内蒙古西部额济纳旗地区X井油气显示特征与油气源探讨

根据内蒙古额济纳旗地区X井白垩系额济纳旗组、侏罗系麻木鸟苏组、古生界顶面风化壳等不同层段的油气显示特征和钻井泥浆烃类气体组分、甲烷C同位素的分析结果,认为侏罗系和白垩系油气显示特征相同,为油与气显示,气体样品的干燥系数(C_1/C_总)为0.80～0.87,甲烷C同位素δ~(13)C_1为-48.19‰～-50,87‰,表现了低成熟热解气的特征;古生界风化壳为气显示,天然气干燥系数(C_1/C_总)为0.91～0.92,甲烷C同位素δ~(13)C_1为-21.56‰-30.91‰,表现了高成熟热解气的特征.该井及邻区的中生界、古生界烃源岩干酪根类型及其演化程度具有显著的差别,中生界烃源岩以低成熟混合型干酪根为主,古生界烃源岩为成熟-高成熟(或过成熟)的混合型-腐泥型干酪根.表明该区存在以中生界侏罗系-白垩系低成熟烃源岩为油气源的油气系统和古生界高成熟(或过成熟)烃源岩为气源的油气系统,指示了古生界油气资源前景.     

北秦岭基性火山岩地球化学特征与上地幔岩浆源区性质

元古代和早古生代是北秦岭两个主要的火山岩浆作用时期,地球化学研究表明,元古代基性火山岩具有相对低SiO_2、Al_2O_3和高TiO_2特征,基性火山岩TiO_2-P_2O_5、MgO/FeO-Y、的变化显示了正常的、稳定的岩浆作用过程,相容元素分配模型表明这一时期基性火山岩与华北区上地幔部分熔融岩浆作用相吻合,早古生代基性火山岩除普遍具有高、低特征外,突出地表现出地球化学成分的不均匀性,多源、混合岩浆作用的干扰使单源岩浆演变特征遭受破坏,相容元素分配模型表明:这一时期基性火山岩浆与引起秦岭区、华北区上地幔岩浆共同作用有关系,北秦岭基性火山岩浆作用的特征与这一地区从元古代到早古生代的构造发展是相适应的,反映了该区上地幔性质及岩石圈构成的重大改变。     

济阳坳陷下古生界碳酸盐岩的分子有机地球化学特征

本文主要针对济阳坳陷车古、义古和桩古潜山带若干钻井的下古生界碳酸盐岩样品,开展分子有机地球化学研究。研究主要揭示了下古生界碳酸盐岩氯仿沥青A中的生标组成及其碳同位素特征,可为环渤海地区下古生界潜在的原生油气藏的判识提供依据;同时研究表明碳酸盐岩晶包有机质中正构烷烃的分布和碳同位素组成与氯仿沥青A中的存在明显差异,早期有机质的特征仍被保留在晶包有机质中,因此可用于古沉积环境的探讨。     

鄂尔多斯盆地下古生界储层气气源探讨

鄂尔多斯盆地下古生界天然气勘探的制约因素是有效烃源岩的问题。笔者通过对鄂尔多斯盆地早古生代的沉积构造演化、沉积环境、生烃潜力、本溪组砂体展布特征与中央大气田藕合关系、上古生界天然气向下穿层运移条件、地球化学等方面的综合分析，指出中央大气田的气源主要来自上古生界的煤系地层及本溪组和太原组中的海相烃源岩，并在此基础上指出下古生界天然气勘探的方针和下一步有利勘探选区。     

鄂尔多斯盆地三叠系延长组长7段物源区分析

随着鄂尔多斯盆地长7段油藏勘探的不断突破,对其物源方向和母岩区性质的分析尤显重要.三叠世延长期鄂尔多斯盆地周缘存在多个古陆,包括北缘的阴山古陆、西北缘的阿拉善古陆、西南缘的陇西古陆及南缘的祁连-秦岭古陆等,它们都是盆地碎屑沉积物的主要供给源.通过碎屑组分、岩屑组分、重矿物、微量元素和稀土元素分析等研究,认为研究区长7段存在东北、西北、西及西南、南部4个方向的物源.轻、重矿物组合综合分析认为,盆地北部母岩主要为太古宙—古生代中—深变质岩和中基性火成岩,西南及南部母岩主要为元古宙—古生代浅变质岩、碳酸盐岩和碎屑岩.微量及稀土元素分析表明母岩以大陆上地壳的长英质岩石为主,并混有一定数量的含长石较高的中—基性岩浆岩如安山岩、碱性玄武岩,母岩中太古代古老地层占有相当大的比重.     

Behavior of mercury in the supergene zone of geothermal deposits,southern Kamchatka

Mercury distribution was determined in all types of solid materials from the supergene zone of geothermal deposits in southern Kamchatka: rocks, hydrothermally altered rocks (metasomatic rocks), soils, soil—pyroclastic cover, bottom sediments of perennial and intermittent streams, hydrothermal clays, artificial siliceous precipitates, and iron sulfides formed owing to thermal water discharge from a well. The mercury content varies from background values for the Kurile-Kamchatka region in fresh rocks to high and extremely high values in hydrothermal clays and monomineralic pyrite samples. The sources, migration conditions, and concentration mechanisms of mercury were evaluated. Mercury is supplied to the surface of geothermal deposits and thermal fields by a deep hydrothermal flow and is concentrated on thermodynamic barriers in hydrothermal clays, siliceous sinters (silica gel), and soils showing high salinity owing to the deposition in them of silica, sulfates, and other compounds from a vapor-water mixture. Newly formed clay minerals, iron sulfides (pyrite), silica gel, and biological materials (peat) can probably efficiently sorb mercury under geothermal conditions at atmospheric pressure and temperatures from 20°C to 120°C.     

下扬子地区海相盆地演化及油气勘探选区评价

从晚震旦世开始至中三叠世,下扬子地区沉积了三套巨厚的海相烃源岩系(Z2-O3、C-P、T1).三套烃源岩热演化特点不同,下古生界烃源岩经历了加里东、印支-燕山期构造阶段的热演化(已达过成熟干气阶段);上古生界烃源岩基本处于生油阶段晚期;三叠系大部烃源岩处于成熟生油阶段,少数处于未成熟阶段.区内下古生界烃源岩经历了两次成油过程,即加里东运动前的盆地沉降阶段和加里东运动后晚古生代陆表海沉积阶段.海相油气储盖条件发育,配置有利,经多年油气勘探证实,下古生界油气勘探应立足于苏北地区;上古生界油气勘探除苏北地区外,尚有皖南与浙西地区.中生界海相油气勘探应集中在几个发育较好的中生代盆地,如常州、句容、无为、望江等盆地.     

黄骅坳陷歧古1井古生界烃源岩的二次生烃演化

黄骅坳陷歧古1井的古生界烃源岩自形成以来经历了复杂的构造—埋藏史,并发生多次生烃演化。基于详细的构造-埋藏史研究,并结合矿物包裹体分析,运用EASY％R_o数值模拟技术,深入研究了歧古1井的古生界烃源岩的埋藏史、受热史和生烃史,阐明了歧古1井古生界生烃作用发生的构造期次、生烃强度,揭示了歧古1井古生界烃源岩曾发生过多次重要的生烃作用过程,其主要发生在海西—印支期和喜马拉雅晚期,得出了主要二次生烃作用发生在喜马拉雅晚期的重要结论,并提出了歧口凹陷是有望实现黄骅坳陷深层古生界找油突破的有利地域。     

Zircon ages,geochemistry, and Nd isotopic systematics of pre-Variscan orthogneisses from the Erzgebirge,Saxony (Germany), and geodynamic interpretation

High grade granitoid orthogneisses occur in several metamorphic units of the Erzgebirge in the Saxothuringian Zone of the Variscan Belt. The determination of protolith ages and the geochemical characterization of these rocks permit a reconstruction of the Neoproterozoic to early Palaeozoic magmatic and geodynamic history of the Erzgebirge. Single zircon Pb-Pb evaporation and SHRIMP ages combined with major and trace element data and Sm-Nd isotope systematics indicate at least two discrete magmatic events concealed in the so-called red gneisses, one at ~550 Ma in rocks of the medium pressure—medium temperature (MP-MT) unit and the other at ~500–480 Ma in rocks of the high pressure units. The transition zones comprise both Neoproterozoic granitoids and early Palaeozoic metarhyolites. The granitoid gneisses represent Neoproterozoic calc-alkaline granitoids with REE patterns similar to those produced in Andean-type continental margins. The early Palaeozoic muscovite gneisses are geochemically distinct from the older granitoids and may be derived from melts generated in a back-arc setting. Initial _Nd values in all samples overlap and range from –4.1 to –9.2, corresponding to crustal sources with average residence times of 1.5 to 1.9 Ga. Zircon xenocryst ages as old as 2992 Ma provide evidence for Grenvillian, Svecofennian-Birimian-Aazonian and older age components and suggest an association of the Erzgebirge with Avalonia.B. Mingram and A. Kröner have shared senior authorship     

苏浙皖地区海相油气地质特征及勘探目标的选择

从晚震旦世开始至中三叠世，苏浙皖（下扬子）地区沉积了三套巨厚的海相烃源岩系，即：上震旦统一上奥陶统，石炭系－二叠系，下三叠统海相烃源岩，三套烃源岩热演化特点不同，下古生界烃源岩经历了加里东、印支－燕山期构造阶段的热演化，已达过成熟干气阶段，上古生界烃源岩基本处于生油阶段晚期；大部分三叠系烃源岩处于成熟生油阶段，少数处于未成熟阶段，区内下古生界烃源岩经历了两次成油过程，第一次发生在加里东运动前的盆地沉降阶段，第二次发生在加里东运动后晚古生代陆表海代积阶段，全区海相油气储盖条件发育，配置有利，经多年油气勘探证实，下古生界油气勘探应立足于苏北地区，上古生界油气勘探除苏北地区外，尚有皖南与浙西地区，中生界海相油气勘探应集中在区内几个发育较好的中生代盆地，如常州、句容，无为，望江盆地等。     

Nature and origin of Palaeozoic volcanic rocks of the Seeberg area (Karawanken/Austria)

In the Seeberg area (Karawanken/Austria) intermediate to acidic pyroclastic rocks of Palaeozoic age are found. These rocks are partly of upper Ordovician age and partly as yet undated. 12 complete chemical analyses of these tuffs and their corresponding modal mineral content are presented. The tuffs differ chemically from the average composition of intermediate to acidic volcanic rocks by their lower alkali and higher H₂O and CO₂ values. It is assumed that the originally glassy parts of the tuffs took up H₂O and CO₂ and lost alkalies and possibly also SiO₂ during diagenesis and tectonic stress. In addition, two other complete chemical analyses of a basic dyke which cuts across Devonian limestones are given. The dyke has a spilitic mineral content which is of secondary origin. The petrographic character of the analysed tuffs is discussed in comparison with Palaeozoic and Tertiary to recent trachytes, alkali rhyolites and rhyolites.     

The geochemistry of mercury in sedimentary rocks and soils in Pennsylvania

The mercury contents of 11 sandstone, 11 shale and 6 limestone samples from Pennsylvania average 7, 23 and 9 ppb Hg, respectively, which is lower than the values for sedimentary rocks reported in the literature. The differences may arise because many of the reported high values are from regions characterized by more mineralization and volcanism than is present in central Pennsylvania. The lowest values found for shale and sandstone in Pennsylvania (0.4 and 0.5 ppb Hg, respectively) are lower by an order of magnitude than the lowest previously reported values. The mercury content of sedimentary rocks varies markedly due to the effects of volcanism, organic material and sulfur in reducing environments, iron and manganese oxides in oxidizing environments, diagenesis, hydrothermal processes, and the thermal history of the rock.Soils in Pennsylvania have much greater amounts of mercury than their parent rocks even after taking into account possible residual concentration, suggesting that mercury is added to the soils from an outside source. Rain is the major source of mercury absorbed by the soil. A portion of the absorbed mercury returns to the atmosphere, establishing a rain-soil-atmosphere mercury cycle. The general enrichment of mercury in soils and sediments compared to rocks is supported by the observation that the mercury content of rain is greater than freshwater. The much higher values of mercury in unconsolidated sediments compared to sedimentary rocks suggest that mercury is lost during diagenesis.Man's contribution of mercury to the surface environment is nearly equal to the natural contribution. Industrial loss contributes more than 65 per cent of man's total, and the contribution of fossil fuel consumption is small, although it may be locally important. The implications of mercury loss and absorption by soils may be an important factor in concentrating mercury in crops and other living matter, especially near industrialized areas.     

华北板块东南缘海相层系演化特征及油气远景

在大别造山带内发现的可燃天然气和发生燃烧的隧道具有明显的区域性,集中分布于磨子潭-晓天断裂以南的北大别杂岩带和信阳-舒城断裂附近的早石炭世变质石英片岩中,磨子潭-晓天断裂和信阳。舒城断裂是连通深部的气源通道断裂;推覆体之下的下寒武统凤台组和北淮阳型石炭系两套海相烃源岩是隧道可燃天然气的主力气源岩,其中下寒武统凤台组属大陆边缘沉积,其发育的海相泥质烃源岩具有高碳,高“R。”,高T…和低氯仿“A”的特点,已进入热演化的过成熟阶段;北淮阳型石炭系处于前陆盆地的沉积中心,地层序列齐全,其煤系源岩有机质丰度高,以Ⅲ型干酪根为主,热演化程度很高,大量的油气已经生成,最重要的是研究其成烃过程与圈闭配套史的关系。大别造山带隧道可燃天然气的发现展示了合肥盆地区深部海相层系可能潜在良好的勘探前景。因此,进一步勘探重心应从“中新生代盆地系统”转移到“深部海相层系”,以寻找“古生古储”或“古生新储”类型油气藏为主。     

Rb‐Sr systematics of the Claret Creek Ring Complex and their bearing on the origin of upper Palaeozoic igneous rocks in northeast Queensland

The Claret Creek Ring Complex forms a minor part of the extensive Upper Palaeozoic calcalkaline province of northeast Queensland. Although the Claret Creek Ring Complex contains 10 mappable units, it was formed about 300 m.y. ago over a time interval no greater than 10 m.y. This interval is short compared with the overall duration of Upper Palaeozoic igneous activity, which lasted from approximately 320 m.y. to 270 m.y. in this area. Although geochemically distinct, the complex shares a common initial ⁸⁷Sr/⁸⁶Sr ratio with the majority of the surrounding igneous rocks; this suggests derivation from different sources with a common initial ratio. Such a relationship could arise by the re‐melting or pronounced fractional crystallisation of magmas which underplated or intruded the lower crust immediately prior to final magma generation. Alternatively, the acidic magmas may have originally formed by partial melting of crustal rocks immediately after a regional isotopic homogenisation. In either case the magmas were derived from originally igneous rocks which were dioritic in chemical composition.     

下古生界海相原油之中蜡的成因分析－－干酪根PY－GC分析提供的证据

塔里木盆地海相原油一般具有低－中含蜡的特征，油源对比表明其生油岩为下古生界寒武、奥陶系。下古生界海相干酪根主要由菌藻类无定形体组成，且具有较高的成熟度。干酪根热解气相色谱分析表明，热解产物中ｎＣ+₂₁具有较高的含量。结合原油的运移效应，从而可以建立海相原油之中含蜡的成因模式。该模式突破了较高含蜡量的原油只能来源于高等植物的传统观点，指出较高成熟度下的细菌母源是塔里木盆地海相原油含蜡的主要成因。     

天山西段木札尔特河和独库公路沿线火山岩与晚古生代板块构造的关系

描述了天山西段两条调查路线上的古生代火山岩的分布和岩相，划分了火山岩的碱度和系列，大多数酸度较低的火山岩碱度较高。根据各种判别图解和方法，运用火山岩岩石化学资料对其构造环境进行了详细的判别分析，结合地质特征对晚古生代火山岩的构造环境进行了推测。最后，主要结合晚古生代板块构造的演化过程，对火山岩的形成在构造上做了概貌性的推断，认为那拉提山和哈尔克山北坡、博罗科努山北坡的石炭纪火山岩为活动陆缘和岛弧的喷发产物，并且后者（即巴音沟一带）还有洋脊火山岩，因而认为巴音沟蛇绿岩是成熟洋盆的洋壳残余；而伊犁地块内部的火山岩是陆内张性环境的喷发产物。     

鄂尔多斯盆地杭锦旗地区上古生界砂岩中储层粘土矿物特征分析

鄂尔多斯盆地杭锦旗地区上古生界砂岩储层中普遍发育粘土矿物,根据岩心薄片观察,自然γ能谱测井交会图识别出的粘土矿物类型有高岭石、伊利石、蒙脱石、绿泥石。薄片分析按粘土矿物形成方式划出沉积粘土和成岩粘土(蚀变、转变及化学成因粘土),以及按其产出状态尚划出构造(骨架)粘土和结构(填隙)粘土,并定量分析出构造粘土和结构粘土含量在多数层段分别为20%以上与10%~18%。依据自然γ能谱测井分析采用多元线性逐步回归分析法,查明各粘土矿物含量同T h,U,K质量分数之间的相关系数都大于0.85,建立了粘土矿物定量计算模型X=a-b×T h c×U d×T h/K还对储层中粘土矿物进行预测及粘土矿物的纵向分布特征分析。     

万山汞矿区汞质沉积成因研究

万山汞矿是典型的层控矿床,属沉积改造成因。矿质主要来自围岩。从寒武纪初至寒武纪末,形成了一个完整的沉积成矿系列,即形成磷、镍、钒、银、钾、汞、铅、锌、金等的沉积或沉积改造矿床。不仅在沉积岩中,而且在一些典型的沉积矿物、生物化石、生物礁中都有高丰度的汞、铅、锌、砷、锑,在三叶虫化石中含汞最高达100ppm。从矿物的结构构造特征方面也可找到沉积汞的证据,典型的沉积辰砂与热液辰砂大有区别,并发现极少数微粒辰砂赋存在透镜状褐铁矿结核的中心。各方面的资料说明,沉积岩中分散状态的汞质是沉积成因的。     

Pre-Permian uplift and diffuse extensional deformation in the High Zagros Belt (Iran): integration in the geodynamic evolution of the Arabian plate

The High Zagros Belt includes exposures of Lower Palaeozoic rocks in the core of several thrusted anticlines developed during the Cenozoic Zagros orogeny. The structural style and tectonic evolution of this area during the Palaeozoic remain poorly understood due to the complexity of the subsequent deformation. We present the preliminary results of a field study focusing on the structural geology of Palaeozoic rocks in this area. We confirm the existence of an angular unconformity below the Lower Permian Faraghan formation. In the geological literature, this unconformity is reported as the “Hercynian Unconformity” suggesting a relationship with the Hercynian (Variscan) orogeny, which affected Western Europe and westernmost Africa during the Carboniferous. Surprisingly the only observable structures sealed by this unconformity are N to NE trending normal faults and tilted blocks without any evidence of compressional deformation. This pre-Permian extensional deformation, which is general at the scale of the HZB, raises questions about the geodynamic significance of the “Hercynian unconformity” in the study area and, more generally, in the Arabian plate.     

Precambrian crustal contribution to the Variscan accretionary prism of the Kaczawa Mountains (Sudetes,SW Poland): evidence from SHRIMP dating of detrital zircons

SHRIMP dating of detrital zircons from sandstones of the Gackowa Formation (Kaczawa Complex, Sudetes, SW Poland) indicates input from late (550–750 Ma) and early Proterozoic to Archaean sources (∼2.0–3.4 Ga, the latter being the oldest recorded age from the Sudetic region). These dates preclude within-terrane derivation from seemingly correlatory acid volcanic rocks of early Palaeozoic age. Rather, they indicate provenance from Cadomian and older rocks that currently form part of other, geographically distant terranes; the most likely source identified to date is the Lusatian Block in the Saxothuringian Zone. Hence, the Gackowa Formation may be late Proterozoic rather than early Palaeozoic in depositional age, possibly coeval with the late Proterozoic (pre-Cadomian) greywackes of Lusatia, being subsequently tectonically interleaved with early Palaeozoic volcanic rocks into the Kaczawa accretionary prism during the Variscan orogeny. However, correlation with the lithologically similar early Ordovician Dubrau Quartzite of Saxothuringia, and so assignation to the early Paleozoic (post-Cadomian) rift succession deposited at the northern margin of Gondwana, cannot yet be precluded.