【作者】 张达玉；

【导师】 周涛发；

【作者基本信息】 合肥工业大学 ， 矿物学岩石学矿床学， 2012， 博士

【摘要】 新疆东天山觉罗塔格地区是指位于中天山地块和吐哈盆地之间、出露石炭系火山-沉积岩为其特征地层的构造条带,地理位置上处于东经89000’-96000’、北纬41040’-42040’之间。觉罗塔格地区在构造位置上隶属于西伯利亚板块和塔里木板块的聚合部位,由北向南可进一步分为小热泉子-镜儿泉火山岩带(北带)、康古尔-黄山韧性剪切带(中带)和阿奇山-雅满苏火山岩带(南带)三个次级构造单元；由东西向展布的区域性深大断裂控制。觉罗塔格地区是新疆北部重要的贵金属、有色金属矿产分布区之一,其成矿作用与构造-岩浆活动密切相关。在综合前人成果基础上,本文对觉罗塔格地区的成岩成矿作用进行了地质和地球化学分析,辨析了东天山觉罗塔格地区晚古生代球动力学演化过程,并评价了区域成矿潜力。取得成果如下：觉罗塔格地区十里坡自然铜矿化玄武岩带形成于晚石炭世末期,玄武岩浆源自90～100千米之间的亏损岩石圈地幔,该地幔源区以石榴子石橄榄岩相为主,并受到了早期岛弧俯冲的改造作用。玄武岩浆上升过程中发生了橄榄石和单斜辉石的分离结晶作用,但地壳混染作用较弱。玄武岩是后碰撞拉张构造背景下加厚岩石圈拆沉作用的产物,与岛弧、地幔柱成因的玄武岩差异显著。玄武岩有关自然铜矿化是成岩后热液作用的产物,Cu主要来自于玄武岩层,成矿流体是由盆地卤水、大气降水和有机质共同组成,具有中低温、低盐度和还原性质等特征,其中有机质是流体中Cu的迁移和沉淀的重要控制因素。自然铜成矿作用与岩浆型矿床无成因联系。觉罗塔格地区内分布的中酸性侵入体从早到晚可分为：晚泥盆世镜儿泉花岗岩带、早石炭世土屋-延东中酸性岩带、早石炭世长条山-百灵山中酸性岩带、早二叠世康古尔剪切带相关中酸性岩带、晚二叠世-中三叠世土墩-双岔沟花岗岩带5个中酸性岩带。晚泥盆世镜儿泉中酸性岩带位于北带,花岗岩浆源于亏损的交代地幔,形成于俯冲岛弧体系；早石炭世土屋-延东中酸性岩带位于北带,岩浆起源于埃达克质岩的亏损地幔源区,形成于靠近洋壳一侧的岛弧-弧后盆地系统；早石炭世长条山-百灵山中酸性岩带位于南带,岩浆起源于壳幔混合源区,形成于靠近陆壳一侧的弧后盆地系统；早二叠世康古尔剪切带中酸性岩带位于中带及其两侧部位,岩浆起源于壳幔混合源区,形成于后碰撞拉张环境；晚二叠世-中三叠世土墩-双岔沟花岗岩带位于中带,岩浆起源于新生地壳源区,岩浆形成于后碰撞-板内过渡环境。觉罗塔格地区与中酸性侵入岩有关的金属矿床有早石炭世斑岩型Cu矿床、早石炭世花岗岩相关的Fe矿床、早石炭世与中酸性浅层侵入体有关VMS型Cu多金属矿床、早二叠世浅层侵入体相关Cu多金属矿床、早二叠世韧性剪切带型Au矿床和中三叠世斑岩型Mo矿床。矿床有北带Cu、南带Fe、中带Au-Ni-Cu-Mo的空间分布特征,总体具有沿着中带对称分布的特点。觉罗塔格地区与中酸性相关成矿作用可划分为早石炭世岛弧体制下火山岩-侵入岩成矿系统,晚石炭世-早二叠世伸展体制下构造-岩浆成矿系统和中三叠世挤压体制下构造-岩浆成矿系统,其中斑岩型矿床在三个成矿系统中均有发育。觉罗塔格地区晚古生代经历了北部的卡拉麦里大洋向南部的中天山地块俯冲的“增生造山”过程。依照晚泥盆世-中三叠世不同阶段的地球动力学背景可分为晚泥盆世岛弧形成阶段、早石炭世弧后盆地演化阶段、晚石炭世早期主碰撞阶段、晚石炭世末期后碰撞岩石圈拆沉阶段、早二叠世后碰撞挤压变形与地幔柱联合作用阶段、晚二叠世-早三叠世后碰撞挤压变形阶段和中三叠世板内阶段。晚泥盆世岛弧形成阶段岩浆作用集中于北带,无明显矿化作用；早石炭世弧后盆地演化阶段,在北带形成了岛弧俯冲相关的埃达克质花岗斑岩及Cu矿床、在南带形成了弧后盆地软流圈上涌的中酸性岩体及Fe矿床,在南带和北带都形成了弧后盆地拉张背景的火山岩-浅层侵入体及Cu-Pb-Zn多金属矿床；晚石炭世早期主碰撞阶段尚未有成岩成矿作用报道；晚石炭世末期后碰撞岩石圈拆沉阶段形成了玄武岩浆作用及其相关Cu矿床；早二叠世后碰撞挤压变形与地幔柱联合作用阶段,在中带形成了基性岩及其相关Cu-Ni矿床、花岗岩及其相关的金矿床,在靠近中带的南北两带形成了浅层中酸性侵入体及其相关的Cu多金属矿床；在晚二叠世-早三叠世后碰撞挤压变形晚阶段岩浆作用集中于中带,并形成了剪切带活动相关的Au矿床；中三叠世板内阶段受到特提斯俯冲的远程挤压影响,在中带形成了花岗岩及其相关Mo矿床。本文研究工作较为清晰的勾勒出了觉罗塔格地区晚泥盆世-中三叠世的地球动力学演化过程,建立了觉罗塔格地区晚泥盆世-中三叠世的地球动力学和成岩成矿作用的耦合模式。提出早石炭世觉罗塔格地区处于弧后盆地背景；康古尔韧性剪切带(中带)是该弧后盆地背景下由北带和南带的结合部位逐步拉张的产物。提出早二叠世晚期觉罗塔格地区受到塔里木地幔柱“平流”作用影响,使得该区不仅发生了沿着岩石圈薄弱带发生了强烈的成岩成矿作用,同时延缓了后碰撞挤压变形阶段的演化过程。研究结果对觉罗塔格地区成岩成矿作用的研究和找矿勘探工作提供了较为重要的依据,也对“后碰撞”和“地幔柱”等地学热点问题的研究提供了范例和佐证。更多还原

【Abstract】 The Jueluotage area is geographically located in the south part of Hami City, which is within the district of the89°00’-96°00’ in east longitude and41°40’-42°40’ north latitude. This area is about560km from east to west and110km from north to south, with about62000km2in covering district. The Jueluotage area is geologically defined as the volcano-sediment exposure belt between the Tu-Ha-(Turpan-Hami) Basin (north) and Middle Tianshan terrene (south), which is within the aggregate places of Siberia and Tarim plates tectonically. The Jueluotage area can be geologically subdivided into3subunits from north to south, including:Xiaorequanzi-Jingerquan volcanic belt (North belt), Kangguer-Huangshan ductile shear belt (Middle belt) and Aqishan-Yamansu volcanic belt (South belt). There intensive late Paleozoic magmatism with multi-types mineralized deposits widely distribute in Jueluotage area, which has been regarded as a key metallogenic belt in North Xinjiang Uygur Autonomous Region.After comprehended and summarized the previous petrogenesis and matallogenesis researches on the geological objects in Jueluotage area, the author firstly systematically introduced the regional geological characters in Jueluotage area, and then detailed illustrated:(1) the petrogenesis of the native copper mineralized basalt(NCMB),(2) the petrogenesis of the late Paleozoic granitoid intrusions,(3) the matallogenesis of native copper mineralization in basaltic strata,(4) the matallogenesis of the multi-type mineralization related with the granitoid intrusions according to their geological and geochemical characters. Moreover, based on the above4research points, petrogenesis and matallogenesis comparative analysis between the NCMB and Cu-Ni mineralized mafic intrusion, and comprehensive analysis of the strata, structure, and geophysical characters in Jueluotage area, the author further identified the late Paleozoic geodynamic process, established the tectonic-magmatism-mineralization coupled evolution model, and predicted regional metallogenic target of multi-type mineralization in study area. The detailed research can be described as follows:The native copper mineralized basalt (NCMB) was erupted in the end of Carboniferous (～310-303Ma). The basaltic magma was derived from depleted lithosphere mantle without distinct crust contamination during its emplacement. Its magmatic source was characterized as90-100km in depth, garnet peridotite face, and crust contaminated by early subduction through their elements and isotopes geochemistry. The NCMB is formed by delamination of thickening lithosphere within post-collisional stage and distinctly different from magmatism in island-arc and mantle plume systems. The NCMB is unrelated with the early Permian Tarim mantle plume, whereas it shared similar magmatic source with the late Carboniferous-early Permian mafic-ultramafic intrusions in Jueluotage area.The native copper mineralization occurred within basaltic strata was formed by hydrotbermal alteration, which is younger than basaltic magma eruption. During metallogenic process, the Cu is probably from the basaltic strata, and its ore-forming fluids was mainly mixed by basin brine, atmospheric water and organic fluid, which is characterized as lower temperature (<250℃), low salty and strong reduction. The participation of the organic matter was probably controlled the migration and deposition of Cu as native copper state in the ore-forming fluids. The metallogenesis of NCMB was similar with hydrothermal alternated deposits, rather than the magmatic Cu-Ni sulfide mineralization in Jueluotage area. The industrial native copper mineralized bodies are probably explored within the thick basalt layer with intensive structure positions, whereas there is little possibility to explore copper-nickel deposits in the NCMB distribution area.The late Paleozoic granitoid intrusions in Jueluotage area can be subdivided into5granitoid belts, including:Late Devonian Jingerquan granitoid belt, Early Carboniferous Tuwu-Yandon granitoid belt, Early Carboniferous Changtiaoshan-Bailingshan granitoid belt, Early Permian Kangguer shear zone granitoid belt and Late Permian-Middle Triassic Tundun-Shuangchagou granitoid belt. These5granitoid belts exhibit spatial and temporal distribution as:North belt (Late Devonian Jingerquan granitoid belt), North belt (Early Carboniferous Tuwu-Yandon granitoid belt), South belt (Early Carboniferous Changtiaoshan-Bailingshan granitoid belt), Middle belt with its both sides (Early Permian Kangguer shear zone granitoid belt), Middle belt (Late Permian-Middle Triassic Tundun-Shuangchagou granitoid belt). The magmatic sources of late Paleozoic granitoid intrusions were indicated as:Metasomatised depleted lithosphere mantle (Late Devonian Jingerquan granitoid belt), Metasomatised depleted lithosphere mantle with adakitic feature (Early Carboniferous Tuwu-Yandon granitoid belt), crust-mantle mixing source with increasing lithosphere mantle proportion (Early Carboniferous Changtiaoshan-Bailingshan granitoid belt), Crust-mantle mixing source(Early Permian Kangguer shear zone granitoid belt), Juvenile crust source(Late Permian-Middle Triassic Tundun-Shuangchagou granitoid belt). The petrogenetic background of the late Paleozoic granitoid intrusions can be analyzed as:subduction island-arc environment (Late Devonian Jingerquan granitoid belt), back-arc basin environment with subduction side (Early Carboniferous Tuwu-Yandon granitoid belt), back-arc basin environment with passive continent (Early Carboniferous Changtiaoshan-Bailingshan granitoid belt), post-collisional environment (Early Permian Kangguer shear zone granitoid belt), post collisional-intraplate transitional environment (Late Permian-Middle Triassic Tundun-Shuangchagou granitoid belt).There are6types granitoid genetically related metal deposits in Jueluotage area, including: Early Carboniferous porphyry Cu deposits, Early Carboniferous granitoid related Fe deposits, Early Carboniferous granite porphyry related VMS type Cu (Pb-Zn) deposits, Early Permian porphyry (skarn) Cu polymetallic deposits, Early Permian granite related Au deposits and Middle Triassic porphyry Mo deposits. The spatial and temporal distribution of granitoid genetically related metal deposits in Jueluotage area can be summarized as both in North belt and South belt (340-320Ma), Middle belt to both North and South belts (290-270Ma), within Middle belts (240-220Ma), which symmetrically distribute along the Middle belt. Their metallogenic favorites are characterized as Cu in North belt, Fe in South belt and Au-Ni-Cu-Mo in Middle belt, and their ore-forming fluids mainly composed by magmatic water. The granitoid genetically related metal deposits in Jueluotage area can be attributed to3metallogenic systems, including:Early Carboniferous tectonic-granitoid metallogenic system in island arc background, Early Permian tectonic-granitoid metallogenic system in extensional background, and Middle Triassic structure-magmatic metallogenic system in compressive background, and the porphyry types mineralization occurred in each metallogenic system.The Jueluotage area experienced the "Hyperplasia type" orogen evolution process, which was formed by the subduction of the Kalamaili oceanic plates (north) into the middle Tianshan block (south). The late Paleozoic geodynamic evolution of Jueluotage area can be subdivided into5stages, including:Juvenile island arc stage (390-360Ma), ack-arc basin stage (360-320Ma), Collisional stage (320-310Ma), Lithosphere delamination stage in post-collisional background (310-300Ma), Shearing and deformation stage in post-collisional background with mantle plume obstruction (300to270Ma), Shearing and deformation stage in post-collisional background (270-240Ma), Intraplate stage with Tethys remote impaction (240-220Ma). In Early Carboniferous (360-320Ma), The Jueluotage area was a back-arc basin, and the suture zone of North belt and South belt was gradually spreading into the Middle belt, where the lithosphere mantle is gradually thinner form both north and south sides toward centre in this system. In early Permian (290-270Ma), the Jueluotage was in the shearing and deformation stage of post-collisional environment, nevertheless, there intensive magmatism and mineralization distributed along the weak lithosphere zone (Middle belt) due to the "Lateral flow" of Tarim mantle plume, which probably delayed the evolution of hearing and deformation stage in Jueluotage area.The late Paleozoic evolution between geodynamic and magmatism-mineralization in the Jueluotage area can be coupled summarized as follows:Late Devonian granitoid magmatism without distinct mineralization in juvenile island-arc stage (Jingerquan granitoid belt), Early Carboniferous adakitic granite magmatism with copper mineralization close with the subduction side of back-arc basin with (Tuwu-Yandon Porphyry Cu deposits); Early Carboniferous granitoid magmatism with iron mineralization close with passive continent of back-arc basin (Changtiaoshan-Bailingshan granitoid related Fe deposits), Early Carboniferous volcano- granitoid magmatism with copper polymetallic mineralization in back-arc extensional background (VMS type Cu-Pb-Zn deposits), Late Carboniferous mafic magmatism with copper-iron mineralization in early post-collisional background (hydrothermal alternation Cu-Fe deposits), Early Permian mafic to felsic magmatism with multi-type metal mineralization distributing along the Kangguer ductile shear zone in post-collisional stage affected with lateral flow activity of Tarim mantle plume (magmatic Cu-Ni deposits; granite related with Au mineralization, porphyry-skarn type Cu-Ag deposits), Late Permian-Middle Triassic granitoid magmatism with gold and molybdenum mineralization within the Middle belt in post collision-intraplate transitional stage with Tethys remote extrusion (ductile shearing related Au mineralization, Porphyry Mo deposits).Jueluotage area is a high potential mining targeting area and widely distributes late Paleozoic multi-type metal deposits, which are significantly controlled by5key regional metallogenic factors, as:geodynamic setting, magmatism, tectonism, base sediments and late Paleozoic volcano-sedimentary strata. The exploration targets of different types metal deposits can be predicted as follow:the extension area of west-east direction of Tuwu-Yandon granitoid belt (Early Carboniferous Porphyry Cu exploration targets), within and around Carboniferous granitoid intrusions in South belt (Early Carboniferous granitoid related Fe exploration targets), the intensively extensional and structural margin positions in both South and North belts(Early Carboniferous granite porphyry related VMS Cu polymetallic exploration targets), the margin places of Carboniferous volcano-sediment strata along the Aqikuduke fault in South belt (Late Carboniferous hydrothermal alteration Cu-Fe exploration targets), the granitoid porphyry intruded along the Kangguer and Yamansu faults in both South belt and North belt(Early Permian porphyry-skarn Cu polymetallic exploration targets), the mafic intrusion distributes along the Kangguer, Yamansu and Aqikekuduke deep faults (Early Permian magmatic Cu-Ni exploration targets), granites intruded along the Kangguer ductile shear zone and strongly deformed by shearing activities (Early Permian-Middle Triassic Au exploration targets), granites intruded along the Kangguer ductile shear zone (Middle Triassic Mo exploration targets).After all the above research work on the late Paleozoic magmatism and mineralization with their related geodynamic evolution in Jueluotage area, it suggests that the Jueluotage experienced integrated orogenic activities in this duration (380-230Ma). The Jueluotage area can be regarded as a good case to research some forefront theories, such as "Hyperplasia-type orogenic evolution","post-collisional background" and "lateral flow of Mantle Plume".更多还原