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1.
侯万荣 《地质与勘探》2014,50(Z1):1213-1223
乌拉山-大青山成矿带为华北板块北缘重要的金多金属成矿带,其中产出有哈达门沟-柳坝沟大型金矿床,金矿床成矿时代和构造背景一直存在争议,长期被认为是中生代构造岩浆活动产物,最近在哈达门沟金矿床深部发现了与金共生的石英脉型和钾化蚀变岩型钼矿化,笔者等利用Re-Os同位素分析方法,首次对与含金黄铁矿共生的辉钼矿进行了年代学研究。4件辉钼矿Re-Os同位素等时线年龄为386.6±6.1Ma（MSWD=1.18）,加权平均年龄为386.4±2.7Ma（MSWD=0.55）,初始187Os值为-0.02±0.41 ng/g。根据辉钼矿的年龄,并且结合其它地质证据,可以推测,哈达门沟地区金矿化发生的事件可追溯到早泥盆世,属海西早期构造-岩浆活动事件,而矿区北部西沙德盖钼矿获得辉钼矿Re-Os年龄为226.4±3.3Ma,钼矿床形成于三叠纪,说明乌拉山地区内至少存在两期钼矿化,其中早期钼矿化与金矿化同时发生,且以金矿化为主,上述数据的取得,对重新认识该区金（钼）矿成矿作用及区域地质演化历史有着重要的理论和实际意义。  相似文献   

2.
内蒙古中西部钼多金属矿床地质特征及其动力学背景   总被引：6，自引：0，他引：6  
侯万荣 《地质与勘探》2010,46(5):751-764
本文首次对内蒙古中西部白乃庙铜-钼-金矿床、大苏计钼矿床、西沙德盖钼矿床、柳坝沟金-钼矿床、哈达门沟金-钼矿床、查干花钼-钨矿床和流沙山钼-金矿床的产出环境、地质特征、成因类型和时空分布特点进行了简要总结,对成矿作用与构造-岩浆活动的关系进行了概略性论述。柳坝沟、哈达门沟和白乃庙矿床均在前寒武纪变质岩地层中产出,大苏计、查干花、西沙德盖和流沙山矿床直接产于海西-印支期中酸性侵入岩中,尽管上述矿床在产出环境和地理位置上存在有一定差别,但是它们均与花岗岩类侵入岩体(或岩脉)具有密切的空间分布关系,属与中酸性侵入岩有关的钼多金属矿床。另外,根据矿床(点)的空间分布特点,可划分出5个钼多金属矿化集中区:即大苏计-明星沟钼矿化集中区、白乃庙-谷那乌苏铜-钼-金矿化集中区、哈达门沟-沙德盖金-钼矿化集中区、马尼图-查干花钼-铋-钨矿化集中区和流沙山-黑鹰山钼-金-铁矿化集中区。研究结果表明,成矿作用与板块消减、碰撞和缝合过程中所诱发的构造-岩浆事件密切相关,是地壳特定演化阶段构造-岩浆活动的产物。  相似文献   

3.
郭晓东 《地质与勘探》2010,46(Z1):1168-1177
[摘要]马厂箐铜(钼、金) 矿床是滇西成矿带上与喜马拉雅期富碱斑岩有关的斑岩型矿床之一。 本文通过对制约马厂箐斑岩型铜钼金矿床成矿的岩浆岩类型、岩浆的氧化性变化以及是否存在大规模 成矿流体活动和成矿的物质基础等成矿的关键因素进行综合分析,进一步评价该矿床的成矿潜力,指出 (似)斑状花岗岩与向阳组地层的北、东接触带是寻找斑岩型矿床的重点部位,宝兴厂矿段与乱硐山矿 段之间的矽卡岩型磁铁矿体(民采大坑)北侧是找金的重点部位,乱硐山矿段具有寻找铜、金矿的前景。  相似文献   

4.
陕西柞—山地区冷(水沟)—池(沟)—色(河铺)金钼铜矿带地处陕西柞—山地区南部,位于小茅岭—陡岭元古宙岛链状隆起带中段,中、南秦岭接合部。该带东西长35.7 km,南北宽7.6 km,已在其中发现多处与燕山期中酸性岩浆活动有关的金钼铜矿床。对带内的冷水沟金铜矿床、池沟金钼铜矿床、色河铺铜矿等主要矿床的地质、矿体、蚀变、矿化规律进行了总结,发现矿化受主斑岩体控制,总体上,往往从斑岩体向围岩,出现内钼、外铜、远金的多金属矿化空间分带性,构成了斑岩型-矽卡岩型-隐爆角砾岩型-构造蚀变岩型金钼铜成矿系列。冷-池-色金钼铜矿带的发现,为中、南秦岭寻找斑岩型钼铜矿床提供了直接证据,拓宽了柞(水)—山(阳)地区的找矿思路和找矿空间。  相似文献   

5.
杏山北钼矿床为胶东半岛一典型矽卡岩型钼矿床,位于著名牟平乳山金成矿带和蓬莱栖霞金成矿带之间,区域上位于胶东辽东钼成矿带,具有较好的成矿地质条件。通过对比胶东地区其他典型钼矿床地质特征,认为胶东半岛钼矿床存在两期成矿时代;矽卡岩型矿床主要受近EW向断裂构造控制,斑岩型矿床主要受近EW向与NE向断裂复合构造控制。通过物探异常预测,认为杏山北钼矿床深部是寻找矽卡岩型和斑岩型铜钼矿床的有利部位。  相似文献   

6.
首次对鸭子沟铜(钼)矿区辉钼矿进行了Re-Os同位素定年。样品的模式年龄介于213.8～231.0Ma之间,11件样品得到187Re-187Os等时线年龄为224.7±3.4Ma(n=11,MSWD=2.7)。文章在分析祁漫塔格-都兰成矿带鸭子沟铜(钼)矿区地质特征和区域成矿特征的基础上,认为该成果不仅说明鸭子沟铜(钼)矿化作用发生于晚印支期,而且在区域成找矿研究上也具有重要的地质意义,揭示了东昆仑地区晚印支-燕山期后碰撞阶段斑岩型Cu、Mo成找矿的良好前景。  相似文献   

7.
小秦岭金(钼)矿省发育大量脉状金(钼)矿床,具有重要经济价值。本次研究选择大湖、灵湖和金渠金(钼)矿床,通过系统的构造-蚀变-矿化研究和金相关黄铁矿原位硫同位素分析,拟查明小秦岭金和钼矿化基础地质异同和硫同位素组成及其控制因素。构造-蚀变-矿化研究表明上述金(钼)矿脉赋矿围岩均为前寒武太华群变质岩,控矿构造主要为近EW向(局部为NW向)剪切带,金和钼矿体发育在同一剪切带不同部位或局部叠加。钼矿脉通常发育钾化和硅化蚀变和辉钼矿和黄铁矿等矿石矿物组合,而金矿脉以绢英岩化蚀变为主,主要发育黄铁矿、多金属硫化物和碲化物等矿石矿物。原位S同位素结果显示大湖矿床钼矿脉中黄铁矿δ34S值为-3.3‰～+3.3‰,而大湖、灵湖和金渠金矿脉中黄铁矿δ34S值为-7.8‰～+8.9‰。大湖和灵湖近EW金矿脉中黄铁矿δ34S值分别为-2.8‰～+0.4‰和-7.8‰～+8.2‰,与大湖金矿脉相比,灵湖金矿脉倾向较缓且发育大量围岩角砾表明上述硫同位素组成可能由差异水力破裂和水岩反应控制。金渠金矿脉近EW和NW向矿脉中黄铁矿δ34  相似文献   

8.
华北地台北缘是中国重要的多金属成矿带,中段部位钼(铜)矿床的分布受区域EW向、NE向、NNE向断裂的联合控制。成矿带东端辽西地区以钼矿为主,西端冀北地区以铜(钼)矿为主。钼矿床的形成与燕山期中酸性小侵入体关系密切,矿床多产于花岗斑岩体之中或内外接触带中,矿床类型以斑岩型、斑岩_矽卡岩型、矽卡岩型为主。同位素研究表明,钼(铜)矿床成矿物质及成矿流体主要来源于下地壳或与太古代结晶基底有关的花岗岩;钼矿的形成主要与中生代富硅、富钾质花岗岩有关,而与铜矿成因有关的花岗岩酸碱度相对较低。成矿年代学研究表明,燕辽钼(铜)成矿带大规模成矿作用发生于180Ma左右和140Ma左右2个时期,其对应的成矿动力学背景分别为华北板块与西伯利亚板块后碰撞造山阶段和中国东部构造体制大转折晚期。  相似文献   

9.
对东秦岭有色金属成矿带中典型矿床赋矿地层的地质地球化学剖面、岩性特征、沉积环境、钼(钨)元素含量、微量元素分布及钼与微量成矿元素相关关系的多元回归分析等研究结果表明,栾川群白术沟、三川、南泥湖、煤窑沟及官道口群龙家园等各组地层是该成矿带中主要控矿层位;滨海相及滞流较深相条件下沉积的陆源碎屑岩类平均含钼(钨)较高,赋矿地层富含钼(钨)可能与继承蚀源区太华群和熊耳群钼、钨高含量有关;钼与钨、锰成显著的正相关,而与铅或锌成负相关;东秦岭赋矿地层的直接标志是钼、钨平均含量均几倍到几十倍地高于它们在地壳中的丰度,该赋矿地层就是矿源层。并分析了主赋矿地层与非主赋矿地层中钼、钨的丰度,证实了矿化与含矿地层之间的内在联系。确认该成矿带中大型铝(钨)层控矿床之赋矿地层既是它们的矿源层,又是它们的围岩,这些含矿地层是形成东秦岭成矿带中大型、特大型钼、钨矿床的物质基础。  相似文献   

10.
三江(怒江、澜沧江、金沙江)地区斑岩型铜矿地质特征   总被引：3，自引：0，他引：3  
根据成矿的地质背景,三江地区域斑岩型铜矿为岛(山)弧型和大陆边缘断裂型,可划分出怒江、澜沧江、金沙江和扎多——芒康——祥云——金平等四条成矿带。根据对成矿特征的认识,提出:岛弧型的金沙江东侧德格——曲登——中甸成矿带为铜(钼)——金(银)型成矿带,除寻找雪鸡坪、昌达沟式斑岩铜矿外,应注意寻找呷村式火山岩型金银矿;大陆边缘断裂型的扎多——芒康——祥云——金平成矿带,为斑岩型铜(钼)、铅(铁)、金成矿带,矿带北段应注意寻找斑岩型钼、铜钼矿,南段应注意寻找斑岩型铜钼、铅铁、金矿。  相似文献   

11.
Police, politics, and the right to the city   总被引：1，自引：0，他引：1  
Mustafa Dikeç 《GeoJournal》2002,58(2-3):91-98
Space and spatiality have recently been at the core of debates concerning the political possibilities of the city. The arguments advanced in this paper might be seen as an attempt to contribute to these debates through a reflection on the spatiality of (in) justice, politics, and the right to the city. The case of French urban policy, with its focus on distressed urban areas, and the `suburban problem' in France are used as examples to make arguments more concrete.  相似文献   

12.
This paper reports the first results of a study of 11 isotope systems (3He/4He, 40Ar/36Ar, 34S/32S, 65Cu/63Cu, 62Ni/60Ni, 87Sr/86Sr, 143Nd/144Nd, 206–208Pb/204Pb, Hf–Nd, U–Pb, and Re–Os) in the rocks and ores of the Cu–Ni–PGE deposits of the Norilsk ore district. Almost all the results were obtained at the Center of Isotopic Research of the Karpinskii All-Russia Research Institute of Geology. The use of a number of independent genetic isotopic signatures and comprehensive isotopic knowledge provided a methodic basis for the interpretation of approximately 5000 isotopic analyses of various elements. The presence of materials from two sources, crust and mantle, was detected in the composition of the rocks and ores. The contribution of the crustal source is especially significant in the paleofluids (gas–liquid microinclusions) of the ore-forming medium. Crustal solutions were probably a transport medium during ore formation. Air argon is dominant in the ores, which indicates a connection between the paleofluids and the atmosphere. This suggests intense groundwater circulation during the crystallization of ore minerals. The age of the rocks and ores of the Norilsk deposits was determined. The stage of orebody formation is restricted to a narrow age interval of 250 ± 10 Ma. An isotopic criterion was proposed for the ore-bearing potential of mafic intrusions in the Norilsk–Taimyr region. It includes several interrelated isotopic ratios of various elements: He, Ar, S, and others.  相似文献   

13.
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14.
The Trinity River (Texas, USA) contains in its watershed 23 different reservoir lakes, the largest one being Lake Livingston situated in the lower Trinity River watershed and two potentially polluting metroplexes, Dallas and Houston. In order to determine fluxes of nutrients and trace metals to Galveston Bay, a survey that included 24 discreet samples collected over a year and at various stages of discharge was carried out during 2000–2001. Geochemical (i.e., sorption by Fe oxyhydroxides), biological (i.e., seasonal uptake by sinking algae in Lake Livingston), and hydrological (i.e., dilution effects by increasing flow rates) controls were found to be mainly responsible for variations in dissolved trace metal concentrations rather than pollution sources. The Trinity River loads of suspended sediments and pollutant trace metals entering Galveston Bay at Anahuac were <20% of those reaching Lake Livingston, and only a few percent of the total upstream trace metal load is entering the Gulf of Mexico. Thus, during the transit through the 23 man-made lakes and an estuary, >96% of the pollutant trace metal load is lost to sediments.  相似文献   

15.
The mineral composition of the Talatui gold deposit has been studied with modern methods. Previously unknown minerals (ilmenite, siegenite, glaucodot, wittichenite, matildite, hessite, pilsenite, zircon, tremolite, cummingtonite, hercynite, and goethite) have been identified in the ore. A high Re content has been detected in molybdenite. The spatiotemporal separation of Au and Ag is caused by different mineral species of these elements and their diachronous precipitation during the ore-forming process. Gold crystallized along with early mineral assemblages, beginning from virtually pure gold (the fineness is 996). Silver precipitated largely at the end of the process as hessite (Ag2Te) and matildite (AgBiS2). The temperature of ore deposition varied from 610 to 145°C, the pressure was 3370–110 bar, and the salt concentration ranged from 56.3 to 0.4 wt % NaCl equiv. The heterogeneous state (boiling) of fluid at the early stages has been documented. The chemical and isotopic compositions of the fluid testify to its magmatic nature and the participation of meteoric water at late stages in the ore-forming process. Thermodynamic modeling reproduces the main specific features of ore formation, including separation of Au and Ag. A physicochemical model of the gold mineralization in the Darasun ore district has been proposed. On the basis of several attributes, the Talatui deposit has been referred to the prophyry gold-copper economic type.  相似文献   

16.
Transport and transformation of nitrate was evaluated along a 1-km groundwater transect from an almond orchard to the Merced River, California, USA, within an irrigated agricultural setting. As indicated by measurements of pore-water nitrate and modeling using the root zone water quality model, about 63% of the applied nitrogen was transported through a 6.5-m unsaturated zone. Transport times from recharge locations to the edge of a riparian zone ranged from approximately 6 months to greater than 100 years. This allowed for partial denitrification in horizons having mildly reducing conditions, and essentially no denitrification in horizons with oxidizing conditions. Transport times across a 50–100-m-wide riparian zone of less than a year to over 6 years and more strongly reducing conditions resulted in greater rates of denitrification. Isotopic measurements and concentrations of excess N2 in water were indicative of denitrification with the highest rates below the Merced River. Discharge of water and nitrate into the river was dependent on gradients driven by irrigation or river stage. The results suggest that the assimilative capacity for nitrate of the groundwater system, and particularly the riverbed, is limiting the nitrate load to the Merced River in the study area.  相似文献   

17.
马元铅锌矿床是近年扬子陆块北缘铅锌找矿的新突破。矿体呈层状、似层状产于碑坝隆起翼部震旦系灯影组角砾状白云岩层间构造带中,围岩蚀变很弱。矿石中硫化物以闪锌矿、方铅矿为主,中粗粒晶质结构,充填于白云岩角砾间。闪锌矿富集Cd、Ge、Ag,贫In、Tl、Se,Ga/In为6~132,Ge/In多1000,成矿温度以中-低温为主。金属硫化物ε~(34)S值相对集中,为12.9‰~19.4‰,平均为17.4‰,来自于海相硫酸盐的还原。铅同位素组成稳定,~(206)Pb/~(204)Pb为17.858~17.918:~(207)Pb/~(204)Pb为15.603~15.694;~(208)Pb/~(204)Pb为37.756~38.046,具有造山带和上地壳铅的特征,震旦系可能提供了金属成矿物质。闪锌矿中流体包裹体的~3He/~4He为0.03Ra~1.05Ra,~(40)Ar/~(36)Ar为326.1~765.1,~(38)Ar/~(36)Ar为0.183~0.204,表明成矿流体主要为地壳流体和饱和大气水(大气降水或海水)的混合。闪锌矿内流体包裹体挥发分δ~(13)C_(CH_4)值为-36.01‰~-28.80‰,δ~(13)C_(C_2H_6)值为-27.72‰~-22.44‰,δ~(13)C_(CO_2)值为-23.24‰~-9.68‰,表明有机流体参与了成矿作用。石英、方解石的H-O同位素结果表明具有海水和有机水混合的特征。可见,成矿流体具有两种流体混合的特征,一为蒸发海水与围岩反应所形成的盆地卤水,二为有机流体。推测矿区可能存在一个古油气藏,由于TSR生成一高硫气藏,为区内还原性有机流体的主要来源。当富含Pb、Zn等成矿物质的成矿流体运移至富含CH_4和H_2S的还原性流体的矿区角砾岩带时,两种流体混合,Pb、Zn等遇到H_2S发生反应而沉淀成矿,并伴生热液白云石等,形成了马元铅锌矿床。综上所述,我们认为马元矿床属MVT型铅锌矿床。  相似文献   

18.
Clay subfractions (SFs) of <0.1, 0.1–0.2, 0.2–0.3, 0.3–0.6, 0.6–2 and 2–5 μm separated from Middle Riphean shales of the Debengda Formation are studied using the TEM, XRD, K-Ar and Rb-Sr isotopic methods. The oxygen and hydrogen isotope compositions in the SFs are studied as well. The low-temperature illite-smectite is dominant mineral in all the SFs except for the coarsest ones. The XRD, chemical and isotopic data imply that two generations of authigenic illite-smectite different in age are mixed in the SFs. The illite crystallinity index decreases in parallel with size diminishing of clay particles. As compared to coarser SFs, illite of fine-grained subfractions is enriched in Al relative to Fe and Mg, contains more K, and reveals higher K/Rb and Rb/Sr ratios. The Rb-Sr age calculated by means of the leachochron (“inner isochron”) method declines gradually from 1254-1272 Ma in the coarsest SFs to 1038-1044 Ma in finest ones, while the K-Ar age decreases simultaneously from 1225–1240 to 1080 Ma. The established positive correlation of δ18O and δD values with dimensions of clay particles in the SFs seems to be also consistent with the mixing systematics. The isotopic systematics along with data on mineral composition and morphology lead to the conclusion that mixedlayer illite-smectite was formed in the Debengda shales during two periods 1211–1272 and 1038–1080 Ma ago. The first period is likely close to the deposition time of sediments and corresponds to events of burial catagenesis, whereas the second one is correlative with the regional uplift and changes in hydrological regime during the pre-Khaipakh break in sedimentation.  相似文献   

19.
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20.
Over the past decade researchers working on the rocks of the Beaufort Group in the main Karoo Basin of South Africa have vastly increased our understanding of this important Permo-Triassic sequence. Many new fossil forms have been discovered, allowing for breakthroughs into the biodiversity, biogeography and biostratigraphy of the group. Taxonomic and phylogenetic advances are many and varied, and cover most of the vertebrate taxa, but with emphasis placed on the temnospondyl amphibians, archosauriforms and non-mammalian synapsids, in particular the anomodontia. Biostratigraphic breakthroughs have centered on the Middle Permian Eodicynodon and Tapinocephalus assemblage zones, the Late Permian Dicynodon Assemblage Zone, and the Triassic Lystrosaurus and Cynognathus assemblage zones. Correlation of these biozones with better dated sequences in Europe, Russia and China has allowed for many chronostratigraphic refinements, which are in turn vital for sequence stratigraphical analysis of the basin fill. Based on fossil data, both the lower (Ecca–Beaufort) and upper (Beaufort–Molteno) contacts of the group have been proved to be highly diachronous. The refined chronostratigraphic framework has also allowed for a better analysis of the basin evolution through time, particularly in terms of the correlation of external stimuli that affect basin sedimentation patterns.  相似文献   

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