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The paper describes the sedimentary features and biostratigraphy of the transitional Jurassic to Cretaceous deposits in the continental basins of Priamurie formed after the collision between the Siberian and North China blocks. In Upper Priamurie, the collision occurred in the late Early Jurassic as dated by the emplacement of the post-collisional granites (191Ma) . While in Lower Priamurie and West Priokhotie it could take place in the late Middle Jurassic on the basis of fossil evidence from an accretionary turbidite complex. This event reflected the environmental change from coastal-marine to alluvial plains, often boggy, where coals accumulated. The environmental change is in harmony with that of biota. Systematic study of floral and spores/pollen assemblages, particularly in the sections of interbedded marine and non-marine deposits, makes clear the chronostratigraphic succession of floral associations and shows the possibility of their application for subdivision and correlation of the continental deposits of Priamurie. The coastal-marine environment of the residual post-collisional sublatitudinal basins in the western part of Priamurie (Upper Amur and Dep basins) was replaced by the continental in the late Middle Jurassic and in the eastern part in the Berriasian-Valanginian ( Torom Basin) . Similar environmental change commenced in the submeridional rift basins: the Bureya Basin in the Callovian and the Partizansk Basin in the Hauterivian. Changes in ecosystems occurred frequently during theMiddle Jurassic-Neocomian, but the most substantial changes took place in the late Middle Jurassic and in the end of Late Jurassic.  相似文献   

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根据砂岩岩石薄片、石英阴极发光和重矿物组合分析,结合沉积构造及地震解释成果,对塔里木盆地库车坳陷东部上三叠统—中侏罗统物源体系及其演化进行详细分析,确定了物源方向及母岩性质。结果表明:塔里木盆地库车坳陷东部上三叠统—中侏罗统物源主要来自北部南天山造山带物源区,以岩浆岩和变质岩母岩为主,兼有少量沉积岩物源的影响。其中,塔里奇克组砂岩中陆源碎屑岩岩屑含量较高,阴极发光条件下不发光石英含量较高,重矿物组合具有高锆石、白钛矿和磁铁矿含量以及低石榴子石含量的特征,母岩可能为上奥陶统—上三叠统早期沉积;阿合组及阳霞组砂岩中岩浆岩岩屑含量升高,重矿物组合以较高的石榴子石含量为特征,阴极发光条件下石英主要为蓝紫色及棕褐色发光,其母岩主要来自二叠系及其下伏地层;克孜勒努尔组及恰克马克组砂岩中变质岩岩屑含量明显升高,石榴子石含量极高,阴极发光条件下棕褐色发光石英含量增多,表明变质岩母岩的影响增强。晚三叠世—中侏罗世,研究区物源区母岩演化具有明显规律性,即晚三叠世受较多沉积岩母岩影响,早侏罗世岩浆岩母岩供给增多,中侏罗世以变质岩母岩为主。晚三叠世,库车坳陷东部南天山造山带大幅抬升,导致大量变质岩母岩卷入造山带遭受剥蚀;早—中侏罗世,南天山造山带中段构造活动具有东西分段的特点,吐格尔明30团剖面以东早侏罗世砂岩率先具有高石榴子石含量的特点,而西部地区中侏罗世砂岩才大量出现石榴子石,表明南天山造山带中段的虎拉山及额尔宾山在早侏罗世隆升-剥蚀强烈,而哈尔克山在中侏罗世才进入强烈抬升期。  相似文献   

4.
本文在野外地质工作基础上,总结了永嘉下龙银金矿床的成矿地质背景,矿床地质特征和找矿方法等。进一步确认该矿体受上侏罗统西山头组酸性火山岩层所控制,矿石自然类型为含金银细脉浸染状黄铁矿化蚀变凝灰岩。属火山热液蚀变型。  相似文献   

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为揭示鄂尔多斯盆地多种能源矿产间的关系,根据盆地石油、油气伴生水以及煤、煤层夹矸、铀矿及围岩样品的氯仿沥青中57种元素的分析结果,进行了Q型聚类分析。结果表明:侏罗系下统延安组石油、侏罗系中统直罗组石油与三叠系延长组石油有相近的成因特征;三叠系延长组石油沥青、三叠系延长组含油砂岩沥青与侏罗系中统直罗组石油沥青具有类似的成因特征;神木侏罗系下统延安组煤沥青、东胜侏罗系中统直罗组煤沥青、铜川陈家山侏罗系下统延安组煤层石油以及铜川陈家山侏罗系下统延安组煤沥青成因特征相近;铜川陈家山侏罗系下统延安组煤层石油沥青可能与准格尔黑岱沟石炭二叠系煤沥青具有成因上的联系;侏罗系下统延安组石油沥青与放射性铀矿的形成具有密切关系;天然气的物质来源复杂,且与石油和煤的进一步演化有一定关系。鄂尔多斯盆地多种能源矿产成因较复杂、相互间关系密切,且具有多源性成藏(矿)特征。  相似文献   

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The Cretaceous of Afghanistan is marked by great facies diversity. The evolution of Cretaceous basins is part of a complex accretionary history involving three distinct tectonic units namely the Asian (Russian) Block separated from the Indian plate by a rather well defined transcurrent fault (Chaman-Nuski). The southwestern component is representedby the Iran-Afghanistan plate. The Lower Cretaceous of the Asian Block is represented by the Red-Grit Series which isconformable to the underlying Upper Jurassic sequences. The transition is marked by evaporitic facies dominated by salt,gypsum and marl deposits. In south Afghanistan volcanic rocks occur at Farah, with the emplacement of plutonics inwest-central Afghanistan. The Upper Cretaceous of north Afghanistan is marked by richly fossiliferous, lime stone-dominated sequences. The Upper Cretaceous of southern Afghanistan is marked by strong ophiolitic magrmatism.  相似文献   

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The Berezovsk coal mine in western Siberia has yielded the most diverse Middle Jurassic limnic and terrestrial vertebrate assemblage of Asia.The vertebrate remains were recovered by screen washing from flood-plain deposits on top of a thick coal seam of the Bathonian Itat Formation.A total of 29 vertebrate taxa has been recorded so far,including hybodontiform sharks,acipenseriforms,palaeonisciforms,amiiforms,dipnoans,anu-rans,caudates,turtles,squamates,choristoderans,crocodyliforms,pterosaurs,dinosaurs,tritylodontids,and a diverse mammaliaform and mammalian assemblage (eleutherodontids,docodontans,?amphilestids,dryo-lestids,and zatherians).The caudates are among the oldest in the fossil record and the anurans represent the oldest Asian record of this group.Among the mammals,Anthracolestes is the oldest and most basal known mem-ber of Dryolestidae and so far the only record from Asia.The vertebrate assemblage from the Berezovsk coal mine is very similar to that from the British Forest Marble Formation (Bathonian)and suggests a limited provin-cialism in the Middle Jurassic Laurasian landmass.  相似文献   

8.
The authors have reconstructed the original shape of Jurassic basin in Daqingshan region and discussed the movement and evolution pattern of the basin. The basin developed between Paleozoic strata sliver and metamorphic rock sliver in late stage of Early Jurassic and extended in latitude direction. The palco - terrene of the basin is higher in north and west than south and east. The boundary of basin is largest in Changhangou stage of Middle Jurassic. After middle Jurassic, the region took place Yenshan movement, and then the basin changed obviously from weakly extending environment of Early and Middle Jurassic to extruding environment of late Jurassic, and the paleoclimate of the basin changed from warmth and wetness to dry. The basin finished the evolution history in the late stage of Late Jurassic with the development of thrust.  相似文献   

9.
The Middle Jurassic Hangfanggou Formation is well exposed in Shangsanjiao and Xiasanjiao villages area,Baimashi town of Huludao,western Liaoning,China.Recently,abundant fossil plants were collected from the Hangfanggou Formation.One new species,Anomozamites sanjiaocunensis sp.nov.(Bennettitales),is described in this study.This is the first report of the genus Anomozamites from the Haifanggou Formation based upon the leaf morphology and epidermal structures.The discovery of the new species extends significantly the stratigraphic and geographic distribution of Anomozamites in the Middle Jurassic.It also shows that Anomozamites was a common member of Bennettitales once lived in the Middle Jurassic warm temperate region.The new species also improves the knowledge on understanding the leaf morphology,epidermal features and the diversity of Anomozamites during the Middle Jurassic.The epidermal characters of the new species and its associated plants reveal that the plants grew in a warm and moderately humid environment in the warm temperate zone.The presence of some deciduous plants,such as ginkgoaleans,czekanowskialeans and conifers,indicate the climate with seasonal fluctuations in temperature.  相似文献   

10.
江平盆地侏罗系为一套内陆河湖相沉积,地层结构及岩性变化复杂。可分3个基本层序组,其变化特征,反映了中晚侏罗世江平盆地从扩张到萎缩时期沉积变化规律和沉积体系域变化过程,具有物源丰富、湖水浅、相变快等沉积特点,其层序地层及体系域特征与大陆边缘盆地相比有较大的差异。  相似文献   

11.
In the Middle Jurassic,a large-scale tectonic-magmatic activities and hydrothermal mineralization occurred in the eastern Jilin province.The deposit types consist of the orogenic gold deposit,porphyry molybdenum deposit and skarn gold deposit,etc.,which constitute regional hydrothermal metallogenic series.The magmatic bodies related to mineralization belong to calc-alkaline series,which are characterized by active continental margins.The above-mentioned different types of deposits formed in a uniform tectonic setting,which resulted from the combined processes between the subduction of Pacific plate under the Eurasia plate and the persistent post-collisional convergent forces between the North China plate and the Siberian plate.The mineralizations were happening in the deceleration period,after which Paleo-Pacific plate was strongly subducted under the Eurasia continental block,i.e.transition period from compression to extension.  相似文献   

12.
辽西中生界义县组时代归属问题 ,争论已久 ,归纳起来主要有三种划分方案 :第一 ,隶属于侏罗纪 ;第二 ,隶属于白垩纪 ;第三 ,归属于为侏罗 -白垩纪 ,属跨纪地层。结合多年来各科研院所及生产单位采集的众多同位素年龄资料的分析及野外所见接触关系研究认为 :原义县组中下部层位岩性组合 ,根据其特征 ,需另建立组级岩石单位 ,应归属到上侏罗统 ,广义义县组上部层位一套岩性组合 ,需重新定义 ,时代应归属到下白垩统。  相似文献   

13.
The article presents the results of many years of studies of the Upper Cretaceous and Paleogene sediments in the territory of West Siberian Plain. The heterogeneous structure of these sediments in different regions of the plain is shown. The lithological and palynological characteristics of a number of studied wells drilled in different years in Omsk and Kulunda Depressions, in Baraba Lowland and Bakchar Basin are given. The obtained palynological data allowed to substantiate the age of the deposits and to make suggestions concerning their depositional environment, and to clarify the subdivision of geological section into formations. The sections of the Upper Cretaceous and Paleogene deposits in different lithofacial regions of the Western Siberia differ from each other in completeness, genesis, and paleontological characteristics. The Upper Cretaceous sediments in Western Siberia are represented by formations of both marine(Pokur, Kuznetzovo, Ipatovo, Slavgorod and Gan'kino Formations) and continental genesis(Lenkovo and Sym formations). The Paleogene sediments, with the exception of Oligocene, mostly have a marine genesis-these are Talitsa-, Marsyat-, Lulinvor-, Tavda-and Yurki formations, but there are also continental sediments(Ostrovnoje Formation). A large stratigraphic break in the Upper Cretaceous and Paleogene boundary deposits, covering a significant part of the Maastrichtian, Paleocene, Ypresian, and Lutetian stages of the Eocene, was established in the sourheast of the West Siberian Plain(Bakchar Basin, Baraba Lowland and Kulunda Depression). The most complete sections are located in the Omsk Depression, where the Upper Cretaceous Gan'kino Formation is covered by Talitsa and Lulinvor Formations of Paleogene age. The most important events occurring at the boundary of the Cretaceous and Paleogene in Western Siberia can be traced currently in a few sections located in the Trans-Ural area, since there was no sedimentation in the rest of the territory at that time.  相似文献   

14.
In the Korean Peninsula the Meso-Cenozoic basins were mainly formed due to fault block and block movement. The Mesozoic fracture structures correspond basically to modem large rivers in direction. Such faults were usually developed to rift and formed lake-type tectonic basin, such as the Amrokgang-, Taedonggang-, Ryesonggang-, Hochongang-, Jangphari-, Susongchon-, Pujon-, and Nampho basins. The Mesozoic strata are considered to be divided into the Lower Jurassic Taedong System, Upper Jurassic Jasong System, Upper Jurassic-early Lower Cretaceous Taebo System, and the Upper Cretaceous-Paleocene ( Chonjaebong, Hongwon, Jaedok Series). The Cenozoic block movement succeeded the Mesozoic fault block movement. The Kilju-Myongchon Graben and Tumangang Basin, etc, are the basins related to the fault zones developed from the Oligocene to Miocene. In addition, the Tertiary basins were formed in many areas in the Miocene (e. g. Sinhung, Oro, Hamhung, Yonghung, Anbyon, Cholwon, etc). The Cenozoic sedimentation occurred mainly from the late Oligocene to Miocene. The Kilju-Myongchon Graben was the fore deep connected to the sea and the basins inclined in the Chugaryong Fault Zone are intramountain basins. Therefore, coal-beating beds and clastic rocks in the intramountain basins and rare marine strata and terrigenous clastic rocks are main sedimentary sequences in the Cenozoic.  相似文献   

15.
新疆西昆仑甜水海地区位于乔尔天山-岔路口断裂带上,是新疆铅锌矿的重要富集区,成矿地质条件优越,已发现的矿(点)床达十余处。本次通过分析甜水海地区区域地质特征、地球化学特征及遥感异常特征等,划出2个铅锌矿成矿远景区,成矿层位主要为断裂带上的蚀变岩地层,矿床类型重点为层控型铅锌矿,找矿标志主要为构造破碎带周围白垩纪或侏罗纪地层及Pb、Zn化学元素异常区。  相似文献   

16.
Cai  Laixing  Xiao  Guolin  Zeng  Zhigang  Zhang  Xunhua  Guo  Xingwei  Wang  Shuping 《中国海洋湖沼学报》2020,38(4):1169-1187
The South Yellow Sea Basin(SYSB) has multiple sets of proven source rocks and good hydrocarbon prospects,but no industrial oil and gas has been explored at present.To solve this puzzle for petroleum geologists,we systematically investigated the marine hydrocarbon geological conditions based on cores and testing data from borehole CSDP-2,the first exploration well with continuous coring in SYSB.The qualities of source rocks are evaluated in detail according to organic matter abundance,type,and maturity.The reservoir characterization mainly includes porosity,permeability,and reservoir space.Displacement pressure test and stratum thickness are the main foundations for defining the caprocks.Then,the oil-source rock correlation in the Permian and stratum model are analyzed to determine the favorable source-reservoir-caprock assemblages.The results show that three sets of effective source rocks(the Lower Triassic,Upper Permian,and Lower Permian),two sets of tight sandstone re servoirs(the Upper Permian and Lower Silurian-Upper Devonian),and two sets of caprocks(the Lower Triassic and Carboniferous) combine to constitute the hydrocarbon reservoir-forming as se mblages of "lower-ge neration and upper-accumlation" and "self-generation and self-accumlation",thus laying a solid foundation for promising petroleum prospects.The three sets of marine source rocks are characterized by successive generation and expulsion stages,which guarantees multistage hydrocarbon accumulation.Another three sets of continental source rocks distributed across the Middle Jurassic,Upper Cretaceous,and Paleogene depression areas,especially in the Northern Depression,may supplement some hydrocarbons for the Central Uplift through faults and the Indosinian unconformity.The favorable Permian exploration strata have been identified in the Central Uplift of SYSB.First,the Lower Permian and Upper Permian source rocks with high organic matter abundance and high thermal maturity supply sufficient hydrocarbons.Secondly,the interbedding relationship between the source rocks and sandstones in the Upper Permian strata ensures that hydrocarbons have been migrated into the nearby Upper Permian sandstones,reflecting near-source hydrocarbon accumulation.Finally,the good sealing property of the Lower Triassic Qinglong Formation caprocks plays an indispensable role in hydrocarbon preservation of the Permian reservoirs.This conclusion is supported by direct oil shows,gas logging anomalous layers,and hydrocarbon-bearing fluid inclusions.  相似文献   

17.
Multiple sets of organic-rich shales developed in the Upper Paleozoic of the northwestern Guizhong Depression in South China. However, the exploration of these shales is presently at a relatively immature stage. The Upper Paleozoic shales in the northwestern Guizhong Depression, including the Middle Devonian Luofu shale, the Nabiao shale, and the Lower Carboniferous Yanguan shale, were investigated in this study. Mineral composition analysis, organic matter analysis(including total organic carbon(TOC) content, maceral of kerogen and the vitrinite reflection(Ro)), pore characteristic analysis(including porosity and permeability, pore type identification by SEM, and pore size distribution by nitrogen sorption), methane isothermal sorption test were conducted, and the distribution and thickness of the shales were determined, Then the characteristics of the two target shales were illustrated and compared. The results show that the Upper Paleozoic shales have favorable organic matter conditions(mainly moderate to high TOC content, type Ⅰ and Ⅱ_1 kerogen and high to over maturity), good fracability potential(brittleness index(BI) 40%), multiple pore types, stable distribution and effective thickness, and good methane sorption capacity. Therefore, the Upper Paleozoic shales in the northern Guizhong Depression have good shale gas potential and exploration prospects. Moreover, the average TOC content, average BI, thickness of the organic-rich shale(TOC 2.0 wt%) and the shale gas resources of the Middle Devonian shales are better than those of the Lower Carboniferous shale. The Middle Devonian shales have better shale gas potential and exploration prospects than the Lower Carboniferous shales.  相似文献   

18.
甘蒙地区北山盆地群发育大量煤系地层,但由于构造演化期次复杂,地震、钻井及相关的古生物资料缺乏,导致煤系地层的时代归属一直存在争议,资源潜力尚未明确。为了明确北山盆地群含煤系地层的时代归属,进一步确定资源潜力,为研究区的能源资源勘探提供基础资料,在系统总结前人研究成果的基础上,以古生物年代学为抓手,以北山盆地群黑鹰山盆地、公婆泉盆地及中口子盆地煤系地层中丰富的孢粉、古生物资料为主要依据,结合煤系地层的岩石组合特征、煤岩工业特性、地震资料等证据对北山盆地群煤系地层时代归属进行了整体研究,重新厘定了北山盆地群煤系地层的时代归属。认为北山盆地群中各个盆地均发育了一套含煤层系,但这套含煤层系的时代归属并不相同,有的属侏罗纪、有的属白垩纪。仅北山盆地群最南部的中口子盆地南部区域以及盆地群最北部的黑鹰山盆地东部的含煤岩系为侏罗系,其他次级盆地的含煤岩系均属于白垩系。盆地群南部中口子盆地含煤岩系的归属问题呈现出和构造相一致的"南北差异",南缘出露煤系地层时代为中侏罗世,北部煤系地层时代为白垩纪。含煤层系归属问题的厘定为进一步确定盆地区的资源潜力提供了依据,可为北山盆地群含煤层系的原型盆地恢复及构造演化等研究提供参考。   相似文献   

19.
1984年秋,我们在山东省莱阳县团旺乡南李格庄和团旺村莱阳组第三段采集了昆虫化石。这个地区以往昆虫化石发现较少,仅秉志(C.Ping)在1928年描述了3个采于团旺的种:黑隐翅摇蚊(Chironomaptura melanura Ping)、长肢裂尾(虫甲)(Coptoclavalongipoda Ping)和莱阳中长蝽(Mesolygaeus laiyangensis Ping)。莱阳盆地南部的昆虫化石极其丰富,本文共描述了其中6科10属10种,其中1新科6新属6新种,两个已知属  相似文献   

20.
Three new species of fossil woods are reported from the Upper Jurassic to Lower Cretaceous in southeastern Mongolia,including Protaxodioxylon mongolense sp. nov. Circoporoxylon mongolense sp. nov. Protocircoporoxylon mongolense sp. nov. The anatomical characters of three new species are described in detail.  相似文献   

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