The Structural Evolution Of Lin Qing And The Effect On Its Neopaleozoic

There had been three large scale tectonic movements happening in eastern part ofLinqing depression and Dongpu depression from Hercynian, which resulted in maldistributionof relic thickness of Neopaleozoic in these areas. The most important tectonic disturbanceform affecting the area was fault. Based on outcome of predecessors, main work of this paperwas described as follows. First, fault activity in the district was analyzed on the basis ofabundant seismic cross sections and log information. Second, plane of unconformity wasrecognized and structural layer was divided. Characteristic of Neopaleozoic was summed upthrough lithology, palaeophyte, well logging, and seismic facies and so on. Based on theseoutcomes, structural evolution of Mesozoic and Cenozoic Era in eastern part of Linqingdepression and Dongpu depression were analyzed through balanced section analysis. Final,combined with denudation recovering of Neopaleozoic, the effect of tectonic movement ofMesozoic and Cenozoic Era to Neopaleozoic was analyzed.It was shown from the result that feature of faults in each stage presented giveninheritance and diversity and basin evolution in Mesozoic and Cenozoic Era could be dividedinto six main stages according to tectonic stress field of the district. First, tectonic frameworkof Neopaleozoic was inherited in Triassic period. Because of Indosinian movement enhancing,the basin was compressed by north-south (or North North East) crustal stress that was resultedfrom collision of southern descending Yanzi plate.Second, Nearly latitudinal trending fold andreverse thrust was developed in the basin so Upper Triassic undergo uplifting and denudationin whole basin. Third, the basin was influenced by Yanshan movement and the NE-SW foldwas developed company with seldom fault. Along with enforced Yanshan movement, NEextension fault grow owing to NW-SE tensile stress and there were some NW faults too fromJurassic to Early Crataceous. Fourth,the basin underwent denudation because of influence ofYanshan movement Late Crataceous. Fifth, in Paleogene faults was well developed owing totensional regional stress field. The aligement of faults was mainly NE with seldom EW.Majority of faults began active in Kongdian-S4 and maximal intensity occurred in S3-S2. Thenthe intensity decreased in S1-Dongying. Tectonic framework and depocencer were controlled by several faults which activity was different in different district. Sixth, majority of faults diedout and region of interest began the stage of depression in Neogene-Quaternary.Neopaleozoic was influenced by structural evolution of Linqing. First, sedimentation oflayer was controlled by framework of basin in Neopaleozoic. Second, Neopaleozoic wascontinuously and deeply buried in Early - Middle Triassic. Third, Neopaleozoic underwentdenudation on regional bulge because the whole basin uplifted. Extent of uplift was large inNortheast and southwest of district and little in middle part. So denuded thickness distributedalong NW in Late Triassic. Fourth, influenced by late activity of faults, Neopaleozoic wasdenuded not only on regional bulge but also on heaved side of some active faults inJurassic-Cretaceous. The denuded districts were situated Neihuang uplift, Wucheng-Guantaobulge and Ningjin bulge. Fifth, majority of faults active intensively in Paleogene, soNeopaleozoic underwent denuded not only on Neihuang uplift but also on heaved side ofsome active faults in western Linqing depression. There was only denudation on Tangyi upliftin eastern Linqing depression. Sixth, Neopaleozoic was deeply buried in Neogene-Quaternary.