| Based on abundant outcrop data, Hechi-Yishan fault zone was analyzed systemically on structure characteristic, geometry and kinematics characteristic, form evolvement and the relation with petroleum and gas, many kinds of technology were used in this research, such as geology structure section, seismic section, equilibrium profile, stress field analysis, and so on. The main results as follows: 1. Hechi-Yishan fault zone is located in the north of Guizhong depression, which general strike is NW-EW and consists of a series of obduction fault. Generally, there are two main faults, the fault-fold belt about 5-20km is made of main faults, subsidiary faults and concomitant folds; The dip of main faults is N or S; It can be divided into four different structural sections along its strike (Hechi section, Yishan section, Liucheng section and Yingshan section). There are some differences among these sections in structure characteristic, such as fault structure, associated structure, fold association style, deformation of rock, and so on. 2. Fault zone is very clear in not only geophysical field but also seismic section, and it controls the development and distribution of sedimentary facies. On its downthrow, extension-depression basin develops, and on the upthrow, neritic carbonate platform or isolated carbonate platform develops, it is the structure--paleo-geography boundary of the two kinds. 3. The structure style of fault zone mainly includes four kinds: compressive structure, extensive structure, inversive structure and strike-slip structure. Hechi section mainly develops back thrusting style and ramp-flat thrust, and Yishan section develops imbricate structure toward south, Liucheng section develops imbricate structure toward north, Yingshan section develops positive flower structure or imbricate structure. 4. Analysis on its kinematics features and equilibrium profiles shows the shortening range of the profiles across four different sections of this fault zone is 8.54km, 17.5km, 11.4km&13km, 2.3km, the shortening rate is 19.1%, 34.3%, 24.8%&21.8%, 7.9%. So it can be concluded that the fault's deformation intensity will strengthen from edges to center. 5. The tectonic deformation of the fault zone is controlled by regional tectonic stress field and deformation variant field. Near SN compressive folding occured in Caledonian orogeny, and at this time this fault zone maybe an unsubstantial tectonic belt; Near SN compressive folding also occurred in Indosinian orogeny, when the early contemporaneous normal fault reversed, and EW fault-fold zone formed; Near NW-SE compressive folding occurred in early Yanshan orogeny, when it began to buckle. Near NNE-SSW compressive folding occurred in late Yanshan orogeny, the fault zone formed basically at this time. Near EW compression occurred in early Himalnyan orogeny; In late Himalnyan orogeny, it mainly show regional elevation. 6. The structural evolution of the fault zone can be divided into: the elementary form period in Caledonian orogeny, the extension-depression period from Hercynian orogeny to early Indosinian orogeny, the structure inversion and compressive deformation period from late Caledonian orogeny to Himalnyan orogeny. 7. In the north of Guizhong depression, basin sedimentation, buried denudation history, thermal and hydrocarbon maturity history are controlled by the structural evolution of the fault zone. The structural trap style and the form, distribution, breakdown and retention of the oil and gas pool are controlled by its structure deformation.
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