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1.
总结前人研究成果和近期勘探成果,重新确立了该区石炭纪地层层序,将原小海子组解体,以其内部存在的沉积间断为界,其上划为下二叠统南闸组,其下归为上石炭统,并命名为喀拉拜勒组;将原巴楚组解体,其上部“双峰灰岩”段及泥岩段仍为下石炭统巴楚组,下部砂泥岩互层段及砂岩段(东河砂岩段)归入上泥盆统,称东河塘组,并对井下石炭系进行了横向对比。  相似文献   

2.
Stable carbon isotopes were used together with molecular markers to constrain genetic relationships between sandstone extracts and potential source rocks in the pre-Tertiary in the Huanghua Depression, North China. Comparison of the extracts from Permo-Carboniferous terrigenous mudstones and Ordovician marine carbonates indicated that their prominent differences are in stable carbon isotopes, molecular markers and thermal maturity. Although the extracts of the Mesozoic and Lower Permian Xiashihezi Formation sandstones have some similar iso-topic characteristics, molecular markers data provide a good correlation between the Upper Jurassic-Lower Cretaceous oils and the Upper Carboniferous Taiyuan Formation mudstones, and between the Lower Permian Xiashihezi Formation oils and the Lower Permian mudstones. The results showed that the Upper Jurassic-Lower Cretaceous sandstone oils were derived chiefly from the Upper Carboniferous Taiyuan Formation terrigenous mudstones and that the Lower Permian Xiashihezi Formation oils were sourced from the Lower Permian Shanxi Formation and Xiashihezi Formation terrigenous mudstones.  相似文献   

3.
The Upper Devonian to Lower Carboniferous Skrinkle Sandstones of the Pembroke Peninsula are predominantly continental deposits from the post-Caledonian synrift succession at the southern margin of the Upper Palaeozoic Welsh Landmass. The lower part of the Sandstones record deposition in the 30 × 10 km Tenby–Angle fault block, from which a 6- to 68-m-thick interval is described and interpreted as a lacustrine deposit succeeded by a high-energy sandy braidplain succession. The lacustrine deposit is dominated by red mudstones and ripple cross-laminated sandstones. Interbedded quartzose sandstones form a coarsening-upward sequence from the red mudstones in the basin centre, suggesting a deltaic origin, and a smooth-fronted braidplain delta model is proposed. The sequence introduces the braidplain succession, composed of groups of horizontal/low-angle laminated and trough cross-bedded sandstones. These are compared with recent ephemeral stream and sheetflood sediments and their characteristics used to depict a system of mutually erosive sheetflood and channel bodies, the latter produced during the rising and falling stages of flood events, which alternate to produce a thick multistorey sandstone. Palaeocurrent data indicate an axial drainage system from the north-west, running parallel to the main faults of the area. This is supported by the maturity and sandy nature of the sediments. Basin closure towards the south and the postulated Bristol Channel Landmass is inferred.  相似文献   

4.
The analysis of Upper Jurassic and Lower Cretaceous marine sections developed in surrounding structures of the Laptev Sea revealed that all of them are composed of terrigenous rocks, which enclose abundant concretions cemented by calcareous material. The Upper Jurassic portion of the section is the most variable in thickness and stratigraphic range of sediments usually including hiatuses. Its Lower Cretaceous part represented by the Boreal Berriasian (=Ryazanian) and lower Valanginian stages is most complete. The Upper Jurassic and Lower Cretaceous sections are usually composed of fine-grained rocks (clays and mudstones) in the west and coarser cemented varieties (siltstones and sandstones) with rare mudstone intercalations in the east. Practically all the investigated Upper Jurassic and Lower Cretaceous sections include readily recognizable age and facies analogs of the Bazhenovo Formation and Achimov sandstones, which are petroliferous in West Siberia. There are grounds to assume the occurrence of these formations also on the Laptev Sea shelf, which is confirmed by seismic records. Conditions favorable for the formation of potential hydrocarbon reservoirs could exist in the western part of the paleobasin along the Nordvik Peninsula coast and northeastern Tamyr Peninsula margin. Paleotectonic reconstructions presented in this work are well consistent with stratigraphic conclusions.  相似文献   

5.
We present new data on the material composition of terrigenous deposits in the pre-Jurassic basement of the West Siberian Plate, which formed on the margin of the Kazakhstan paleocontinent. Studies of the sections of several wells drilled in the east of the Kurgan Region showed that the Middle–Upper Devonian and lower Lower Carboniferous continental and littoral deposits are graywackes rich in rock and plagioclase clastics. Quartz grains amount to no more than 3–5%. The rock clastics are mainly volcanics of basic and normal compositions, which were supplied, most likely, from acting volcanoes of the marginal belt. By genesis, these are predominantly tephroids. Along with allothigenic components of sandstones, we consider authigenic minerals, which permit treating the postsedimentational transformation of the Middle Devonian and Early Carboniferous rocks as early catagenesis. By the vitrinite reflectance, the Lower Visean sandstones correspond to gradations MC2 and MC3 (medium catagenesis).  相似文献   

6.
A succession of about 300 m of fluvial sediments from the Lower Carboniferous of northwest Ireland is described and interpreted. A lower, mainly red, formation contains fluvial channel deposits dominated by flat laminated sandstone. These are separated by interbedded sandstones and mudrocks with local caliche horizons and abundant mudcracks interpreted as levee and flood basin deposits. An upper, mainly non-red, formation contains fluvial channel deposits with common trough cross-stratification and epsilon cross-stratification also separated by interbedded sandstones and mudrocks. Evidence of desiccation is less common in the uppermost beds which pass transitionally upwards into marine sediments.The change in fluvial channel style is interpreted as due to increasing sinuosity and permanence of flow which may have been partly temporally and partly spatially controlled. The predominance of coarse sediments is thought to be largely controlled by limited subsidence. The Lower Carboniferous transgression was the major overall control of alluviation.  相似文献   

7.
塔西南白垩系发育,可分为上、下两统。下白垩统克孜勒苏群可分4段,多以陆相沉积为主,富含棕红色砂砾岩夹少许砂岩、粉砂岩、泥岩和砾岩。上白垩统英吉沙群为海陆相并存,库克拜组可分2段,常见泥岩、膏岩和海相化石;乌依塔格组多为红色泥岩、泥质粉砂岩夹砂岩;依格孜牙组多见灰岩、白云质灰岩,富含海相化石;吐依洛克组为棕红色泥岩、石膏和砂、砾岩,含海相化石。通过勾勒9个岩性单元的沉积相展布,分析昆仑山前白垩纪的沉积环境演化过程。克孜勒苏群西区多为陆相快速堆积,东区远离陆源为三角洲和滨岸沉积,具有宽泛的冲积扇—辫状河三角洲相分布。库克拜组总体显示为辫状河三角洲—潮坪相变的过程;乌依塔格组以潮坪为主;依格孜牙组表现为碳酸盐岩台地—台地边缘的演化;吐依洛克组为宽广潮坪。  相似文献   

8.
新疆阿尔泰铁矿:地质特征、时空分布及成矿作用   总被引:18,自引:9,他引:9  
在前人工作基础上,文章综述了新疆阿尔泰铁矿地质特征和成矿背景.新疆阿尔泰铁矿赋矿地层主要为上志留统一下泥盆统康布铁堡组、中上泥盆统阿勒泰镇组和中泥盆统北塔山组,少数为下石炭统和下古生界.成因类型可划分为火山岩型、矽卡岩型、伟晶岩型、与花岗岩有关的热液型、与基性岩体有关的钒钛磁铁矿型和砂矿型6种,其中火山岩型和矽卡岩型为...  相似文献   

9.
安徽巢湖凤凰山石炭纪岩石特征及沉积环境分析   总被引:10,自引:0,他引:10  
巢湖市北郊石炭纪地层发育齐全,沉积环境多样,海平面升降频繁。根据岩性、生物与沉积构造等相标志,将其划分为开放海湾、潮坪、潮下浅滩、开阔台地等沉积相。对和州组顶部炉渣状灰岩的形成机制提出不同见解。  相似文献   

10.
依据在湖北武汉古姆山志留系浅海红层中新发现的古鱼类化石,确证了兰多维列统特列奇阶下部红层——志留系下红层在鄂东南地区广泛存在,并在前人工作基础上对武汉地区原坟头组进行了重新厘定,将其一分为二,上部仍为坟头组,下部则称清水组。新厘定后的坟头组以黄绿色、灰绿色、灰黄色泥岩、泥质粉砂岩、粉砂岩为主,富含腕足类、双壳类、腹足类、三叶虫和遗迹化石; 清水组下部以紫红色、红褐色泥岩、泥质粉砂岩为主,夹少量石英砂岩,上部以紫红色、黄绿色石英砂岩为主,夹泥岩、泥质粉砂岩、粉砂岩。在清水组上部新发现的鱼类化石包括盔甲鱼类锅顶山汉阳鱼(Hanyangaspis guodingshanensis)、意外洪山鱼(Hongshanaspis inexpectatus)、后棘江夏鱼(Jiangxialepis retrospina)及软骨鱼类中华棘鱼(Sinacanthus)、新中华棘鱼(Neosinacanthus)。这些新发现的古鱼均为张家界脊椎动物群温塘鱼类化石组合中的成员,其中,后棘江夏鱼可以跟产自江西武宁地区下红层清水组中的九江江夏鱼(J. jiujiangensis)直接对比,二者同属于真盔甲鱼目曙鱼科江夏鱼属,而曙鱼科成员则可以作为志留系下红层的标志性分子。根据鱼群面貌和地层层序,武汉地区的志留系下红层可以与皖、苏地区的侯家塘组、浙西北地区的唐家坞组、赣西北地区的清水组、湘西北地区的溶溪组以及新疆塔里木地区的塔塔埃尔塔格组进行很好的对比,其时代为志留纪兰多维列世特列奇期早期。华南板块志留系下红层的分布特征表明, 在特列奇期早期,上、下扬子海之间存在一狭长的浅海区域,这为盔甲鱼类在湖北武汉和江西武宁两地之间的扩散与交流提供了便利条件和可能。  相似文献   

11.
The island of Ishigaki Jima, located in the western part of the southern Ryukyu Arc, Japan, is underlain by a basement comprising the Tumuru and Fu-saki formations. The former is a pelitic glaucophane schist with a metamorphic age of 220–190 Ma, and the latter is a weakly metamorphosed accretionary complex, composed mainly of chert, mudstone and sandstone with minor amounts of limestone and mafic rocks. The Fu-saki Formation was weakly metamorphosed at ∼140 Ma. Latest Carboniferous–Early Jurassic microfossils have been obtained from the limestones, cherts and siliceous mudstones of this formation, but no fossils have been collected from the phyllitic mudstones. The radiolarian fauna of the phyllitic mudstones described herein indicates a late Pliensbachian–early Toarcian (Early Jurassic) age. This result, when combined with existing data, enables the reconstruction of an oceanic plate stratigraphy, showing a succession of (in ascending order) Upper Carboniferous–Triassic cherts, Sinemurian–lower Pliensbachian siliceous mudstones and upper Pliensbachian–lower Toarcian phyllitic mudstones and sandstones. The radiolarians from the phyllitic mudstones are important in constraining the timing of the accretion of the Fu-saki Formation to the base of the Tumuru Formation.  相似文献   

12.
Hydrocarbon shows occur in Cambrian sandstones in the Welsh Borderland. In Shropshire, sandstones of the Upper Comley Group in particular contain hydrocarbons infilling residual primary porosity and secondary porosity after leaching of feldspars. In the Malvern Hills, the Hollybush Sandstone is locally black due to an impregnation by hydrocarbons. Evidence from the distribution of hydrocarbons in other Lower Palaeozoic rocks and in Precambrian rocks in Shropshire suggests that they have migrated from hydrocarbon-bearing Carboniferous sandstones. However, the source of hydrocarbons for the Hollybush Sandstone may be the immediately superjacent Upper Cambrian black shales.  相似文献   

13.
邓敏  程锦翔  唐勇  付国斌  王正和  冯伟明  李嵘 《地质论评》2024,70(2):2024020016-2024020016
准噶尔盆地东部石钱滩凹陷石炭系巴塔玛依内山组火山岩之后发育一套连续稳定的碎屑岩沉积。笔者等通过XRD、主微量元素分析等手段针对其中的细粒沉积岩开展元素地球化学研究,其结果对恢复准东地区晚石炭世源区风化特征、古气候、判断其源岩性质及源区构造背景具有重要意义。研究表明,巴山组—石钱滩组泥岩具有低石英含量特点,其中巴山组泥岩黏土含量稍高,而石钱滩组泥岩中长石含量高,两者黏土成份均为蒙脱石(>99%),反映了干燥、寒冷的气候特征且沉积介质长期为碱性;CIA结果显示巴山组—石钱滩组时期经历了中等—弱化学风化作用,并具有干湿交替气候变化特征;主微量元素及相关判别图解显示巴山组—石钱滩组泥岩的源岩多以偏中性的长英质火山岩为主,少量中基性及少量偏酸性的火山岩物源,并且多数为未分异的弧;泥岩的地球化学特征反映了沉积物源区构造背景主要为大陆岛弧背景,结合石钱滩组碎屑锆石峰值年龄及主要物源区分析认为,野马泉地体与其南部的准噶尔地体东北缘于335 Ma左右开始由俯冲转变为碰撞造山。  相似文献   

14.
东昆仑地区发育一套显生宙碎屑岩地层,包括下寒武统沙松乌拉组、中—上奥陶统纳赤台群、上石炭统—下二叠统浩特洛哇组、下三叠统洪水川组、中三叠统希里科特组以及上三叠统八宝山组。研究区砂岩的CIA值反映沙松乌拉组砂岩源区化学风化程度较高,其余各组砂岩源区化学风化程度较低。主量和微量元素研究结果表明各组砂岩源区以长英质岩石为主,包含少量中性成分。La、Ce、Th、U、∑REE含量和La/Sc、Th/Sc、Sc/Cr、La/Y比值指示沙松乌拉组和纳赤台群砂岩沉积环境为大陆岛弧或活动大陆边缘,浩特洛哇组砂岩形成于被动大陆边缘环境,洪水川组砂岩沉积环境为活动大陆边缘,希里科特组砂岩的微量元素含量及其比值接近于活动大陆边缘和被动大陆边缘,八宝山组砂岩沉积环境为活动大陆边缘。综合分析认为沙松乌拉组和纳赤台群砂岩形成于原特提斯洋俯冲阶段,浩特洛哇组砂岩形成于古特提斯洋持续扩张阶段,洪水川组砂岩形成于古特提斯洋俯冲阶段,希里科特组砂岩形成于陆(弧)陆初始碰撞阶段,八宝山组砂岩形成于陆陆全面碰撞—碰撞后阶段。  相似文献   

15.
长江三峡东部地区震旦纪事件沉积?   总被引:1,自引:0,他引:1       下载免费PDF全文
长江三峡东部地区震旦纪先后发生了热事件、冷事件、重力事件等突发性灾变沉积。早震旦世发育由河流作用与陆地冰川作用形成的陆源碎屑沉积;晚震旦世则发育由两次台地-盆地-台地的海进-海退旋回形成的巨厚海相碳酸盐沉积。热事件沉积产物见于下震旦统莲沱组,夹于河流相沉积的砂岩及粉砂岩中。根据凝灰碎屑的岩石学特征,可将其分为降落型凝灰碎屑和水携型凝灰碎屑两类。冷事件沉积产物为下震旦统南沱冰碛层,属低纬度低高程的大陆冰川沉积。重力事件可分为滑塌事件和浊流事件,其沉积产物均分布于上震旦统,夹在大套的深水碳酸盐岩中。其中滑塌事件的沉积产物主要为滑塌角砾白云岩(石灰岩),浊流事件的沉积产物主要为浊积颗粒石灰岩(白云岩)。  相似文献   

16.
New outcrops of Middle Carboniferous glacigenic deposits found in the Guandacol Formation (western Paganzo Basin) are described in this paper. The study locality of Los Pozuelos Creek (northwestern Argentina) includes coarse-grained diamictites, rhythmites, laminated pebbly mudstones and shales that represent an expanded column of the Gondwanic glaciation in this region. Thirteen lithofacies recorded at the measured section have been grouped into three facies associations. Facies Association I is composed of coarse-grained massive and stratified diamictites (lithofacies Dmm, Dms, Dmg, Dcs), laminated siltstones with dropstones (Fld) and interstratified sandstones and mudstones (Fl, Sr). These rocks represent both tillites and resedimented diamictites closely associated to small water bodies where laminated siltstones with dropstones and stratified sandstones and mudstones were deposited. Facies Association II comprises couplets of matrix-supported thinly bedded diamictites (Dmld) and laminated mudstones with dropstones (Fld). This facies association results from the combination of three different processes, subaqueous cohesionless debris flows, coeval rainout of ice-rafted debris and settling of fine-grained particles from supension. Finally, Facies Association III is made up of laminated mudstones without dropstones, thin marl levels and scarce fine- to very fine-grained sandstones. This assemblage clearly suggests sedimentation in a deep marine environment below the wave base.The architecture of the glacigenic deposits has been investigated using photomosaic panels. The geometry of the depositional bodies and facies suggest that Los Pozuelos Creek outcrops exhibit a well preserved three-dimensional example of a grounding-line system. In particular, three different subenvironments of a morainal bank were interpreted: a bank-front, a bank-core and a bank-back. The bank-front assemblage is characterized by coarse-grained, mainly resedimented, diamictites grading laterally to prograding clinoforms composed of interbedded matrix-supported thinly bedded diamictite and mudstones. The bank-core assemblage is formed by a stacking of coarse-grained diamictites where at least five major erosional surfaces, bounding four multistory diamictite bodies, can be recognized. Finally, the bank-back assemblage corresponds to discontinuous intervals of striated lodgement till, and coarse-grained resedimented diamictites showing important post-depositional deformation. The retrogradational stacking of the morainal banks indicate an overall glacial retreat and a glacioeustatic sea-level rise. Erosional surfaces at the base of each morainal bank suggest intervening short term episodes of ice advance.The new data presented here confirm the existence of "true" tillites in western Paganzo Basin and suggest several (at least four) pulses of glacial advance and retreat during the Namurian glaciation in the region and permit a more refined interpretation of the glacial deposits in the Huaco area.  相似文献   

17.
从岩相古地理论中国南方石炭系油气潜景   总被引:8,自引:4,他引:4       下载免费PDF全文
石炭系是中国南方重要的海相含油气地层之一。下石炭统的油气生成条件比上石炭统的好,这和早石炭世的盆地面积较大有关。石炭系下伏的志留系和上覆的二叠系的油气生成条件比石炭系还要好。上石炭统的油气储集条件比下石炭统的好,这和上石炭统的白云岩和滩相石灰岩分布较广有关。石炭系油气藏的直接盖层是下二叠统下部的梁山组,区域盖层是中新生代的泥岩为主的地层。南方石炭系油气生储盖条件的配置关系相当好。但是,南方石炭系以及整个古生代和三叠纪海相地层均经历了多次大的构造变动,其油气藏形成条件遭受相当大的破坏。在有利的生储配置关系的基础上,在区域盖层和保存条件较好的及面积较大的中新生代沉积盆地中,尤其是在邻近石炭系本身或其下伏志留系油气源岩的地区,是寻找和发现石炭系新的油气藏的有利地区。  相似文献   

18.
塔里木盆地塔中32井中上奥陶统内潮汐沉积   总被引:11,自引:1,他引:11       下载免费PDF全文
塔里木盆地塔中32井的中、上奥陶统钻遇厚度为1 462 m。它是一套巨厚的深灰色泥岩、页岩与灰色砂岩、粉砂岩互层夹少量灰岩的地层。其中深灰色泥岩、页岩最多;砂岩和粉砂岩主要分布于上部和下部,中部砂岩和粉砂岩较少;鲕粒灰岩数量少,主要夹于深灰色泥页岩中。这些砂岩和鲕粒灰岩既可单独成层,但更常见它们与深灰色泥页岩组合成薄互层。薄互层中发育脉状、波状和透镜状层理,并普遍发育交错层理和双向交错纹理。这些特征表明砂岩和鲕粒灰岩为深水斜坡上的内潮汐沉积的产物。这些内潮汐沉积进一步划分为4种类型:双向交错纹理细砂岩型、单向交错层和双向交错纹理中-细砂岩型、韵律性砂泥岩薄互层型和鲕粒灰岩型。它们具有5种垂向沉积层序,在剖面上常形成多旋回韵律性沉积组合。  相似文献   

19.
Magmatic activity associated with the Munster Basin has been more widespread than previously reported. The Munster Basin is a substantial sedimentary basin, and towards the end of its extensional phase of development, at the beginning of the Variscan orogeny in Ireland, numerous intrusions were emplaced into consolidated Upper Devonian and Lower Carboniferous sediments on the Beara Peninsula. One hundred and sixty-four sills and dykes have been mapped which are subalkaline to alkaline in nature. Two separate suites have been identified. The northern suite comprises subalkaline basalts of Cod's Head and Dursey Island which are intruded into Devonian Red Beds, and the southern suite comprises alkali basalts, trachytes and phonolites which crop out along 9 km of the south coast of the Beara Peninsula and are suggested as Brigantian in age. They are intruded into Devonian Red Beds and marine Lower Carboniferous strata and are therefore later than the tholeiitic magmatism on the Iveragh peninsula to the north. The alkaline magmatism on Beara was induced by lithospheric thinning and controlled partly by pre-existing zones of weakness in the Caledonide crust and partly by fracture zones that developed parallel to the Munster Basin margin as it subsided. In contrast to the Iveragh Peninsula, the stretching factor for the Beara lithosphere was never large enough to lead to the production of tholeiitic magmas. © 1997 John Wiley & Sons, Ltd.  相似文献   

20.
楚雄盆地是青藏高原东缘“三江”构造带与扬子地台西缘结合部重要的含矿沉积盆地之一,以白垩纪地层赋存多个层位的砂岩型铜矿床为特征而不同于其他沉积盆地,长期备受关注。前人曾从矿床学角度进行砂岩铜矿床成矿作用相关研究,相对缺乏沉积学方面工作,进而导致对含矿岩系沉积环境及盆地属性和矿床成因认识的分歧。对楚雄盆地北部包括大村铜矿区在内的桂花地区晚白垩世含矿岩系进行了系统的地表调查、坑道及钻孔观测和沉积环境研究,认为该区上白垩统马头山组和江底河组是一套连续沉积组合,由河道亚相和边滩亚相沉积共同组成,形成于相对干旱的气候环境;沉积物源区位于盆地的北侧,曾出露有基性火山岩、花岗质岩石、碎屑岩、碳酸盐岩以及少量的变质岩等;晚白垩世时期,楚雄盆地具有北高南低的古地理格局,且在江底河组沉积成岩过程中,盆地总体曾经历了区域挤压作用引起的隆升破坏,也是区内砂岩型铜矿床的主要成矿时期。  相似文献   

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