天然气水合物区多相流体运移模型：以南海神狐海域为例          下载免费PDF全文

叶鸿  杨涛  朱国荣  蒋少涌 《高校地质学报》2018,24(5):734

天然气水合物是重要的海洋油气资源,近年来利用孔隙水地球化学手段结合流体反应运移模型对水合物进行勘探已 成为研究热点。文章针对南海神狐海域钻探GMGS-1航次的数据资料,用孔隙水溴碘摩尔数比值拟合全新世流体运移速率, 构建了二期次非稳态水合物多相流体运移模型,并以SH7站位作为应用,发现自更新世以来研究区水合物成藏系统处于衰 退状态。通过模型参数敏感性分析,了解到影响模型输出的参数权重从高到低依次是沉积物孔隙度、有机质含量和沉积埋 藏速率。进一步数值分析表明,在水合物成藏系统中,有机质含量与水合物饱和度满足线性相关,其他主要参数与饱和度 的关系并非单调函数,且主导水合物稳定区内的甲烷物源是深部外源流体所携带的甲烷。多相流体运移模型对水合物资源 勘查具有一定的理论意义。  相似文献   

内蒙古白乃庙铜-金-钼矿床成矿机制——来自流体包裹体和He-Ar同位素的证据   总被引：1，自引：0，他引：1       下载免费PDF全文

周振华  车合伟  欧阳荷根  马星华 《地质学报》2017,91(3):542-560

白乃庙铜-金-钼矿是华北板块北缘中段一个重要矿床,其矿化特征既显示斑岩型蚀变特征,同时又表现出明显的后期造山作用改造的特点。本次研究通过系统的流体包裹体显微测温、激光拉曼和气液相色谱分析揭示其成矿流体为中—低温、中低盐度的CO_2(CO)-H_2O-CH_4(C_2H_2+C_2H_4)-NaCl-CaCl_2体系,流体混合作用和CO_2逃逸为成矿主要因素。富还原性流体的存在可能促使气相流体携带大量的Cu、Au等成矿元素迁移至较远点的白乃庙群地层,沿着片理或裂隙沉淀成矿。对不同成矿阶段矿石中黄铁矿的He-Ar同位素组成测试结果显示白乃庙矿床黄铁矿流体包裹体的~3He/~4He比值在0.06~0.71Ra之间,~(40)Ar/~(36)Ar比值为375.5~1436.3,指示成矿体系由不同性质和组成的两个端元流体混合而成,即混入了类似于MORB型地幔端元的高温高盐度流体和富含地壳放射成因氦但具有空气氩同位素组成特征的低温大气降水。白乃庙矿床属受后期造山作用改造的斑岩型铜-金-钼矿床,形成于古亚洲洋板块持续向南俯冲背景。  相似文献   

西藏多龙矿集区地堡铜(金)矿床年代学、流体包裹体、地球化学特征及其成因类型研究   总被引：3，自引：0，他引：3  

乔东海  赵元艺  汪傲  李玉彬  郭硕  李小赛  王松 《地质学报》2017,91(7):1542-1564

多龙矿集区位于班公湖-怒江成矿带西段北侧、羌塘地块南缘,是我国近年来发现的最大斑岩-浅成低温热液型Cu(Au)矿集区。地堡是多龙矿集区最西南边缘的矿床,资源潜力巨大,有望达到超大型规模,但研究程度薄弱。本次工作对地堡Cu(Au)矿开展了锆石U-Pb测年、流体包裹体、地球化学等方面的研究,为推动资源勘查和矿集区成矿规律的总结提供理论依据。含矿斑岩锆石206 Pb/238 U平均加权年龄为111.2±0.4Ma(MSWD=0.67),与矿集区成矿岩浆活动时限一致,是矿集区重要组成部分。石英脉流体包裹体显示矿床主成矿期成矿流体温度集中于140~382℃,主要集中在240~280℃。成岩阶段石英斑晶中Ⅰ型包裹体盐度范围为0.2%~20.7%NaCleqv.,含盐子晶包裹体盐度为33.6%NaCleqv.和43.9%NaCleqv.;成矿阶段不含石膏石英脉Ⅰ型包裹体盐度范围为0.2%~20.8%NaCleqv.,黄铁矿石英脉Ⅰ型包裹体盐度范围为1.1%~11.1%NaCleqv.,石膏中Ⅰ型包裹体盐度范围为0.5%~9.3%NaCleqv.。对钻孔DNZK6428样品进行主微量元素测试并进行因子分析计算,结果表明F1、F2、F3代表成岩阶段,因子主成分为Y-Ho-Er-Tm-Yb-Dy-Lu-Tb-Eu-Gd-Sm-La-Ce-Pr-Nd-SiO_2-Al_2O_3-CaO等,F4和F5代表铜金矿化阶段,因子主成分为Sn-Sb-Ba-Fe_2O_3-Sr-|SiO_2|-Ni-Cu-U-In-Cd-Au-Zn。黄铁矿δ34SV-CDT值总体较为集中,呈"双峰塔式"分布,变化范围为-7.8‰~4.1‰,均值为-4.23‰,为深源岩浆硫,硫的来源接近地幔硫。矿床粒状黄铁矿Co/Ni比值为0.207~10.775,平均值4.39,脉状黄铁矿Co/Ni比值为0.353~23.155,平均值3.802,均为热液成因。矿相学与岩相学研究结果显示矿床具明矾石和硫砷铜矿典型高硫化浅成低温热液矿床的矿物组合,地堡Cu(Au)矿为高硫型浅成低温热液矿床。  相似文献   

湖南祁东清水塘铅锌矿床成矿物质来源同位素示踪   总被引：3，自引：0，他引：3       下载免费PDF全文

路睿  缪柏虎  徐兆文  陆建军  王汝成  左昌虎  屈金宝  赵增霞 《地质学报》2017,91(6):1285-1298

清水塘铅锌矿床位于湖南省祁东县北东部,是一个中型矿床。在详细的野外地质调查基础上,本文通过矿石硫、铅同位素,含矿石英氢、氧同位素和含矿方解石碳、氧同位素等综合研究,探讨清水塘铅锌矿床成矿物质来源和成因。硫同位素研究结果表明,清水塘铅锌矿床中黄铁矿、方铅矿和闪锌矿的硫同位素δ~(34)S介于-7.41‰~2.91‰之间,重晶石的硫同位素δ~(34)S介于11.49‰~12.34‰之间,表明矿石中的硫主要来源于深源岩浆,并受到上部地壳物质的混染。黄铁矿、方铅矿和闪锌矿的Pb同位素~(206)Pb/~(204)Pb介于17.810~18.710之间,~(207)Pb/~(204)Pb介于15.497~15.726之间,~(208)Pb/~(204)Pb介于37.858~38.834之间;其中闪锌矿变化范围略偏大,表明矿石中的铅主要来源于地壳,可能混有少量地幔物质。含矿石英的氢、氧同位素δD_(SMOW)介于-87.4‰~-79.3‰之间,δ~(18)O_(H_2O)介于-8.10‰~0.63‰之间,表明成矿流体以岩浆水为主,晚期有大气降水的混入。含矿方解石的碳、氧同位素δ~(13)C_(VPDB)介于-5.3‰~-4.6‰之间,δ~(18)O_(SMOW)介于12.30‰~13.48‰之间;与地层灰岩的δ~(13)C_(VPDB)(0.9‰~2.6‰),δ~(18)O_(SMOW)(21.86‰~23.39‰)不一致;说明成矿流体中的碳主要来自深源岩浆。以上研究表明,清水塘铅锌矿床的成矿物质主要来自地壳熔融形成的岩浆,混合作用是成矿的主要机制。  相似文献   

南大巴山前陆冲断褶皱带断裂流体地球化学特征及构造保存研究          下载免费PDF全文

周业鑫  丁俊  余谦  王剑  熊国庆  门玉澎  熊小辉  邓奇 《地质学报》2017,91(6):1169-1180

南大巴山前陆构造带位于城口断裂与铁溪-巫溪断裂之间,为研究该构造带断裂对烃类运移及构造对页岩气保存的影响,本文对该构造带内断裂流体的碳氧同位素和流体包裹体进行了测试分析。测试结果显示,研究区断裂流体碳氧同位素整体较围岩更为分散,δ~(13)C_(PDB)介于-2.9‰~3.9‰之间,属正常海相碳酸盐层的碳同位素值,坪坝断裂附近δ~(13)C_(PDB)呈明显亏损,具外来流体混合的特征。流体包裹体为含烃的气液二相盐水包裹体,气相成分为CH_4,液相为H_2O。包裹体均一温度以城口断裂附近最高,主要为311~336℃,频率峰值温度为328℃;往南叠瓦带流体均一温度主要位于183~269℃之间,峰值为230℃,断褶带峰值为213℃,滑脱褶皱带为170℃,整体表现为向盆内方向降低。盐度主要为4.43%~8.6%NaCl。研究表明,城口断裂作为大巴山构造带南北分界的主干断裂,古流体的形成温度和热演化程度最高,且从盆地向北至城口断裂,各构造带流体的热演化程度、成岩温度、古流体压力均逐渐升高,说明随着构造活动的增强,构造带中的流体更为活跃,持续时间更长,导致流体形成的深度和温度变化较大。构造带内的流体总体上形成于封闭体系,在主构造应力的驱动下,盆地深部含烃流体沿断裂向浅部运移,并与浅部地层流体发生混合,运移通道整体处于封闭状态;而构造带内的一些次级断裂,因其形成的时间以及向下延伸的深度不足以触及下古生界烃源岩层,因此其对流体封闭性的影响有限。  相似文献   

Geochemical characteristics of mud volcano fluids in the southern margin of the Junggar basin,NW China: implications for fluid origin and mud volcano formation mechanisms     

Zhifeng Wan  Xianqing Wang  Ye Lu  Yuefeng Sun  Bin Xia 《International Geology Review》2017,59(13):1723-1735

Mud volcanoes can provide important information about the underlying strata, hydrocarbon accumulation, and recent neotectonic movements in an area. The fluids erupting from mud volcanoes provide important information about their formation and evolution. The ion concentration and the hydrogen and oxygen isotopes of the fluids that were erupted from the three mud volcano groups, Baiyanggou, Aiqigou, and Dushanzi, and nearby rivers in the southern margin of the Junggar basin, northwestern China, are studied. The concentrations of Na and Cl in mud volcano fluids are clearly elevated, displayed as the Na-Cl type. The δD and δ18O values of the fluids are similar between the Baiyanggou and Dushanzi mud volcanoes, which are mainly from ancient sedimentary pore water. However, the Aiqigou mud volcano is depleted in dissolved Cl and shows lower δ18O values with mixed sources, including deep pore and local meteoric water. Two types of mud volcanoes are proposed in this study. One type is low-energy mud volcanoes with a low volume of fluid of deep origin on the hillcrest, which display as mud pool/pie/hole. The other type is high-energy mud volcanoes having mixed fluid origin in the valley and formed in the shape of a mud cone (dome).  相似文献   

An experimental investigation of wave‐induced sediment responses in a natural silty seabed: New insights into seabed stratification          下载免费PDF全文

Xiaolei Liu  Yonggang Jia  Jiewen Zheng  Mingzheng Wen  Hongxian Shan 《Sedimentology》2017,64(2):508-529

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The Chalukou deposit in the North Great Xing’an Range of China: A protracted porphyry Mo ore-forming system in a long-lived magmatic evolution cycle     

《Ore Geology Reviews》2017

The Chalukou deposit is located in the North Great Xing’an Range of the Xing’an-Mongolia Orogen bordering and to the northeast of the North China Craton. The deposit is a high-F-type porphyry Mo deposit hosted by the Chalukou composite igneous body containing small intrusive bodies genetically related to Mo mineralization. The composite igneous body includes pre-mineralization dolerite, monzogranite and syenogranite, syn-mineralization rhyolitic porphyry, granitic porphyry and fine-grained monzogranite, and post-mineralization rhyolitic porphyry, quartz porphyry, dioritic porphyry and andesitic porphyry. Detailed laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U-Pb zircon dating of the igneous components of the composite igneous body was carried out to determine the temporal framework for magmatism in the Chalukou region. The new LA-ICP-MS U-Pb ages constraint documented here, together with the published ages, indicate that there was a protracted porphyry Mo ore-forming event of approximately 7 million years between ca. 152 when the ore related rhyolitic porphyry was emplaced and ca.145 Ma when molybdenite ceased being deposited. The dating reveals that the mineralization is a part of relatively long-lived magmatic cycle involving the emplacement of small doleritic stocks at ca. 165 Ma that progressively evolved into extensive granitic intrusions at ca. 164 Ma, and then diminished with the emplacement of mineralization-related porphyries to ca. 152 Ma. The emplacement of barren Early Cretaceous magmatism, represented by volcanic units in the ca. 136 Ma Guanghua Formation and porphyries, followed the mineralized magmatism.The syn-mineralization porphyry units associated with Mo contain zircons assaying ∼15 times higher in U and Th than the pre-mineralization magmatic phases. This indicates that there was a significant enrichment of Mo, U and Th in the magma, and directly associated with ore fluid exsolution. The return to their normal levels in the three elements in the post-mineralization magmatic phases indicates that they were exhausted from the magma chamber in the later phases. A genetic model is proposed for the enormous introduction of ore metals and enrichment at the Chalukou deposit. The protracted and multiphase igneous activity during the long-lived magmatism reflects a multistage enrichment of metal, and may play a crucial role in the formation of a volatile-enriched, fertile and large-volume magma chamber beneath the Chalukou deposit. Such a chamber is envisaged to be required for the formation of porphyry Mo deposits in general.  相似文献   

Au-Pb compounds in nature: A general overview and new evidence from the Inagli Pt–Au placer deposit,the Aldan Shield,Russia     

《Ore Geology Reviews》2017

This study presents a new and first finding of Au-Pb intermetallic compounds in the Inagli Pt–Au placer deposit, the Republic of Sakha (Yakutia), Russia. This is the first time that all three accepted minerals (hunchunite, anyuiite and novodneprite), as well as unnamed Au-Pb intermetallics, corresponding in composition to Au_1.5Pb and AuPb, are present together in the same locality. We provide chemical compositions of Au-Pb compounds and host gold particles, describe morphology and relationships between different mineral phases. We also present an unexpected finding of unusual inclusion of Pb-Fe-aluminosilicate associated with K-feldspar and anyuiite in the gold grain. The new data together with data from other occurrences of Au-Pb compounds worldwide were reviewed to discuss type localities, mineralogy, conditions and possible mechanisms of formation of Au-Pb intermetallics and to provide an overview of current knowledge about these uniquely rare but naturally occurring minerals.  相似文献   

广西西大明山弄屯铅锌矿床断裂构造解析   总被引：1，自引：0，他引：1  

李赛赛  冯佐海  单永磐  付伟  乐兴文  刘武文  徐文忠 《矿床地质》2017,36(2):275-290

弄屯矿床是西大明山地区新发现的规模最大的铅锌矿床,是受断裂控制的典型热液脉型矿床。文章在充分搜集已有勘查资料的基础上,认为铅锌矿体主要受NE向和(近)EW向断裂控制,矿体主要产在断裂浅部产状较缓的部位,向深部断裂产状变陡,矿体厚度减薄直至尖灭;而且主矿体沿NE向断裂具有向SW侧伏的趋势。在此基础上,利用控矿断裂的擦痕、阶步以及伴生的节理、牵引褶皱等小构造,对控矿断裂的运动学和动力学特征进行了解析,分析认为控矿断裂在成矿期表现为逆断层活动特征,是受近SN向主压应力作用下形成的。利用SPSS、Surfer软件对矿体的产状、有用组分含量等数据进行统计分析并绘制了等值线图,研究得出成矿热液是先由F1断裂进入NE向断裂中,随后沿NE向断裂由西南向北东运移,并最终导致Zn、Pb先后沉淀富集形成厚大的矿体。根据已有的同位素数据和构造解析资料,可基本确定弄屯铅锌矿床形成于燕山晚期。  相似文献