本文選題：南秦嶺　切入點：燕山期　出處：《長安大學》2017年博士論文　論文類型：學位論文

【摘要】：秦嶺造山帶作為復合型、多旋回的大陸造山帶一直以來都是地學界關注的熱點,有關秦嶺造山帶的研究很早就已展開,并積累了大量的認識成果。普遍認為其是揚子板塊和華北板塊共同作用的結果,多階段造山運動和構造熱事件引起秦嶺造山帶內發(fā)生了一系列的成礦作用。南秦嶺構造帶是秦嶺造山帶中規(guī)模最大、發(fā)展演化復雜的構造單元,也是秦嶺造山帶的主體。南秦嶺地區(qū)分布的礦產資源類型豐富,其中金礦資源儲量可觀,繼續(xù)深入對南秦嶺地區(qū)展開研究有助于取得更大的找礦成果。此外,三疊紀以后的“陸內造山”階段對南秦嶺地區(qū)具有劃時代的意義,而前人對該階段的研究相比印支期板塊碰撞造山階段明顯偏弱,因此有必要加強對陸內造山期的構造-巖漿-成礦事件研究。礦田(金屬礦田)是在空間、時間、構造建造及成因上相類似的一些礦床及礦化點集中賦存的區(qū)域,其指示為成礦作用集中發(fā)育的地質單元。通過礦田地質學研究可以有效掌握礦田尺度上各礦床與礦體的形成特點、分布特征及改造規(guī)律等,對礦產資源的勘探開發(fā)具有著重要意義。南秦嶺漢陰北部金礦田位于南秦嶺構造帶的中部,東西長約50km,南北寬約10~20 km,為陜西石泉-漢陰-旬陽金礦整裝勘查區(qū)內的一個重要礦田。近年來礦田內已經探明數(shù)十處規(guī)模不等的金礦床。然而隨著探礦工程的不斷深入,金礦的勘查工作明顯遇到了一定的瓶頸,迫切需要進一步的理論研究來指導生產實踐。此外對于該區(qū)金礦的成礦類型多有爭議,對礦田內廣泛分布的巖漿巖脈重視不夠,尤其巖漿巖同金礦之間的關系幾乎未見討論。本論文以中國地質調查局《陜西石泉-旬陽金礦整裝勘查區(qū)專項填圖與技術應用示范》項目為依托,以漢陰北部金礦田為研究對象,在充分搜集、分析和研究前人成果的基礎上,首先通過野外對典型礦區(qū)進行大比例尺構造-巖相填圖、實測剖面與探礦工程測量等,查明了礦田的巖石地層特征、構造變形樣式、礦床地質特征和礦化蝕變信息等;其次,通過室內大量的綜合研究和編圖等工作,進一步掌握了礦田構造特征及各主要控礦要素特點;此外,通過大量采集各類巖石和礦石樣品,進行實驗室分析和測試,明確了與金礦成礦作用相關的各類信息;基于以上工作,進行深入分析和總結,明確了礦田內金礦的成礦規(guī)律及成礦模式。取得成果如下。(1)漢陰北部金礦田內可劃分出五條近東西向、北西向展布的大型脆-韌性剪切帶,其形成的時代為早侏羅世開始的陸內造山階段,形成的環(huán)境為礦田南北兩側的寧陜和安康斷裂發(fā)生大規(guī)模走滑剪切運動、中間塊體整體向東擠出。(2)礦田內五條大規(guī)模的脆-韌性剪切帶為成礦期構造,其控制著各金礦床的空間分布位置,而脆-韌性剪切帶內的次級斷層破碎帶則控制了金礦體產出的具體部位。(3)礦田內的構造變形面理大致可劃為三期,以S2面理占絕對主導,S2面理對金礦具有顯著控制作用,屬成礦期構造。(4)巖漿巖的鋯石U-Pb同位素測年顯示觀音河花崗閃長巖侵位時代為180.2±3.6 Ma,柳坑細晶花崗巖形成時代為176.0±1.9 Ma,均屬早燕山期,而巖漿巖同構造侵位于S2面理則指示了S2面理也形成于該時期,并且?guī)r漿熱液活動參與了金礦的成礦,且可能為成礦作用提供部分物源。(5)典型礦區(qū)不同期次石英脈流體包裹體研究表明,礦田內金礦的成礦溫度大體介于190~300℃,屬中-低溫成礦,成礦壓力范圍大約為20.61~100.77 Mpa,成礦深度范圍大約為0.76~3.74 km。(6)明確了金礦田內成礦物質主要來源于梅子埡組原始沉積地層,成礦期構造脆-韌性剪切帶和S2面理形成于燕山早期的信息指示了成礦時代為早燕山期,主要成礦作用動力機制為韌性剪切作用。(7)明確漢陰北部金礦田的成礦類型為韌性剪切蝕變巖型并疊加巖漿期(后)熱液,建立漢陰北部金礦田成礦模式演化圖,并提出找礦思路和指明找礦方向。本研究成果能夠為漢陰北部金礦田及鄰區(qū)未來的金礦找礦勘探工作提供重要的參考價值和理論指導,有助于獲取更多的金資源量。
[Abstract]:The Qinling Mountains orogenic belt as a complex, multi cycle orogenic belt has always been to focus in the academic circles, the study of the Qinling Mountains orogenic belt is already started, and accumulated a lot of understanding of the results. It is generally thought that it is the result of Yangtze plate and North China plate, multi stage and orogeny the tectonic thermal events caused by the mineralization of the Qinling Mountains orogenic zone. A series of southern Qinling Mountains tectonic belt of Qinling Mountains orogenic belt is the largest, the evolution of tectonic unit complex, is also the subject of the Qinling Mountains orogenic belt in southern Qinling Mountains. The distribution of mineral resources are abundant, the gold resource reserves, to continue in-depth study will help to achieve greater prospecting results of South Qinling Mountains area. In addition, the later Triassic intracontinental orogenic stage of southern Qinling Mountains has epoch-making significance, and previous studies on this phase Than the Indosinian plate collision orogenic stage was weak, so it is necessary to strengthen the research on the tectonic intracontinental orogenic period of magmatic events. Ore field (metal ore field) in space, time, some deposit and mineralization formation and tectonic origin of similar concentration occurrence area, indicating the geological unit concentrated ore the role of development. Through the study of ore field geology can effectively grasp the scale of the deposit formation characteristics of ore field and the ore body, the distribution characteristics and transformation rules, exploration and development of mineral resources has important significance. In southern Qinling Mountains, northern Hanyin, located in the southern Qinling Mountains gold ore field tectonic belt in the middle, something about 50km, north-south width of 10~20 km, Shaanxi - Hanyin - Xunyang Shiquan gold mine exploration is an important field in the region. In recent years the ore field has proven dozens of different scale gold deposit. However, with the continuous exploration engineering Further, the exploration of gold was encountered a bottleneck, further theoretical research urgently needed to guide the production practice. In addition to the metallogenic types of gold deposits in this area have much controversy, magmatite veins are widely distributed in the gold field is not enough, especially the relationship between magmatite with gold almost no discussion. In this paper, China the geological survey of "Shaanxi Shiquan - Xunyang gold mine exploration area special mapping and application demonstration > project, in northern Hanyin gold field as the research object, in the full collection, analysis and research based on the previous research, first through the field of typical mining area of large scale tectonic lithofacies mapping, measured profiles and exploration engineering measurement, rock formation characteristics of ore field to identify the tectonic deformation style, geological features and mineralization alteration information; secondly, through a lot of comprehensive research and The mapping work, and further understand the characteristics of orefield structure and major ore controlling factors; in addition, by collecting a large number of various types of rock and ore samples, laboratory analysis and testing, the various kinds of information related with gold mineralization; based on the above work, in-depth analysis and summary, the metallogenic regularity and model of ore field gold. The results are as follows. (1) can be divided into five nearly East-West to the north of Hanyin gold field, North West to the large scale distribution of brittle ductile shear zone, intracontinental orogenic stage of the formation of the early Jurassic era began, the formation of healthy environment for Ningshan and the South and north sides of fracture field the occurrence of large-scale strike slip movement, the middle block overall eastward extrusion. (2) in the ore field five large-scale brittle ductile shear zone is metallogenic structure, the spatial distribution of the position control of all gold deposit, and brittle 闊ф，

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