本文選題：大水金礦 + 原生暈　； 參考：《中國(guó)地質(zhì)大學(xué)(北京)》2017年碩士論文

【摘要】：大水金礦是西秦嶺地區(qū)一個(gè)典型的富赤鐵礦的超大型金礦床,該礦床產(chǎn)于三疊系一套碳酸鹽巖中,嚴(yán)格受斷裂帶控制。礦化蝕變主要為硅化、赤(褐)鐵礦化和碳酸鹽化,硅化和赤鐵礦化蝕變?cè)綇?qiáng),礦體越發(fā)育。大水金礦與礦區(qū)發(fā)育的中酸性脈巖具有密切的時(shí)-空關(guān)系,部分脈巖可直接蝕變礦化為礦體。原生暈法是國(guó)內(nèi)外公認(rèn)的尋找盲(或隱伏)礦體最有效的方法。為探討大水金礦深部找礦潛力,本文基于對(duì)大水金礦礦床地質(zhì)特征認(rèn)識(shí)的基礎(chǔ)上,從礦區(qū)的地球化學(xué)背景、礦床元素含量特征和Au2礦體原生暈軸向分帶特征等幾方面有針對(duì)性地對(duì)Au2礦體開展了原生暈研究。礦區(qū)內(nèi)Au、Sb、Ag、As、Hg、U等元素背景含量較高,總體來看格爾括合巖體中元素平均含量較灰?guī)r地層元素含量高。地球化學(xué)數(shù)據(jù)為成分?jǐn)?shù)據(jù),為滿足數(shù)據(jù)統(tǒng)計(jì)分析要求,需要消除成分?jǐn)?shù)據(jù)的“閉合效應(yīng)(closure effect)”。本文則使用對(duì)數(shù)比(log-ratio)變換法對(duì)地化成分?jǐn)?shù)據(jù)進(jìn)行處理,并對(duì)比地化數(shù)據(jù)變換前后基于主成分法(PCA)分析地化數(shù)據(jù)的差異,表明成礦元素組合為Au、Ag、As、Sb、Hg、W、Te(Mo、Se)等元素。Au2礦體原生暈濃度分帶總體上呈現(xiàn)出前緣暈元素異常發(fā)育明顯,而尾暈元素濃度異常相對(duì)較弱的特點(diǎn);Au、Ag、Hg、As、Sb、Te、W等元素的內(nèi)、中、外帶異常發(fā)育較完整,且具有多濃集中心,表明大水金礦原生暈具有疊加特征。在標(biāo)高3800m附近前緣暈元素As、Sb異常與W、Ni、Co、V等尾暈指示元素形成前、尾暈疊加或共存,指示上部有礦體剝蝕;而在礦體下部(尾部)又發(fā)育Hg、Te、As、Sb等前緣暈元素的內(nèi)、中帶強(qiáng)異常,是深部盲礦體前緣暈疊加的結(jié)果。礦體中Au元素的濃集中心有向下濃集的趨勢(shì),尤其在標(biāo)高3500m-3600m間顯著。Au2礦體原生暈軸向分帶序列呈現(xiàn)“反分帶”現(xiàn)象,前緣暈/尾暈比值在3490中段附近仍繼續(xù)升高,表明深部仍有礦體延伸或盲礦體存在。最后,基于大水金礦的礦床地質(zhì)和原生暈特征,建立了大水金礦的原生疊加暈?zāi)Ｊ?并總結(jié)了大水金礦的原生暈找礦標(biāo)志。
[Abstract]:Dashui gold deposit is a typical super-large hematite rich gold deposit in the West Qinling area. It occurs in a set of carbonate rocks of the Triassic and is strictly controlled by the fault zone. The mineralization alteration is mainly silicification, red (brown) iron ore and carbonization. The stronger the silicification and hematite alteration, the more developed the orebody. The Dashui gold deposit has a close time-space system with the intermediate-acid dikes developed in the ore area, and some of the dikes can be directly altered and mineralized into orebodies. Primary halo method is the most effective method to find blind (or concealed) orebodies at home and abroad. In order to discuss the deep prospecting potential of Dashui gold deposit, this paper based on the understanding of the geological characteristics of the Dashui gold deposit, from the geochemical background of the ore area. The primary halo of Au2 orebody was studied in several aspects, such as the element content characteristics of the deposit and the primary halo axial zonation of the Au2 orebody. In the mining area, the background content of elements such as Au-SbSbAg-Ag-As-HgGU is relatively high, and the average content of elements in the Gehuahe rock mass is higher than that in limestone strata as a whole. Geochemical data are component data. In order to meet the requirement of statistical analysis, it is necessary to eliminate the closure effect of composition data. In this paper, the log-ratio transformation method is used to process geochemical composition data, and the differences of geochemistry data before and after geochemistry data transformation based on principal component method (PCA) are compared. The results show that the ore-forming element assemblage is composed of elements such as Au-Ag-As-SbSbSg-HgSG-HgSG-SbTeMo-See). The primary halo concentration zonation of the Au2 orebody shows that the anomaly of the leading halo elements is obvious, while the anomaly of the tail halo element is relatively weak. The anomalies in the middle and outer zones are relatively intact in the inner, middle and outer zones of the elements such as Au-Ag-HgSG-SgSG-SbTeW, and so on. The multiple concentration centers indicate that the primary halo of Dashui gold deposit is superimposed. Before the formation of the leading halo element As-Sb anomaly near 3800m and the tail halo indicator element WNI-CoCoV, the caudal halo superposes or coexists, indicating the denudation of the ore body in the upper part, while in the lower part of the orebody (tail), there is a strong anomaly in the middle zone of the front halo elements, such as Hgn TeAsSb, etc., which are found in the lower part of the orebody (tail). It is the result of the superposition of the front halo of the deep blind orebody. The concentration center of au in the orebody tends to be concentrated downwards, especially in the striped 3500m-3600m. Au2 orebody presents a "reverse zoning" phenomenon in the primary halo axial zonation sequence, and the ratio of front halo to tail halo continues to increase near the middle section of 3490. The results indicate that there are still extended orebodies or blind orebodies in the deep part. Finally, based on the geological and primary halo characteristics of Dashui gold deposit, the primary superimposed halo model of Dashui gold deposit is established, and the primary halo prospecting criteria of Dashui gold deposit are summarized.
【學(xué)位授予單位】：中國(guó)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)】：P618.51
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本文編號(hào)：1940081