本文關(guān)鍵詞： 音頻大地電磁法 電性結(jié)構(gòu) GOCAD 地質(zhì)建模　出處：《成都理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：研究區(qū)位于龍門山構(gòu)造帶北段的三堆鎮(zhèn)地區(qū)。區(qū)內(nèi)地表構(gòu)造復(fù)雜,地表覆蓋層發(fā)育,許多重點(diǎn)填圖區(qū)域的地質(zhì)地層單元、斷裂構(gòu)造等地表地質(zhì)特征模糊,嚴(yán)重影響區(qū)域地質(zhì)填圖工作。特別是斷層表現(xiàn)為脆韌性特征,在地表無明顯的邊界地質(zhì)信息,深部延伸情況不明確;飛來峰群在地表的邊界位置模糊、深部構(gòu)造樣式的展布特征不甚清楚等�；谝陨显�,僅僅通過地表調(diào)查開展深部地質(zhì)填圖具有較大局限性,深部地質(zhì)填圖急需深部地球物理數(shù)據(jù)的支持。音頻大地電磁法(AMT)勘探作為一種中淺部勘探技術(shù),具有工作效率高、不受高阻層屏蔽和對低阻層分辨率較高等優(yōu)點(diǎn),因此在本地區(qū)采用音頻大地電磁法(AMT)勘探地下結(jié)構(gòu)。本文首先介紹了研究區(qū)的地質(zhì)、地球物理特征;然后針對地面地質(zhì)調(diào)查遇到的上述問題,結(jié)合研究區(qū)內(nèi)的地質(zhì)和物性資料,建立斷層、褶皺和飛來峰等地電斷面模型及測線深部粗結(jié)構(gòu)模型,開展AMT正演模擬及反演計(jì)算,并分析電磁響應(yīng)特征、探討AMT法對典型地電模型的分辨能力;接著使用SSMT2000和MTSOFT-2D軟件對實(shí)測AMT數(shù)據(jù)進(jìn)行處理,獲取測線深部2km以淺電阻率剖面圖,結(jié)合研究區(qū)地質(zhì)、物性資料對剖面進(jìn)行地質(zhì)地球物理綜合解釋;最后使用GOCAD軟件完成AMT剖面局部約束下的深部地質(zhì)建模。通過以上研究,取得如下主要成果:(1)研究區(qū)的巖層巖石電阻率測試結(jié)果表明,主要探測目標(biāo)內(nèi)部不同巖體、不同地層電性差異明顯,滿足進(jìn)行電法勘探的物性基礎(chǔ),可以在測區(qū)合理布置測線,獲取高質(zhì)量數(shù)據(jù),能夠達(dá)到較好的勘探效果。(2)對音頻大地電磁測深的數(shù)據(jù)進(jìn)行處理后,對單點(diǎn)測深曲線以及視電阻率和相位斷面進(jìn)行定性研究,隨后,選擇非線性共軛梯度(NLCG)反演方法對大地電磁資料進(jìn)行反演處理,結(jié)合地表地質(zhì)填圖資料對AMT反演結(jié)果進(jìn)行解釋,對梨樹壩斷層深部構(gòu)造樣式、蓮花石飛來峰的地下展布有了清晰的認(rèn)識。(3)GOCAD地質(zhì)建模的結(jié)果表明在AMT數(shù)據(jù)的約束下能夠解決梨樹壩斷層深部延伸情況、飛來峰構(gòu)造深部樣式及測區(qū)主要地層深部邊界等地質(zhì)問題,結(jié)果說明了音頻大地電磁(AMT)探測成果能為深部地質(zhì)調(diào)查及三維建模提供可靠參考資料。
[Abstract]:The study area is located in Sanduizhen area in the northern section of Longmen Mountain structural belt. The surface structure in the area is complicated, the surface overburden is developed, the geological stratigraphic units of many important mapping areas, the fault structure and other surface geological features are vague. It seriously affects the regional geological mapping. Especially, the fault shows brittle toughness, no obvious boundary geological information on the surface, the deep extension is not clear, the position of Feilai peak group in the boundary of the surface is fuzzy, the fault is characterized by brittleness and toughness, and there is no obvious boundary geological information on the surface. The distribution characteristics of deep structural styles are not very clear, etc. For the above reasons, it is more limited to carry out deep geological mapping only through surface survey. The deep geological mapping needs the support of the deep geophysical data. As a medium and shallow exploration technique, the Audio magnetotelluric (AMT) exploration has the advantages of high working efficiency, not being shielded by the high resistivity layer, and high resolution to the low resistivity layer, etc. Therefore, the Audio magnetotelluric method (AMT) is used to explore underground structures in this area. This paper first introduces the geological and geophysical characteristics of the study area, and then, in view of the above-mentioned problems encountered in the surface geological survey, combines the geological and physical data of the study area. The geoelectric cross section model such as fault, fold and Feilai peak and the coarse structure model in the depth of the survey line are established, the forward modeling and inversion calculation of AMT are carried out, and the characteristics of electromagnetic response are analyzed, and the resolution ability of the AMT method to typical geoelectric model is discussed. Then the SSMT2000 and MTSOFT-2D software are used to process the measured AMT data, and the shallow resistivity profile is obtained at the depth of 2 km. The geological geophysical comprehensive interpretation of the profile is carried out in combination with the geological and physical data of the study area. Finally, GOCAD software is used to complete the deep geological modeling under the local constraint of AMT profile. Through the above research, the following main results are obtained: 1) the resistivity test results of rock strata in the study area show that the main exploration targets are different rock masses. The difference of electrical properties in different strata is obvious, which satisfies the physical property foundation of electrical exploration, and can reasonably arrange the surveying lines in the survey area, obtain high quality data, and can achieve a better exploration effect. (2) after processing the data of Audio magnetotelluric sounding, Qualitative study on the single point bathymetric curve, apparent resistivity and phase section is carried out. Then, the nonlinear conjugate gradient inversion method is selected to process the magnetotelluric data, and the AMT inversion results are interpreted in combination with the surface geological mapping data. For the deep structural style of Lishuba fault, the underground distribution of Lianhuashifenglai peak is clearly understood. The results of geological modeling show that the deep extension of Lishuba fault can be solved under the constraint of AMT data. The geological problems such as the deep style of Feilefeng structure and the deep boundary of the main strata in the survey area are discussed. The results show that the detection results of Audio magnetotelluric (AMT) can provide reliable reference data for the deep geological survey and 3D modeling.
【學(xué)位授予單位】：成都理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P631.325

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本文編號：1547690