本文選題：湘中盆地 + 疊加褶皺�。� 參考：《中國地質(zhì)大學(xué)(北京)》2017年碩士論文

【摘要】：湖南省湘中盆地經(jīng)多期次構(gòu)造演化活動(dòng)形成了一系列穹窿狀構(gòu)造,前人進(jìn)行過詳細(xì)的地質(zhì)調(diào)查和研究工作,但對(duì)于穹隆體的構(gòu)造性質(zhì)及其疊加過程存在不同的認(rèn)識(shí),并進(jìn)而制約了對(duì)雪峰山及其相鄰區(qū)域大地構(gòu)造的認(rèn)識(shí)。為此,本文選取湘中地區(qū)的龍山構(gòu)造穹隆體,通過詳細(xì)的野外地質(zhì)調(diào)查、構(gòu)造解析和構(gòu)造物理模擬工作,揭示疊加褶皺穹窿的形成過程。構(gòu)造解析結(jié)果表明龍山穹窿屬構(gòu)造變形穹窿,是兩次或多次褶皺橫跨疊加變形的結(jié)果,穹窿的構(gòu)造樣式受斷層相關(guān)褶皺疊加作用控制。依據(jù)剖面上區(qū)域性角度不整合和基底拆離斷層的存在,確認(rèn)兩套可能為區(qū)域性潛在構(gòu)造滑脫層。對(duì)龍山穹窿區(qū)域上系統(tǒng)地進(jìn)行地層產(chǎn)狀和劈理產(chǎn)狀系統(tǒng)測(cè)量和赤平投影基礎(chǔ)上,結(jié)合褶皺樣式與軸面劈理的配套關(guān)系分析,并根據(jù)軸面劈理的錯(cuò)切關(guān)系確定NE-SW向褶皺疊加在近WNW ESE向褶皺之上。結(jié)合卷入疊加變形的地層,確定龍山穹窿是加里東期和燕山期褶皺疊加變形的結(jié)果。以區(qū)域性劈理和擦痕數(shù)據(jù)測(cè)量結(jié)果,對(duì)二期古構(gòu)造應(yīng)力場(chǎng)進(jìn)行了恢復(fù),并重建了區(qū)域構(gòu)造演化。在此基礎(chǔ)上,建立了穹窿體構(gòu)造模式。設(shè)計(jì)了兩組近似橫跨疊加干涉的縱彎擠壓砂箱構(gòu)造物理模型。根據(jù)相似性原理,在模型中設(shè)立不同軟弱層數(shù)、厚度。以觀察褶皺疊加變形過程中強(qiáng)弱巖層的變形行為,進(jìn)一步驗(yàn)證了軟弱層的分層構(gòu)造變形特征。疊加褶皺構(gòu)造解析和砂箱構(gòu)造物理模擬結(jié)果綜合表明,二期橫跨疊加干涉模型較好地模擬了龍山穹窿中加里東期縱彎褶皺作用形成的近WNW ESE向直立褶皺與燕山期NE-SW向褶皺的橫跨疊加過程,并有以下主要變形特點(diǎn):疊加褶皺發(fā)育過程中,早期褶皺軸面和樞紐在晚期褶皺作用過程中會(huì)發(fā)生彎曲和遷移,并被高角度逆沖斷層改造;由于軟弱巖層的拆離滑脫作用,導(dǎo)致分層變形作用,使得不同深度的疊加干涉樣式不同。因此,巖層能干性差異導(dǎo)致的疊加褶皺構(gòu)造樣式和疊加類型的區(qū)別,可能是疊加褶皺穹隆形成的主要因素。在龍山穹隆野外露頭尺度變形行為和疊加機(jī)制分析基礎(chǔ)上,結(jié)合構(gòu)造物理模擬實(shí)驗(yàn)中不同巖性層變形行為和疊加效果,并與前人相關(guān)疊加褶皺機(jī)制結(jié)果進(jìn)行比較,探討并提出了新的疊加過程成因機(jī)制模式。
[Abstract]:A series of dome structures were formed in Xiangzhong basin of Hunan province through multiple tectonic evolution activities. The predecessors have carried out detailed geological investigation and research work, but there are different understandings on the tectonic properties and superposition process of the dome. Furthermore, it restricts the understanding of Xuefeng Mountain and its adjacent regional geotectonics. Therefore, this paper selects Longshan structural dome in central Hunan, through detailed field geological survey, structural analysis and structural physical simulation work, reveals the forming process of superimposed fold dome. The structural analysis results show that the Longshan fornix belongs to the tectonic deformed dome, which is the result of two or more folds crossing the superimposed deformation. The structural style of the dome is controlled by the fault-related fold superposition. Based on the existence of regional angle unconformity and basement detachment faults in the section, it is confirmed that the two sets may be regional potential tectonic slip beds. On the basis of systematic measurement of stratigraphic and cleavage occurrence systems and plain projection in Longshan fornix region, the matching relationship between fold pattern and axial cleavage is analyzed. According to the shear relationship of axial cleavage, the NE-SW fold is superimposed on the near WNW ESE fold. Combined with the strata involved in superimposed deformation, it is determined that the Longshan Dome is the result of superimposed deformation of folds in Caledonian and Yanshanian periods. Based on the regional cleavage and scratch data, the second stage paleotectonic stress field was restored and the regional tectonic evolution was reconstructed. On this basis, the fornix structure model is established. Two sets of physical models of longitudinal bending extruded sand box are designed. According to the principle of similarity, different soft layers and thickness are established in the model. By observing the deformation behavior of strong and weak strata in the process of fold superposition deformation, the characteristics of stratified structural deformation of weak layers are further verified. The analysis of superimposed fold structure and the results of physical simulation of sand box structure show that, The two-stage cross-stack interference model well simulates the cross-stacking process of the vertical WNW ESE folds in the Calidon stage and the NE-SW fold in the Yanshanian period in the Longshan fornix. The main deformation characteristics are as follows: during the development of superimposed folds, the axial plane and hinge of the early fold will bend and migrate during the late stage of fold action and be transformed by high angle thrust fault. The effect of delamination deformation results in different superimposed interference patterns at different depths. Therefore, the difference of superimposed fold structure style and superimposed type may be the main factor in the formation of superimposed fold dome. Based on the analysis of field outcrop deformation behavior and stacking mechanism of Longshan dome, combined with the deformation behavior and superposition effect of different lithologic layers in the structural physical simulation experiment, the results of superimposed fold mechanism are compared. A new mechanism model of superposition process is discussed and put forward.
【學(xué)位授予單位】：中國地質(zhì)大學(xué)(北京)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：P542
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本文編號(hào)：1831561