gou upheaval and Tangyuan fault basin there are two kinds of coupling, which are slow upheaving of mountain and quick sedimentation of basin and slow upheaving of mountain and slow sedimentation of basin. The represent of fist kind coupling occurred in Wuyun, Xinancun and Baoquanling period, and the other developed in the Dalianhe period.