双王角砾岩型金矿床地质地球化学及成矿机制

文章在对双王角砾岩型金矿床地质特征进行简要描述的基础上，探讨了含金角砾岩体的成因，系统地研究了流体包裹体的特征和矿石碳、氢、氧同位素的组成。结果表明双王金矿床成矿流体以富CO2、高温、中低盐度为特征，碳明显具有深源(幔源)特征，而成矿流体以典型岩浆水为主，混入有一定程度的变质水，在成矿作用晚期可能有大气降水加入到成矿系统中。结合区域地质构造背景和成岩成矿年代资料，探讨了双王金矿床的成矿作用和成矿机制。     

四川大渡河金矿田成矿流体来源的氦氩硫氢氧同位素示踪

四川大渡河金矿田位于扬子地台西缘金成矿带北段,受大渡河剪切带控制。本文以该矿田黄金坪、白金台子、黑金台子金矿为例,根据对黄铁矿流体包裹体氦氩同位素、黄铁矿硫同位素以及与黄铁矿共生的石英流体包裹体的氢氧同位素组成测定,讨论了大渡河金矿田成矿流体的来源。结果显示,该金矿田黄铁矿流体包裹体中的~3He/~4He变化较小,为0.16～0.86Ra,而~(40)Ar/~(36)Ar的变化较大,为298～3288;而黄铁矿δ~(34)S同位素变化范围较窄,一般为0.7‰～4.2‰,集中于2.5‰～3‰,显示硫地幔来源的特点;石英流体包裹体的氢、氧同位素分别为-2.6‰～ 3.64‰和-39.13‰～-108.23‰,说明成矿流体为岩浆水和大气降水的混合流体。本文认为大渡河金矿田成矿流体是地幔流体与地壳流体的混合作用的结果,而以地壳流体占主导地位。其中,地幔流体为与下伏隐伏岩体有关的岩浆水,而地壳流体端元则是含有一定放射成因Ar的大气降水,并且温度小于200℃。     

柴达木盆地西部地区古近纪与新近纪沉积相

利用数十口井的电性、岩性及分析化验资料，将柴达木盆地西部地区古近纪与新近纪沉积相划分为七种相和亚相：洪积锥、水下冲积扇、河道和泛滥平原、滨湖、浅湖、较深湖和三角洲。沉积相的空间展布概括起来分为三大带：（1）阿尔金山前西段陡坡带洪积锥-水下冲积扇-扇三角洲-河道和泛滥平原-湖相 (2)阿尔金山前中段陡坡带洪积锥-水下冲积扇-湖相；（3）昆仑山前洪积锥-河道和泛滥平原-三角洲相。沉积相不仅影响着碎屑岩的成分和结构，而且也影响其物性与含油性。由洪积锥到水下冲积扇，到河道和泛滥平原，到三角洲，到湖相，石英和胶结物含量逐渐升高，岩屑和杂基含量逐渐降低，分选及磨圆变好，颗粒的粒级变细。浅层以河道和泛滥平原及三角洲相的物性最好，深层以三角洲相的物性最好，次为冲积扇，湖相最差。碎屑岩的油气富集以河道、泛滥平原和三角洲相最好，滨浅湖相油气富集最差。     

正十八烷的裂解动力学研究（Ⅰ）：气态烃组分及其碳同位素演化特征

本文通过对纯烃类化合物——正十八烷的动力学模拟实验，阐述了正十八烷裂解过程中气态烃组分及其同位素的演化特征，获得了产自正十八烷的甲烷生成动力学参数。运用动力学参数将模拟实验结果外推到地质条件下，表明由烷烃裂解形成的甲烷主要生成于150～200C（Easy％Ro介于1．0％～2．0％）的范围，裂解产生的甲烷、乙烷、丙烷的碳同位素分馏效应与Easy％Ro的关系曲线受升温速率的影响，不能直接应用于地质条件。     

Hydrogen isotopic compositions, distributions and source signals of individual n-alkanes for some typical crude oils in Lunnan Oilfield, Tarim Basin, NW China

Petroleum mainly comprises carbon and hydrogen elements. The stable carbon isotopic analysis for whole oil was undertaken as early as the 1930s. After decades, the stable carbon isotopic analytical methods have been developed from analysis for whole oil and oil fractions (e.g., saturated, aromatic and polar frac-tions) into compound-specific isotopic analysis with the emergence of the newly developed GC-C-IRMS analytical technique. Especially, by using com-pound-specific isotopic analytical…     

Origin of Mesozoic gold mineralization in South Korea

Abstract   The Mesozoic gold–silver deposits in South Korea are closely associated with the Mesozoic granitoids. The Jurassic gold–silver deposits can be distinguished from the Cretaceous ones in terms of occurrence, alteration style, gold fineness, associated mineral assemblage, fluid inclusion and stable isotopic compositions. The Jurassic deposits were formed in mesozonal environments related to deep-seated granitoids, whereas the Cretaceous ones were formed in epizonal environments related to shallow-level granitoids. The Jurassic auriferous deposits (about 165–145 Ma) show fluid characteristics typical of an orogenic-type gold deposit, and were probably generated in a compressional regime caused by an orthogonal convergence of the Izanagi oceanic plate into the Asiatic margin. However, strike-slip faults and caldera-related fractures, together with subvolcanic to volcanic activity, may have played an important role in the formation of Cretaceous gold–silver lode deposits (about 110–45 Ma) under a continental arc setting.     

层序地层地球化学及其在油气勘探中的作用

层序地层地球化学主要研究基于层序地层格架下的烃源层空间分布特征和源岩有机质的地球化学性质随层序、体系域的变化规律。以大民屯凹陷为实例的研究结果表明,层序地层地球化学研究在油气勘探中具有4个方面的主要作用:(1)预测未钻井或未取心地区烃源层空间分布特征和源岩有机质地球化学性质;(2)通过细化烃源岩评价单元,提高资源量计算中烃源岩体积估算和有机质性质评价的精度;(3)为基于层序地层格架的油气成藏系统研究提供“油气源”和“资源量”的要素;(4)可以作为盆地沉积充填分析的线索,并对已建立的层序地层格架进行检验和校正。层序地层地球化学研究不仅对中国东部老油田隐蔽油气藏的勘探工作具有重要的意义,对勘探程度低、钻井少、源岩取心少的西部含油气盆地中的烃源岩评价工作更为有效。     

渤中25-1地区油气运移的输导通道及其示踪分析

渤中25-1地区是渤中坳陷重要的含油气区,具有复杂的构造演化与沉积充填史,输导通道一直是该地区成藏动力学研究的关键.采取宏观与微观相结合的研究思路,在理清研究区构造演化、沉积充填及其油气地质特征的基础上,讨论了油气运移的输导通道并对其进行了示踪分析,进而总结了该区的油气成藏模式.研究表明,长期继承性活动的基底断层是油气垂向运移的主输导通道,原油性质及地层水化学特征证实了断层的输导作用.上新统明化镇组和渐新统沙河街组渗透性储层是油气侧向运移的主要通道.沙河街组油藏具有自源压控侧向运移成藏的特点,明化镇组油藏具有它源断控垂向运移成藏的特点.     

江西金山金矿床成矿流体地球化学及矿床成因讨论

对金山韧性剪切带型金矿床石英及方解石中流体包裹体的研究表明:成矿流体具有中低温、低盐度和低密度的特征;富含Ca2 ,Mg2 ,SO42-,CO2等;主要来源有变质热流体、富含有机质的大气降水形成的热流体和深源流体;流体的性质在时间和空间上都有一定的变化,矿床的形成主要是两期流体成矿作用的结果,是热液与构造的耦合;不同种类流体的混合、单一流体不混溶分离作用和盐水体系中有机质的参与是矿床形成的关键因素.     

Distribution of major hydrocarbon source rocks in the major oil-gas-bearing basins in China

The distribution characteristics of major hydrocarbon source rocks in the major oil-gas-bearing basins in China were discussed in this paper, and differences between the East and the West basins in tectonic setting, age, lithology, sedimentary environment, and hydrocarbon generation feature and potential were also studied. Considering the Lieiliang Mountains-Dalou Mountains as the boundary, source rocks in the East basins are distributed mainly in three NNE-trend subsiding belts, and those in the West basins are distributed in the north and south of the Tianshan Mountains and Qilian Mountains. They are mainly NWW trending and can be divided into four basin groups.