【作者】 王立社；

【导师】 朱赖民；

【作者基本信息】 西北大学 ， 矿物学、岩石学、矿床学， 2009， 博士

【摘要】 对陕西秦岭黑色岩系的调查研究发现区内黑色岩系主要由碳质泥板岩、碳质硅质泥板岩、泥板岩、硅质岩、泥灰岩、石煤-含碳灰岩等岩类组成;岩系可见磷结核、以黄铁矿为主的草莓金属硫化物及重晶石;地球化学研究表明陕西秦岭黑色岩系形成于不同程度的缺氧环境,岩石形成时有热水沉积物及生物物质加入;黑色岩系中成矿物质来源具多源性和复杂性。黑色岩系中生物标志物特征研究表明其有机碳质源于浮游生物、菌藻类等,个别样品中有后期高等植物有机碳质的加入。岩系中有机碳含量变化较大,并且构造作用强烈的地区有机碳含量相对较低,岩石热解分析表明样品经历了较强的热演化,烃类物质已经损失。根据地质背景、岩石组合、成矿元素组合可将陕西秦岭黑色岩系分为南、北、中三个带:北带庙湾组产于华北板块活动陆缘边缘海环境:岩石多高钾、富铁和铝、钠质变化大,硅质岩不如中、南带发育,有机碳含量较高为2.52～4.7%;物源为陆缘并有生物物质、热水物质加入,其中热水与基性岩和酸性岩关系密切;成矿元素组合为Mo-Ni-Cu-Pb-Zn-U;产Ni-Mo矿床。中带水沟口组产于秦岭微板块古隆升岛链特定的深水-半深水滞留断陷盆地之边缘海向深海过渡环境;岩系多硅质岩,有机碳含量变化大:物源为陆源且有生物、热水物质的加入,热水与基性岩有关;成矿元素组合为Au-V-P-U-Cu-Pb-Zn;产金、钒矿。南带鲁家坪组和斑鸠关组形成于大陆边缘堑.垒相间裂谷断陷盆地中;其中磷块岩、石煤、重晶石、毒重石发育,局部夹火山岩:物源为陆源并有热水和生物物质加入,热水与基性岩有关:成矿元素组合为V-Mo-Ba-P-Au、V-Mo-Au-P-Se-石煤;产重晶石矿、毒重石矿和钒矿。北带清岩沟Ni-Mo矿床的Ni、Mo源于奥陶系庙湾组黑色岩系本身而与后期岩浆无关,据δD—δ¹⁸O图解、矿床地质特征及氧同位素分析认为,成矿流体为强烈改造的大气降水,并有变质热液及少量岩浆水的混入的特点。矿床的形成经历了沉积成矿预富集期、区域变质作用期、构造+热液作用成矿期。主要矿物为辉钼矿、镍黄铁矿、磁黄铁矿。原生含矿石英细脉包裹体均一温度211.4～444.9℃,成矿温度属中～高温,盐度NaCleq.7.02～19.21%,成矿温度和盐度随时间而降低。矿体赋存于绢云碳质千枚岩段再经韧.脆性剪切变形叠加的地层与构造联合控制的容矿带中,具明显的层控.岩控与构造-热液成矿及控矿的特征。中带的中村银花钒矿属沉积—成岩成因矿床,矿体呈层状产出,矿层是寒武系水沟口组下段地层的组成部分,钒超常富集稳定:富矿岩石高Al和K、低钙,贫矿岩石Ca高、Al和K低;岩石的含矿性与稀土含量、钡存在较好正消长关系;有机碳质和有机磷对的钒超常富集有利;钒在泥质岩中占75.2%,硅质岩中仅占24.8%,硅质岩型矿石中钒主要以类质同象存在（占74.17%）,泥质岩型矿石中钒主要以吸附状态存在（占66.38%）。夏家店金矿是黑色岩系容矿的微细浸染型金矿床,兼具黑色碳质岩系和热水沉积预富集的成矿作用,后期韧-脆性构造叠加以及大气降水为主含矿热液改造的类卡林型金矿床。含矿岩系为水沟口下部地层,富矿岩石高硅、铁、碳和钾。矿化石英、方解石流体包裹体均一温度集中在140℃～336℃范围,具中—低温热液成矿特征。成矿压力为370×10⁵～820×10⁵pa:早期硅化石英流体包裹体盐度3.27（NaCl）wt%,中晚期石英流体包裹体盐度5.25（NaCl）wt%。矿床的形成经历了早古生代沉积预富集、中新生代的韧脆性构造及热液叠加富集和新生代至今的剥蚀氧化成矿作用。南带黄柏树湾毒重石矿床属于受轻微改造的海相热水沉积矿床,矿石主要为毒重石和重晶石,矿体严格受寒武系鲁家坪组下部地层控制;标志层位是硅质岩向碳质粉砂质板岩过渡部位,与含胶磷矿的薄层硅岩和重晶石密切共生:海绵骨针、有孔虫的发现表明其形成于较深拉张裂陷环境。鲤鱼山钒矿床为沉积成岩—经轻微改造成因矿床;矿层为寒武系鲁家坪组下部地层,由粘土质板岩夹含硅岩薄层组成,矿层中具钼超常富集;该区地层受热水影响小,而构造改造较强,其余特点与中村钒矿相似。黑色岩系矿床的成矿物质源自黑色岩系本身,沉积成岩阶段Au、Mo、Ni初步富集而钒工业富集。后期弱改造对钒影响不大,强烈构造作用及热液多期多阶段的活动造就了金矿床和Ni—Mo矿床。黑色岩系中成矿元素与其产出的大背景小环境、陆源和基底剥蚀区、热水物质、生命活动等有关,与地外物质关系不明显。夏家店金矿和清岩沟镍.钼矿黑色岩系有机碳含量较低,可能与后期局部强烈构造作用、热解作用有关;热解作用所产生的液态烃、气态烃在成矿过程中对成矿物质的萃取、迁移发挥了重要作用,为成矿作了自我牺牲。黑色岩系岩性复杂（特别是处于旋回过渡期的沉积类型）、生物作用和热水作用强烈、岩石组合类型完整对成矿元素的富集有利。更多还原

【Abstract】 The black rock series in Qinling Mountains are made up of carbonaceous argillite, carbonaceous siliceous argillite,silicalite,argillite,marl,stone coal and carbonaceous limestone.Phosphatic podule,pyrite and barite are always found in these rocks.Geological and geochemical study shows that the black rock series were formed by hydrothermal fluids and biological action in anoxic environment.Complex metallogenic matter had multi-source.The character of biomarkers indicate that the organic matter derived from plankton, bacterium and alga.The organic compenent in some samples has the characteristic of advanced plant.Organic-carbon in Qinling black rock series could vary from low to high,the content of carbon under tectonic metamorphic rocks is less than that of other black rocks. Black rocks in Qinling are lower dissolved hydrocarbons and hydrocarbons originated from kerogen cracking for thermal decomposition in advance.The black rock series of Qinling orogenic belt can be divided into three parts（north belt, middle belt and south belt） in consideration of the geological background,rocks and metallogenic elements combination.The Miaowan Formation as the north belt black rocks formed in fringe sea which belongs to an active continental margin,and contains high K,Fe, Al and low Si,variational Na,with Toe raging from 2.52%to 4.7%.The metallogenie matter is from terrigenous component adding biological component and hot water which is relevant with basalts and granites.Combination of metallogenic elements is Mo,Ni,Cu,Pb,Zn and U. A Ni-Mo deposit was found in it.The middle belt of black rock series has more silicalite and variational Toe and lies in the bottom of Shuigoukou Formation which was from profundal or semiprofundal stagnant fault basin around paleo-uplift-belt of Qinling micro-plate.The source belt was like north belt rocks,while hot water matter could only be correlated with basalts. The combination of metallogenic element is Au-V-P-Cu-Pb-Zn-U.Au and V deposits were found in it.The south black-rock belt was formed in horst-lift basins of continental fringe which was made up of Lujiaping and Banjiuguan Formations,There are more phosphorite, stone coal,barite and witherite while less volcanic rocks in some parts.The source is continental matter,biological component and hot water related with basalts.Combinations of minerogenic element are V-Mo-Ba-P-Au and V-Mo-Au-P-Se-C.Barite deposits,witherite deposits and V deposits were found in this belt.The Ni and Mo elements of Qinyangou Ni-Mo ore are from the black rocks in Miaowan Formation,but posterior magma.According toδD-δ¹⁸O diagram,geologic feature and oxygen-isotope of ore,the ore-forming solution was intensively reconstructive meteoric water, metamorphic hydrothermal solution and small quantity of magmatic water.Forming process of ore had come through primary enriching period,regional metamorphism period,tectonic and superimposed hydrothermal solution reconstrueturing period.The main minerals are molybdenite,pentlandite and pyrrhotite.The homogenizational temperatures of inclusions in ore-bearing quartz vein were from 211.4 to 444.9℃,corresponding to middle to high temperature.The salinity of these inclusions had large scope（7.02～19.21%）.Both the temperature and salinity decreased following the time sequence.The ore-body which consists in serieite carbonaceous phyllite part,which has the feature of superimposed strata deformed by tenacity-brittle shear.The ore was controlled by strata,rock,structure and hydrothermal solution.The Zhongcun-Yinhua vanadium ore was caused by sediment -diagenesisdiagenism.The ore body was in the bottom of Shuigoukou Formation.The rich ore rocks were rich in Al and K,poor in Ca,while the contrary contents are in poor-ore rocks.Ore-bearing rocks and rare-earth content,Ba has better relations between growth and decline.Better ore-forming always has more Toc or organic substance.The content of V is 75.2%in argillite（existing as isomorphism）,and is 24.8%in silicalite（existing as adsorption）Xiajiadian micro-disseminated type gold deposit is a middle-large-sized sedimentary-structural-hydrothermal-reconstruction Au metal deposit hosting in black-rock-series.In this deposit,rich-ore rocks contain more Si,Fe,C and K than others.The homogenizational temperature of fluid inclusion in mineralized quartz and calcite is from 140 to 336℃,and the mineralized pressure is in the range from 370×10⁵ to 820×10⁵Pa,the mineralized salinity varied from 3.27 wt%to 5.25 wt%.The deposit has experienced pre-enriching process in Paleozoic,ductile-brittle structure and hydrothermal superposition process in Neozoic,erosion-oxidation process in subsequent time.Huangboshuwan witherite in the south belt is a marine thermal water sedimentary deposit which had been slightly rebuilt by tectonics.The major metallogentic minerals are witherite and barite.The ore body were stringently controlled by the bottom strata of Lujiaping Formation.The indicator horizon is transition-passage between silicalite and carbonaceous siltstone.The witherite was intimate inter-growth with barite and thin layer silicalite with cellophane.The discovery of sponge-spicule and foraminfera fossil indicates that the sedimentary environment was dominant by profundal depressed fault basins in marine bottom. The vanadium deposit of Liyushan is a middle-sized sediment-reformed deposit in the lower Lujiaping Formation in south belt.Clay slate and intercalated siliealite made up of the stratum and Mo is super-enriched in these particular parts.The strata had been strongly affected by tectonics and slightly affected by hydrothermal,The other features of the deposit are similar to that of Zhongeun vanadium deposit.Mineral matter of ore come from the black rock series themselves,The elements of Au, Mo and Ni are original enrichment,while V is industrial enrichment during sedimentary-diagenetic stage.The weak reconstruction had little effect on mode of occurrence of V,while strong tectonics and hydrothermal liquid made Au,Ni-Mo conglomerated during different periods.The sources of mineral elements were correlated with tectonic background, sedimentary mieroenvironment,erosion area of land and basement rocks,thermal hydrodynamics and microorganism rather than other cosmic matter.The lower content of Toc in Au deposit of Xiajiadian and Ni-Mo deposit of Qingyangou are probably caused by strong tectonics and pyrogenation process.The liquid state and gaseity hydrocarbon from Toc played an important role in the process of ore-forming.The factors such as complex lithology,active- biological processes,much thermal hydrodynamics and complete rock types are advantaged to form ore deposit.更多还原