Sedimentological evidence of climate-tectonic interaction in the upper Satluj catchment of NW Himalaya

Quaternary valley fill deposits in the Upper Satluj Valley of NW Himalaya act as archives of changing climate-tectonic dynamics in a region.Quaternary landforms help in decoding the relationship between climate and tectonics.Kinnaur region is traversed by several active faults and thrusts such as the Kaurik-Chango Fault(KCF)and Sangla Detachment(SD),thereby making upper Satluj Valley tectonically active.Morphotectonic parameters such as width of valley floor(Vfw),Normalized Steepness Index(KSn)and geomorphological evidences such as the presence of huge strath terraces,narrowing of the river valley and palaeolake deposits point towards the tectonically active nature of the terrain.This arid,high elevation region is also climatically sensitive as it falls in a transient climatic zone which receives rainfall only during abnormal monsoon months.Excessive rainfall causes outburst floods,a common phenomenon in the area due to the blocking of headwater in the upper reaches of the Satluj valley.As a result,the Quaternary sequence is modified from time to time.The transition from hypo concentrated deposits to channel deposits and ponding events are prominent in the depositional sequence,resulting from a response to climate.The studied Quaternary sediments reveal that the Trans-Himalayan region of the upper Satluj valley is affected by tectonic-climate variability,making it vulnerable to geohazards.

Evolution of lithofacies and paleogeography and hydrocarbon distribution worldwide(I)

By using a large amount of geological and geophysical data, the geological characteristics such as lithofacies and paleogeography of 4981 geological units at thirteen key geological periods or epoches since the Precambrian in the world have been figured out. The global lithofacies and paleogeography charts have been compiled by ArcGis mapping technology. Combined with the results of plate-paleogeography reconstruction, the lithofacies and paleogeography as well as the prototype basins of these global paleoplates have been restored with the Gplate software. Results show that there are 22 kinds of lithofacies combinations and 10 types of paleogeography units developed since Precambrian. These features of lithofacies and paleogeography as well as their evolution were mainly controlled by the divergent and convergent movements of those plates. Taking the results of the lithofacis and paleogeography at the present and paleoplate location during the seven key geological periods from the Precambrian to Paleozoic for example, during the Late Precambrian and Cambrian, the large-scale disintegration of the Rodinia supercontinent resulted in reduction of uplift denudation area and clastic terrestrial facies area, the expansion of coastal-shallow marine facies and shallow-water carbonate platform. In Devonian, uplift denudation area and clastic terrestrial facies area began to increase and littoral-shallow marine facies area and shallow-water carbonate platform shrank as a result of the formation of Larussia supercontinent. In the Permian, with the formation of the Pangea continent, the development of the global uplift denudation area and clastic terrestrial facies reached its peak, while the littoral and shallow marine facies were very limited in distribution. The lithofacies and paleogeography features and evolution patterns of different stages lay a solid foundation for analyzing the formation conditions of geological elements, such as source rocks, reservoirs and cap rocks for oil and gas accumulation, and revealing the distribution regularity of oil and gas around the world.

Geochemistry of sedimentary rocks from Permian–Triassic boundary sections of Tethys Himalaya: implications for paleo-weathering, provenance, and tectonic setting

The geochemical characteristics of two sections—the Permian–Triassic boundary(PTB) Guryul Ravine section, Kashmir Valley, Jammu and Kashmir,India; and the Attargoo section, Spiti Valley, Himachal Pradesh, India—have been studied in the context of provenance, paleo-weathering, and plate tectonic setting.These sections represent the siliciclastic sedimentary sequence from the Tethys Himalaya. The PTB siliciclastic sedimentary sequence in these regions primarily consists of sandstones and shales with variable thickness. Present studied sandstones and shales of both sections had chemical index of alteration values between 65 and 74; such values reveal low-to-moderate degree of chemical weathering. The chemical index of weathering in studied samples ranged from 71 to 94, suggesting a minor K-metasomatism effect on these samples. Plagioclase index of alteration in studied sections ranged from 68 to 92, indicating a moderate degree of weathering of plagioclase feldspars. The provenance discriminant function diagram suggests that the detritus involved in the formation of present studied siliciclastic sedimentary rocks fall in quartzose sedimentary and felsic igneous provenances. These sediments were deposited in a passive continental margin plate tectonic setting according to their location on a Si_2 O versus K_2O/Na_2 O tectonic setting diagram.

Evolution of lithofacies and paleogeography and hydrocarbon distribution worldwide(Ⅱ)

Based on the compilation and analysis of the lithofacies and paleogeography distribution maps at present and paleoplate locations during six key geological periods of the Mesozoic and Cenozoic,the lithofacies and paleogeography features and their development laws were expounded.Based on our previous research results on lithofacies and paleogeography from Precambrian to Paleozoic,we systematically studied the features and evolution laws of global lithofacies and paleogeography from the Precambrian and their effects on the formation of source rocks,reservoirs,cap rocks and the distribution of oil and gas worldwide.The results show that since Precambrian,the distribution areas of uplift erosion and terrestrial clastic deposition tended to increase gradually,and increased significantly during the period of continental growth.The scale of coastal and shallow marine facies area had three distinct cycles,namely,from Precambrian to Devonian,from Carboniferous to Triassic,and from Jurassic to Neogene.Correspondingly,the development of shallow carbonate platform also showed three cycles;the lacustrine facies onshore was relatively developed in Mesozoic and Cenozoic;the sabkha was mainly developed in the Devonian,Permian and Triassic.The Cretaceous is the most important source rock layers in the world,followed by the Jurassic and Paleogene source rocks;the clastic reservoirs have more oil and gas than the carbonate reservoirs;the basins with shale caprocks have the widest distribution,the most abundant reserves of oil and gas,and the evaporite caprocks have the strongest sealing capacity,which can seal some huge oil and gas fields.

矿田构造岩相学填图理论及应用

开展成矿蚀变−构造岩相解析建相和建模预测研究已成为矿田构造与找矿预测的创新方向之一。文章对国内外8类重要的成矿蚀变−构造岩相模型和形成机制进行论述总结,南美洲智利科皮亚波地区IOCG型矿田受到主岛弧带−弧相关盆地及岩浆叠加−盆地变形样式的复合控制,而中国云南东川沉积岩型铜矿床(SSC型)+IOCG型铁铜矿田受陆缘裂谷盆地、盆地变形构造样式和岩浆叠加侵入构造系统的复合控制。中国内蒙古甲−查浅成低温热液型银铅锌矿田受火山洼地、火山穹隆构造、火山岩岩相类型和火山热液隐爆角砾岩的复合控制,而深成岩浆弧控制了蒙古国南戈壁斑岩型金铜钼−浅成低温热液金银矿田;中国秦岭热水沉积型(SEDEX)银铜铅锌−菱铁矿−重晶石矿田受到陆缘拉分盆地内三级热水沉积盆地、同生断裂带和热水沉积岩相的控制。大陆造山带内不同层次的脆韧性剪切带,控制了金矿田和金钼多金属矿田定位。在新疆塔西盆−山−原镶嵌区盆地系统内,侏罗系煤系烃矿源岩是金属矿田和天然气气田的成矿成藏物质供给源区;乌拉根砂砾岩型天青石−铅锌矿田受到山前挤压—伸展转换盆地、气成热流柱构造和山前冲断褶皱带的复合控制;萨热克铜多金属矿田赋存于旱地扇杂砾岩,受到对冲式厚皮型逆冲推覆断裂带和幔源热流柱带的复合控制。其中在矿集区−矿田尺度上,电气石热流柱构造、岩浆气囊构造、复合岩溶构造岩相等是成矿蚀变−构造岩相的3种新类型;在归纳前期对矿田构造岩相、矿田构造古地理单元和典型矿田构造岩相形成机制研究基础上,文章提出了矿田成矿蚀变−构造岩相类型的新划分方法和划分原则方案,并划分确定了12种变形构造岩相类型。研究成果为矿田构造研究和找矿预测提供了新理论和新方法支撑。

基于构造变形岩相带的覆盖区化探资料解释与找矿应用:以广西金秀镍钴多金属矿田为例

覆盖区化探资料复杂,解释难度大,亟须加强构造控矿要素方面的约束。不同类型覆盖区的构造形迹出露程度差别很大,因此需要从多个级别的构造体系中提取含矿构造变形岩相带的分布信息。本文提出基于地质力学构造体系阶段性演化特征判别覆盖区有利含矿构造走向,解译化探资料的成矿信息,以快速圈定找矿靶区的新思路。首先,从已知的地质、遥感和物探资料中解译出矿田的构造形迹和热液矿床的成矿信息;其次,依据成矿期的构造应力场特征确定主应力方向;第三,将张扭性和张性构造变形岩相带作为有利的含矿构造;最后,根据数据处理结果确定找矿异常区。将上述方法应用在广西金秀镍钴多金属矿田,确定了两个主要的含矿构造方向,即NWW—EW—NEE向断裂和NW—NNW向断裂,它们的形成时期不同,分别控制富砷化物型和富硫化物型的镍钴多金属矿脉。该方法和找矿思路可在覆盖区矿产资源勘查工作中进一步推广。

Tectonic Related Lithium Deposits Another Major Region Found North East Tanzania—A New Area with Close Association to the Dominant Areas: The Fourth of Four

The current “mega” interest in Lithium resources was spurred by the development of Lithium-Ion batteries to aid in restructuring the world’s reliance on carbon spewing power petroleum reserves. Current resources of lithium recovery have fallen into two main categories—Pegmatite, found worldwide associated with felsic intrusions and Brine Related, and now with development in the Southwest United States of America (SWUS), a third category— Tertiary Volcanic clays, are specifically associated with Tertiary volcanics and major Tectonic Plate interactions. “Active” Plate tectonics is important as both the SWUS, the Lithium Triangle of South America (LTSA) and the Tibetan Plateau of China (TPC) producing tertiary (Miocene) volcanism that is important to the development of Lithium resources. The Tanzanian part of the East Africa Rift System (EARS) has features of both the SWUS, tertiary volcanic related “playas” and Continental rifting, the LTSA, tertiary volcanic related “Brines” and a major Tectonic plate event (subduction of an Oceanic Plate beneath the Continental South American Plate) and the TPC, tertiary volcanics (?) and major tectonic plate event (subduction of the Indian Continental Plate under the Eurasian Continental Plate). As well as the association of peralkaline and metaluminous felsic volcanics with Lithium playas of the SWUS and the EARS (Tanzania) “playas”. These similarities led to an analysis of a volcanic rock in Northeast Tanzania. When it returned 1.76% Lithium, a one-kilometer spaced soil sampling program returned, in consecutive samples over 0.20% Lithium (several samples over 1.0% lithium and a high of 2.24% lithium). It is proposed that these four regions with very similar past and present geologic characteristics, occur nowhere else in the world. That three of them have produced Lithium operations and two of them have identified resources of Lithium clay and “highly” anomalous Lithium clays should be regarded as more than “coincidental”.

鄂尔多斯盆地奥陶系马家沟组一段—三段构造沉积演化及其油气地质意义

基于测井、岩心、薄片、地球化学分析,重建鄂尔多斯盆地奥陶系马家沟组一段—三段(简称马一段—马三段)构造-岩相古地理格局,探讨构造沉积演变特征及其油气地质意义。研究表明:①马家沟组底部稳定发育一套穿时的、高自然伽马值段、边缘相泥质白云岩,分布于怀远运动期构造不整合面之上,具有与早奥陶世弗洛期全球海侵可对比的δ13C正漂移特征;②奥陶系马一段—马二段沉积期全球海平面上升、古陆淹没为水下隆起,形成一隆两坳构造格局,中央隆起首次接受沉积;随后马三段沉积期盆外俯冲挤压、盆内隆坳分异,乌审旗—靖边凸起活化;③构造格局演变对沉积古环境产生显著影响,马一段沉积期向西超覆,东部坳陷内海侵封隔形成大规模盐质蒸发潟湖;马二段沉积期持续海侵并沟通广海,环东部坳陷发育大规模颗粒滩,晚期干化收缩形成小规模蒸发潟湖;马三段沉积期受高地封隔影响,向东侧水体渐次分异分别形成云膏质和盐质蒸发潟湖,同时颗粒滩环凹沿高地展布;④马家沟组底部发育烃源岩,马二段和马三段滩相储层环坡展布,源储配置良好,有利于天然气成藏,具有一定勘探潜力。

苏北盆地古近纪构造-层序岩相古地理特征与演化

以板块构造学和层序地层学理论为指导思想,把苏北盆地古近纪划分为3个构造-层序,分别为古新世(TS1)、始新世(TS2)和渐新世(TS3)构造-层序。在此基础上,以构造-层序界面和最大洪泛面为界,以湖盆扩张体系域和湖盆收缩体系域为编图单元,编制了苏北盆地古近纪各地质时期的构造-层序岩相古地理图,探讨了各构造-层序岩相古地理特征及演化,为该地区油气勘探有利区块的预测和评价提供了更为可靠的依据。

胶东典型含矿构造岩相带的地质-地球物理信息预测方法与找矿实践

地质与地球物理相结合的隐伏矿床定位预测是矿产勘查领域的世界性难题,相关的理论与技术是研究热点。构造是成矿的决定性因素,准确识别控矿构造是预测成功的首要条件,有利的成矿构造部位就是含矿的构造岩相带。依据构造岩相标志及其物性参数特点,提出了面向找矿预测目标的矿床地球物理类型划分方案。摆脱经济指标对矿体范围的限制,将更大规模的含矿构造岩相带作为预测目标,提高了物探方法的识别精度,预测成功率随之显著提高。选择胶东金矿集区内受断裂构造控制的焦家、蓬家夼、七宝山3个典型金多金属矿田,具体介绍了该预测方法的操作程序。首先,在详细的地质观察测量基础上,分析成矿规律,识别含矿构造岩相带,建立成矿地质模型。然后,测量含矿地质体的物性参数,研究其分布规律和影响因素,进而选择有效的地球物理方法和观测系统,完成数据采集、处理和解释,建立地质-地球物理勘查模型,优选找矿靶区靶位。最后,实施工程验证,取得良好的找矿效果。

塔里木盆地寒武系盐下构造-岩相古地理、规模源储分布与勘探区带评价

针对塔里木盆地寒武系盐下领域(上震旦统—中寒武统)源储分布不清的问题,利用最新采集/拼接处理的50余条地震大测线、三维地震数据体、22口钻井与周缘剖面等资料,开展以组为单元的构造-岩相古地理研究,落实规模性源储分布,评价有利勘探区带。结果表明:①该盆地经历了缓坡→深水富泥质缓坡→缓坡→弱镶边-强镶边台地演化序列,台内分异受前寒武系古裂陷控制;②罗南—玉北古裂陷控制下寒武统玉尔吐斯组烃源岩分布,与北部坳陷共同构成主力烃源岩区;③发育上震旦统奇格布拉克组、下寒武统肖尔布拉克组和吾松格尔组3套规模性储集层,古丘滩、早期白云石化及多级不整合控制储集层的发育;④评价出塔中北斜坡、麦盖提上斜坡、柯坪—温宿周缘及塔北南斜坡等4个有利区带,塔中北斜坡为勘探突破最现实领域,塔北南斜坡是探索上震旦统大型风化壳白云岩的最佳领域,麦盖提斜坡及柯坪—温宿周缘勘探潜力得到明显提升,值得加快探索。

胶东大尹格庄金矿田构造物理化学参量急变带成矿特征

在金属内生矿矿田地质研究中,构造变形岩相既能反映矿田形成的构造应力场特征,又能揭示其地球化学特征和物理化学条件。胶东金矿集中区在全球金矿中独具特色,其金矿储量规模位居世界第三,大尹格庄金矿田是区内特大型金矿田之一。在矿田构造蚀变岩相研究基础上,厘清矿田成矿构造物理化学参量之间的关系,探讨构造作用通过影响矿田成矿物理化学条件驱动金成矿作用问题显得尤为必要。本文选取代表成矿流体成分、温压、性质和成矿构造等条件的构造物理化学参量,采用因子分析法,探讨矿田构造成岩成矿问题。结果显示:流体包裹体成分CO_(2)/H_(2) O、酸碱度(pH)、氧逸度(lgfO_(2))、构造附加静水压力(Ps)、流体包裹体均一温度以及流体包裹体最小压力(Pmin)等参量代表的构造物理化学条件对成矿的影响较大,CO_(2)/H_(2)O、lgfO_(2)、Ps、均一温度、Pmin所代表的成矿流体成分、性质、温压条件及构造作用的影响是正相关的,而pH影响是负相关的;矿田黄铁绢英岩带、黄铁绢英岩化花岗质碎裂岩带和强钾长石化花岗岩带中,构造附加静水压力(Ps)、流体包裹体成分CO_(2)/H_(2) O、氧逸度(lgfO_(2))、流体包裹体最小压力(Pmin)和均一温度均依次呈现先升高再降低的趋势。流体包裹体成分Na^(+)/K^(+)、F^(-)/Cl^(-)参量代表的成矿物理化学条件对于成矿的影响是负相关的,在黄铁绢英岩带、黄铁绢英岩化花岗质碎裂岩带和强钾长石化花岗岩带中,F^(-)/Cl^(-)依次呈现逐渐降低的趋势,Na^(+)/K^(+)则依次呈现逐渐增大的趋势。构造附加静水压力(Ps)能够促使成矿流体从Ps较高的部位向较低的部位运移并沉淀成矿。构造物理化学参量的高低值之间存在构造物理化学界面,金矿体主要位于界面的构造应力松弛部位。

塔北地区寒武纪深层白云岩构造-岩相古地理特征及勘探方向

由于塔北地区寒武系深层白云岩资料点少,有效恢复岩相古地理成为制约寒武系深层白云岩勘探领域优选的关键地质要素之一。利用有限的14口钻井和4个野外露头地质资料点以及地震资料,探讨了塔北地区寒武纪深层白云岩岩相古地理特征,精细刻画了台地类型及台缘特征,并尝试刻画台内沉积分异。塔北地区寒武纪总体发育轮南断控陡坡型台缘和北部沉积缓坡型台缘2种类型的台缘,台内滩、膏云坪、膏盐湖及台内洼地等沉积单元分异明显。台缘特征及台内沉积分异控制了储盖组合的配置,由此得出长期继承性隆起上的寒武系台缘礁滩、礁后滩白云岩与蒸发盐湖相膏盐岩和蒸发潮坪相膏泥质白云岩形成的优质储盖组合为有利的勘探方向。塔北地区寒武系具有2个现实的有利勘探区带:轮南陡坡型台缘带和北部缓坡型台缘带,其中,轮南台缘带后侧、泻湖靠海一侧的礁后滩储层上覆致密碳酸盐岩盖层;北部台缘带藻丘及滩体复合型白云岩储层上覆中、下寒武统泥晶白云岩、膏质白云岩及含泥白云岩等致密盖层。北部缓坡型台缘带储盖组合要优于轮南陡坡型台缘带,勘探前景更为乐观。

塔里木盆地下寒武统肖尔布拉克组构造-岩相古地理特征

为了查明塔里木盆地下寒武统肖尔布拉克组构造-沉积响应特征与演化规律,为该区深层油气勘探寻找新的接替区,以海相碳酸盐岩层序地层学和储层沉积学理论体系为指导,在岩心、薄片、测录井以及地震等资料的基础上,结合构造古地貌特征,明确下寒武统肖尔布拉克组主要发育局限-半蒸发台地、开阔台地、台地边缘与斜坡-盆地相,又可划分为多个亚相和微相,沉积相的分布具有典型的分带性和继承性。基于横跨盆地的二维地震测线精细解释,确定了塔里木盆地寒武系主要沉积相类型的地震相响应特征,识别出了6种地震相(Seismic Facies)类型,分别为台内(丘)滩(SF1)、台内洼地(SF2)、丘(滩)间海(SF3)、膏盐湖(SF4)、台地边缘(SF5)和斜坡-盆地(SF6),进而圈定了各相带的平面沉积相边界,揭示了各相带发育分布与古构造和古地貌的联系。根据肖尔布拉克组厚度分布,明确了盆地南部存在东西走向的古隆起区,东部和中部存在两个洼陷区;盆地西南部存在一级阶地,以宽缓的一级坡折向中部低洼区过渡;盆地中部存在窄陡的二级坡折,向东快速过渡为深洼区。再结合地震解释成果、野外露头、取心井观察和室内镜下岩石薄片鉴定等资料,编制下寒武统肖尔布拉克组岩相古地理图,为塔里木盆地下寒武统肖尔布拉克组深层碳酸盐岩油气勘探提供了有利证据。

川滇黔桂地区志留纪构造-岩相古地理

晚奥陶世与早志留世之间的都匀运动 ,使滇中古隆起与黔中古隆起成为一个整体隆起带(习惯上称黔中古陆 ) ,把滇东南 黔南地区与滇东北 黔北 川南地区分隔为南、北两个不同的构造沉积域。南侧的曲靖一带出露下、中寒武统 ,其上分别与中、上志留统和下泥盆统呈假整合 ,其间缺失奥陶纪和早志留世的沉积物。北侧的禄劝—武定一带 ,下古生界的沉积序列与之相反 ,有完整的奥陶纪沉积组合 ,上与泥盆系假整合 ,其间无志留纪的沉积。这表明黔中古隆起两侧的沉积域各为独立的系统。中、晚志留世 ,黔中古隆起南侧应归属于上扬子与滇黔桂地块前陆挠曲盆地的一部分 ,由曲靖向北东经赫章的哑都到贵阳南转向湘西 ,向南则与云南的绿春海相连 ,黔中古隆起北侧的沉积域则为上扬子前陆 (川南 黔北 )盆地的边缘相。

陕西陈耳金矿床不同构造-岩相带微量元素地球化学特征及构造控矿机理

通过对陈耳金矿床两类不同构造-岩相带微量元素分布特征分析,发现元素特别是成矿元素Au的含量从片理化带→破碎蚀变带→石英脉逐渐增强。构造-岩相带内变形岩石的石英Rf/φ法有限应变测量表明,片理化带应变强度最大,破碎蚀变带应变强度小,应变集中在韧性剪切带边部的片理化带内。R型聚类分析表明Au与Ag、Cu、Pb及Zn的相关系数远大于Au与Ni、Co元素的相关系数,甚至接近于1。研究认为:破碎蚀变带内由于应变软化导致脆性裂隙大量发育,易于成矿流体的迁入与淀积而强富集;片理化带由于应变集中,造成成矿流体的迁出而弱富集。韧性剪切带脆-韧性变形转换不仅控制了矿体就位空间,同时也决定着元素迁移的方向。

陕川丁家林-太阳坪-董家院金矿带的矿田构造-岩相学研究

陕西丁家林-四川太阳坪-四川董家院北东向金矿带位于后龙门山陆内造山带,构造动力学背景为陆-陆板块碰撞而形成的逆冲推覆造山带,金矿带内发育一系列与陆内造山作用密切有关的北东向递进脆-韧性剪切带。本文以构造-岩相学新方法为指导,在矿田构造-岩相学层次上,通过实测构造-岩相学剖面和岩石地球化学研究,对该金矿带物质学和运动学特征研究表明,赋矿地层志留系黄坪组(S1-2hn)区域性岩相学特征整体为陆棚相。黄坪组中部层间流体活动强烈,地壳浅部富Fe-Mg-CO32–型构造流体活动形成了斑点状铁碳酸盐千枚岩相;随构造变形层次加深,强应变带发育构造片岩相和初糜棱岩相,富Si O2型流体排泄的构造分异成岩作用形成了流变状糜棱岩相。强烈的构造成岩作用及造山带流体的大规模排泄形成了糜棱岩相,同位发育密集的流变状糜棱岩相和蚀变菱铁矿铁白云石网脉相。构造流体成岩成矿作用集中于强应变带形成蚀变糜棱岩相,后期脆性蚀变碎裂岩相叠加时,金矿化(体)发育。早期韧性剪切和脆韧性剪切变形并叠加有后期脆性变形构造,富集Au-Cu-Sb-W-Bi等元素组合。本区缺少或未见早三叠世以后形成的岩浆活动。大规模富Fe-Mg碳酸盐型流体及同构造期造山带流体活动与龙门山陆内造山带密切相关,表明丁家林-太阳坪-董家院金矿为造山型金矿。

胶东变质岩型金矿构造-岩相特征及其控矿作用

本文简述了胶东变质岩型金矿的构造－岩相特征。通过对构造体系及其复合成分的控矿和成矿作用，断裂性质和规模控制矿化类型和蚀变特征，构造－岩相类型控制矿化分带和矿体组合特征等方面的综合研究，分析了构造－岩相型式的控岩控矿作用，并对胶东变质岩型金矿构造－岩相成矿系列和成矿模式进行了探讨。

塔西地区富烃类还原性盆地流体与砂砾岩型铜铅锌-铀矿床成矿机制

塔西地区萨热克大型砂砾岩型铜矿床和乌拉根铅锌矿床进入矿山开发期,今后找矿潜力大但成矿机制不明,制约了成矿与找矿预测。基于构造岩相学和地球化学岩相学,以西南天山造山带为核心,塔西地区前陆盆地、山间盆地和后陆盆地对于砂砾岩型铜矿床、铅锌矿床和铀矿床有不同控制作用:1在西南天山造山带北侧的托云中—新生代后陆盆地系统中,其次级盆地(萨热克巴依中生代山间拉分断陷盆地)上侏罗统库孜贡苏组上段为萨热克式砂砾岩型铜矿赋存层位;2在西南天山造山带南侧的前陆盆地系统中,乌拉根砂砾岩型铅锌矿赋存在下白垩统克孜勒苏群顶部与古近系底部,巴什布拉克大型砂岩型铀矿床赋存在伽师前陆盆地克孜勒苏群中;3在前陆盆地系统中,古近系顶部和新近系渐新统—中新统为砂岩型铜矿床赋存层位。富烃类还原性盆地流体识别构造岩相学标志为沥青化蚀变相、沥青化—褪色化蚀变带、碎裂岩化相和沥青化蚀变相多重耦合结构;地球化学岩相学标志包括富含有机碳,矿物包裹体中含有含烃盐水、气态烃-液态烃-气液态烃、轻质油和沥青等有机质类包裹体,低盐度和中盐度成矿流体,Cu-Ag-Mo同体共生矿体,氧化相铜、硫化相铜和钼硫化物等。砂砾岩型铜铅锌-铀矿床成矿机制主要包括:1同生断裂带由走滑拉分断陷发生构造反转后,转变为挤压收缩体制,即烃源岩大规模生烃-排烃机制;2反转构造带、区域性不整合面、滑脱构造带、高孔隙度和渗透率砾岩等构造岩相带为富烃类还原性盆地流体大规模运移构造通道;3高孔隙度和渗透率砾岩类下部低渗透率泥质粉砂岩和上部含膏泥岩为岩相岩性圈闭构造岩相学标志;4大规模富烃类还原性盆地流体与含铜紫红色铁质杂砾岩(氧化相铜)有多相流体多重耦合结构,可能是砂砾岩型铜矿床大规模富集成矿机制,低温卤水沉积叠加富烃类还原性盆地流体成矿可能是形成砂砾岩型铅锌矿床机制,富烃类还原性盆地流体多期次混合与氧化相铀被还原可能是砂岩型铀矿富集成矿机制。

新疆萨热克铜矿床绿泥石化蚀变相与构造-岩浆-古地热事件的热通量恢复

据新疆萨热克铜矿区内绿泥石化蚀变相的产状可划分为A型、B型、C型和D型4期。采用绿泥石矿物温度计和地球化学岩相学研究,认为4种绿泥石蚀变相为陆内红层盆地中紫红色铁质碎屑岩系发生褪色化蚀变机制之一。A型和B型绿泥石相为中-晚侏罗世—早白垩世构造-热事件所形成,A型自生粒间状绿泥石在侏罗系-下白垩统中总体顺层分布,形成温度在163~217℃,与辉铜矿共生且形成于埋藏-压实成岩期,热流密度为40.39~48.43 Jm-2s-1,热通量较小。B型微细脉型绿泥石化蚀变相形成于盆地流体改造期,总体沿切层裂隙和显微裂隙分布,与辉铜矿和斑铜矿等共生,形成温度为188~219℃,热流密度较大,在116.90~330.49 Jm-2s-1。斑铜矿+辉铜矿型(196~237℃)和斑铜矿型(203~226℃)铜矿石带指示了盆地流体改造富集成矿的中心部位,热流密度在330.49~878.78 Jm-2s-1,其热流密度明显较大。B型绿泥石相与碎裂岩化相和沥青化蚀变相具有多重耦合结构,形成温度越高,裂隙渗透率越高,可达30×10-6 cm2/211~227℃,推测存在热启裂隙作用。C型和D型绿泥石相为构造-岩浆-热事件所形成,C型团斑状-细脉状绿泥石化蚀变相分布在辉绿辉长岩脉群边部和外接触带含铜漂白-褪色化蚀变带中,含铜蚀变辉绿岩发生绿泥石化相蚀变温度为平均为175℃,平均热流密度321.46 Jm-2s-1,在克孜勒苏群褪色化杂砾岩中其绿泥石形成温度较高(236~238℃),热流密度高达442.86~922.63 Jm-2s-1;而D型绿泥石化蚀变相分布在碎裂岩化蚀变辉绿辉长岩脉群中,揭示遭受构造热事件的古地温在121~185℃,平均热流密度为239.59 Jm-2s-1。四种类型绿泥石蚀变相揭示萨热克铜矿区经历了异常古地场演化和古热事件。