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1.
Paul Duuring Stephen M. Rowins Bradley S. M. McKinley Jenni M. Dickinson Larry J. Diakow Young-Seog Kim Robert A. Creaser 《Mineralium Deposita》2009,44(4):435-462
Kemess South is the only Cu–Au–Mo mine in the Toodoggone district and a major Cu and Au producer in British Columbia. Porphyry-style
Cu–Au–Mo mineralization is mainly hosted by the tabular, SW-plunging, 199.6 ± 0.6-Ma Maple Leaf granodiorite, which intrudes
tightly folded, SW-dipping, Permian Asitka Group siltstone and limestone and homogeneous Triassic Takla Group basalt. Southwest-dipping
194.0 ± 0.4-Ma Toodoggone Formation conglomerate, volcaniclastic, and epiclastic rocks overlie the granodiorite and Asitka
Group rocks. Minor Cu–Au–Mo mineralization is hosted by the immediate Takla Group basalt country rock, whereas low-tonnage
high-grade Cu zones occur beneath a 30-m-thick leached capping in supergene-altered granodiorite and in exotic positions in
overlying Toodoggone Formation conglomerate. Granodiorite has an intrusive contact with mineralized and altered Takla Group
basalt but displays a sheared contact with unmineralized and less altered Asitka Group siltstone. The North Block fault is
a deposit-scale, E-striking, steeply S-dipping normal fault that juxtaposes the granodiorite/basalt ore body against unmineralized
Asitka Group rocks. Younger NW- and NE-striking normal–dextral faults cut all rock types, orebodies, and the North Block fault
with displacements of up to 100 m and result in the graben-and-horst-style block faulting of the stratigraphy and ore body.
Both basalt and granodiorite host comparable vein sequence and alteration histories, with minor variations in hydrothermal
mineral assemblages caused by differing protolith chemistry. Early potassic alteration (and associated early-stage Cu ± Au ± Mo
mineralization) is partly replaced by phyllic and intermediate argillic alteration associated with main-stage Cu–Au–Mo mineralization.
Two main-stage veins have Re–Os molybdenite ages of 201.3 ± 1.2 and 201.1 ± 1.2 Ma. These mineralization ages overlap the
199.6 ± 0.6-Ma U–Pb zircon crystallization age for the Maple Leaf granodiorite. Late-stage pyrite-rich stringer veins and
related phyllic alteration assemblages are cut by anhydrite-rich, carbonate-rich, and chlorite veins. Fluids and metals associated
with early-, main-, and late-stage veins were probably derived principally from the same deep magma chamber as the Maple Leaf
granodiorite. These magmatic-derived fluids interacted with Asitka and Takla Group country rocks and possibly with meteoric
and metamorphic fluids prior to mineralization. 相似文献
2.
坦桑尼亚的Sangambi地区位于姆贝亚的东北部、卢帕金矿田的东部。通过1∶10 000土壤地球化学测量,圈定了6个Au,Cu,Cr,Ni元素的组合异常,其中ZH-1和ZH-6组合异常与金、铜的矿化关系密切,而ZH-3和ZH-4组合异常与铬、镍(铜)矿化有一定关系。在片麻状花岗岩、细晶闪长岩和花岗闪长岩中发育大量NW向的韧性剪切带和断裂构造,其中的石英脉中经常见有黄铁矿、黄铜矿和金的矿化,刻槽取样最高品位w(Au)=11.5×10-6。土壤测量的结果证实,在卢帕金矿田的东部依然存在金成矿的潜力。 相似文献
3.
甲玛是西藏冈底斯成矿带规模大、品位富的超大型矿床,也是勘查和研究程度最高的矿床之一。其中,南坑矿段由于富含高品位的矽卡岩型铜铅锌矿石,且具大型规模,已被纳入矿区首采矿段之一,然而关于其控岩控矿机制以及其与主矿段的耦合关系却仍不明确。本次基于详细的钻孔编录和野外地质证据,判定其成矿作用与中新世的花岗闪长斑岩等中酸性斑岩体有关,结合高精度的U-Pb年代学分析,厘定含矿花岗闪长斑岩结晶年龄为（15.5±0.3）Ma,与辉钼矿成矿年龄（15.23±0.22）Ma一致。南坑矿段作为甲玛矿床多中心复合成矿作用模型的重要组成部分,其矽卡岩矿体主要产于林布宗组角岩与多底沟组大理岩之间的层间接触带,属于中新世岩浆热液活动的产物。矿体形成后,受滑覆构造及次级断裂影响,矿体发生错断或破坏。对于南坑矿段后续的勘查评价,应注意与含矿斑岩和矽卡岩的蚀变与矿化分带特征,定位致矿热液中心。 相似文献
4.
Christopher J. Yeats Ernst A. Kohler Neal J. McNaughton Luke J. Tkatchyk 《Mineralium Deposita》2001,36(2):125-136
The 7 million oz. Jundee–Nimary lode-gold deposit occurs in the northern portion of the Yandal greenstone belt in the northeastern
part of the Archean Yilgarn Craton of Western Australia. Gold mineralization at Jundee–Nimary is similar in structural style,
mineralogy, geochemistry and relative timing with respect to deformation and metamorphism, to other Western Australian Archean
greenstone-hosted gold deposits, but is unusual in the fact that mineralized structures are crosscut by structurally late
intermediate to felsic dykes. Within the Deakin South open cut, gold mineralization is hosted in brittle–ductile shear zones
primarily developed within the dacitic Mitchell Porphyry. The Moore Porphyry, a broad dyke of porphyritic granodiorite, intrudes
the Mitchell Porphyry, crosscutting and post-dating gold mineralization. Analytically indistinguishable SHRIMP U–Pb zircon
ages of 2678 ± 5 Ma for the Mitchell Porphyry and 2669 ± 7 Ma for the Moore Porphyry require that gold mineralization at Jundee–Nimary
occurred at ca. 2680–2660 Ma, approximately 40 million years earlier than the majority of published robust ages for gold mineralization
in the Yilgarn Craton, which mostly overlap at ca. 2640–2630 Ma. The close spatial and temporal relationship between gold
mineralization and felsic to intermediate magmatism at Jundee–Nimary also raises the possibility of a genetic link between
hydrothermal and igneous activity. However, additional work is required to establish a firm connection. Current research on
lode-gold mineralization in Archean, Paleozoic and Phanerozoic terranes suggests a model which postulates that these deposits
formed during transpressional to compressional deformation in accretionary and collisional orogens and that their formation
is intimately related to orogenic processes. Consequently, mineralization and regional metamorphism are expected to be diachronous,
as terranes are accreted and the front of orogenesis migrates. Consideration of the new data presented in this paper in conjunction
with previously published dates supports the hypothesis that gold mineralization, along with regional metamorphism, was generally
diachronous from northeast to southwest across the Yilgarn Craton, over a period of approximately 40 million years from ca.
2680–2660 Ma to ca. 2640–2630 Ma. This is directly analogous to the accepted model for the timing of orogenic lode-gold mineralization
in other provinces and therefore provides further support for a unified model for this style of deposit through geological
time.
Received: 17 March 2000 / Accepted: 8 September 2000 相似文献
5.
The Guelb Moghrein Fe oxide–Cu–Au–Co deposit, with a total resource of 23.6 Mt at 1.88% Cu, 1.41 g/t Au, and 143 g/t Co, is hosted by an extensive metacarbonate body. However, it is restricted to up to 30-m wide tabular breccia zones developed parallel to discrete shear zones that transect the host metacarbonates. The Fe–Mg clinoamphibole–chlorite schists represent up to 1-m thick interlayer metasediments and localized viscous shearing in these shear zones. Siderite of the metacarbonate body was deformed into a breccia and was replaced by an ore and alteration assemblage comprised of Fe–Mg clinoamphibole, magnetite, pyrrhotite, chalcopyrite, graphite, Fe–Co–Ni arsenides, arsenopyrite, cobaltite, uraninite, and Bi–Au–Ag–Te minerals. In contact with wall rock amphibolites, the metacarbonate body is enveloped by an alteration halo up to 40 m wide, consisting of biotite, actinolite, grunerite, chlorite, calcite, albite, and quartz. The Guelb Moghrein ore body is structurally controlled by shear zones that developed in the footwall of a regional thrust zone. This thrust separates greenschist facies quartz–sericite schists and biotite–garnet–quartz schists of the Sainte Barbe volcanic unit in the hanging wall from amphibolite facies metavolcanic rocks, metacarbonates, and the Guelb Moghrein ore body of the Akjoujt metabasalt unit in the footwall. Peak temperatures of the latter unit are estimated by hornblende–plagioclase thermometry at 580±40°C. Thrusting was retrograde for the Akjoujt metabasalt unit, but prograde for the Sainte Barbe volcanic unit at P–T conditions of about 410±30°C and 2–3 kbar (garnet–biotite thermometry). Structural and petrological evidences suggest that the ore fluids migrated along the shear zones and reacted with the siderite in the metacarbonate. This evolution and the setting of Guelb Moghrein in the fold-and-thrust belt of the Pan-African to Variscan Mauritanides (Mauritania, West Africa) resemble Proterozoic Fe oxide–Cu–Au–Co deposits such as examples from the Tennant Creek and Mount Isa Inliers, Australia.Electronic Supplementary Material Supplementary material is available for this article at 相似文献
6.
皖南宁国竹溪岭钨银矿床是近年来发现的一个与花岗岩类有关的矽卡岩型矿床,准确厘定其成矿年龄及相关侵入岩体的年龄有利于深入认识区域岩浆作用与成矿作用的规律。本文在矿床地质调查的基础上,应用现代同位素定年技术开展地质年代学研究,获得矿床矿石中的辉钼矿Re-Os模式年龄为142.7±2.1 Ma和142.9±2.1 Ma,相关侵入岩体花岗闪长岩、花岗斑岩和花岗闪长斑岩的LA-ICP-MS锆石U-Pb年龄分别为139.8±1.8 Ma、143.3±1.9 Ma、140.2±1.7 Ma,显示矿床的成矿年龄与侵入岩体的成岩年龄基本一致,为燕山晚期早白垩世。矿床矿石中的辉钼矿的Re含量指示成矿物质来源于地壳和地幔的混合;与成矿相关侵入岩的稀土元素和Hf同位素组成特征指示成岩物质也具有壳幔混源特征,显示成矿物质来源与成岩物质来源具有一致性。区域岩浆岩和矿床的对比表明,与之相邻的长江中下游地区、浙西地区和赣东北地区乃至整个华南地区这一时期发生了大规模的岩浆作用和钨锡多金属成矿作用,显示扬子板块在此阶段处于岩浆–成矿大爆发时期,皖南地区的成矿时代对应于华南中生代三次大规模岩浆作用和成矿作用的第二阶段。 相似文献
7.
Tran Tuan Anh I.V. Gas’kov Tran Trong Hoa P.A. Nevol’ko Pham Thi Dung Pham Ngoc Can 《Russian Geology and Geophysics》2012,53(7):623-635
The Pb–Zn deposits in the Lo Gam structure, northeastern Vietnam, account for>80% of all the Pb and Zn resources of Vietnam. All the deposits make up four isolated ore districts (Thai Nguyen, Cho Don, Cho Dien, Na Son), which can be combined in one metallogenic zone extending for >100 km from southeast to northwest. The Pb–Zn deposits in all the ore districts show some similarity to stratiform (Mississippi-type) deposits: confinement to Devonian carbonate sediments; localization at the intersection of faults of different orientations; vein and stockwork (pocket-vein-disseminated) morphology of the mineralized zones; evidence for hydrothermal-metasomatic formation (carbonate-rock marbleization, quartz–carbonate veins, etc.); and low and moderate mineralization temperatures (<250 °C). On the other hand, some differences from stratiform deposits are observed: widespread occurrence of Permo-Triassic igneous rocks in the above ore districts; absent tabular orebodies, which are typical of stratiform deposits; large set of trace elements (In, Bi, Sb, Au, Ag, Cu, Cd) not typical of stratiform deposits; and an endogenic primary source, as evidenced by the isotope composition of sulfur (δS34= 2.68‰), which is close to meteoritic, and the set of trace elements, which are mainly of deep genesis. All this indicates that the above Pb–Zn deposits within the carbonate units are low-and moderate-temperature hydrothermal-metasomatic products associated with active magmatism which took place in this region in the Permo-Triassic.The differences in the mineral composition of the deposits, as well as in the trace-element set and contents at different deposits, clearly indicate an intricate ore formation process and the relation of the deposits with magmatism of different compositions. The simple mineral composition and the limited set of trace elements (Cd, Ag, Sb, As) at the Lang Hich deposit are closer to the characteristics of stratiform deposits. Also, manifestations of magmatism are almost absent here. On the contrary, unusually high (ppm) In (75.8), Sn (307.5), Cu (1080), Ag (157.7), Bi (99), and As (13,650) contents were observed at the deposits of the Cho Don and Cho Dien districts, with widespread granitoid magmatism in the Phia Bioc complex. Rare-earth mineralization (orthite) and high Mo, Re, and Rb contents at the deposits of the Na Son district are probably due to the widespread occurrence of stratified alkaline volcanics and their subvolcanic analogs, which belong to the Pla Ma complex (ξγPZ2 pm). 相似文献
8.
华北克拉通南缘秦岭成矿带发育大量金矿、钼矿及铅锌多金属矿床。卢氏多金属矿集区位于东秦岭成矿带,主要矿床有夜长坪钼钨矿、八宝山铁铜矿、楼房银铜矿、柳关铅锌矿等。其中楼房银铜矿为热液脉状多金属矿床,矿床赋存于太华群角闪斜长片麻岩中,矿体受构造蚀变破碎带控制,矿床中划分出两个成矿阶段:石英-黄铁矿-黄铜矿组合和石英-黄铁矿-方铅矿-闪锌矿-方解石组合,其中前者是铜成矿阶段,后者为铅锌成矿阶段。柳关铅锌矿为矽卡岩矿床,矿体产于官道口群白云岩与花岗斑岩岩体或隐爆角砾岩接触矽卡岩化带内,矿床划分出两个成矿阶段:透辉石-透闪石-阳起石-石榴石-磁铁矿组合和方铅矿-闪锌矿-黄铁矿-绿帘石-蛇纹石-石英-方解石组合,前者为磁铁矿成矿阶段,后者是铅锌成矿阶段。金属硫化物定年结果表明,楼房银铜矿黄铜矿Rb-Sr等时线年龄为127. 8±3. 1Ma(2σ,MSWD=1. 1),初始87Rb/86Sr为0. 710998±0. 000068;柳关铅锌矿黄铁矿Rb-Sr等时线年龄为124. 8±1. 6Ma(2σ,MSWD=1. 4),初始87Rb/86Sr为0. 711074±0. 000064。研究表明卢氏多金属矿集区内热液多金属矿床形成于早白垩世,其形成与区内早白垩世岩浆活动有关。综合区域地质研究,区内多金属矿床形成于早白垩世与克拉通破坏有关的构造环境。 相似文献
9.
墨西哥中新生代岩浆作用与太平洋板块向东俯冲消减作用及晚白垩-始新世的拉腊米期造山运动有关,岩浆作用控制了矿床的分布规律。文章通过综合分析大量墨西哥中新生代岩浆岩和矿床资料,讨论了岩浆活动规律及构造活动和成矿作用的关系。墨西哥主要有5个岩浆活动时期,分别为晚古生代岩浆作用、早-中侏罗世岩浆作用、白垩世岩浆作用、古近纪岩浆作用、中新世岩浆作用。墨西哥的成矿作用主要与拉腊米期岩浆活动有关(约80 Ma—40 Ma),中新生代的矿床明显分成晚侏罗世(J3)、早白垩世(K1)、晚白垩世(K2)、古新世(E1)、始新世(E2)、渐新世(E3)、中新世(N1)等地质时期。古太平洋板块、法拉隆板块和科科斯板块等三大板块俯冲消减形成3个俯冲成矿系列,即从沿海到内陆依次发育有IOCG型铁铜金成矿带→斑岩型铜钼金成矿带→浅成低温热液型银金多金属成矿带,分别代表太平洋古板块、法拉隆板块和科科斯板块向北美板块从俯冲挤压到碰撞后伸展的岩浆成矿环境。 相似文献
10.
In the southwestern Carpathians of SW Romania and E Serbia calc-alkaline Upper Cretaceous-Paleogene subduction related magmatic rocks occur in two main zones. The Ridanj-Krepoljin belt (E Serbia) represents the southern part of the western zone. In this belt Early Maastrichtian dacites and subordinate andesites occur, but there are indications of an unexposed granodioritic (?) magmatism about 60 Ma old. Pb-Zn-Ag and only subordinate Cu mineralization is associated with this igneous activity. The Timok magmatic complex (E Serbia) composed of Upper Cretaceous (-Paleocene?) andesites and analogue intrusives represents the eastern zone south of the Danube. Associated with this magmatism are Cu (+Au) and very subordinate Zn (±Pb) mineralization. To the north (SW Romania) in both zones mainly intrusive bodies (diorites, quartz diorites, granodiorites, monzonites) of Campanian-Paleocene age are exposed. Porphyry copper (+Mo) and in north Pb-Zn (±Cu) mineralization are related to those intrusives. The petrological and geochemical features of all these calc-alkaline rocks are very similar. It appears, however, that the associated polymetallic and the copper mineralization are both spatially and vertically separated. 相似文献
11.
广东中生代与壳幔岩浆活动有关的成矿作用十分强烈,多期成矿作用明显.在前人工作的基础上,根据矿床的成矿时代、成矿地质构造环境、主要成矿作用及形成的矿床组合,将中生代与岩浆作用有关的矿床厘定为6个矿床成矿系列：1）云开与印支期岩浆活动有关的铌、钽、磷、铁矿床成矿系列;2）粤北与燕山期花岗岩有关的有色金属、稀有金属、贵金属、非金属、铀矿床成矿系列;3）深大断裂带与燕山期基性-中酸性侵入岩有关的铜、铅、锌、金、铁、钼、钨、水晶、砷、硫铁、钒、钛矿床成矿系列;4）深变质带与区域变质、动力变质及燕山期花岗岩类有关的金、银矿床成矿系列;5）沿海与燕山期火山-侵入活动有关的铁、铜、金、银、铅、锌、钨、锡、钼、铌、钽、硫铁、水晶、萤石、叶蜡石、重晶石矿床成矿系列;6）阳春-罗定与燕山晚期壳源花岗岩类侵入活动有关的锡、钨、钼、铜、铁、铅、锌、银矿床成矿系列.论述了各成矿系列的基本特征,并对成矿系列形成的构造背景和成矿作用的时空分布及演化规律进行了探讨. 相似文献
12.
Yang Shiyu 《中国地球化学学报》1991,10(1):21-35
Pneumato-hypothermal to meso-epithermal tin-polymetallic (W, Be, Bi, Mo, Cu, Pb, Zn and Ag) deposits, dominated by cassiterite-sulfide
type and cassiterite-quartz type, are extensively developed around granite intrusives in the Southeast Yunnan Tin Belt genetically
related to Yenshanian tecto-magmatism. The deposits are grouped into two classes, four associations and fourteen types according
to the classification scheme proposed by the author to reflect their geological and genetic characteristics as well as economic
implications. The deposits are arranged in an apparent zonal pattern from the granite body outwards in terms of “association”
(cassiterite-feldspar → cassiterite-quartz → cassiterite sulfide), typical ore-forming metals (Sn-W-Be-Mo-Nb-Ta-Tr → SnW-Cu-In
→ Sn-Pb-Zn-As-Cd), and formation conditions (pneumato-hypothermal → hypothermalmesothermal → mesothermal-epithermal), although
such distribution pattern may be more or less complicated by local specialities of granite petrochemistry, host rock lithology
and structure. 相似文献
13.
The Yidun Arc was formed in response to the westward subduction of Garze–Litang Ocean (a branch of Paleotethys) in the Late Triassic, where abundant porphyry Cu–Mo deposits (221–213 Ma) developed along the regional NW–SE sinistral faults and emplaced in the southern portion of the arc. The ore-related porphyries are mostly metaluminous or slightly peraluminous, belonging to shoshonitic high-potassium calc-alkaline I-type granites, with εHf(t) values of −6.64 to +4.12. The ore-bearing magmas were probably derived from the partial melting of subduction-metasomatic-enriched mantle, with the contamination of underplated mafic materials. The Late Cretaceous (88–80 Ma) highly fractionated I-type granite belt and related porphyry Cu–Mo deposits and magmatic-hydrothermal Cu–Mo–W deposits occur along approximately N–S-trending faults in the Yidun Arc. This belt extended across the Yidun Arc and Garze–Litang suture zone to the north and across the Yangtze Craton to the south, intruding the Late Triassic porphyry belt. The ore-related porphyries are characterized by high silica and high total alkalis, with enrichment in large ion lithophile elements (LILEs; Rb, U and K) and depletion in high field strength elements (HFSE; Nb, Ta, P and Ti) and Ba. They have lower εHf(t) values varying from −9.55 to −2.75, and significant negative Eu anomalies, indicating that the ore-bearing porphyritic magmas originated from ancient middle-upper crust. Two-stage magmatism and mineralization were superimposed in the Xiangcheng-Shangri-La district. Some ore deposits comprise two episodes of magmatism and associated mineralization such as both 207 ± 3.0 Ma granodiorite and 82.1 ± 1.2 Ma monzogranite intruded in the Xiuwacu deposit, causing Cu–Mo–W polymetallic mineralization. To date, 11 Late Triassic porphyry Cu deposits (e.g. the Pulang giant deposit with 5.1 Mt Cu), and five Late Cretaceous porphyry Cu–Mo (W) deposits (e.g. Tongchanggou Mo deposit with 0.59 Mt Mo) have been evaluated in the Xiangcheng-Shangri-La district. The continuity and inheritance of multiphase magmatism and the new understanding of superimposed mineralization will help to guide future exploration. 相似文献
14.
A. P. Kozlov V. A. Chanturiya E. G. Sidorov N. D. Tolstykh Yu. M. Telegin 《Geology of Ore Deposits》2011,53(5):374-389
The results of mineralogical-technological studies of PGM mineralization in zonal mafic-ultramafic complexes of the Ural-Alaskan
type are given. All studied massifs in the Urals and Kamchatka are characterized by similar evolution of mineral assemblages.
The chromite (platinum-chromitite-dunite) and dunite (platinum-pegmatoid dunite) geological-economic types of small platinum
deposits and occurrences are separate enriched sites (ore shoots) of large-volume platinum ore deposits. These are rather
thick and extended zones of recrystallized dunites with attributes of high-temperature structural deformations and intense
fluid reworking. Low Pt grade in ore (<0.5 gpt) is determined by fine and very fine (grain size class — 80 μm) euhedral PGM
crystals distributed rather uniformly in ore mass. The high and occasionally anomalous Pt contents (up to 1 kgpt and higher)
are related to large xenomorphic segregations of PGM, which concentrate largely in the marginal parts of separate chromite
segregations. The significant part of productive Pt-bearing mineralization is hosted in olivine matrix of igneous rocks, so
that recovery of platinum cannot be associated only with separation of chromite ore. The direct gravity concentration of platinum
ore without preliminary separation of chromite concentrate is recommended as the main technique of platinum recovery. The
technological scheme provides for two-stage comminution of ore with between-cycle separation of coarse the PGM fraction into
the concentrate as a commodity product. The results obtained allow us to regard the aforementioned mineralization as a new
geological and economic type of lode platinum deposits, whose potential is comparable with active platinum reserves in the
complex Cu-Ni ores of the Noril’sk district. 相似文献
15.
I.G. Tretiakova A.S. Borisenko V.I. Lebedev G.G. Pavlova V.A. Goverdovsky A.V. Travin 《Russian Geology and Geophysics》2010,51(9):1078-1090
The paper discusses the spatiotemporal and genetic relationships of hydrothermal Co mineralization in the Altai–Sayan orogen with mafic, alkaline mafic, and granitoid magmatism on the basis of isotopic, geochemical, and geochronological investigations. Four stages of Co mineralization have been distinguished for this region: Early Devonian (D1), Late Devonian–Early Carboniferous (D3–C1), Permo-Triassic (P2–T), and Early Cretaceous (K1). They correspond to periods of large-scale mafic magmatism. Isotopic (Pb, Sr, He) and geochemical studies have shown that Co mineralization is genetically related to mafic and granitoid magmatism. Also, these studies have confirmed that Co deposits are formed with the participation of mantle fluids and are related to chambers of mafic and alkaline mafic melts. Besides, it has been found that ore originated both from magmatic sources and host rocks. A pulsed facies endogenic zonation has been established for Co deposits, Co-bearing ore clusters, and zones with high-temperature Co–As and low-temperature Ni–Co–As mineralization. It has been first established that ores at hydrothermal Co deposits are rich in Pt and Pd. 相似文献
16.
鄂东南铁铜矿集区铜山口铜(钼)矿床40Ar/39Ar年代学及对区域成矿作用的指示 总被引：11，自引：0，他引：11
铜山口铜-钼矿床发育有夕卡岩型和斑岩型两类矿化,是鄂东南矿集区内典型的夕卡岩-斑岩复合型矿床。成矿作用与铜山口花岗闪长斑岩岩株和大冶群碳酸盐岩有关,矿体主要沿两者的接触带分布。本文利用激光阶段加热技术分别对两类矿化有关的蚀变矿物金云母和绢云母进行40Ar／39Ar年龄测定。结果表明,铜山口矿区经历了两次蚀变一矿化事件:铜山口矿床成矿作用发生于约143±0．3 Ma,而矿区东南缘的牛鼻峰石英二长斑岩的热液蚀变发生于约129 Ma。牛鼻峰石英二长斑岩的侵位及蚀变对铜山口矿床斑岩型矿化的部分地段产生热扰动, 导致绢云母40Ar／39Ar年龄比实际矿化蚀变年龄偏年轻。铜山口矿区两次蚀变-矿化年龄分别与长江中下游成矿带早晚两期成岩成矿事件(145-133 Ma和130-120 Ma)一致。岩石圈伸展及幔源玄武质岩浆底侵作用可能是区域上大规模岩浆活动与成矿作用的深部地球动力学因素。 相似文献
17.
牛苦头矿床和卡而却卡矿床是青海祁漫塔格地区重要的多金属矿床。利用LA-ICP-MS锆石U-Pb法测得牛苦头矿床花岗闪长岩成岩年龄为394.0±1.3Ma,卡而却卡矿床B区黑云母二长花岗岩的成岩年龄为406.4±4.2Ma。这些年龄与区内野马泉、乌兰乌珠尔及夏日哈木矿床成矿岩体的形成时代范围基本一致,说明青海祁漫塔格地区早、中泥盆世可能发生了大规模的岩浆作用和与之有关的成矿作用。结合区域地质特征和已发表的地质年代学及岩石地球化学数据可知,青海祁漫塔格地区早、中泥盆世处于后碰撞伸展的构造背景,暗示早、中泥盆世可能是青海祁漫塔格地区又一个重要的多金属成矿期。 相似文献
18.
The Duobaoshan ore concentration area, located in Nenjiang County of Heilongjiang Province, is an important porphyry Cu-Mo ore concentration area in China, which is characterized by complex magmatic activities and multi–phase overprinting metallogenesis. On the basis of field geological observation, systematic sampling, in-lab analysis and the metallogenic regularity in the Xiang'an–Mongolian metallogenic belt, this work carried out high-precision dating and geochemical analysis on the Yuejin, 173-kilometer and Wolihedingzi rock bodies. These rock bodies are renamed monzonitic granite and their consistent age(238 Ma) show that they were formed not in Variscan but in Indosinian. Therefore, it is inferred that the ore spots formed in the potassium silicate and sericite alteration zones of the rock mass also belong to Indosinian. In addition, we collected granodiorite from the Tongshan mining pit, and its zircon age is 223.1±2.8 Ma and the Cu content of the sample is high. The Tongshan mineralization is inferred to undergo the superimposition of Indosinian diagenetic mineralization. The age of the granodiorite porphyry related to copper-molybdenum mineralization in the Xiaoduobaoshan area is 222.1±5.5 Ma, and the earlier age of granodiorite is 471.8±7.4 Ma, indicating that the initial magmatic activities belong to the Duobaoshan porphyry system in the Caledonian period. The geochemical characteristics of the Indosinian rock samples show continental arc features, with reference to tectonic-magmatic activities of the whole Daxing'anling area. We consider that the magmatic activities and mineralization of the Indosinian period are affected by the southward subduction of Okhotsk Ocean since Late Permian. By combining the mineralization rules of Daxinganling area and the structural systems of Duobaoshan ore concentration area, we divide two rock-mineralization belts in this area including the Yuejin–Duobaoshan–Tongshan belt and 173-kilometer–Xiaoduobaoshan–Wolihedingzi belt, which are distributed nearly parallel along the NW-trending fractures and show similar geotectonic settings and the timing of the magmatic activities. It is favorable for discovering porphyry Cu-Mo deposits in these two metallogenic belts, especially in the Yuejin, 173-kilometer and Wolihedingzi areas where less research work has been made. 相似文献
19.
We present new Re–Os molybdenite age data on three porphyry Cu–Mo–Au deposits (Yulong, Machangqing, and Xifanping). These deposits are associated with the Himalayan adakitic magmatism that occurred in a continental collision environment, controlled by large-scale Cenozoic strike-slip faults in the eastern Indo–Asian collision zone. Three distinct episodes of Cu–Mo–Au mineralization are recognized. At Yulong, Re–Os isotopic data of four molybdenite samples from sulfide-quartz veins in the quartz–sericite alteration zone yield an isochron with an age of 40.1±1.8 Ma (2σ), coincident to a zircon sensitive high-mass resolution ion microprobe (SHRIMP) age of 40.9±0.1 Ma for the host monzogranite. The molybdenite Re–Os dates, together with K–Ar, Rb–Sr, U–Pb, and 40Ar/39Ar dates on the pre- and intra-ore porphyries, suggest that Cu–Mo–Au mineralization formed during the late stage (∼40 Ma) of regional porphyry magmatism, but hydrothermal activity probably lasted to at least ∼36 Ma. At Machangqing, molybdenite Re–Os data from the K–silicate and quartz–sericite alteration zones yield an isochron with an age of 35.8±1.6 Ma (2σ), which is identical to the zircon SHRIMP and bulk-rock Rb–Sr ages (35∼36 Ma) of the host granite, but older than bulk-rock K–Ar dates (31∼32 Ma) for associated Au-bearing quartz syenite with advanced argillic alteration. At Xifanping, five molybdenite samples from the K–silicate alteration zone yield the youngest Re–Os isochron age in the area, at 32.1±1.6 Ma (2σ). The Re–Os molybdenite dates here are younger than K–Ar ages (33.5∼34.6) for hydrothermal biotite and actinolite. There is a positive correlation between the absolute age of the deposits and their Cu and Au reserves in the eastern Indo–Asian collisional zone. Episodic stress relaxation probably caused multiple magmatic intrusions, which most likely resulted in three episodes of Cu–Mo–Au mineralization in the eastern Indo–Asian collision zone. 相似文献
20.
中国天山东部铁矿分布规律 总被引：5，自引：0，他引：5
中国天山东部地区(简称东疆)作为一个铁的矿化集中区,是早已公认的事实。然而,究竟是什么原因导致在东径89°—97°,北纬41°—42°之间这一狭长地带中,铁矿分布如此密集并明显呈带状分布呢?此早已引起地质工作者的极大兴趣。 相似文献