漠河盆地依列克得组火山活动间歇期烃源岩有机地球化学特征研究   总被引：1，自引：1，他引：0  

齐跃春  高红梅  鲍志东  高福红  张月巧 《沉积学报》2011,29(1):164-172

漠河盆地早白垩世为一火山岩断陷盆地,广泛发育火山岩夹沉积岩的二元沉积建造。依列克得组烃源岩为一套发育在玄武岩系之间的湖沼相沉积岩系,烃源岩岩性为油页岩、页岩及煤岩。该套烃源岩与其周围玄武岩为同期不同相产物,与该套烃源岩直接接触的火成岩为火山熔岩或火山碎屑直接进入湖盆水体而形成。利用热解、GC, GC—MS等地球化学分析技术,对该套烃源岩生油潜力进行了初步评价,并探讨了该套烃源岩的沉积环境、母源特征及火山活动对该套烃源岩的影响。分析显示,该套烃源岩有机质丰度较高,有机质类型油页岩以Ⅱ型为主,页岩和煤岩主要为Ⅲ型,火山岩浆活动对烃源岩的烘烤作用不明显（Ro=0.56%~0.59%）,有机质热演化处于刚进入生烃门限的低成熟阶段,综合评价具有较好的生烃潜力;该套烃源岩沉积于强还原—弱还原水体环境,在垂向上含盐度具有较快的波动,处于淡水—咸水交替变化状态;母质来源具有水生生物和陆生植物混源输入特征,煤岩陆源有机质输入更丰富。  相似文献   

湘西北张家界地区早寒武世牛蹄塘组黑色岩系镍钼矿层生物标志物的特征   总被引：1，自引：1，他引：0  

黄燕  林丽  杨永军  马莉燕  李德亮  庞艳春 《地质通报》2011,30(1):126-133

以湖南张家界天门山地区下寒武统牛蹄塘组底部的黑色页岩镍钼矿层为研究对象,对其进行了生物标志化合物特征的分析。发现该矿层的正构烷烃、类异戊二烯烃、萜类化合物和甾类化合物具有以下特征：①正构烷烃OEP(奇偶优势)接近1.0,无明显奇偶优势;(nC21+nC22)/(nC28+nC29)比值为0.7~10.4,平均为6.16,显示轻烃组分占绝对优势;样品富含姥鲛烷(Pr)和植烷(Ph),比值平均为0.26,具有植烷优势。②萜烷相对丰度三环萜烷>五环三萜烷>四环萜烷;三环萜烷中C21、C23、C24呈倒V字形分布;C24四环萜与相邻C26三环萜比值为0.50;Ts/(Tm +Ts)比值在0.40~0.43之间,平均为0.42;γ-蜡烷指数介于0.10~0.17之间,平均值为0.13。③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规则甾烷/C29规则甾烷平均比值为1.46(>1);检测出一定丰度的4-甲基甾烷。这些特征共同指示了张家界地区早寒武世黑色岩系形成于菌藻类(蓝绿藻、甲藻等)和低等浮游生物大量繁殖的浅海还原环境。  相似文献   

Khasib and Tannuma oil sources, East Baghdad oil field, Iraq     

T.K. Al-Ameri 《Marine and Petroleum Geology》2011,28(4):880-894

This work presents new insights of the generation, quality and migration pathways of the hydrocarbons in the East Baghdad Oil Field.The Khasib and Tannuma formations in East Baghdad are considered as oil reservoirs according to their high porosity (15-23%) and permeability (20-45 mD) in carbonate rocks. The hydrocarbons are trapped by structural anticline closure trending NW-SE. Gas chromatography analysis on these oil reservoirshave shown biomarkers of abundant ranges of n-alkanes of less than C22 (C17-C21) with C19 and C18 peaks. This suggests mainly liquid oil constituents of paraffinic hydrocarbons from marine algal source of restricted palaeoenvironments in the reservoir. The low non aromatic C15 + peaks are indicative for slight degradation and water washing. Oil biomarkers of Pr./Ph. = 0.85, C31/C30 < 1.0, location in triangle of C27-C29 sterane, C28/C29 of 0.6 sterane, Oleanane of 0.01 and CPI = 1.0, indicate an anoxic marine environment with carbonate deposits of Upper Jurassic to Early Cretaceous age. Four Miospores, seven Dinoflagellates and one Tasmanite species confirm affinity to the upper most Jurassic to Lower Cretaceous Chia Gara and Ratawi Formations.The recorded palynomorphs from the Khasib and Tannuma Formations are of light brown color of TAI = 2.8-3.0 and comparable to the mature palynomorphs that belong to the Chia Gara and the Lower part of Ratawi Formations.The Chia Gara Formation generated oil during Upper Cretaceous to Early Palaeogene and accumulated in structural traps of Cretaceous age, such as the Khasib and Tannuma reservoirs. The Chia Gara Formation generated and expelled high quantities of oil hydrocarbons according to their TOC wt% of 0.5-8.5 with S2 = 2.5-18.5 mg Hc/g Rock, high hydrogen index of the range 150-450 mg Hc/g Rock, good petroleum potential of 4.5-23.5 mg Hc/g Rock, mature (TAI = 2.8-3.0 and T_max = 428-443C), kerogen type II and palynofacies parameters of up to 100% AOM (Amorphous Organic Matters). This includes algae deposits in a dysoxic-anoxic to suboxic-anoxic environment.Alternative plays are discussed according to the migration pathways.  相似文献   

Organic biomarkers to describe the major carbon inputs and cycling of organic matter in the central Great Barrier Reef region     

Kathryn Burns  Diane Brinkman 《Estuarine, Coastal and Shelf Science》2011

Controversy surrounds the sources and transport of land derived pollutants in the Great Barrier Reef ecosystem because there is insufficient knowledge of the mechanism of movement of organic contaminants and the cycling of organic matter in this dynamic system. Thus a sediment and sediment trap study was used to describe the composition of resuspended and surface sediments in the south central Great Barrier Reef and its lagoon. This region is characterised by strong tides (6–8 m at Mackay) and trade winds regularly about 15–20 knots. A series of organic biomarkers detailed the cyclical processes of sediment resuspension, recolonising with marine algae and bacteria, packaging into zooplankton faecal pellets and resettlement to sediments where the organics undergo further diagenesis. With each cycle the inshore sediments are diluted with CaCO₃ reef sediments and moved further offshore with the strong ebb tide currents. This results in transport of land derived materials offshore and little storage of organic materials in the lagoon or reef sediments. These processes were detailed by inorganic measurements such as %CaCO₃ and Al/Ca ratios, and by the compositions of hydrocarbon, sterol, alcohol, and fatty acid lipid fractions. Persistent contaminants such as coal dust from a coastal loading facility can be detected in high concentration inshore and decreasing out to the shelf break at 180 m approximately 40 nautical miles offshore. The normal processes would likely be amplified during cyclonic and other storms. The lipids show the sources of carbon to include diatoms and other phytoplankton, creanaerchaeota, sulfate reducing and other bacteria, land plants including mangrove leaves, plus coal dust and other petroleum contaminants.  相似文献   

Paleoenvironmental Characteristics of Paleogene Lacustrine Source Rocks in the Western Bozhong Sag, Bohai Bay Basin, China: Evidence from Biomarkers, Major and Trace Elements     

WANG Xiang  LIU Guangdi  SONG Zezhang  SUN Mingliang  WANG Xiaolin  WANG Feilong  CHEN Rongtao  GENG Mingyang  LI Yishu 《《地质学报》英文版》2024,98(1):220-240

The organic matter (OM) enrichment mechanisms and depositional environment characteristics of lacustrine source rocks in the western Bozhong Sag, Bohai Bay Basin in Northeast China remain controversial. To address these issues, based on Rock-Eval pyrolysis, kerogen macerals, H/C and O/C ratios, GC-MS, major and trace elements, the Dongying Formation Member (Mbr) 3 (E3d3), the Shahejie Formation mbrs 1 and 2 (E2s1+2), and the Shahejie Mbr 3 (E2s3) source rocks in the western Bozhong Sag were studied. The above methods were used to reveal their geochemical properties, OM origins and depositional environments, all of which indicate that E2s1+2 and E2s3 are excellent source rocks, and that E3d3 is of the second good quality. E3d3 source rocks were formed under a warm and humid climate, mainly belong to fluvial/delta facies, the E3d3 sediments formed under weakly oxidizing and freshwater conditions. Comparatively, the depositional environments of E2s1+2 source rocks were arid and cold climate, representing saline or freshwater lacustrine facies, and the sediments of E2s1+2 belong to anoxic or suboxic settings with large evaporation and salinity. During the period of E2s3, the climate became warm and humid, indicating the freshwater lacustrine facies, and E2s3 was characterized by freshwater and abundant algae. Moreover, compared with other intervals, the OM origin of E3d3 source rocks has noticeable terrestrial input. The OM origin of the E2s1+2 and E2s3 are mainly plankton and bacteria. Tectonic subsidence and climate change have affected the changes of the depositional environment in the western Bozhong Sag, thus controlling the distribution of the source rocks, the geochemical characteristics in the three intervals of lacustrine source rocks have distinct differences. Overall, these factors are effective to evaluate the paleoenvironmental characteristics of source rocks by biomarkers, major and trace elements. The established models may have positive implications for research of lacustrine source rocks in offshore areas with few drillings.  相似文献   

UNUSUAL DISTRIBUTION OF TRITERPANE AND STERANE TERRESTRIAL BIOMARKERS IN YACHENG CONDENSATES FROM YING-QIONG BASINS, SOUTH CHINA SEA   总被引：1，自引：0，他引：1  

周毅  盛国英  傅家膜  耿安松  陈军红  张启明  潘贤庄  黄保家 《中国海洋湖沼学报》2002,20(2):182-190

The condensates from the Yacheng Gas Field, Ying-Qiong Basins, have unusual chemical characteristics, with distribution dominated by terpanes and steranes derived from higher-plants. Pr/Ph ratios (6- 11 ) are very high. Drimane, cadinanes and homocadinanes exist in high concentration. Anomalously abundant 18α(H)-oleanane and remarkably abundant bicadinanes are present in Yacheng condensates, while 17α( H)-hopanes are in extremely low concentration. Taraxastane and significantlyabundant 17α(H)-diabopanes occur in the condensates. In addition, a number of C29 and C30 unknown pentacyclic triterpanes were monitored in the condensates, some of which are abundant. The unknown compounds may be terrestrial biomarkers or their occurrence may suggest a sub-oxic (dyacrobic) clay-rich depositional environment. C29 homologues are relatively predominant in regular and rearranged steranes. The concentration of diasteranes is markedly higher than that of regular steranes. The characteristics of Yacheng condensates are indicative of terrestrial source input. Based on condensate-condensate and con-densate-rock correlations, combined with results of studies on sedimentary facies. Yacheng condensates may be sourced from Yacheng and Lingshui Formations in the Qiongdongnan Basin. The maturity of Yacheng condensate is relatively high, at late oil window stage ( corresponding to 0.9 % - 1.3 % R0 ),based on sterane and terpane maturity parameters.  相似文献   

Biogeochemistry of sterols in plankton, settling particles and recent sediments in a cold ocean ecosystem (Trinity Bay, Newfoundland)     

Edward D. Hudson  Christopher C. Parrish  Robert J. Helleur 《Marine Chemistry》2001,76(4)

In the context of a multidisciplinary study to determine current and past ecosystem health and the relative contributions of sources of organic matter (marine vs. terrestrial and natural vs. anthropogenic input), sterols were determined in plankton, settling particles and sediments from Trinity Bay, Newfoundland, a sub-polar Atlantic Ocean ecosystem. The centric diatoms Chaetoceros spp., Thalassiosira spp. and Leptocylindrus danicus were all prominent in the plankton samples, and centric diatoms predominated in the settling particles. Plankton samples contained 0.4±0.4 mg/g dw (1995) or 1.4±1.3 mg/g dw (1996) total sterols, with cholesta-5,24-dien-3β-ol (mean 26% of total sterols), cholest-5-en-3β-ol (24%) and cholesta-5,22(E)-dien-3β-ol (13%) chief among these, denoting diatom and zooplankton sources. In settling particles, the prominence of cholesta-5,24-dien-3β-ol (24%), cholest-5-en-3β-ol (24%), cholesta-5,22(E)-dien-3β-ol (13%) and 24-methylcholesta-5,22(E)-dien-3β-ol (9%) again suggested mainly marine sources. The sterol composition of plankton and settling particles from different sampling periods showed a high degree of consistency. Higher plant C₂₉ sterols (notably 24-ethylcholest-5-en-3β-ol, 9–26%) were prominent in sediments from both inshore and offshore sites. No decreasing trend in total or individual sterols was observed down the 30-cm sediment cores, suggesting good overall preservation. No 5β-stanols such as 5β-cholestan-3β-ol (coprostanol) were detected in offshore sediments, plankton or settling particles, with only low levels (5β-cholestan-3β-ol max. 4.4%, 5β-cholestan-3α-ol max. 5.1%) in certain inshore sediments. This suggests that raw sewage discharges in rural Newfoundland are being efficiently degraded or dispersed, or that inputs are highly localized. Source apportionation of organic matter in the sediment samples based on sterol composition was attempted. This highlighted the large terrestrial contribution to the sterols in marine sediments (up to 58% of sterols inshore, 24% offshore) and suggests either degradation or effective recycling of marine sterols.  相似文献   

Fatty acid composition of phytoplankton, settling particulate matter and sediments at a sheltered bivalve aquaculture site   总被引：5，自引：0，他引：5  

S. M. Budge  C. C. Parrish  C. H. Mckenzie 《Marine Chemistry》2001,76(4)

Fatty acid biomarkers were used to investigate the biogeochemistry of a former blue mussel (Mytilus edulis) aquaculture site in a shallow, sheltered cove in northeastern Newfoundland. High levels of polyunsaturated fatty acids (PUFA) in net-tow and sediment trap samples indicated a substantial phytoplankton source of organic matter, and fluctuations in specific fatty acid biomarkers reflected the changing abundances of diatoms and dinoflagellates. In comparison, sediments contained very low levels of PUFA (<15%) and were dominated by terrestrial and bacterial markers. In a separate study, blue mussels were grown at this closed site, providing the opportunity to examine the relationship between lipid supply, as recorded by net-tow and trap samples, and bivalve requirements. The average plankton fatty acid composition throughout the year agreed well with that of the adult blue mussels, suggesting that fatty acids were provided in proportions very similar to the bivalves' requirements. The fatty acid composition of the blue mussels was typical of those collected elsewhere, with PUFA proportions near 50%. However, examination of fatty acid data of plankton sampled in other areas revealed that the plankton in the current study may have been unusual in providing fatty acids at levels required by the bivalves.  相似文献   

Reply to D. F. Lascelles. Discussion on ‘Microplaty hematite—its varied nature and genesis’ by R. C. Morris and ‘Genesis modelling for the Hamersley BIF-hosted iron ores of Western Australia: a critical review’ by R. C. Morris and M. Kneeshaw     

R. C. Morris  M. Kneeshaw 《Australian Journal of Earth Sciences》2013,60(8):1145-1150

Abstract

The third (Es₃) member of the Eocene Shahejie Formation is the main hydrocarbon source rock interval in the Raoyang Sag of the Bohai Bay Basin. The lower Es₃ (Es₃^L) and upper Es₃ (Es₃^U) submembers display clear differences in source rock quality. The formation mechanisms of the source rocks are investigated via geochemical methods using 60 samples from three wells to reconstruct the paleo-environment during deposition. The major element parameters exhibit changes in paleoclimate from humid to arid. Indicators such as Sr/Ba, B/Ga, the gammacerane index and isotopic data suggest fresh–brackish and hydrological open lakes with unstable water column stratification likely occurred during deposition of the Es₃^L submember and saline and hydrologically closed lakes with stable water column stratification likely during deposition of the Es₃^U submember. Carbon isotope values of organic matter, trace elements and biomarker parameters suggest that the Es₃^L submember had moderate productivity, with a significant contribution from terrigenous organic matter whereas the Es₃^U submember had slightly enhanced productivity, with no or minor contributions from terrigenous organic matter. Furthermore, the pristane/phytane ratio and the enrichment of Mo and U indicate that the euxinic bottom-water conditions (sulfidic) of the lakes during deposition of the Es₃^U submember were best for preserving organic matter. Comparison of the models of source rock deposition of the Es₃^L and Es₃^U submembers indicates that the redox conditions play an important role in the formation of organic-rich source rocks in the Raoyang Sag.  相似文献   

新疆喀什凹陷乌拉根铅锌矿床有机质特征及其地质意义   总被引：2，自引：0，他引：2  

董新丰  薛春纪  李志丹  刘增仁 《地学前缘》2013,20(1):129-145

乌拉根铅锌矿床位于新疆喀什凹陷北部,矿区及外围发育大量有机物质,有机质与铅锌成矿的关系备受关注。文中采用有机质抽提、族组分分离、定量及饱和烃色谱-质谱等实验分析方法对铅锌矿区有机物质及外围油砂中氯仿沥青"A"和生物标志物进行分析,研究铅锌矿区及外围有机质特征及其地质意义,并对有机质与铅锌矿化的关系进行了探讨。结果表明,近矿围岩和外围油砂中氯仿沥青"A"族组成及其饱和烃的主要生物标志物特征均较相似,CPI=1.11～1.17,Pr/Ph=0.68～1.08,C27、C28、C29规则甾烷具有C27>C28相似文献