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1.
中国上石炭统上部及下二叠统海相地层中阶的划分   总被引:8,自引:0,他引:8       下载免费PDF全文
明确而详细地提出了中国上石炭统上部及下二叠统海相年代地层单位的具体框架。将上石炭统上部划分为消遥阶、下场家河阶;下二叠统划分为上杨家河阶、范家河阶、垭口阶及隆林阶。明确了阶的定义、动物群特征、磁性地层特征及其与相关地层的关系。所划分的阶均能与世界标准年代地层进行详细而有依据的对比。  相似文献   

2.
The Rotliegend beds of the middle of the Kusel Group to the middle of the Lebach Group in the Saar-Nahe Basin are characterized by sedimentary sequences which developed in streams, deltas, and lakes. The stream sequences consisting of cross-stratified sandstone units are attributed to braided fluvial environment. The lake-delta sequences usually show gradual transition from lacustrine mudstones to delta-front cross-stratified sandstones and to floodbasin, crevasse and overbank sandstones and mudstones. Loaded high-intensity flows occasionally result in deformation- and erosion-structures. Low-energy lacustrine sedimentation is evident from paper-shales and massive mudstones. The mudstones alternate with cross-laminated sandstones where influenced by terrigenous influx.  相似文献   

3.
鄂尔多斯盆地上石炭统—中二叠统砂岩物源分析*   总被引:5,自引:3,他引:5       下载免费PDF全文
对区域地质、地层接触关系、砂岩组分、重矿物及微量元素等的综合分析与研究结果表明,鄂尔多斯盆地北部上石炭统—中二叠统砂岩的物源区主要为再旋回造山带物源区,并可划分出乌海—银川、杭锦旗—东胜及准格尔旗—府谷3个物源区。受物源分异的影响,盆地内部石英砂岩分布以杭锦旗—东胜为界,具有明显的东西分区性。其中石英砂岩主要分布于盆地西部,古水流、重矿物及砂岩组分指示物源来自阿拉善古陆。而盆地东部总体上是岩屑砂岩的覆盖区,物源主要来自盆地北部和东北部阴山地区。盆地西南部及南部砂岩的物源区为克拉通地块和再旋回造山区,物源区与秦祁造山带的演化关系密切,具有稳定与活动的双重特性,可划分出海原、同心—中宁,平凉—固原、环县及耀县—宜君、富县3个主要物源区。南北物源汇水区在环县—富县—乡宁一带,呈北西西向狭长带状延伸,并从山西期—盒8期呈逐渐南移趋势。盆地西部物源到下石盒子组沉积时期才提供粗碎屑物质补给,以含有较多的长石石英砂岩为特征。周至柳叶河石炭—二叠系砂岩的物源区为再旋回造山带物源区和陆块物源区,为北秦岭造山带内山间盆地,属于盆地外缘,并与鄂尔多斯盆地呈连续过渡的关系。  相似文献   

4.
贵州盘县达拉上石炭统—下二叠统含(竹蜓)地层   总被引:1,自引:1,他引:1  
<正> 贵州的石炭二叠系发育齐全,分布广泛,出露良好,生物化石极为丰富。作者观察了紫云、六枝、朗岱、普安、晴隆和盘县等地石炭二叠纪地层剖面,实测了盘县达拉剖面,(竹蜓)类自上而下可分为5个化石带: 下二叠统:  相似文献   

5.
利用110余口钻井的录井和测井资料,结合地震资料,运用沉积学原理和层序地层学原理,建立了塔里木盆地上泥盆-下石炭统层序地层格架.自下而上,塔里木盆地上泥盆-下石炭统发育东河层序(SQd)、巴楚1层序(SQb1)、巴楚2层序(SQb2)、卡拉沙依1层序(SQk1)共4个三级层序,每个层序均可划分出海侵体系域(TST)和高...  相似文献   

6.
本文划分论述了浙江省上石炭统-中二叠统16条化石带(其中11条为新建化石带),对比研究结果表明它们分布于老虎洞组、黄龙组、船山组、梁山组、栖霞组、孤峰组、龙潭组下部的地层,可分别与滑石板阶、达拉阶、逍遥阶、紫松阶、隆林阶、栖霞阶、祥播阶、茅口阶、冷坞阶等9个阶对比.探讨研究了上石炭统底界、下二叠统底界和中二叠统底界;指出上石炭统未见底,缺失罗苏期的沉积;下二叠统底界位于Sphaeroschwagerina subrotunda带之底,以Sphaeroschwagerina属的始现作为底界的标准;石炭-二叠系界线位于Triticites subcrassulu (竹蜒)带与Sphaeroschwagerina subrotund (竹蜒)带之间;中二叠统的底界位于Orthotichia chekiangensis腕足组合带之底,以Orthotichia chekiangensis的始现作为中二叠统底界的标准.进一步论证了船山组是一个跨越石炭-二叠系界线的岩石地层单位,下部归属上石炭统逍遥阶,中部归属下二叠统紫松阶和上部归属下二叠统隆林阶.  相似文献   

7.
Investigation of the Upper Carboniferous to Lower Permian sedimentary strata of central Spitsbergen shows that this highly cyclic rock succession is composed of four long-term transgressive–regressive cycles. These long-term cycles are themselves composed of stacked higher order cycles. Transgressive phases are characterized by increasing accommodation space, and include a basal transgressive part of marked retrogradation of facies belts and thickening-upward component cycles. Regressive phases are characterized by decreasing accommodation space, displayed by progradation of facies belts, overall shallowing and increased restriction of the depositional environment, influx of coarse terrigenous sediments and increasing evidence of exposure and/or non-deposition. The oldest transgressive–regressive sequence identified, Sequence 1, is of Serpukhovian to Bashkirian age and represents a syn-rift sequence. Also composed of syn-rift sediments is the transgressive–regressive Moscovian to mid-Gzhelian-aged Sequence 2. The late Gzhelian to late Asselian Sequence 3 is mainly a post-rift sequence. The youngest sequence, Sequence 4, is of Sakmarian to possible Artinskian age, and is also composed of post-rift sediments. The individual transgressive–regressive cycles are defined as second-order cycles, based on lithological signatures, lateral extent of bounding unconformities, and the actual time period the cycles span. Local tectonic activity is believed to control to some extent the development of short-term cycles in the syn-rift succession. However, cyclicity within the long-term cycles is mainly controlled by eustatic sea-level fluctuations, and therefore enables them to be correlated to other Circum-Arctic regions. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

8.
Deposition of the Gully Oolite was locally interrupted by emergence and a regionally extensive palaeosol is present at the top of the unit. Early diagenetic phases include isopachous, fibrous submarine cements, nonluminescent vadose cements, and mixing zone dolomite. Subsequent nonferroan phreatic cements are non- to dully luminescent and in restricted vertical intervals predate significant compaction. More usually, however, phreatic cements postdate extensive overpacking of allochems. Ooid isotopic composition (δ18O=-7·80° to -3·10° and δ13C = -2·38° to +3·28°) is similar to that of associated phreatic cements and the data suggest that the bulk of ooid stabilization and cementation occurred within meteoric groundwaters. The extensive allochem overpacking appears to have occurred during the first few tens of metres of burial and intergranular macroporosity was eliminated prior to deep burial. Fracturing of the Gully Oolite during the Hercynian Orogeny and subsequent post-orogenic uplift led to localized dolomitization, several generations of calcite veins, and the restricted occurrence of 18O depleted cements in inter- and intragranular microporosity. Some of the veins clearly relate to Triassic exhumation of the Carboniferous Limestone, but others may be related to post-Mesozoic uplift and erosion of South Wales. Fracture-associated dolomitization may have occurred within a large-scale post-orogenic groundwater system, with Mg2+ being supplied through the release of deeply buried diagenetic brines.  相似文献   

9.
10.
Upper Devonian and Lower Carboniferous Sequence Stratigraphy of South China   总被引:9,自引:0,他引:9  
SequencestratigraphyhashopaidmoreattentionforitSrelativelycompletetheoreticalsyStemandgreatsuchesinpracticesinceitwasadvancedinthe197ds.Integratingonthedataofbiostratiglaphy,lithostratigraphy,seismicstfstigraphy,geochendstryandsedirnentology,sequencestratigraphyattemptStoestablishachronostratigraphicframeworkandcormectsdepositionalsequencewithglobalsealevelchange,andhencemakeSitpossibletOpreciselycorrelatethestrataindifferentfactesareasoveraconsiderabledistance,evenovertheworld.TheUpperDevon…  相似文献   

11.
下扬子盆地石炭纪的岩石学特征及沉积相   总被引:5,自引:0,他引:5  
位于扬子板块东部的下扬子盆地,在石炭纪时,为被动大陆边缘的陆表海沉积,陆源碎屑来自于北边的胶南古陆和南边的江南古陆东延部分─—皖浙赣古陆。石炭系分为上、下两统。早石炭世,盆地南部宣城、广德等地主要发育碎屑岩,中部巢县、南京一带以及北部滨海、洪泽一带为碎屑岩和碳酸盐岩沉积。从南往北,金陵期从滨岸碎屑岩相→开阔海台地碳酸盐岩相→潮坪碳酸盐岩和碎屑岩相;高骊山期为滨岸平原沼泽碎屑岩相→浅海陆棚碎屑岩相→海岸萨布哈白云岩、石膏、碎屑岩相;和州期盆地南部隆起,中部到北部为礁及礁后泻湖一潮坪碳酸盐岩相→开阔海台地碳酸盐相。晚石炭世主要是碳酸盐沉积,黄龙期从滨岸石英砾岩相→潮坪白云岩相→开阔海台地碳酸盐岩相;船山期是黄龙期开阔海台地碳酸盐岩相的继续,以发育核形石生物碎屑颗粒岩为特征。整个盆地的岩相带均以NEE—NE方向展布。  相似文献   

12.
广东省二叠纪含煤地层分布很广,其含煤性居各主要含煤地层之首,占目前全省探明储量的70%,是勘探和开采的主要对象。为了进一步探索二叠纪的成煤规律,扩大找煤远景,对二叠纪地层进行深入研究与划分对比,很有必要。  相似文献   

13.
Volcanic breccias near an intrusive rhyolite dome in the Permian Saar-Nahe trough of southwest Germany have been identified as complex pipe-like subsidence-structures occupying the site and immediate neighbourhood of explosive volcanoes.At the Rödern, at first fine-grained, well-bedded and later coarser-grained and poorly bedded pyroclastic materials were deposited on top of a lava flow that formed the regional surface. Collapse along a ringfault with differential subsidence of 500 to 700 m produced a saucer-shaped structure in which steeply dipping pyroclastic beds still overlie the lava flow on which they were originally deposited. In the actual feeder, large blocks of country-rock subsided individually prior to wholesale subsidence of the entire feeder-content. Intrusion of a high alumina quartz tholeiite into the pyroclastic beds terminated the activity.The Hirschberg structure has essentially the same history, but is more fragmented. Subsidences vary between 150 and 260 m. Intrusion of petrographically and chemically similar basalt took place mainly near the margin of the ringfault.Three smaller structures also contain bedded pyroclastic deposits that subsided approximately 600, 1100, and 1400 m. The surface expressions of these five collapse structures are assumed to have been small collapse-calderas with diameters of several 100 m. to 1.5 km.
Zusammenfassung Vulkanische Brekzien im Rotliegenden der Umgebung des Donnersberges in der Saar-Nahe-Senke/Pfalz liegen in Einbruchsstrukturen vor, die den ursprünglichen Schlot und seine unmittelbare Umgebung einnehmen.Am Rödern wurden ehemals auf einer Olivin-Basalt-Lava feinkörnige und spÄter grobkörnige Pyroclastica abgelagert. Einbruch an einem Ringbruch und differentielle Absenkung zwischen 500 und 700 m führte zur Anlage der trichterförmigen Struktur der geschichteten Pyroclastica. Trotz der Absenkung liegen sie immer noch mit ungestörtem Kontakt, jedoch nun steil einfallend, dem mitabgesenkten Olivin-Basalt auf.Am ursprünglichen Schlot ist Absenkung einzelner gro\er Nebengesteinsschollen und nachfolgend des gesamten Schlotinhaltes festzustellen. Die vulkanische AktivitÄt wurde durch Intrusion eines high-alumina Quarz-Tholeiites abgeschlossen.Der Hirschberg weist im wesentlichen die gleiche Struktur und Entwicklungsgeschichte auf, ist jedoch in mehrere Schollen untergliedert. Die BetrÄge der differentiellen Absenkung liegen zwischen 150 und 260 m. Infolge der Zerblockung innerhalb des Ringbruches intrudierte Basalt vorwiegend im Bereich der Verwerfungen, also am Ringbruch und zwischen einzelnen Schollen.Drei kleinere Strukturen enthalten ebenfalls geschichtete Pyroclastica und weisen maximale AbsenkungsbetrÄge von 600, 1100 und 1400 m auf.Im Bereich der ursprünglichen ErdoberflÄche müssen infolge der Einbrüche tiefe Krater vorgelegen haben, die als kleine Einbruchscalderen bezeichnet werden können.

Résumé Aux alentours du «Donnersberg» dans la «Saar-Nahe-Senke» (Palatinat, Sudouest de l'Allemagne) des brèches volcaniques du Permien inférieur sont conservées à l'intérieur de structures d'effondrement. Celles-ci se trouvent au lieu mÊme de la cheminée originale et à ses alentours immédiats.Une de ces structures, le «Rödern», est caractérisée par des dépÔts pyroclastiques — fins à la base et plus grenus vers le sommet — couvrant des laves basaltiques à olivine. L'effondrement à l'intérieur d'une faille annulaire et une subsidence différentielle de 500 à 700 m ont eu comme résultat une structure rappelant un entonnoir. Les dépÔts pyroclastiques stratifiés reposent, quoiqu'avec un pendage fort, toujours en superposition normale et non faillés sur les basaltes à olivine qui eux aussi ont été affectés par la subsidence.A la cheminée mÊme on constate l'affaissement de grands panneaux de roches encaissantes suivi de l'effondrement de tout le remplissage de cheminée. L'activité s'achève par des venues d'une «high-alumina Quarz-Tholeiite».Le «Hirschberg», dont la structure et l'évolution ressemblent à celles du «Rödern», est caractérisé par une fragmentation du bloc effondré. L'affaissement de différents panneaux varie entre 150 et 260 m. Suite à la fragmentation de nouvelles venues basaltiques prennent place, soit le long de la faille annulaire, soit le long des failles entre les differents panneaux.Des dépÔts pyroclastiques stratifiés sont conservés encore dans trois autres structures plus petites. L'affaissement à l'intérieur de ces structures est de 600, 1100 et 1400 m au maximumQuant à la morphologie de la région après l'effondrement, on peut supposer qu'elle était caractérisée par l'existence de cratères profonds (caldères d'effondrement).

, Donnersberg ( -, ) , . - Rödern - , . - 500–700 , . , .- , . . - Hirschberg, , , . 150–260 . , . . . - ; 600, 1100 1400 . - , , , , .
  相似文献   

14.
根据镜下薄片统计结果,参照野外观察,采用R型和Q型聚类分析方法对贵州省紫云县宗地乡上石炭统达拉阶—下二叠统隆林阶的沉积环境进行了研究。分析结果表明,贵州宗地达拉阶—隆林阶存在11种微相类型,分别为深水局限泻湖、浅水局限泻湖、深水藻丘、接近浅滩的洼地、台地边缘浅滩、深水泻湖、浅水藻丘、浅水泻湖或潮坪、潮汐砂坝、局限浅滩或泻湖和深水斜坡等环境的沉积。不同的微相类型在剖面纵向上构成了6个微相组合,代表了沉积环境依时间变化的6个基本过程:浅滩或潮坪—开阔台地—藻丘—局限台地—深水斜坡—局限藻丘。  相似文献   

15.
宜洛盆地晚二叠世-三叠纪沉积充填演化是秦岭造山带与华北克拉通共同作用的结果,物源分析是揭示盆山耦合的重要手段之一。论文采用沉积地球化学分析的方法对宜洛盆地上二叠统-下三叠统泥质岩地球化学特征与物源进行了研究,结果表明:宜洛盆地泥质岩稀土元素球粒陨石标准化曲线显示轻稀土元素富集,重稀土亏损,为右倾式曲线,元素Eu中度负异常,元素Ce轻微亏损,符合上地壳稀土元素分布特征。泥质岩源区源岩属性判别图解显示,宜洛盆地物源以长英质岩为主,主要来自于上地壳,孙家沟组后期有少量古老基底杂岩混入。构造背景判别图解显示,研究区物源经历了被动大陆边缘为主(孙家沟组下段)-活动大陆边缘为主(孙家沟组上段和刘家沟组)-大陆岛弧为主(和尚沟组)的演化;华北克拉通和秦岭造山带是宜洛盆地重要物源区,华北地台北部内蒙古隆起可能提供了一定量的物源。孙家沟组早期以克拉通内部物源为主,孙家沟组土门段之后秦岭微地块物源供给明显,体现了华北克拉通南缘基底隆升,由被动大陆边缘向秦岭初始"弧-陆"碰撞隆升的构造演化过程。这对深入揭示南华北盆地与周围造山带之间的耦合关系具有重要意义。  相似文献   

16.
Sediments of the Upper Carboniferous to Lower Jurassic Karoo Supergroup (∼ 4.5 km thick) were deposited in the mid-Zambezi Valley Basin, southern Zambia. The Upper Palæozoic Lower Karoo Group in this area ends with a Late Permian sedimentary unit called the Madumabisa Mudstone Formation. The formation is 700 m thick and comprises four lithofacies grouped into two facies assemblages, collectively interpreted as lacustrine deposits. Sediments of a massive mudrock facies assemblage were deposited from suspension, probably from sediment-laden rivers entering a lake. Concretionary calcilutite beds probably mark the positions of palæosediment-water interfaces where calcite was precipitated. A laminated mudrock facies assemblage is attributed to lacustrine deposition from inflowing rivers at the lake margins and shallow parts of the lake. Repeated thickening-upward cycles are evidence of upward shallowing, interrupted by events of more abrupt deepening. Sandstone interbeds are interpreted as fluvial deposits laid down during low lake stands, with cross-lamination and asymmetrical ripples indicating current rather than wave deposition. A fossil assemblage of ostracods, bivalves, gastropods, fish scales, the alga Botryococcus sp. and fossil burrows is consistent with a lacustrine origin for the formation.  相似文献   

17.
Prabir Dasgupta   《Sedimentary Geology》2008,205(3-4):100-110
Four types of soft-sediment folds of distinct geometry can be recognized in the upper part of the Talchir Formation (Lower Permian) of Jharia Basin, India. These folds, on systematic examination, indicate some events of progressive deformation. Experimental study reveals that if a layered stack of clay and overlying sand is allowed to flow slowly down a slope, differential velocity due to viscosity contrast leads to the deformation of the rheologic interface. The sharp planar contact gradually becomes wavy leading to the development of round-hinged folds involving sediments adjacent to it. With the advancement of the flow these folds gradually become overturned with the rotation of the axial plane in the direction of flow. Computer simulation suggests that progressive deformation of these folds by simple shearing may lead to the formation of tight isoclinal folds, which on dislocation along intrastratal normal faults may lead to the development of rootless isoclinal folds. The sheath folds observed in the studied section also indicate accentuation of the curved hinge due to simple shearing. The spatial distribution of these fold types in conjunction with the inferred direction of progressive deformation indicate basinward translation of the slump slice. If the same stack of sediments rapidly flows down the slope, the waveform generated at the interface quickly breaks in the form of roll-up recumbent fold due to Kelvin–Helmholtz instability.  相似文献   

18.
提要:笔者在查干敖包地区开展1∶5万区域地质调查工作时,发现本区出露的宝力高庙组层序齐全、植物化石丰富、划分标志明显,通过路线调查、剖面测量对其进行了重新划分,即据岩性组合、生物面貌等特征划分为4个岩性段,一段为河湖相灰色、灰绿色碎屑岩夹少量中性火山岩,在粉砂岩中采到了大量安格拉植物化石;二段为中偏碱性-酸性砖红色、紫色火山岩夹砂(砾)岩,其中粗面岩获得锆石U-Pb同位素年龄为(297.0±1.2) Ma;三段为灰色、灰紫色安山质火山岩夹碎屑;四段以灰白色流纹质火山岩为特征,夹砂岩、泥灰岩等,在砂岩中采到了大量安格拉植物群化石。据植物化石鉴定结果、同位素年龄资料将其形成时代确定为晚石炭—早二叠世。  相似文献   

19.
王薇  季汉成  门相勇  艾嘉仪 《现代地质》2013,27(5):1051-1057
近几年的勘探开发发现,鄂尔多斯盆地东南缘下二叠统具有巨大的非常规天然气资源潜力。为探明其沉积环境,在详细的岩心、测井及室内分析化验的基础上,运用沉积学理论,对鄂尔多斯盆地东南缘下二叠统沉积相进行研究。研究结果表明:太原组发育障壁岛、泻湖、潮坪、浅海陆棚沉积,山西组发育三角洲、湖泊沉积;自太原组至山西组沉积环境经历了由海陆过渡相至陆相的演化过程。  相似文献   

20.
Dolomite occurs in open-shelf packstones and grainstones of the Vincent House Member of the Woo Dale Limestones Formation (Lower Carboniferous) in the Wye Valley area, east of Buxton, Derbyshire, Central England. Two stages of dolomitization can be recognized. Stage 1 consists of limpid, non-luminescent dolomite lacking detectable iron and manganese. Stage 2 comprises cloudy, inclusion-rich, orange-red luminescing dolomite with significant iron and manganese. The contact between the two stages is irregular and suggests a hiatus between dolomite growth stages. Dolostones lacking any unreplaced limestone may contain up to 35% calcite cement rilling intercrystal porosity. This cement shows a characteristic zonal sequence and is normally in optical continuity with the surrounding dolomite crystals. In some cases, precementation compaction of the dolomite mosaic caused fracturing of the crystals. Sherds of dolomite on the floors of pore-spaces then provided the nucleus for growth of calcite cement. The petrographic character and stratigraphic distribution of the dolomite suggest that dolomitization occurred at depth, during burial of the Woo Dale Limestones in the Late Carboniferous. Dolomitizing solutions, expelled from basinal shales, moved up-dip along permeable limestones or along the sub-Carboniferous unconformity. Fluids responsible for the generation of stage 2 dolomite may have been contaminated by ions such as iron and manganese released from the alteration of volcanic rocks which occur beneath the Carboniferous Limestone in the Wye Valley area.  相似文献   

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