大分子烃类拉曼光谱特征及在烃包裹体研究中的意义

拉曼光谱分析发现,无论大分子烃类含碳数如何不同,分子结构如何复杂,大分子烃类的拉曼谱图有很多相同性,即烃类的拉曼谱图只受烷烃骨架、环烷基和苯环等的影响,并由此形成了四类大分子烃类的拉曼谱图：烷烃类、复杂烷烃类（以环烷基为主）、结构平坦相连的芳香烃类和结构复杂的芳香烃类。烃是石油的主要组分,因此,被包裹在矿物中的石油——烃包裹体的拉曼谱图也只有四种：发强荧光烃包裹体、含沥青烃包裹体、含低碳数芳烃包裹体和烷烃包裹体。激光拉曼对烃包裹体组分有个总体特征的体现,用激光拉曼分析烃包裹体组分中具体烃的种类是不科学的。但通过烃包裹体的拉曼谱图特征,可以研究烃包裹体组分特征、古油藏成熟度及油气演化程度等信息。     

页岩油在纳米级狭缝中吸附特征的分子动力学模拟

利用分子动力学模拟方法研究了页岩油在纳米级有机质狭缝内和二氧化硅矿物狭缝内的吸附特征。在COMPASS(condensed-phase optimized molecular potential for atomistic simulation study)力场下模拟了355K、18 MPa(松辽盆地青山口组Ro=0.9%时的地质条件)条件下,混合烃类分子在纳米级狭缝内的吸附行为,对比了有机质和矿物的吸附能力以论证前人的研究,证明了模拟的正确性;分析了混合烃、各烃组分在二氧化硅狭缝和有机质狭缝中的密度分布特征及温度对有机质狭缝内烃分子吸附的影响。结果表明:(1)混合烃类分子在纳米级狭缝壁面处出现了3个较明显的吸附层,每个吸附层的厚度在0.4~0.5nm之间,且石墨烯单位面积的吸附能力约为石英的1.31倍;(2)由于竞争吸附作用,并非所有的烃类都在靠近固体壁面处吸附最多,那些容易扩散的气态烃和拥有特殊化学键的芳香烃更容易吸附在狭缝壁面处;(3)温度升高,使狭缝内混合烃类分子吸附相密度降低,但由于多组分竞争吸附作用的存在,并不是所有烷烃的密度峰值随着温度的升高而降低,5种混合烃类分子中的正构烷烃和支链烷烃的第1吸附层的密度峰值有所升高。     

天津地区主要河流表层沉积物中饱和烃的组成与分布特征

根据不同环境功能区 9条河流表层沉积物样品中饱和烃污染物的分析结果,讨论了天津地区河流沉积物中饱和烃化合物的组成与分布特征,初步分析了饱和烃污染物的污染源.结果表明,不同河流表层沉积物中均分布有多种类型的饱和烃化合物,主要包括正构烷烃、无环类异戊二烯烷烃、异构与反异构烷烃、烷基环己烷和甾、萜类等.不同河流及同一河流不同河段的表层沉积物中可抽提有机物(EOM)、烃类化合物含量和饱和烃化合物的组成特征均存在明显的差别,其中北塘排污河(北排污河)和大沽排污河(南排污河)沉积物中 EOM的含量相对较高,海河及津北地区的潮白新河、蓟运河、永定新河、北京排污河的沉积物中 EOM的含量相对较低;北运河、南运河及大沽排污河巨各庄河段的沉积物中烃类化合物含量相对较高,海河、大沽排污河和北塘排污河表层沉积物中烃类污染物的含量相对较低.位于市区北部的河流,靠近市区的河段沉积物中 EOM含量有增加的趋势,而位于市区下游的河流,靠近市区的上游河段的沉积物中 EOM含量相对较高,下游河段的有所降低.河流中烃类污染物主要来源于矿物油及其衍生物、高等植物蜡和藻类的降解产物,不同河流及相同河流不同河段污染源的相对贡献存在明显的差别.     

辽河原油好氧生物降解模拟过程中化学组成及其碳同位素值的变化

对辽河盆地中央凸起南部潜山原油进行了好氧生物降解模拟实验,分析了辽河原油在轻度至中度(PM 1~4级)的好氧生物降解过程中化学组分的变化,以及在此过程中原油族组分和正构烷烃单体的稳定碳同位素值的变化。结果显示,饱和烃组分的消耗速率最快,正构烷烃的消耗速率高于异构烷烃,低碳数正构烷烃的消耗速率高于高碳数正构烷烃。正构烷烃的疏水性及其在原油中的相对浓度可能是影响微生物选择性地消耗正构烷烃的主导因素,即低碳数的正构烷烃由于在油水界面上的表面张力较小而更容易被微生物降解。正构烷烃单体(C_(14)~C_(30))稳定碳同位素值在生物降解过程中较稳定,未产生明显的碳同位素分馏效应。正构烷烃的好氧降解产物主要是脂肪酸、醇和CO_2。辽河原油中正构烷烃组分的δ~(13)C值较饱和烃、芳烃、胶质和沥青质组分都要偏重,降解产物中水溶性较低的高碳数脂肪酸和醇大部分进入胶质中,少部分通过氢键缔合和形成酯键等方式进入到沥青质组分中,造成沥青质组分的δ~(13)C值发生相应的变化,即对沥青质的δ~(13)C值产生"拉动效应";而降解产物中高水溶性的低碳数烷基酸和醇会进入水相而脱离原油,导致残余油的整体δ~(13)C值相应变轻。因此,假如易受生物降解的烃类如正构烷烃等的δ~(13)C值与原油的δ~(13)C值差别比较大,那么生物降解过程中随着原油化学组成的改变,原油本身及其族组分的δ~(13)C值均可能发生明显的变化。     

烟草叶中异构和反异构烷烃的成因及其光合作用C同位素分馏效应

烟草叶是目前惟一可以通过生物合成得到大量异构和反异构烷烃的植物,然而许多文献对化合物中甲基碳位和奇偶碳数的变化成因未提及.对其成因进行了文献追踪,并对温室不同生长条件(温度、CO2和光照)下培育的烟草叶中的长链正构烷烃、异构和反异构烷烃的单体稳定C同位素组成进行了分析,以期对烟草叶中特殊脂类化合物的生物化学合成同位素分馏效应进行探索研究.与正构烷烃和异构烷烃相比,反异构烷烃的δ13C值平均相对偏重2‰,证明反异构烷烃确实具有不同的合成前身物(2-甲基丁酰辅酶A).比起甲基基团,脱羧反应很可能使得乙酰辅酶A的羧基基团δ13C值偏轻.本研究中异构烷烃和正构烷烃δ13C值的相似性,说明乙酰辅酶A和前身物2-甲基丙酰辅酶A(C4-CoA)之间的C同位素组成很可能是相似的.用水量越多,烟草叶中异构、反异构烷烃和正构烷烃稳定C同位素组成越偏轻.与强光条件比,弱光条件下培育的烟草叶中正构烷烃的稳定C同位素组成偏轻约2.2‰,异构和反异构烷烃稳定C同位素组成也分别偏轻1.8‰和1.9‰.温度对烟草叶正构烷烃、异构烷烃和反异构烷烃的稳定C同位素组成影响甚小,与Farquhar(1980)有关植物体C同位素组成的报道相吻合.     

南海东北部东沙海域沉积物烃类有机地球化学研究及其意义

采用GC—MS技术测定了南海东北部东沙海域沉积物柱样HD196A中的有机物，共检测出90多种烃类化合物：正构烷烃、类异戊二烯、支链烷烃、多环芳烃等化合物。正构烷烃分布曲线的形状、碳数范围、主峰位置以及CPI值和0EP值说明，沉积物中的有机质主要来源是大陆高等植物和海洋浮游生物藻类和细菌源，并以陆源高等植物来源占优势。研究还表明，随着深度增加，柱样中重烃减少，而轻烃增加，奇偶优势指数趋近于1，长链烷烃和支链烷烃减少，芳烃的甲基化和甲基重排作用等，均显示出该区沉积物成熟度较高。同时结合该区已有的研究资料（烃类气体——甲烷、重烃组分分布，以及热释光、有机碳等），其高值异常区与本次研究站位相吻合，显示该海区具有烃渗漏来源，是海底油气和天然气水合物找矿的有利地区。     

川西北侏罗系沙溪庙组固体沥青包裹烃的释放及其地球化学意义

固体沥青分子结构中可能存在类似于沥青质的吸附包裹现象,其包裹烃组分属于成熟度较低条件下的产物,包含有早期的地球化学信息.选用 H2O2/CH3COOH 作为氧化体系对其进行轻度化学氧化降解释放其中的包裹烃,并结合有机地球化学研究手段对川西北下寺侏罗系沙溪庙组固体沥青进行研究.结果显示,该固体沥青可溶组分中烷烃类包括生物标志物基本未检测到,仅残留一些简单的芳烃化合物,很难提供有用的地球化学信息.而其包裹组分中检测到一系列偶碳数正构-1-链烯、正构烷烃和部分异构烷烃以及生物标志物等.包裹组分中 Ts/(Ts+Tm)比值为0.26, C29甾烷20S/(20S+20R)比值为0.43,均反映了固体沥青低成熟度的特征;规则甾烷相对含量 C29>C27>C28,显示弱的 C29优势,其中(C27+C28)占52.1%, C29占47.9%;正构烷烃的分布呈微弱偶碳数优势;固体沥青总碳同位素值为–21.5‰,显示强烈富集13C 的特征.分析表明,藻类等低等水生生物对源岩母质有重要贡献,但不能确定是否有陆生高等植物的输入,母源可能沉积于弱的还原环境.沙溪庙组固体沥青与该地区其他层位固体沥青、油砂和油苗可能有不同的来源.     

贵州瓮安陡山沱组磷块岩生物标志物特征及对沉积环境的指示

贵州瓮安新元古界陡山沱组磷块岩中发现的瓮安生物群主要包括多细胞藻类、蓝菌、疑源类、后生动物休眠卵及胚胎、管状后生动物和两侧对称的后生动物等化石类型。对瓮安陡山沱组磷块岩的有机地球化学分析表明,烃类有机组分包括正构烷烃、萜类、甾类和类异戊二烯烃。正构烷烃主峰为C21,碳数分布范围宽;OEP值为1．03,接近1。Pr／Ph比值为0．95,植烷略显优势。规则甾烷呈不对称的“V”字形分布,表现为C27〉C29〉C28的分布特征。C27占优势可能是由大量的带刺疑源类昕致。生物标志物特征指示瓮安陡山沱组磷块岩中的有机物来源于藻类和细菌,显示还原性、较高盐度的成磷沉积环境。     

湖南沃溪金矿区及其外围烃汞叠加晕找矿方法的应用效果

为解决沃溪矿区鱼儿山矿段及其外围的红岩溪—马儿桥矿段深部找矿问题,在区内开展了构造叠加晕和烃汞综合气体测量试验工作。通过对已知矿区鱼儿山矿段的不同地质体、不同标高烃汞组分演化规律和矿体上部土壤形成的地球化学烃汞异常的特征研究,总结土壤地球化学异常场结构、叠加特点及其空间对应关系来开展深部找矿预测,并对外围的红岩溪—马儿桥预测区开展烃汞叠加晕找矿方法的综合研究。经研究发现:红岩溪—马儿桥矿段土壤地球化学场存在两种不同类型叠加场,一类是深源叠加场,Au与烃类组分相关性较好,烃类异常组分齐全,同时Au、Hg异常较好,具有深源成矿热液叠加,深部找矿潜力较大;二类是同生叠加场,Au与烃类组分相关性较差,元素组合相对简单,缺少烃类组分异常,找矿意义不大。烃类异常模式以对偶双峰异常模式为主,在烃类异常双峰之间的低值区发育有较好的烃汞类综合叠加异常,说明深部具有平行盲脉存在。经钻探验证,深源叠加场深部见真厚度8.58 m、平均品位3.55×10^-6的金矿体,而同生叠加场只见有金矿化,故本次研究取得了良好的预测效果。     

四川盆地东部天然气地球化学特征与TSR强度对异常碳、氢同位素影响

对四川盆地东部50个天然气样品组分和碳、氢同位素组成分析结果显示,天然气以烃类气体为主,干燥系数高(C1/C1+=0.975~1.0),H2S含量变化较大(H2S=0.00%~16.89%)。利用烷烃气碳、氢同位素组成和判识油型气热演化程度图版,确定四川盆地东部天然气主要为原油裂解气,且热演化程度已处于油气裂解阶段。在四川盆地东部,烷烃气碳、氢同位素组成普遍存在局部倒转现象,即δ13C1δ13C2δ13C3和δD1δD2,这主要与研究区域不同硫酸盐热化学还原作用(TSR)强度有关,因为在该反应过程中不仅会产生大量的CH4,其碳同位素较重,同时,水参与了硫酸盐与烃类的化学还原反应使得水中的H+与烃类中H+发生同位素交换,从而引起TSR生成CH4的氢同位素分馏大于干酪根直接生烃过程造成的氢同位素分馏。异常δ13CCO2值与TSR反应过程中部分碳同位素较轻的CO2与硫酸盐中金属离子(Mg2+、Fe2+、Ca2+等)以碳酸盐的形式沉淀后,导致气藏中残余重碳同位素组成的CO2与酸性气体腐蚀碳酸盐岩储集层形成的CO2相混合有关。     

The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures,South Wales,UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)

Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.     

Définition d'une limite multicritère ; stratigraphie du passage Campanien–Maastrichtien du site géologique de Tercis (Landes,SW France)Definition of a multi-criteria boundary; stratigraphy of the Campanian–Maastrichtian interval of the geological site at Tercis (Landes,SW France)

Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414.     

The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts

The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H₂O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H₂O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species.     

Late Wuchiapingian (Late Dzhulfian,early Late Permian) limestone olistolites within the Tertiary flysch of Glypia Unit (Mount Parnon,central–eastern Peloponnesus,Greece)

Some olistolites reworked in a Tertiary flysch of Mount Parnon (Peloponnesus, Greece) exhibit a Late Permian assemblage, dominated by Paradunbarula (Shindella) shindensis, Hemigordiopsis cf. luquensis and Colaniella aff. minima. This association corresponds to the Late Wuchiapingian (=Late Dzhulfian), a substage whose algae and foraminifera are generally little known. Contemporaneous limestones crop out in the middle part of the Episkopi Formation in Hydra, but they are rather commonly reworked in Mesozoic and Cainozoic sequences. The palaeobiogeographical affinities shared by the foraminiferal markers of Greece, southeastern Pamir, and southern China, are very strong (up to the specific level), and are congruent with the Pangea B reconstructions. To cite this article: E. Skourtsos et al., C. R. Geoscience 334 (2002) 925–931.     

PALEONTOLOGY

正20141596 Liu Yunhuan(School of Earth Sciences and Resources,Chang’an University,Xi’an 710054,China);Shao Tiequan Early Cambrian Quadrapyrgites Fossils of Xixiang Boita in Southern Shaanxi Province(Journal of Earth Sciences and Environment,ISSN1672-6561,CN61-1423/P,35(3),2013,p.39-43,3 illus.,20 refs.)     

GEOCHEMICAL EXPLORATION

正20141719 Chen Zhijun(State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Wuhan 430074,China);Chen Jianguo Automated Batch Mapping Solution for Serial Maps:A Case Study of Exploration Geochemistry Maps(Journal of Geology,ISSN1674-3636,CN32-1796/P,37(3),2013,p.456-464,2 illus.,2 tables,10 refs.)     

MICROPALAEONTOLOGY

正20140962 Chen Fenning(Xi’an Institute of Geology and Mineral Resources,Xi’an710054,China);Chen Ruiming Late Miocene-Early Pleistocene Ostracoda Fauna of Gyirong Basin,Southern Tibet(Acta Geologica Sinica,ISSN0001-5717,CN11-1951/P,87(6),2013,p.872-886,6illus.,56refs.)     

PETROLOGY

正1.IGNEOUS PETROLOGY20142008Cai Jinhui(Wuhan Center,China Geological Survey,Wuhan 430205,China);Liu Wei Zircon U-Pb Geochronology and Mineralization Significance of Granodiorites from Fuzichong Pb-Zn Deposit,Guangxi,South China(Geology and Mineral Resources of South China,ISSN1007-3701,CN42-1417/P,29(4),2013,p.271-281,7illus.,     

ENVIRONMENTAL GEOLOGY

正20141205Cheng Weiming(State Key Laboratory of Resources and Environmental Information System,Institute of Geographic Sciences and Natural Resources Research,CAS,Beijing 100101,China);Xia Yao Regional Hazard Assessment of Disaster Environment for Debris Flows:Taking Jundu Mountain,Beijing as an