钼催化作用下的煤成烷烃气碳同位素演化

为了阐释钼催化作用下的煤成气碳同位素演化特征和机理,采用在原煤中添加单质钼的方式,开展催化生气模拟试验,测定模拟系列气样的单体烷烃气碳同位素组成,并对其演化规律和模式进行探讨.结果表明:无论加钼与否,模拟气甲烷碳同位素组成(δ(13C1))均以镜质组反射率1.1%为界分为演化趋势截然相反的2个阶段,乙烷碳同位素组成(δ(13C2))不存在明显的演化阶段性,但加钼煤样δ(13C2)由在较低成熟度阶段重于原煤样变为在较高成熟度阶段轻于原煤样;加钼条件下,模拟烷烃气呈现出正碳同位素系列,δ(13C1)为(-25~-45)×10-3,δ(13C2)重于-29×10-3,表明钼催化成因气属于有机热成因气范畴.对比模拟烷烃气碳同位素组成与镜质组反射率之间的关系,发现模拟烷烃气碳同位素组成演化规律与前人模式有所不同.加钼煤样的不同单体烷烃气碳同位素组成随有机质成熟度变化速率的不同而不同,指示生气作用在钼催化作用下得到增强,这一效应在裂解气生成过程中更为显著;加钼煤样δ(13C2)在较高成熟度条件下轻于原煤样δ(13C2)的原因可能在于钼催化效应促进了煤中壳质组裂解生气.     

从He同位素组成探讨塔里木盆地与东部诸含油气盆地天然气的成气机制

通过天然气中He同位素组成来研究天然气的成气机制。用VG-5400静态真空质谱计测定了采自塔里木盆地古生代和中生代地层中天然气的He同位素,其He/4He=2.58×10-8～8.33×10-8,R/Ra=0.019～0.059Ra,平3均值为0.031Ra,而我国东部几个主要含油气盆地天然气的R/Ra平均比值则变化于1.21～2.30Ra。He同位素组成对比研究表明,东部含油气盆地成烃作用是在幔源热流驱动下热水流体与烃源岩水岩反应形成的,而塔里木盆地成烃热源则主要是盆地地热增温热水流体与烃源岩水岩反应形成的。     

Temporal and spatial variations of atmospheric methane concentration and δ^13 C-CH4 near the surface on the Millor Peninsula, East Antarctica

During the 22nd Chinese Antarctic Research Expedition(CHINARE-22,2005/06),the atmospheric gas samples near the surface were taken on the Millor Peninsula and adjacent areas,east Antarctica,using Tedlar gas bags.The methane(CH4) concentration and δ13C-CH4 in those samples were analyzed in the laboratory.The average value of atmospheric CH4 concentration on this peninsula was(1.87±0.12)×10-6,slightly higher than the global average CH4 concentration.The summertime variation of CH4 concentrations showed a large...     

Methane-rich fluid inclusions and their hosting volcanic reservoir rocks of the Songliao Basin, NE China

Methane-rich fluids were recognized to be hosted in the reservoir volcanic rocks as primary inclusions.Samples were collected from core-drillings of volcanic gas reservoirs with reversed δ12C of alkane in the Xujiaweizi depression of the Songliao Basin. The volcanic rocks are rhyolite dominant being enriched in the more incompatible elements like Cs, Rb, Ba, Th, U and Th with relative high LREE, depleted HREE and negative anomalies of Ti and Nb,suggesting a melt involving both in mantle source and crustal assimilation. Primary fluids hosted in the volcanic rocks should have the same provenance with the magma. The authors concluded that the enclosed CH4 in the volcanics are mantle/magma-derived alkane and the reversed δ13C of alkane in the corresponding gas reservoirs is partly resulted from mixture between biogenic and abiogenic gases.     

Origin of ore-forming fluids in Qinggouzi stibnite deposit,NE China:Constraints from fluid inclusions and H-O-S isotopes

The Qinggouzi stibnite deposit is located in Huashan Town, Jilin Province, in the northeastern margin of North China Craton(NCC). It is controlled by fault structures, hosted within structurally controlled felsic dykes, predominantly surrounded by phyllite, schist and quartzite. This study presents the results of fluid inclusions studies, intending to determine the source of the fluid responsible for ore-formation, hence exploring its metallogenesis. The aqueous biphase inclusions are identified in the stibnite-bearing quartz veins of the deposit. Moreover, aqueous biphase inclusions are further classified into(1) biphase liquid-rich inclusions(1 a) and(2) biphase gas-rich inclusions(1 b) depending upon liquid to gas ratio trapped within the fluid inclusions. Homogenization temperatures for(1 a) and(1 b) range between 114.8℃ to 422℃ and 128.3℃ to 267.5℃, respectively. 1 a and 1 b have salinities of 0.18% to 16.14% NaCl_(eqv) and 1.22% to 12.88% NaCl_(eqv), and density range from 0.43 to 1.02 g/cm~3 and 0.81 to 0.98 g/cm~3, respectively. Sulfur isotopic analysis indicates δ~(34)S_(V-CDT) from 4.4×10~(-3) to 6.5×10~(-3), with an average of 5.2×10~(-3), whereas H isotopes values on δD_(V-SMOW) standard are-100.8×10~(-3) and-107.5×10~(-3), while O isotopes data on δ~(18)O_(V-SMOW) standard range between 20.1×10~(-3) and 20.4×10~(-3). Fluid inclusions study, combining with sulfur and H-O isotopic data reveal that the ore-forming fluids originated from deep source and were subsequently contaminated by meteoric water. Hydrostatic pressure calculation shows that the minimum and maximum pressures are 11.65 and 42.33 MPa, and relevant depths of deposit are estimated to be 1.16 and 4.23 km. Finally, we inferred that Qinggouzi stibnite deposit is a medium-low temperature, low salinity hydrothermal deposit, which is formed by deep source and later contaminated by meteoric water, and is classified as epizonal deposit in terms of orogenic series.     

Geology and geochemistry of Huanggangliang stratabound skarn deposit in Inner Mongolia, China

Over the recent three decades,exploration of a large-size Sn-Fe polymetallic ore deposit at the Huanggangliang, the Da Hinggan Mountains, Inner Mongolia, China, has been largely focused on the premise that the mineralization represents epigenetic magmatic hydrothermal ore deposit in genetic connection with the Mesozoic magmatism. The Huanggangliang Sn-Fe polymetallic ore deposits occurred in Permian strata, with siltstone/marble of the Zhesi Formation and spilite/andesite/tuff of the Dashizhai Formation. The characteristics of geological and geochemical data demonstrated that sedimentary hydrothermal mineralization occurred during the basin evolution at the Permian, rather than representing epigenetic magmatic hydrothermal genesis with the following evidences. The ore-bearing skarns are stratiform with underlying metasedimentary rocks and overlying volcanic sedimentary rocks. Sedimentary hydrothermal textures and structures are observed in the stratabound ore-bearing skarn such as bedded-laminated skarn and magnetite ores with small-size folding or soft deformation, synsedimentary breccia of skarn and magnetite ores and concentric shell structure of magnetite ores. So the stratabound ore-bearing skarns associated with magnetite ore and micro-disseminated tin, are peculiar examples of exhalite. The REE contents of the stratabound ore-bearing skarns display ΣLREE-rich (36.91×10-6) but ΣHREE-depletion (6.42×10-6), with positive Eu anomaly (Eu/ Eu 1.28) and negative Ce anomaly (Ce/Ce 0.88), which is totally different from REE pattern of the Huanggang magmatic rocks(with ΣREE 277.73×10-6, ΣLREE 220.24×10-6, ΣHREE 57.49×10-6, Eu/Eu 0.06, Ce/ Ce 1.52), which is comparable with modern sea-floor hydrothermal fluid,sedimentary hydrothermal ore deposit and associated hydrothermal sedimentary rocks. Calcite samples with δ13CPDB from -5.400 ‰ to -4.397 ‰ and δ18OSMOW from 9.095 ‰ to 9.364 ‰ in the stratabound ore-bearing skarns show sedimentary hydrothermal genesis of the Huanggangliang deposit. This proposition is useful not only for interpretation of the genesis of the Huanggangliang large Sn-Fe polymetallic ore deposit but also significant for mineral exploration in the area especially for finding large deposits caused by sedimentary exhalative mineralization processes.     

温度对马尾藻及其油页岩混合物热解产气特性的影响

【目的】研究马尾藻及其油页岩混合物在不同温度下的热解产气特性。【方法】利用燃烧烟气污染物测试实验台,测量马尾藻及其油页岩混合物在温度区间400℃至800℃下CO和H_2的排放特性,包括峰值浓度、峰值时间和平均浓度。【结果】马尾藻以及其油页岩混合物的热解过程可分为慢速析出、快速析出和降速三个阶段。马尾藻单独热解实验中,排放的CO体积分数峰值达到10 367×10~(-6)。温度的升高有利于马尾藻在热解中CO和H_2的析出,反应的开始时间和完成时间均有所提前。在马尾藻与油页岩混合物的热解中,H2的析出在700℃时达到最高(体积分数峰值为1 254×10~(-6))。油页岩的加入迟滞了CO和H_2的排放时间。【结论】油页岩的加入有效减少马尾藻热解过程中CO的排放并缩短反应时间,提高效率节省能源,马尾藻与油页岩的混合热解具有良好的应用前景。     

邹平火山岩盆地铜多金属成矿对构造岩浆事件的响应

通过邹平火山岩盆地不同岩石类型岩石化学特征的对比分析:认为火山活动总的趋势是由弱到强,爆发指数为38—68—92;火山岩3个亚组SI值均<40,表明母岩浆可能是由幔源岩浆经分异演化或同化而形成的;侵入岩σ介于2.39～4.99,属钙碱性-碱性岩系;DI为65.15～88.98,岩浆分异演化程度相对较高;A/NKC为0.96～1.02,岩石为弱过铝质。该区岩浆岩属壳幔型中性岩—壳幔型和铝质地壳过渡区中酸性岩—酸性岩的岩浆岩区。铜多金属对构造-岩浆事件的响应可描述为:长期继承性活动的区域性构造和振荡性的岩浆侵入活动,致使富碱质岩浆热液与已结晶的二长质岩石在地球化学界面发生交代蚀变,并进行了物质交换。     

地幔橄榄岩中橄榄石的指示意义

橄榄石是地幔橄榄岩和辉石岩的主要组成矿物,但也经常以斑晶和捕虏晶的形式出现在玄武质岩石中。结合近年来在地幔橄榄岩的主要元素(如Mg和Fe)组成特征以及Li、Mg和Fe稳定同位素地球化学方面的研究成果,重点对橄榄石的地球化学特征与华北克拉通岩石圈地幔演化过程之间的联系进行了讨论,旨在加深对华北克拉通岩石圈地幔演化过程的理解。现有研究表明:地幔橄榄岩中橄榄石的矿物学特征、元素和同位素地球化学组成能够很好地指示岩石圈地幔的特征及其演化过程,因而具有重要的意义。对于克拉通地区的地幔橄榄岩来说,橄榄石的Mg#通常可以指示岩石圈地幔的属性,古老、难熔的地幔橄榄岩中的橄榄石一般具有较高的Mg#(>92),而新生的岩石圈地幔橄榄岩中的橄榄石则具有较低的Mg#(<91)。因此,地幔橄榄岩中橄榄石的Mg#在一定程度上具有年龄意义。橄榄岩中橄榄石的Li、Mg和Fe同位素组成也可以明确指示岩石圈地幔的属性及其所经历的演化过程,正常地幔的δ7Li、δ26Mg和δ57Fe组成相对均一,如果上述同位素组成偏离正常地幔值,则说明岩石圈地幔经历了熔体/流体的交代作用。华北克拉通地区地幔橄榄岩捕虏体中橄榄石的Li、Mg和Fe同位素组成研究表明:该区的岩石圈地幔经历了多个阶段、不同来源的熔体/流体的改造过程。     

Altitudinal trends in δ<Superscript>13</Superscript>C value,stomatal density and nitrogen content of <Emphasis Type="Italic">Pinus tabuliformis</Emphasis> needles on the southern slope of the middle Qinling Mountains,China

In this study, a coniferous tree species (Pinus tabuliformis Carr.) was investigated at a moderate-altitude mountainous terrain on the southern slope of the middle Qinling Mountains (QLM) to detect the trends in carbon isotope ratio (δ¹³C), leaf nitrogen content (LNC) and stomatal density (SD) with altitude variation in north-subtropical humid mountain climate zone of China. The results showed that LNC and SD both significantly increased linearly along the altitudinal gradient ranging from 1000 to 2200 m, whereas leaf δ¹³C exhibited a significantly negative correlation with the altitude. Such a correlation pattern differs obviously from that obtained in offshore low-altitude humid environment or inland high-altitude semi-arid environment, suggesting that the pattern of increasing δ¹³C with the altitude cannot be generalized. The negative correlation between δ¹³C and altitude might be attributed mainly to the strengthening of carbon isotope fractionation in plants caused by increasing precipitation with altitude. Furthermore, there was a remarkable negative correlation between leaf δ¹³C and LNC. One possible reason was that increasing precipitation that operates to increase isotopic discrimination with altitude overtook the LNC in determining the sign of leaf δ¹³C. The significant negative correlation between leaf δ¹³C and SD over altitudes was also found in the present study, indicating that increases in SD with altitude would reduce, rather than enhance plant δ¹³C values.     

山东胶东地区盘子涧金矿成矿流体He-Ar同位素地球化学特征

盘子涧金矿地处山东胶东地区蓬莱—栖霞金成矿带南部,是典型的石英脉型金矿,Au品位高,目前对该矿床成矿流体来源的研究尚不深入。在详细的矿相学观察及黄铁矿显微结构研究基础上,对盘子涧金矿主成矿阶段(石英-黄铁矿(绢云母)阶段和金-石英-多金属硫化物阶段)的载金黄铁矿进行了流体包裹体He-Ar同位素组成分析。结果表明:盘子涧金矿载金黄铁矿中流体包裹体的3He丰度为(3.49~8.50)×10^-14 cm^3 STP·g^-1,4He丰度为(2.46~5.06)×10^-8 cm^3 STP·g^-1,3He/4He值为0.8 Ra^1.2 Ra(Ra为大气3He/4He值,Ra=1.39×10^-6),成矿流体表现出以富集地幔为主导的壳幔混合特征;40Ar丰度为(1.02~2.65)×10^-7 cm^3 STP·g^-1,40Ar/36Ar值为896.3~1724.1,是大气饱和水40Ar/36Ar值的2~3倍,与中国东北部幔源岩样品40Ar/36Ar值相近,推测成矿流体主要来源于富集地幔,成矿流体中存在着一定量的地壳放射性成因40Ar,表明地壳流体参与了成矿作用。综上所述,推断山东胶东地区盘子涧金矿成矿流体为以富集地幔流体为主导的壳幔混合流体。     

江汉平原高砷地下水稳定碳同位素特征及其指示意义

溶解性有机碳（DOC）是地下水中砷释放过程的关键因素,为查明江汉平原高砷地下水稳定碳同位素特征,识别有机质的降解过程对砷富集的影响,采用稳定碳同位素分析测试技术并结合地下水化学特征,对江汉平原典型砷中毒病区的浅层地下水进行了区域采样分析。结果表明:浅层承压水的砷质量浓度为0.23~2 621 μg/L。地表水较地下水具有更负的δ13C_DOC、δ13C_DIC值。地下水中溶解性无机碳（DIC）的δ13C_DIC值在-11.9‰~-3.99‰之间,溶解性有机碳的δ13C_DOC值在-28.5‰~-19.6‰之间。地下水的δ13C_DIC-δ13C_DOC差值与ρ（As）呈一定负相关关系,表明微生物作用下有机质的降解促进了As的富集。δ13C_DIC-δ13C_DOC差值与δ13C_DIC和ρ（DOC）均具有较显著的正相关关系,表明地下水中有机质的氧化分解是导致δ13C_DIC贫化的重要过程,微生物作用下溶解性有机质的降解是地下水中无机碳的重要来源。此外,江汉平原少数高砷地下水呈现较大的δ13C_DIC值,推断江汉平原高砷含水层强还原环境下可能存在的产甲烷过程导致了明显的碳同位素分馏。      

Isotopic tracing of ore-forming source materials for Dexing porphyry copper deposit of Jiangxi, China

Dexing copper deposit is the biggest porphyry copper deposit in China. By researching isotopes of C,Si and Cu from the samples of Tongchang and Fujiawu ore-field, the authors found that δ13CPDB values of siderite were close to the δ13CPDB value of original magma; δ30Si values of the samples at the ore-forming stage were close to the δ30Si value range of magma, δ30Si values of partial samples were far away from it; Cu isotopic compositions of massive chalcopyrite formed at the early ore-forming stage are higher than that of veinal chalcopyrite formed at the later ore-forming stage. The results show that ore-forming materials were mainly derived from the porphyry body, and part of them were from wall rock materials.     

海拉尔盆地碎屑岩地层断裂带内部结构及断层封闭性

根据盆地演化规律及断层穿层性,将海拉尔盆地断裂分为盆地基底断裂和盖层断裂;根据活动时期和变形特征,分为早期伸展断裂系统、中期张扭断裂系统、早期伸展)中期张扭断裂系统、中期张扭)晚期反转断裂系统和早期伸展)中期张扭)晚期反转断裂系统.结合海拉尔盆地岩心和野外观察,建立3种断裂带内部结构模式:致密储层中断层角砾岩结构、泥质岩盖层中泥岩涂抹结构和泥质岩盖层内断层泥结构.与油气垂向运移有关的断裂系统包括早期伸展)中期张扭)晚期反转断裂系统(正反转断层)、早期伸展)中期张扭)晚期反转活动的断裂系统(反转再活动正断层)和中期张扭)晚期反转活动的断裂系统.该研究成果可以为海拉尔盆地断层封闭性评价提供指导.     

Characteristics of helium isotopes in natural gas and its tectonic implication in Bohai Bay Basin

1 INTRODUCTION Helium is a trace element in natural gas and the lightest element of all rare gases. It is formed during natural nuclear processes and it is chemi- cally stable. Because of its strong diffusibility and permeability, it is used as a very sen…     

Oxygen isotopic composition and its application to the study of tracing oceanographical process in Bering Sea and Chukchi Sea

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Zircon U-Pb geochronology and Hf isotopic constraints on petrogenesis of Carnian Huanglonggou granodiorites in Wulonggou area of Eastern Kunlun Orogen,NW China

The Wulonggou area located in the Eastern Kunlun Orogen in NW China is characterized by extensive granitoid magmatism,ductile faulting and orogenic gold mineralization.The Huanglonggou granodiorite is cut by an orogenic gold-bearing fault.This study investigated the major and trace-element compositions,zircon U-Pb dates and zircon Hf isotopic compositions of the Huanglonggou granodiorite.One Huanglonggou granodiorite sample yielded a weighted mean U-Pb zircon age of~221 Ma(Carnian).The Carnian granodiorite is metaluminous,with high alkalis contents of 6.37%--8.86%,high Al_2O_3contents of 15.41%--16.19%,high Sr contents of(426--475)×10~(-6),relatively high Sr/Y ratios,high(La/Yb)_Nvalues and low HREE,suggesting an adakite type high-Si O_2granite.The Huanglonggou granodiorite sample has zirconε_(Hf)(t)values ranging from-4.4 to+1.1.These Hf isotopic data suggest that the Carnian granodiorite was likely derived from the partial melting of subducted Paleo-Tethys oceanic slab.It is suggested that the Late Triassic granodiorite was emplaced during the northward subduction of Paleo-Tethys oceanic slab.Orogenic gold mineralization in the Wulonggou area formed after the emplacement of the Late Triassic intrusive rocks.     

塔里木河流域综合治理生态要素变化的遥感分析

采用多种类、多时相遥感数据对塔里木河流域综合治理后的耕地变化和干流绿色走廊带的植被、沙质荒漠化和盐碱质荒漠化等主要生态要素进行了动态监测,结果表明:(1)1999-2008年间,流域耕地面积逐步扩大,从167.17万hm2增长到207.51万hm2。其中,塔里木河干流区耕地面积增加最快,叶尔羌河、开都河-孔雀河与和田河三流域稳步增加,而阿克苏河流域耕地面积先增加,后减少。除阿克苏河流域外,塔里木河流域等其他三流域和塔里木河干流,在2004-2008年间的面积增长速度明显大于1999-2002年和2002-2004年两个时段。(2)2002-2004年间,塔里木河干流绿色走廊带生态环境明显改善,主要表现为植被覆盖度的提高、沙质荒漠化土地面积的减小和强度减弱、盐碱质荒漠化土地的强度减弱等。耕地面积的大幅度增加引起的灌溉用水量的增大,对长期采用输水实现塔里木河的生态功能恢复具有长期性制约作用。     

凡纳滨对虾不同生长阶段食物组成结构的研究

利用稳定同位素碳比率δ13C作为天然示踪物,对高位养殖池生态系统中人工饲料和天然饵料提供的能源物质对养殖凡纳滨对虾生长的贡献比率进行研究。结果表明:虾体的δ13C值受食物δ13C值的影响,由于其摄食饵料的δ13C值逐渐减小,虾体的δ13C值也逐渐降低,逐渐接近于最后人工饲料的δ13C值,试验虾体的δ13C值由养殖开始时的-19.52‰±0.09‰变为实验结束时的-21.74‰±0.17‰;对虾的食性在10d左右时发生转变,34d左右时人工饲料和浮游动物对虾体的能量贡献基本相同,养殖结束时对虾生长能量的97.29%±0.98%来源于人工饲料。     

Oil and Gas Distribution in Hailar Basin,Northeast China

Through petroleum exploration of 20 years, a new petroleum production area has been constructed in Hailar Basin. Their petroleum geological characteristics and hydrocarbon distribution has been known in detail. The Hailar Basin is a basin group consisted of many scattered sub-basins with similar structural developed history. Each sub-basin has unique hydrocarbon distributing rules, including (1) oil/gas reservoir distribution is controlled by the oil/gas sag, and the oil/gas bearing in big sag is rich; (2) underwater fan and turbidity fan are the most favorable reservoirs; structure zone controlled by main fault is favorable zone of forming composite oil/gas accumulation; (3) lower fault-block in higher rise and higher fault-block in lower rise are favorable to oil/gas accumulation; (4) deep fault and granite body are closely related to oil/gas reservoir, its distributing area is favorable area of oil and mantle source non-hydrocarbon gas formation;(5) higher geothermal area is favorable oil/gas bearing area.