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1.
ＩＮＴＲＯＤＵＣＴＩＯＮＳｈｏｓｈｏｎｉｔｅｓａｒｅｐｏｔａｓｓｉｃｉｇｎｅｏｕｓｒｏｃｋｓｗｈｉｃｈｏｃｃｕｒｍａｉｎ－ｌｙｉｎｓｕｂｄｕｃｔｉｏｎ－ｒｅｌａｔｅｄｔｅｃｔｏｎｉｃｓｅｔｔｉｎｇｓ（Ｍｏｒｒｉｓｏｎ,１９８０）．Ｔｈｅｙａｒｅｃｏｍ... 相似文献
2.
Many metallic ore deposits of the Late Cretaceous to Early Tertiary periods are distributed in the Gyeongsang Basin. Previous and newly analyzed sulfur isotope data of 309 sulfide samples from 56 ore deposits were reviewed to discuss the genetic characteristics in relation to granitoid rocks. The metallogenic provinces of the Gyeongsang Basin are divided into the Au–Ag(–Cu–Pb–Zn) province in the western basin where the sedimentary rocks of the Shindong and Hayang groups are distributed, Pb–Zn(–Au–Ag–Cu), Cu–Pb–Zn(–Au–Ag), and Fe–W(–Mo) province in the central basin where the volcanic rocks of the Yucheon Group are dominant, and Cu(–Mo–W–Fe) province in the southeastern basin where both sedimentary rocks of the Hayang Group and Tertiary volcanic rocks are present. Average sulfur isotope compositions of the ore deposits show high tendencies ranging from 2.2 to 11.7‰ (average 5.4‰) in the Pb–Zn(–Au–Ag–Cu) province, ?0.7 to 11.5‰ (average 4.6‰) in the Cu–Pb–Zn(–Au–Ag) province, and 3.7 to 11.4‰ (average 7.5‰) in the Fe–W(–Mo) province in relation to magnetite‐series granitoids, whereas they are low in the Au–Ag(–Cu–Pb–Zn) province in relation to ilmenite‐series granitoids, ranging from ?2.9 to 5.7‰ (average 1.7‰). In the Cu(–Mo–W–Fe) province δ34S values are intermediate ranging from 0.3 to 7.7‰ (average 3.6‰) and locally high δ34S values are likely attributable to sulfur derived from the Tertiary volcanic rocks during hydrothermal alteration through faults commonly developed in this region. Magma originated by the partial melting of the 34S‐enriched oceanic plate intruded into the volcanic rocks and formed magnetite‐series granitoids in the central basin, which contributed to high δ34S values of the metallic deposits. Conversely, ilmenite‐series granitoids were formed by assimilation of sedimentary rocks rich in organic sulfur that influenced the low δ34S values of the deposits in the western and southeastern provinces. 相似文献
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To discriminate the mineral potentiality of the trachybasalt around the Miocene Sarcheshmeh porphyry copper deposit, petrogeochemical characteristics of more than 45 samples of the volcanic rocks were studied. Sarcheshmeh is one of the world's largest Miocene porphyry copper deposits in a continental arc setting and contains about 1200 million tonnes of ores with an average grade of 1.2 percent copper, 0.03 percent molybdenum, 3.9 g/t Ag and 0.11 g/t Au. The biotized and sericitized trachybasalts around the Sarcheshmeh deposit are associated with chalcopyrite, pyrite and molybdenite and and are enriched in Cu (>3108 ppm), K2O (>4.2%), Rb (>155 ppm) and MgO (>2.9%), but depleted in yttrium (<11 ppm), MnO (<0.06%), CaO (<0.6%), Na2O (<0.33%), Sr (<107 ppm), and Ba (<181 ppm). The propylitized trachybasalts are enriched in CaO (>9.1%), Na2O (>3.2%), MnO (>0.24%), Y (>18.2 ppm), and Ba (>323 ppm). The results demonstrate that the diagrams of loss on ignition ? Cu, Cu ? Y, K2O/K2O + Na2O + CaO ? Cu and Y ? MnO may be used as an exploration guide for undiscovered porphyry copper mineralization in the Central Iranian volcano—plutonic copper belt. 相似文献
5.
The Ciemas gold deposit is located in West Java of Indonesia,which is a Cenozoic magmatism belt resulting from the Indo-Australian plate subducting under the Eurasian plate.Two different volcanic rock belts and associated epithermal deposits are distributed in West Java:the younger late Miocene-Pliocene magmatic belt generated the Pliocene-Pleistocene epithermal deposits,while the older late Eocene-early Miocene magmatic belt generated the Miocene epithermal deposits.To constrain the physico-chemical conditions and the origin of the ore fluid in Ciemas,a detailed study of ore petrography,fluid inclusions,laser Raman spectroscopy,oxygen-hydrogen isotopes for quartz was conducted.The results show that hydrothermal pyrite and quartz are widespread,hydrothermal alteration is well developed,and that leaching structures such as vuggy rocks and extension structures such as comb quartz are common.Fluid inclusions in quartz are mainly liquid-rich two phase inclusions,with fluid compositions in the NaCl-H20 fluid system,and contain no or little CO_2.Their homogenization temperatures cluster around 240℃-320℃,the salinities lie in the range of 14-17 wt.%NaCl equiv,and the calculated fluid densities are 0.65-1.00 g/cm~3.The values of δ~(18)O_(H2O-VSMOW)for quartz range from +5.5‰ to +7.7‰,the δD_(VSMOW) of fluid inclusions in quartz ranges from-70‰ to-115‰.All of these data indicate that mixing of magmatic fluid with meteoric water resulted in the formation of the Ciemas deposit.A comparison among gold deposits of West Java suggests that Miocene epithermal ore deposits in the southernmost part of West Java were more affected by magmatic fluids and exhibit a higher degree of sulfldation than those of Pliocene-Pleistocene. 相似文献
6.
Guangming LI Jinxiang LI Kezhang QIN Ji DUO Tianping ZHANG Bo XIAO Junxing ZHAO 《Resource Geology》2012,62(1):99-118
The Duobuza gold‐rich porphyry copper district is located in the Bangongco metallogenetic belt in the Bangongco‐Nujiang suture zone south of the Qiangtang terrane. Two main gold‐rich porphyry copper deposits (Duobuza and Bolong) and an occurrence (135 Line) were discovered in the district. The porphyry‐type mineralization is associated with three Early Cretaceous ore‐bearing granodiorite porphyries at Duobuza, 135 Line and Bolong, and is hosted by volcanic and sedimentary rocks of the Middle Jurassic Yanshiping Formation and intermediate‐acidic volcanic rocks of the Early Cretaceous Meiriqie Group. Simultaneous emplacement and isometric distribution of three ore‐forming porphyries is explained as multi‐centered mineralization generated from the same magma chamber. Intense hydrothermal alteration occurs in the porphyries and at the contact zone with wall rocks. Four main hypogene alteration zones are distinguished at Duobuza. Early‐stage alteration is dominated by potassic alteration with extensive secondary biotite, K‐feldspar and magnetite. The alteration zone includes dense magnetite and quartz‐magnetite veinlets, in which Cu‐Fe‐bearing sulfides are present. Propylitic alteration occurs in the host basic volcanic rocks. Extensive chloritization‐silicification with quartz‐chalcopyrite or quartz‐molybdenite veinlets superimposes on the potassic alteration. Final‐stage argillic alteration overlaps on all the earlier alteration. This alteration stage is characterized by destruction of feldspar to form illite, dickite and kaolinite, with accompanying veinlets of quartz + chalcopyrite + pyrite and quartz + pyrite assemblages. Cu coexists with Au, which indicates their simultaneous precipitation. Mass balance calculations show that ore‐forming elements are strongly enriched during the above‐mentioned three alteration stages. 相似文献
7.
Lucas Donny Setijadji Shigeo Kajino Akira Imai Koichiro Watanabe 《Resource Geology》2006,56(3):267-292
Abstract. Java island, regarded as a classic example of island arcs, is built through multi events of Cenozoic arc magmatism produced by the subduction of Indian‐Australian oceanic crusts along the southern margin of Eurasian plate. Regional crustal compositions, subducted slabs, and tectonics determined the spatial‐geochemical evolution of arc magmatism and regional metallogeny. Tertiary geodynamics of island arc was dominated by backarc‐ward migrations of volcanic centers. Only after the Miocene‐Pliocene roll‐back effects of retreating slab, slab detachment, and backarc magmatism took place in central Java. The source of arc magmas is mainly partial melting of mantle wedge, triggered by fluids released from dehydrated slabs. Increasing potassium contents of arc magmas towards the backarc‐side and younger magmas is typical for all magmas, while alkali and incompatible trace elements ratios are characteristics for different settings of volcanic centers. The oceanic nature of crust and the likely presence of hot slab subducted beneath the eastern Java determine the occurrences of adakitic magmas. Backarc magmatism has a deeper mantle source with or without contributions from subduction‐related materials. The domination of magnetite‐series magmatism determines the sulfide mineralization for the whole island. District geology, geodynamics, and magma compositions in turn control particular styles and scales of precious metals concentrations. Deep‐seated crustal faults have focused the locations of overlapping volcanic centers and metalliferous fluids into few major gold districts. Porphyry deposits are mostly concentrated within Lower Tertiary (early stage) volcanic centers in eastern Java which are not covered by younger volcanic centers, and whose sulfides are derived from partial melting of basaltic parental materials. On the other hand, high‐grade low‐sulfidation epithermal gold deposits formed in later stages of arc development and are spatially located within younger volcanic centers (Upper Miocene‐Pliocene) that overlap the older ones. Gold in low‐sulfidation epithermal system is likely to be derived from crustal materials. The overall interacting factors resulting in the petrochemical systematics that are applicable for exploration: 1) early‐stage volcanic centers with high Sr/Y and Na2O/K2O ratios are more prospective for porphyry mineralization, while 2) later‐stage volcanic centers with high K2O, total alkali, and K2O/Na2O ratios are more prospective for low‐sulfidation epithermal mineralization. 相似文献
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安徽沿江地区岩浆成矿带 总被引：9，自引：0，他引：9
安徽沿江地区可分为三个岩浆成矿带：内带（主带） 、北（ 外） 带和南（ 外） 带。内带沿长江断裂带分布，与地幔隆起带一致，幔源高钾碱性玄武岩浆通过不同程度的ＡＦＣ混合机制和结晶分异机制，形成了不同的岩石组合和矿床，基性岩到酸性岩均有分布，其共同点是高钾富碱，侵入岩以高钾钙碱性岩系为主，火山岩以橄榄安粗岩系为主，广义矽卡岩型Ｃｕ、Ｆｅ、Ｓ、Ａｕ 及火山岩型Ｆｅ、Ｓ矿床是主要的矿床类型；南（外） 带以花岗闪长斑岩为主，高硅低碱，属钙碱性岩系，是上地壳下部易熔组分重熔的产物，成矿元素也由主带的Ｃｕ、Ｆｅ、Ｓ、Ａｕ 转向Ｐｂ、Ｚｎ（Ａｇ） 、Ｃｕ、Ｍｏ、Ｗ 等，是斑岩型Ｍｏ、Ｃｕ 矿床的远景带；北（外） 带比较复杂，主体部分属钙碱性岩系，花岗岩与花岗闪长岩侵入体是下地壳重熔的产物，部分花岗闪长斑岩形成广义矽卡岩型Ｃｕ、Ａｕ 矿床，另一部分以幔源物质为主的闪长玢岩，形成斑岩型Ｃｕ 矿。不同的岩浆成矿带受不同的基底控制。Ｎｄ 、Ｓｒ、Ｐｂ 同位素研究表明，主带和北带存在太古宙麻粒岩相变质基底，南带岩浆岩则源于元古宙角闪岩相到绿片岩相变质基底。地幔隆起与幔源物质参与成矿作用，以及由地幔隆起带来的高热流是成矿的最有利条件。建议深入研究幔脊 相似文献
10.
新疆西天山吐拉苏火山岩盆地浅成低温热液-斑岩型金多金属成矿系统的形成与演化 总被引：1，自引：0，他引：1
新疆西天山吐拉苏地区发育的与中酸性火山-次火山岩有关的浅成低温热液-斑岩型金多金属成矿系统,是在晚古生代北天山洋向南部伊犁-中天山板块之下俯冲消减的活动大陆边缘背景下形成的。赋矿的大哈拉军山组火山岩及相关的次火山岩形成于晚泥盆世-早石炭世,岩石总体显示钾质-高钾质、准铝质-过铝质的钙碱性-高钾钙碱性特征,其轻稀土富集、Eu负异常显著、大离子亲石元素富集和高场强元素亏损等,均显示出俯冲带岛弧岩浆作用的特点。阿希(低硫型)和京希-伊尔曼得(高硫型)浅成低温热液金矿床以及塔北、吐拉苏铅锌矿床,受大哈拉军山组火山岩中的断裂破碎带以及具高孔隙度和渗透率的岩性控制;塔吾尔别克斑岩型金矿化主要受斑岩体及火山岩中的断裂和裂隙系统控制,并很可能存在浅成低温热液型金矿化的套合或叠加。硫、铅、碳、氧同位素特征显示,成矿物质主要来自岩浆所分泌的热液和/或赋矿的火山-次火山岩。根据成矿系统形成后的保存和变化情况,认为在吐拉苏盆地内剥蚀程度较低的地区,浅成低温热液型金铅锌矿床具备良好的保存条件,同时在其深部还应注意寻找斑岩型或矽卡岩型铜金矿床。 相似文献
11.
Ömer Elitok Züheyr Kamaci M. Nuri Dolmaz Kamil Yılmaz Meltem Şener 《Journal of Earth System Science》2010,119(6):853-860
Potassium-rich volcanic rocks in the Isparta area (SW Turkey) consist mainly of older (Pliocene) volcanic rock suites (e.g.,
lamprophyre, basaltic trachyandesite, trachyandesite, trachyte) and younger (Quaternary) caldera forming lava dome/flows (e.g.,
tephriphonolite, trachyte) and pyroclastics (ash/pumice fall deposits and ignimbritic flows). The magnetic susceptibility
(K) was performed for both groups. The magnetic susceptibility value of the less evolved rocks characterized by SiO2 < 57 wt% (e.g., basaltic trachyandesite, tephriphonolite, lamprophyric rocks) and having mostly mafic phenocrysts such as
pyroxene, amphibole, and biotite-phlogopite is over 10 (10−3 [SI]). Fine to medium-grained and subhedral to anhedral opaque minerals are scattered especially in the matrix phase of the
less evolved volcanic rocks. However, the K value of the more evolved rocks (e.g., trachyte and trachyandesites) with SiO2 over 57 wt% vary between 0.1 and 28, but most of them below 10. SI values are negatively correlated with SiO2, Na2O, but positively correlated with Fe2O3, CaO, MnO, P2O5 and MgO contents, suggesting inverse variation of SI with fractionation of potassic magma. That is to say that less evolved
volcanic rocks have relatively higher magnetic susceptibility values in the volcanic suite. Fine to medium-grained and subhedral
to anhedral Fe-Ti oxides are scattered mainly in the matrix phase of the less evolved volcanics, presumably cause the pronounced
relatively higher magnetic susceptibility. 相似文献
12.
Middle Paleozoic to Middle Jurassic terrane assemblies in the Klamaths and Sierran Foothills consist of mafic–ultramafic complexes + fine‐grained terrigenous strata derived from previously accreted continental‐margin belts. Sutured oceanic terranes reflect c. 230 Myr of margin‐parallel slip involving chiefly transtension and transpression. Quartzofeldspathic clastic rocks and blueschists ± eclogites are very rare. Little devolatilization occurred at magmagenic depths; hence, coeval hydrothermal ore deposits and granitoids are uncommon. In contrast, nearly head‐on Cretaceous subduction of the Farallon plate generated the massive Klamath–Sierra Nevada volcanic–plutonic arc, reflecting dewatering of the eastward descending oceanic lithosphere in the magmagenic zone. Immature Great Valley forearc and Franciscan trench deposits shed from the arc record c. 70 Myr. of rapid crustal growth. Au‐bearing solutions rising from magmagenic depths, exsolved from plutons, and expelled from heated wall rocks were mobilized attending arc construction. Precipitation of gold‐bearing quartz veins occurred where H2O + CO2‐bearing fluids encountered major geochemical discontinuities in the wall rocks. 相似文献
13.
Miocene igneous rocks in the 1,600 km-long E–W Gangdese belt of southern Tibet form two groups separated at longitude ～89° E. The eastern group is characterized by mainly intermediate–felsic calc-alkaline plutons with relatively high Sr/Y ratios (23 to 342), low (87Sr/86Sr)i ratios (0.705 to 0.708), and high εNdi values (+5.5 to ?6.1). In contrast, the western group is characterized by mainly potassic to ultrapotassic volcanic rocks with relatively high Th and K2O contents, low Sr/Y ratios (11 to 163), high (87Sr/86Sr)i ratios (0.707 to 0.740), and low εNdi values (?4.1 to ?17.5). The eastern plutonic group is associated with several large porphyry Cu–Mo ± Au deposits, whereas the western group is largely barren. We propose that the sharp longitudinal distinction between magmatism and metallogenic potential in the Miocene Gangdese belt reflects the breakoff of the Greater India slab and the extent of underthrusting by the Indian continental lithosphere at that time. Magmas to the east of ～89° E were derived by partial melting of subduction-modified Tibetan lithosphere (mostly lower crust) triggered by heating of hot asthenospheric melt following slab breakoff. These magmas remobilized metals and volatile residual in the crustal roots from prior arc magmatism and generated porphyry Cu–Mo ± Au deposits upon emplacement in the upper crust. In contrast, magmas to the west of ～89° E were formed by smaller volume partial melting of Tibetan lithospheric mantle metasomatized by fluids and melts released from the underthrust Indian plate. They are less hydrous and oxidized and did not have the capacity to transport significant amounts of metals into the upper crust. 相似文献
14.
Endeavour 42 is a structurally controlled Au deposit with similarities to adularia‐sericite deposits. It is the largest of four gold prospects discovered in the Late Ordovician Lake Cowal volcanic complex, adjacent to the Gilmore Fault Zone, in central New South Wales, Australia. The Lake Cowal volcanic complex consists of calc‐alkaline to shoshonitic volcanic rocks and related sedimentary rocks that were deposited in a relatively deep‐water environment. The volcanic and sedimentary rocks of the Lake Cowal volcanic complex were intruded by diorite and granodiorite. Low‐grade porphyry Cu (0.2–0.35% Cu) mineralisation is developed in parts of the granodiorite intrusion. The gold deposits are developed north of the porphyry Cu mineralisation and occur within a north‐south corridor adjacent to a north‐south‐oriented body of diorite. The Endeavour 42 deposit is hosted by three volcanic units and a diorite. The stratigraphic units at Endeavour 42, consistently strike 215° and dip 50°NW, and comprise an upper unit dominated by redeposited pyroclastic debris and a lower conglomerate unit with clasts of reworked volcanic rocks. Separating these units is a sequence of trachyandesite lava and hyaloclastite breccias. Laminated mudstone and siltstone throughout the sequence are indicative of a relatively deep‐water, below wave‐base, environment. Porphyritic dykes, which are typically associated with zones of faulting, cross‐cut both the volcano‐sedimentary sequence and the diorite. The major fault orientations are 290° and 340°, forming subparallel conjugate fault sets. Both sets of faults are mineralised, contain deformed porphyritic dykes and are associated with sericitic alteration. Endeavour 42 is a sulfide‐poor gold deposit with free native Au and Au associated with pyrite and sphalerite. Minor galena, pyrrhotite and chalcopyrite are also observed. Irregular pyrite veinlets and carbonate‐sulfide veinlets occur in the upper unit of re‐deposited pyroclastic debris. Auriferous veins are parallel‐sided dilatant veins with quartz‐sulfide‐carbonate‐adularia. These veins display a consistent strike of 305° and a dip of 35°SW. Alteration and mineralisation were influenced by host‐rock composition and rheology. A pervasive alteration assemblage of chlorite‐carbonate‐hematite‐epidote is developed throughout the Lake Cowal volcanic complex. This is overprinted by sericite‐silica‐carbonate alteration around fault zones and dykes, with patchy and pervasive alteration of this type developed in the lava sequence and upper volcani‐clastic unit, reflecting permeability and probable alteration zoning. In the lower clastic unit, the diorite and, in parts of the lava sequence, a chlorite‐carbonate‐pyrite assemblage partially overprints sericite‐silica alteration, suggesting an evolving fluid composition, changing physico‐chemical conditions or a different alteration fluid. Age dating of the intrusive phases and sericitic alteration associated with mineralisation at Endeavour 42 yields ages of 465.76 ± 1 and 438.6 ± 0.5 Ma, respectively, suggesting that mineralisation post‐dates the Lake Cowal intrusive event and is related to intrusion of magma during the 440 Ma mineralising event, an important period in the eastern Lachlan Fold Belt. 相似文献
15.
Alan J. Wainwright Richard M. Tosdal Joseph L. Wooden Frank K. Mazdab Richard M. Friedman 《Gondwana Research》2011,19(3):764-787
Uranium–Pb (zircon) ages are linked with geochemical data for porphyry intrusions associated with giant porphyry Cu–Au systems at Oyu Tolgoi to place those rocks within the petrochemical framework of Devonian and Carboniferous rocks of southern Mongolia. In this part of the Gurvansayhan terrane within the Central Asian Orogenic Belt, the transition from Devonian tholeiitic marine rocks to unconformably overlying Carboniferous calc-alkaline subaerial to shallow marine volcanic rocks reflects volcanic arc thickening and maturation. Radiogenic Nd and Pb isotopic compositions (εNd(t) range from + 3.1 to + 7.5 and 206Pb/204Pb values for feldspars range from 17.97 to 18.72), as well as low high-field strength element (HFSE) contents of most rocks (mafic rocks typically have < 1.5% TiO2) are consistent with magma derivation from depleted mantle in an intra-oceanic volcanic arc. The Late Devonian and Carboniferous felsic rocks are dominantly medium- to high-K calc-alkaline and characterized by a decrease in Sr/Y ratios through time, with the Carboniferous rocks being more felsic than those of Devonian age. Porphyry Cu–Au related intrusions were emplaced in the Late Devonian during the transition from tholeiitic to calc-alkaline arc magmatism. Uranium–Pb (zircon) geochronology indicates that the Late Devonian pre- to syn-mineral quartz monzodiorite intrusions associated with the porphyry Cu–Au deposits are ~ 372 Ma, whereas granodiorite intrusions that post-date major shortening and are associated with less well-developed porphyry Cu–Au mineralization are ~ 366 Ma. Trace element geochemistry of zircons in the Late Devonian intrusions associated with the porphyry Cu–Au systems contain distinct Th/U and Yb/Gd ratios, as well as Hf and Y concentrations that reflect mixing of magma of distinct compositions. These characteristics are missing in the unmineralized Carboniferous intrusions. High Sr/Y and evidence for magma mixing in syn- to late-mineral intrusions distinguish the Late Devonian rocks associated with giant Cu–Au deposits from younger magmatic suites in the district. 相似文献
16.
Regional Metallogenesis of the Chang’an Gold Ore Deposit in Western Yunnan: Evidences from Fluid Inclusions and Stable Isotopes 总被引：2，自引：0，他引：2
<正>The Chang'an gold ore deposit in western Yunnan is located at the southern segment of the Ailaoshan metallogenic belt.The ore bodies are preserved in fractured Ordovician sedimentary clastic rocks.The gold-bearing minerals occur dominantly in sulfide-quartz veins.Fluid inclusion analysis shows that the Chang'an gold ore deposit is characterized by epithermal gold mineralization at temperatures between 200℃and 280℃at a shallow crustal level.The mineralizing fluids have intermediate to low salinity(6%-18%) and low densities(0.72-1.27 g/cm~3).The ore minerals haveδ~(34)S in a range from -13‰to 3.57‰,concentrated from -2.06‰to 3.57‰with an average of 1.55‰.The ~(206)Pb/~(204)Pb,~(207)Pb/~(204)Pb and ~(208)Pb/~(204)Pb values are 18.9977-19.5748,15.7093-15.784,39.3814-40.2004 respectively.These isotope data suggest that the ore-forming elements were mainly derived from mixed crustal and mantle sources.The Chang'an gold ore deposit and Tongchang Cu-Mo deposit are closely related to each other in their spatial distribution and age of formation.They have similar sources of mineralizing elements and identical ore-forming metal elements,and show a close relationship in physical and chemical conditions of mineralization.The two deposits constitute an epithermal-porphyry -skarn type Cu-Mo-Au mineralization system in the Tongchang-Chang'an area,which is related to the Cenozoic high-K alkaline magmatism. 相似文献
17.
喀拉果如木铜矿是近年在新疆喀喇昆仑地区发现的铜多金属矿.铜矿化赋存在二长花岗斑岩中,矿石呈细脉浸染状、斑点状.矿石矿物主要为黄铜矿,少量黄铁矿、斑铜矿和毒砂.围岩蚀变有硅化、绢云母化和青磐岩化,具有与斑岩铜矿类似的蚀变组合.二长花岗斑岩主要由斜长石、钾长石、石英、黑云母及蚀变的暗色矿物组成.二长花岗斑岩的SiO2(67.28％ ～73.08％)、Al2 O3(13.38％～15.53％)、K2O(2.92％ ～6.15％)和Na2O(2.78％ ～4.89％)含量较高,CaO和TiO2含量较低,属于高钾钙碱性系列;富集大离子亲石元素(LILE),亏损高场强元素(HFSE)和重稀土元素,Nb和Ta负异常,显示准铝质-弱过铝质过渡的特点,岩浆结晶分异作用明显,具有陆缘孤花岗岩的地球化学亲缘性,微量元素显示其为同碰撞-后碰撞花岗岩.成矿岩体锆石LA-ICP-MS测年结果为189.3 ±2.8Ma,成岩成矿作用发生在早侏罗世.结合区域地质演化,本文认为喀拉果如木铜矿形成于南昆仑地体与喀喇昆仑-甜水海地体之间的古特提斯洋消减闭合之后的后碰撞伸展背景,喀喇昆仑在晚三叠世-早侏罗世进入后碰撞造山时期. 相似文献
18.
Zhenjun Sun Zongqi Wang Henan Yu Chengyang Wang Guanghu Liu Xaingdong Bai 《Resource Geology》2019,69(1):1-21
The Zhuanshanzi gold deposit lies in the eastern section of the Xingmeng orogenic belt and the northern section of the Chifeng‐Chaoyang gold belt. The gold veins are strictly controlled by a NW‐oriented shear fault zone. Quartz veins and altered tectonic rock‐type gold veins are the main vein types. The deposits can be divided into four mineralization stages, and the second and third metallogenic stages are the main metallogenic stages. In this paper, based on the detailed field geological surveys, an analysis of the orebody and ore characteristics, microtemperature measurement of fluid inclusions, the Laser Raman spectrum of the inclusions, determination of C? H? O? S? Pb isotopic geochemical characteristics, and so on were carried out to explore the origin of the ore‐forming fluids, ore‐forming materials, and the genesis of the deposits. The results show that the fluid inclusions can be divided into four types: type I – gas–liquid two‐phase inclusions; type II – gas‐rich inclusions; type III– liquid inclusions; and type IV – CO2‐containing three‐phase inclusions. However, they are dominated by type Ib – gas liquid inclusions and type IV – three‐phase inclusions containing CO2. The gas compositions are mainly H2O and CO2, indicating that the metallogenic system is a CO2? H2O? NaCl system. The homogenization temperature of the ore‐forming fluid evolved from a middle temperature to a low temperature, and the temperature of the fluid was further reduced due to meteoric water mixing during the late stage, as well as a lack of CO2 components, and eventually evolved into a simple NaCl? H2O hydrothermal system. C? H? O? S? Pb isotope research proved that the ore‐forming fluids are mainly magmatic water during the early stage, with abundant meteoric water mixed in during the late stage. Ore‐forming materials originated mostly from hypomagma and were possibly influenced by the surrounding rocks, suggesting that the ore‐forming materials were mainly magmatic hydrothermal deposits, with a small amount of crustal component. The fluid immiscibility and the CO2 and CH4 gases in the fluids played an active and important role in the precipitation and enrichment of Au during different metallogenic stages. The deposit is considered a magmatic hydrothermal deposit of middle–low temperature. 相似文献
19.
埃达克岩与Cu-Au成矿作用：有待深入研究的岩浆成矿关系 总被引：29，自引：19，他引：29
研究表明，环太平洋地区新生代斑岩铜矿和浅成热液金矿与同期的埃达克质岩浆活动存在密切的时空与成因联系。埃达克岩是许多世界级的斑岩铜矿的容矿岩，也是许多浅成热液矿化系统的成矿母岩浆。根据目前的研究，二者成因联系可能在于埃达克质岩浆的富流体、高氧逸度和基性源岩等固有属性，有利于Cu、Au等深源金属元素的萃取与富集成矿一因此，这可能是一种潜在的岩浆成矿专属性关系，但对产生这种关系的原因与机制仍然不十分清楚。这有待于今后深入开展成矿与无矿的埃达克岩、成矿的埃达克岩与非埃达克岩、无矿的埃达克岩与非埃达克岩等方面的对比研究，以揭示这种成矿专属性的本质。 相似文献