内蒙古二连盆地上古生界油气勘探前景

二连盆地晚古生代海相—海陆交互相碎屑岩和碳酸盐岩沉积建造广泛发育,主体未遭受区域变质,暗色泥岩和碳酸盐岩类烃源岩发育良好。地质调查和烃源岩初步分析评价结果表明,该区发育泥鳅河组、本巴图组、阿木山组、寿山沟组、哲斯组、林西组6套烃源岩系和多套有利的生储盖组合,其中的暗色泥岩/灰岩可达到中等—好烃源岩标准,有机质类型属于Ⅱ2~Ⅲ型,热演化程度总体处于成熟—凝析油湿气阶段,具有较大的油气资源潜力,可作为二连盆地油气勘探的重要新层系。     

柴达木盆地东部石炭系烃源岩评价

柴达木盆地东部地区石炭系暗色泥岩、碳酸盐岩、煤及炭质泥岩均发育.大量区域地质调查及有机地球化学分析表明,石炭系烃源岩主要以暗色泥岩和碳酸盐岩为主,炭质泥岩和煤可能具有生烃能力.暗色泥岩有机碳含量平均为1.13%,有机质类型以Ⅲ型和Ⅱ2型为主,为中等-好的烃源岩;碳酸盐岩有机碳含量低,平均为0.26%,有机质类型为Ⅱ1与Ⅱ2型,属中等-差的烃源岩.除都兰地区有机质成熟度过高、处于过成熟的生干气阶段外,其他地区有机质成熟度中等,正处于生、排烃高峰期,具有良好的油气勘探前景.石灰沟地区烃源岩厚度大、丰度高,暗色泥岩和碳酸盐岩分别达到了好烃源岩和中等烃源岩的标准,有机质成熟度中等,生烃潜力较大.     

柴达木盆地东部石炭系烃源岩评价

柴达木盆地东部地区石炭系暗色泥岩、碳酸盐岩、煤及炭质泥岩均发育.大量区域地质调查及有机地球化学分析表明,石炭系烃源岩主要以暗色泥岩和碳酸盐岩为主,炭质泥岩和煤可能具有生烃能力.暗色泥岩有机碳含量平均为1.13%,有机质类型以Ⅲ型和Ⅱ2型为主,为中等-好的烃源岩;碳酸盐岩有机碳含量低,平均为0.26%,有机质类型为Ⅱ1与Ⅱ2型,属中等-差的烃源岩.除都兰地区有机质成熟度过高、处于过成熟的生干气阶段外,其他地区有机质成熟度中等,正处于生、排烃高峰期,具有良好的油气勘探前景.石灰沟地区烃源岩厚度大、丰度高,暗色泥岩和碳酸盐岩分别达到了好烃源岩和中等烃源岩的标准,有机质成熟度中等,生烃潜力较大.     

塔里木西南地区含油气系统特征

根据对塔里木西南坳陷可能的烃源岩有机地球化学的分析、评价及已知油气藏和重要油气显示点的油(气)岩的对比结果,该区存在着6套现实的烃源岩(1)下寒武统暗色泥岩及碳酸盐岩;(2)奥陶系的碳酸盐岩和暗色泥岩;(3)石炭系碳酸盐岩和暗色泥页岩;(4)下二叠统暗色泥页岩(5)中下侏罗统的暗色泥岩;(6)上白垩-古近系的碳酸盐岩及暗色泥岩.这几套烃源岩除白垩-古近系有待落实外,其它各套烃源岩均已形成油气显示或工业油气流.综合评价结果最为有利的含油气系统是寒武系,其次为石炭系,根据2个含油气系统的地理分布看,前者主要分布于巴楚隆起及麦盖提斜坡上倾部,后者主要分布于山前坳陷.     

柴达木盆地东部石炭系烃源岩评价

柴达木盆地东部地区石炭系暗色泥岩、碳酸盐岩、煤及炭质泥岩均发育。大量区域地质调查及有机地球化学分析表明,石炭系烃源岩主要以暗色泥岩和碳酸盐岩为主,炭质泥岩和煤可能具有生烃能力。暗色泥岩有机碳含量平均为1.13%,有机质类型以Ⅲ型和Ⅱ2型为主,为中等—好的烃源岩;碳酸盐岩有机碳含量低,平均为0.26%,有机质类型为Ⅱ1与Ⅱ2型,属中等—差的烃源岩。除都兰地区有机质成熟度过高、处于过成熟的生干气阶段外,其他地区有机质成熟度中等,正处于生、排烃高峰期,具有良好的油气勘探前景。石灰沟地区烃源岩厚度大、丰度高,暗色泥岩和碳酸盐岩分别达到了好烃源岩和中等烃源岩的标准,有机质成熟度中等,生烃潜力较大。     

断陷盆地海陆过渡相烃源岩发育模式:以西湖凹陷平湖组为例

始新统平湖组是东海盆地西湖富生烃凹陷的主力烃源岩系,也是中国东部断陷盆地海陆过渡相烃源岩的典型代表.利用钻井、地震及烃源岩有机地球化学、古生物等资料,在烃源岩特征及其发育的构造-沉积与古气候背景分析的基础上,探讨了平湖组烃源岩发育的主控因素,并建立了相应的形成模式.平湖组暗色泥岩分布广、厚度大,夹多套薄煤层及碳质泥岩,总体烃源岩质量较高.平湖组烃源岩发育于半封闭的海湾环境和温暖-潮湿南亚热带型气候条件,以陆生有机质输入为主.平湖组烃源岩的发育主要受沉积-沉降速率、母质来源及有机质保存条件等因素控制,其形成模式可概括为"快速沉降;气候温暖-潮湿;陆生有机质输入为主;淡水-半咸水;氧化性较强的环境".      

羌塘盆地石炭—二叠系烃源岩地球化学特征讨论

长期以来,羌塘盆地烃源岩的研究一直限于中生代地层,而对其古生代地层生烃能力一直缺乏系统研究。针对这一问题,本文选择羌塘盆地石炭—二叠系8条剖面的暗色泥岩及碳酸盐岩样品,对其从有机质丰度、有机质类型和热演化程度等方面进行了有机地球化学特征的分析。研究发现,石炭—二叠系可能烃源岩类型包括泥岩和碳酸盐岩两种,其分布总体上受沉积相的控制,碳酸盐岩烃源岩可能为局限台地相发育的泥晶灰岩,而泥质烃源岩主要为三角洲及斜坡相发育的暗色泥岩及凝灰质泥岩。石炭—二叠纪泥岩有机碳含量较高,具有较好生烃能力,大多达到烃源岩标准,尤其是刻莫石炭系剖面及贡日二叠系剖面,大多为中等—好烃源岩。碳酸盐岩有机碳含量总体比较低,为非烃源岩。石炭—二叠系碳酸盐岩烃源岩有机质类型为Ⅱ1型,泥质烃源岩有机质类型主要为Ⅱ2-Ⅲ型。石炭—二叠系烃源岩热演化程度总体较高,除盆地东部刻莫石炭系剖面处在成熟阶段外,大都处在高成熟—过成熟阶段,非常有利于天然气的生成,具备良好的天然气勘探前景。     

南祁连盆地木里坳陷烃源岩评价与资源潜力

为评价南祁连盆地木里坳陷油气勘探潜力,利用木参1井分析化验资料,对木里坳陷烃源条件与勘探潜力进行了系统分析。结果表明,上三叠统尕勒得寺组(T_3g)和侏罗系暗色泥岩发育,侏罗系也发育碳质泥岩和煤。T_3g和侏罗系的暗色泥岩有机质丰度高,综合评价为中等-好烃源岩;T_3g烃源岩的有机质类型为Ⅲ型和Ⅱ2型,侏罗系烃源岩有机质类型多样,主要为Ⅲ型和Ⅱ型,部分暗色泥岩有机质类型为Ⅰ型。T_3g和侏罗系烃源岩有机质分别处于高-过成熟的生气阶段和成熟阶段;2套烃源岩均经历了二次生烃,烃源岩的热演化过程在流体包裹体数据中得到了较好地反映;初步计算结果显示木里坳陷油资源量为1140×10~4 t,天然气资源量为(545~2180)×10~8 m~3,具备较大的勘探潜力。     

松辽盆地滨北地区晚古生代林西组油气条件分析

以松辽盆地滨北地区为研究区,结合野外露头资料,钻井及地震资料,围绕晚古生代林西组开展油气地质特征研究。结果表明,滨北地区晚古生代林西组发育厚层暗色泥岩,向盆地内部方向暗色泥岩增厚;林西组暗色泥岩有机质丰度为0.96%～2.79%,Ro为2.28%～5.53%,处于高-过成熟阶段。有机质类型以Ⅱ、Ⅲ型干酪根为主,为有效烃源岩;烃源岩发育区范围依据暗色泥岩厚度而圈定,主要分布在林甸断陷和任民镇地区。     

鄂尔多斯盆地延长组长1段烃源岩有机地球化学特征

鄂尔多斯盆地三叠系延长组长1段发育一套深湖相浊积岩及数层暗色泥岩。根据实测的有机碳含量、可溶有机质及族组分含量、有机元素和同位素等数据可知,该泥岩为一套较好—好的烃源岩。镜质体反射率及生物标志化合物成熟度指标显示,该段烃源岩有机质处于低成熟到成熟阶段。该套烃源岩的发现为陕北地区寻找新的油气勘探目标提供了依据。      

Isotopic systematics of He,Ar, S,Cu, Ni,Re, Os,Pb, U,Sm, Nd,Rb, Sr,Lu, and Hf in the rocks and ores of the Norilsk deposits

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.     

高压微波消解法测定醋酸纤维过滤器采集的微尘粒子中的砷镉钴铬铜铁锰镍铅钒锌

最新的流行病学研究表明,空气中较高浓度的悬浮细颗粒可能对人类的健康有不利的影响。根据该项研究显示,由于心脏病、慢性呼吸问题和肺功能指标恶化而导致死亡率的升高与细尘粒子有关。这些研究结果已经促使欧盟于1999年4月出台了限制空气中二氧化硫、二氧化氮、氧化氮、铅和颗粒物含量的法案(1999/30/EC),对各项指标包括对可吸入PM10颗粒的浓度提出了新的限制性指标。PM10颗粒是指可以通过预分级器分离采集的气体动力学直径小于10μm的细颗粒。目前研究的兴趣重点逐步偏向PM2.5这些更细微颗粒物,PM2.5这种颗粒物对健康有明显的不利影响。在欧盟指令2008/50/EC中,对PM10和PM2.5都提     

Wavelength-dispersive X-ray fluorescence spectrometric determination of Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in komatiites

Komatiites are mantle-derived ultramafic volcanic rocks. Komatiites have been discovered in several States of India, notably in Karnataka. Studies on the distribution of trace-elements in the komatiites of India are very few. This paper proposes a simple, accurate, precise, rapid, and non-destructive wavelength-dispersive x-ray fluorescence (WDXRF) spectrometric technique for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in komatiites, and discusses the accuracy, precision, limits of detection, x-ray spectral-line interferences, inter-element effects, speed, advantages, and limitations of the technique. The accuracy of the technique is excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Zr, Nb, Ba, Pb, and Th and very good (within 4%) for Y. The precision is also excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th. The limits of detection are: 1 ppm for Sc and V; 2 ppm for Cr, Co, and Ni; 3 ppm for Cu, Zn, Rb, and Sr; 4 ppm for Y and Zr; 6 ppm for Nb; 10 ppm for Ba; 13 ppm for Pb; and 14 ppm for Th. The time taken for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in a batch of 24 samples of komatiites, for a replication of four analyses per sample, by one operator, using a manual WDXRF spectrometer, is only 60 hours.     

Regional distribution of Al,B, Ba,Ca, K,La, Mg,Mn, Na,P, Rb,Si, Sr,Th, U and Y in terrestrial moss within a 188,000 km2 area of the central Barents region: influence of geology,seaspray and human activity

Five hundred and ninety-eight samples of terrestrial moss (Hylocomium splendens and Pleurozium schreberi) collected from a 188,000 km² area of the central Barents region (NE Norway, N Finland, NW Russia) were analysed by ICP-AES and ICP-MS. Analytical results for Al, B, Ba, Ca, K, La, Mg, Mn, Na, P, Rb, Si, Sr, Th, U and Y concentrations are reported here. Graphical methods of data analysis, such as geochemical maps, cumulative frequency diagrams, boxplots and scatterplots, are used to interpret the origin of the patterns for these elements. None of the elements reported here are emitted in significant amounts from the smelting industry on the Kola Peninsula. Despite the conventional view that moss chemistry reflects atmospheric element input, the nature of the underlying mineral substrate (regolith or bedrock) is found to have a considerable influence on moss composition for several elements. This influence of the chemistry of the mineral substrate can take place in a variety of ways. (1) It can be completely natural, reflecting the ability of higher plants to take up elements from deep soil horizons and shed them with litterfall onto the surface. (2) It can result from naturally increased soil dust input where vegetation is scarce due to harsh climatic conditions for instance. Alternatively, substrate influence can be enhanced by human activity, such as open-cast mining, creation of ‘technogenic deserts’, or handling, transport and storage of ore and ore products, all of which magnify the natural elemental flux from bedrock to ground vegetation. Seaspray is another natural process affecting moss composition in the area (Mg, Na), and this is most visible in the Norwegian part of the study area. Presence or absence of some plant species, e.g., lichens, seems to influence moss chemistry. This is shown by the low concentrations of B or K in moss on the Finnish and Norwegian side of the (fenced) border with Russia, contrasting with high concentrations on the other side (intensive reindeer husbandry west of the border has selectively depleted the lichen population).     

Petrographic, mineralogy, and geochemistry of coals of Pabedana, Kerman Province, Central Iran

This paper discusses the result of the detailed investigations carried out on the coal characteristics, including coal petrography and its geochemistry of the Pabedana region. A total of 16 samples were collected from four coal seams d2, d4, d5, and d6 of the Pabedana underground mine which is located in the central part of the Central-East Iranian Microcontinent. These samples were reduced to four samples through composite sampling of each seam and were analyzed for their petrographic, mineralogical, and geochemical compositions. Proximate analysis data of the Pabedana coals indicate no major variations in the moisture, ash, volatile matter, and fixed carbon contents in the coals of different seams. Based on sulfur content, the Pabedana coals may be classified as low-sulfur coals. The low-sulfur contents in the Pabedana coal and relatively low proportion of pyritic sulfur suggest a possible fresh water environment during the deposition of the peat of the Pabedana coal. X-ray diffraction and petrographic analyses indicate the presence of pyrite in coal samples. The Pabedana coals have been classified as a high volatile, bituminous coal in accordance with the vitrinite reflectance values (58.75–74.32 %) and other rank parameters (carbon, calorific value, and volatile matter content). The maceral analysis and reflectance study suggest that the coals in all the four seams are of good quality with low maceral matter association. Mineralogical investigations indicate that the inorganic fraction in the Pabedana coal samples is dominated by carbonates; thus, constituting the major inorganic fraction of the coal samples. Illite, kaolinite, muscovite, quartz, feldspar, apatite, and hematite occur as minor or trace phases. The variation in major elements content is relatively narrow between different coal seams. Elements Sc,, Zr, Ga, Ge, La, As, W, Ce, Sb, Nb, Th, Pb, Se, Tl, Bi, Hg, Re, Li, Zn, Mo, and Ba show varying negative correlation with ash yield. These elements possibly have an organic affinity and may be present as primary biological concentrations either with tissues in living condition and/or through sorption and formation of organometallic compounds.     

Coprecipitation of Ti,Mo, Sn and Sb with fluorides and application to determination of B,Ti, Zr,Nb, Mo,Sn, Sb,Hf and Ta by ICP-MS

We examined the coprecipitation behavior of Ti, Mo, Sn and Sb in Ca–Al–Mg fluorides under two different fluoride forming conditions: at < 70 °C in an ultrasonic bath (denoted as the ultrasonic method) and at 245 °C using a Teflon bomb (denoted as the bomb method). In the ultrasonic method, small amounts of Ti, Mo and Sn coprecipitation were observed with 100% Ca and 100% Mg fluorides. No coprecipitation of Ti, Mo, Sn and Sb in Ca–Al–Mg fluorides occurred when the sample was decomposed by the bomb method except for 100% Ca fluoride. Based on our coprecipitation observations, we have developed a simultaneous determination method for B, Ti, Zr, Nb, Mo, Sn, Sb, Hf and Ta by Q-pole type ICP-MS (ICP-QMS) and sector field type ICP-MS (ICP-SFMS). 9–50 mg of samples with Zr–Mo–Sn–Sb–Hf spikes were decomposed by HF using the bomb method and the ultrasonic method with B spike. The sample was then evaporated and re-dissolved into 0.5 mol l^− 1 HF, followed by the removal of fluorides by centrifuging. B, Zr, Mo, Sn, Sb and Hf were measured by ID method. Nb and Ta were measured by the ID-internal standardization method, based on Nb/Mo and Ta/Mo ratios using ICP-QMS, for which pseudo-FI was developed and applied. When 100% recovery yields of Zr and Hf are expected, Nb/Zr and Ta/Hf ratios may also be used. Ti was determined by the ID-internal standardization method, based on the Ti/Nb ratio from ICP-SFMS. Only 0.053 ml sample solution was required for measurement of all 9 elements. Dilution factors of ≤ 340 were aspirated without matrix effects. To demonstrate the applicability of our method, 4 carbonaceous chondrites (Ivuna, Orgueil, Cold Bokkeveld and Allende) as well as GSJ and USGS silicate reference materials of basalts, andesites and peridotites were analyzed. Our analytical results are consistent with previous studies, and the mean reproducibility of each element is 1.0–4.6% for basalts and andesites, and 6.7–11% for peridotites except for TiO₂.     

Mercury,arsenic, antimony,and selenium contents of sediment from the Kuskokwim River,Bethel, Alaska,USA

The Kuskokwim River at Bethel, Alaska, drains a major mercury-antimony metallogenic province in its upper reaches and tributaries. Bethel (population 4000) is situated on the Kuskokwim floodplain and also draws its water supply from wells located in river-deposited sediment. A boring through overbank and floodplain sediment has provided material to establish a baseline datum for sediment-hosted heavy metals. Mercury (total), arsenic, antimony, and selenium contents were determined; aluminum was also determined and used as normalizing factor. The contents of the heavy metals were relatively constant with depth and do not reflect any potential enrichment from upstream contaminant sources.     

Roles of xenomelts,xenoliths, xenocrysts,xenovolatiles, residues,and skarns in the genesis,transport, and localization of magmatic Fe-Ni-Cu-PGE sulfides and chromite

Most sulfide-rich magmatic Ni-Cu-(PGE) deposits form in dynamic magmatic systems by partial melting S-bearing wall rocks with variable degrees of assimilation of miscible silicate and volatile components, and generation of barren to weakly-mineralized immiscible Fe sulfide xenomelts into which Ni-Cu-Co-PGE partition from the magma. Some exceptionally-thick magmatic Cr deposits may form by partial melting oxide-bearing wall rocks with variable degrees of assimilation of the miscible silicate and volatile components, and generation of barren Fe ± Ti oxide xenocrysts into which Cr-Mg-V ± Ti partition from the magma. The products of these processes are variably preserved as skarns, residues, xenoliths, xenocrysts, xenomelts, and xenovolatiles, which play important to critical roles in ore genesis, transport, localization, and/or modification. Incorporation of barren xenoliths/autoliths may induce small amounts of sulfide/chromite to segregate, but incorporation of sulfide xenomelts or oxide xenocrysts with dynamic upgrading of metal tenors (PGE > Cu > Ni > Co and Cr > V > Ti, respectively) is required to make significant ore deposits. Silicate xenomelts are only rarely preserved, but will be variably depleted in chalcophile and ferrous metals. Less dense felsic xenoliths may aid upward sulfide transport by increasing the effective viscosity and decreasing the bulk density of the magma. Denser mafic or metamorphosed xenoliths may also increase the effective viscosity of the magma, but may aid downward sulfide transport by increasing the bulk density of the magma. Sulfide wets olivine, so olivine xenocrysts may act as filter beds to collect advected finely dispersed sulfide droplets, but other silicates and xenoliths may not be wetted by sulfides. Xenovolatiles may retard settling of – or in some cases float – dense sulfide droplets. Reactions of sulfide melts with felsic country rocks may generate Fe-rich skarns that may allow sulfide melts to fractionate to more extreme Cu-Ni-rich compositions. Xenoliths, xenocrysts, xenomelts, and xenovolatiles are more likely to be preserved in cooler basaltic magmas than in hotter komatiitic magmas, and are more likely to be preserved in less dynamic (less turbulent) systems/domain/phases than in more dynamic (more turbulent) systems/domains/phases. Massive to semi-massive Ni-Cu-PGE and Cr mineralization and xenoliths are often localized within footwall embayments, dilations/jogs in dikes, throats of magma conduits, and the horizontal segments of dike-chonolith and dike-sill complexes, which represent fluid dynamic traps for both ascending and descending sulfides/oxides. If skarns, residues, xenoliths, xenocrysts, xenomelts, and/or xenovolatiles are present, they provide important constraints on ore genesis and they are valuable exploration indicators, but they must be included in elemental and isotopic mass balance calculations.