【作者】 任小华；

【导师】 钱壮志；

【作者基本信息】 长安大学 ， 矿产普查与勘探， 2008， 博士

【摘要】 勉略宁地区位于扬子地台西北缘，摩天岭构造带的东端，该地区基本地质构造框架是一个由新太古代渔洞子岩群和中-新元古代碧口岩群两个变质基底岩系经晋宁构造事件拼合而成的复合地体。其形成经历了加里东和印支构造事件，先后增置于扬子板块北缘和秦岭微板块，具有相对独立的演化历史。研究区北侧的勉-略构造混杂岩带和南部的汉江深断裂带，分别属秦岭-大别缝合带和扬子板块西北缘龙门-锦屏缝合带的重要组成部分。因区域构造部位处于两构造带交汇的三角区，许多文献习称勉略宁三角地区（带），为南秦岭重要内生多金属矿集区之一。勉略宁地区具有复杂的地质构造背景和金属成矿作用，基于此，本文研究重点围绕基底变质岩系的岩石-构造环境，基底拼合岩浆-构造带和勉略构造混杂带的基本地质构造特征以及与其相关的成矿作用展开，应用理论涉及到了岩石-构造环境及其成矿作用、流体成矿作用、剪切-推覆构造成矿作用等诸多方面。同时根据矿床分布、成矿作用与构造环境，详细划分了金属矿床成矿系列并对典型矿床进行了深入分析。进而在深入研究金属矿床成矿规律和找矿标志的基础上，提出了不同矿化类型金属富集规律和找矿勘查标志，并从找矿实际出发，进行了大比例尺的找矿预测，为作者所在的勘查部门今后的地质找矿提出了方向和靶区。本文研究获得的主要进展和找矿预测成果如下：（1）通过对本区地质背景的研究和前寒武系变质地层地体研究，系统探讨基底岩浆-构造带和勉略构造带形成发展过程和内部结构，提出勉略宁地区“两体-三带”是本区基本构造框架，也是影响本区成岩、成矿的重要构造条件。徐家坝-黑木林-峡口驿-煎茶岭超基性-基性、中酸性-酸性岩浆岩带及其线状火山机构是地体拼合作用重要的岩石记录和识别标志，拼合带内超基性岩体多为层状或似层状，与地层发生同步褶皱。其早期伸展-裂陷环境应为沿太古代渔洞子地体边缘裂陷近南北向展开，现存方位和层状岩体的褶曲形态是经区域构造变形后的产物。研究结果显示基底拼合构造带和勉略混杂构造带是两个时间、空间演化各异的地质单元，但具有类似的内部结构特点和相似的成岩、成矿作用。其发生与发展对本区主要金属矿床的形成和改造产生着重大影响，是研究区金属矿床分布的两大集中区。（2）依据已知矿床、矿点主要控矿地质要素，系统论述了多金属成矿作用并划分出本区成矿系列方案和主要矿床类型。以具有相似的地质构造条件和成矿作用的矿化集中区做为研究典型矿床的窗口，对煎茶岭矿田（金、镍矿床）、铜厂矿田（铜厂铜矿床、东沟坝金多金属矿床）、干河坝金矿床等进行了深入研究，对比分析后首次提出了勉略宁地区主要矿床类型及其成矿作用与超基性岩、中酸侵入岩（酸性）、基性-中酸火山岩密切相关，“三位一体”是矿床形成的基本地质要素和找矿有效模式。根据采矿深部地质信息和近期找矿成果研究提出：煎茶岭金矿床控矿构造是与主逆冲推覆剪切构造(F⁴⁵)配套产生的次级断层、裂隙含矿构造系统。金矿体内富、厚矿块的形成取决于与主剪切断裂相交的次级构造的发育程度，在勘查时期提出的由主断面倾角发生改变而形成富矿的找矿模式值得商榷。并根据这一现象进一步提出在深部超基性岩一侧、与主断面相交的次级构造密集部位寻找富矿体的找矿建议。（3）应用岩石-构造环境与金属矿床成矿理论，系统阐述了渔洞子地体、碧口地体、基底拼合构造带以及勉略构造混杂岩带岩石-构造条件与成矿作用，提出本区基底火山岩系中与成矿作用密切相关的碧口群郭家沟组、东沟坝组岩石组合具有钙碱性系列的大洋拉斑玄武岩和岛弧拉斑玄武岩的特征，成岩古构造环境应形成于局部洋盆裂陷和岛弧。勉略宁中部地区超基性、中酸性火成岩岩石-构造分析研究后认为，初步判断研究区火成岩为同一岩浆源不同构造阶段演化的产物。（4）在总结区域成矿规律的基础上，全面阐述了重大地质事件演化与本区金属成矿作用的关系，揭示了本区地质构造演化史与成矿阶段的时、空对应与制约条件。应用流体成矿、剪切带成矿等理论研究认为，本区金属成矿作用的主要特点为火山岩源区成矿作用、岩浆-流体成矿作用和断裂构造成矿作用等；针对典型矿床的范例和主要成矿地质现象系统讨论了成矿作用对成矿元素迁移-富集影响。重点分析了壳、幔源岩浆流体对煎茶岭镍、金矿床、铜厂铜矿床改造或直接富集成矿作用。强调成矿作用的根源仍是基底拼合带、勉略构造带在不同构造阶段形成与演化的结果。复合成矿作用是本区金属矿床形成源-运-储成矿的基本特征。（5）集多年工作经验和本次研究成果，应用现代预测理论，本着科研为生产服务方向，遵循具体化、精细化、可操作性强的找矿靶区预测原则，在总结老区找矿预测工作存在问题的前提下，建立了找矿靶区五项预测准则，提出了徐家沟地区、金子山地区、煎茶岭地区（南带）三个重点靶区和五个后续靶区。并在开题初期，借助于现工作岗位条件，提出了预测靶区工程验证的方案并取得了良好的预测效果。预测成果说明本次研究工作的理论、方法和指导思想是基本可行的，所建立的找矿标志为勉略宁地区今后地质找矿提供了方向和可借鉴的理论方法。更多还原

【Abstract】 Located in northwestern margin of the Yangtze Platform and eastern end of the MotianlingTectonic Belt,Mian-Lue-Ning Region（MLNR）is a composite landmass coalesced by the LateArchaean Yudongzi Block and Meso-Neoproterozoic Bikou Block through the Jinning TectonicEvent.These two blocks were respectively accreted to the northern margin of the Yangtze Plateand the Qinling Microplate after the Caledonian Tectonic Event,together constituting animportant part of the Qinling Orogenic Belt.The north-west spreding Mian-Lue TectonicMelange Belt and the north-east spreading Hanjiang Fault,respectively to the north and southof the research target region,tectonically outline the boundaries between the research targetregion and the Qinling Orogenic Belt as well as the Yangtze Plate.The triangle-shape researchregion is gifted with most significant endogenetic mineral resources in southern Qinling andgeographically named“Mian-Lue-Ning Triangle（Region）”.Considering the complex tectonic and metallogenetic background in the region,thisresearch systematically focused on the lithologic-tectonic setting of basal igneous rocks,fundamental geology of the Magmatic-Tectonic Belt resulted from the basal coalescence and theMian-Lue Tectonic Melange Belt,and their related primary metallogeneses.Thiscomprehensive research involved a variety of metallogeneses relevant to lithologic-tectonicsetting,ore-bearing fluids,tectonic shear-thrust system,etc.In addition,based on theanalysis of rudimental metallogeneses,the author thoroughly classified the metallogeneticseries and dissected some typical mineral deposits in this region.Based on detailed research onmetallogenetic rules and mineral-prospecting signitures,the author carried out large-scaleprospecting work on the prediction of mineral resources in this region.This work has offeredfavorable orientations for and will contribute to prospective mineral surveys in Mian-Lue-NingRegion.The primary theoretic and practical achievements for mineral prospecting are summedup as follows:1.Based on analysis of basic geological backgrounds and various tectonic architectures inthis region,this paper discusses the developmental processes and interior structures of the basalMagmatic-Tectonic Belt and the Mian-Lue Tectonic Belt,the author proposes the essential tectonic framework of Mian-Lue-Ning Region as“Two Blocks and Three Belts”,whichprovided tectonically significant advantages for diageneses and mineralogeneses.TheXujiaba-Heimulin-Xiakouyi-Jianchaling ultramafic-mafic or intermediate-acidic magmatic rocksas well as linear volcanic systems serve as indicative signatures of the basement coalescence,which was previously split north-southward and subsequently folded and deformed by regionalcompressions.Thus the author presents that the formerly-formed ultramafic intrusives in thecoalescence belt have bedded or sub-bedded structure and experienced later folding synchronousto the overlying stratigraphic succession,concluding that the central Basement CoalescenceBelt and the Mian-Lue Tectonic Melange Belt,though representing different special andtemporal evolution pathways yet sharing analogous interior structures and diagenetic andmetallogenetic characteristics,both yield paramount bonanzas in this region.2.The author systematically and innovatively discusses and classifies the metallogeneticseries and corresponding control factors.Metallogenetically concentrated localities with similargeological and mineralogenetic advantages are utilized as templates to probe into the JianchalingAu-Ni deposit,Tongchang Cu deposit,Dongouba Au-polymetallic deposit and Ganheba Audeposit.After comparison and investigation,the author revealed the close relationship betweenthe primary metallogeneses and the presence of ultramafic rocks,intermediate-acidic（or acidic）rocks and mafic volcanic-sedimentary rocks,consequently reasoning out an effective model formineral prospecting in the Mian-Lue-Ning Region.Considering geological information acquiredfrom the Jianchaling Au deposit during mining in the depth as well as from recent progress ofmineral prospecting in the southern belt,this paper,for the first time,presents that auriferousenrichments tend to occur where the primary shearing fault(F⁴⁵)gave rise to subordinate faultsthat intersected the primary fault plane during late thrust and shear resulting in the accumulationand expansion of orebodies,instead of occurring where the dip of the primary fault planechanged.Accordingly,the author recommends to pay more attention to deep-seated intersectingsub-faults together with ultramafic wallrocks in terms of prospecting for enriched mineralresources.3.Based on petrologic-tectonic mineralogenetic theories,this research explicates theYudongzi Block,Bikou Block,Basement Coalescence Belt as well as the petrologic-tectonicsetting and corresponding metallogeneses in this region,indicates that the volcanogeneticGuojiagou Formation and Donggouba Formation of Bikou Group are litho-tectonicallycharacterized by alkali-series oceanic tholeiite and island-arc tholeiite respectively,indicativeof oceanic rifting & depressing and island-arc palaeogeography.The litho-tectonic analysis on ultramafic,intermediate-acidic and acidic intrusive rocks show they originated from ahomologous chamber yet from different intrusive stages.4.Based on modern metallogenetic theories on plutonic fluids and shear belts,themetallogeneses in this region can be classified into four categories,i.e.,（1）source-elementmetallogenesis,（2）magmatic-tectonic metallogenesis,（3）fluid metallogenesis,and（4）shear-thrust metallogenesis.Systematical studies were also implemented regarding thetheoretical foundation of various metallogeneses and concrete geological phenomena,especially the influences of crust-and mental-originated fluids on the alteration ormetallogeneses of the Jianchaling Ni enrichment,Jianchaling Au alteration deposit anddKuangchang Cu hydrothermal deposit.The author herein highlights that all the metallogeneseswere rudimentally based on the multistage evolution of the Basement Coalescence Belt and theMian-Lue tectonic Belt.These various metallogeneses provided necessary pathways for theconcentration,transportation and preservation of mineral resources in this region.5.After integrating the regional mineralogenetic rules,this research exhaustively depictsthe relationship between significant geological events and metallogeneses,and indicates thespecial and temporal connections between tectonic evolutions and metallogenetic progresses.6.To provide detailed,precise and practical guidance for mineral prospecting inMian-Lue-Ning Region,the author,after fully taking into account previous problems inmineral resources predictions,refines his experience and achievements obtained in the pastdecades of years into establishing some principles for prospecting and prediction of targetresources in the region,i.e.,indicating three prospective resource key targets including theXujiagou,Jinzishan,Jianchaling（southern belt）and four candidates.As a matter of fact,these prospective targets have well stood the test and verification of the subsequent mining andshow desirable effects in prediction.Thus the theory,method and guidance of this researchproved practical and feasible.As a result,the other prospective resource targets will beconsequently favorably verified.Conclusively,the prospecting signatures established in thisresearch are providing indicative guidance and effective methods for geological surveys inMian-Lue-Ning Region.更多还原