共查询到19条相似文献，搜索用时 406 毫秒
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辽宁侏罗系—白垩系的界限有五种以上的划法。同位素年龄料资提供了以义县组底部为白垩系底界的时代依据,而焦点仍是热河生物群的时代归属问题。其中植物、孢粉、轮藻、介形虫及昆虫等群类都支持热河群属早白垩世。一些有争议的鱼、叶肢介、瓣腮,腹足等动物化石,从国内外的分布看,可以进入早白垩世,故本文将含热河生物群的义县组以上层位归于白垩系,即侏罗—白垩系的界限应置于上侏侏罗统土城子组与下白垩统义县组之间。 相似文献
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《广东海洋大学学报》2018,(6)
【目的】研究鄂尔多斯盆地南部油砂的时代归属及古气候特征。【方法】基于油砂上下层段的孢粉化石的研究,追溯了孢粉组合的时代,并通过古植被分布特征恢复古气候。【结果】本组合中以裸子植物花粉占绝对优势,其中以古松柏类Paleoconiferae和松科Protopinus、Pseudopicea、Piceites、Pseudopinus为主,蕨类植物孢子较少。同时我们识别出多个具有时代特征的孢粉类型。【结论】推测油砂富集层位可能为下侏罗统延安组。依据孢粉谱和孢粉类群的古生态特征,认为在下侏罗统延安组沉积时期,气候温暖潮湿,大量存在常绿针叶林植被及少量草本和灌木,整体属于温带—亚热带气候。 相似文献
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根据华北地层大区下寒武统引用地层单位的特征岩性组合构成及其与鲁中特征岩性组合序列的对比,按照"两灰两红"的沉积格局,建立完整连续的岩石地层单位序列:雨台山组—李官组—余粮村组—馒头组。山西及以西各地的霍山组与馒头组的底部层位相当。 相似文献
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田师傅植物群系我国北方典型的早中侏罗世植物群之一,产自辽宁本溪田师傅盆地及风城赛马-(?)阳盆地的下侏罗统长梁子组、中侏罗统大堡组及三个岭组。该植物群由34属77种植物组成。本文通过含植物化石地层剖面简介阐明化石的产地和层位,对以往的化石名单进行修订,对部分重要化石作了描述。 相似文献
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通过对漠河盆地东北部"上侏罗统"开库康组的研究,发现了其与下伏中侏罗统二十二站组之间的不整合面,同时对开库康组砂岩和火山岩夹层进行了LA-MC-ICP-MS锆石U-Pb定年,获得的2个样品中最年轻的碎屑锆石206Pb/238 U加权平均年龄均为159 Ma,反映了沉积下限不早于晚侏罗世;在其内的火山岩夹层中获得的岩浆锆石206Pb/238 U年龄分别为(136.6±1.9)、(137.5±2.5)Ma,该年龄与开库康组内发育的Coniopteris-Phoenicopsis植物群晚期化石组合和Ruffordia-Onychiopsis早期化石组合反映的时代吻合,表明开库康组形成于早白垩世早期,而非原划分的晚侏罗世。开库康组形成时代及其下伏地层锆石U-Pb年龄揭示了构造不整合面形成于137~145Ma,进一步约束了蒙古—鄂霍茨克洋闭合之后漠河逆冲推覆构造形成时间及从侏罗纪伸展盆地转化为白垩纪挤压山间盆地的时代。开库康组时代的重新厘定对进一步研究漠河盆地与蒙古—鄂霍茨克造山带的关系提供了新的资料。 相似文献
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本文根据天台测区1：5万区域地质调查工作成果，综合测区构造，岩石组合，岩石化学、化石，接触关系特征等资料分析，对三门海游构造火山盆内龙珠山─下路朱一带及芹溪、三门中学等地出露约70km2的火山─沉积岩系地层，进行层位归属讨论。指出海游盆地内龙珠山、里金、下路朱一带及芹溪、三门中学等地出露的火山─沉积岩地层，其层位应归属下白垩统永康群馆头组和朝川组，系属北北东向展布的早白垩世临海断陷地的组成部分。 相似文献
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楠溪江中下游地区发育大面积中生代火山-沉积岩系。可分为晚株罗世和早白垩世两个时代的不同火山岩系,其岩石化学、地球化学、同位素等均具不同的演化规律和模式,岩浆来源也有区别。粗安质或粗面质火山岩的发育可能是浙东南沿海白垩纪火山岩的一个特色。 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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DING Qiuhong FU Xiaoping LI Yong ZHANG Wu . Shengyang Center of Geological Survey China Geological Survy Bureau Shenyang China . Shenzhen Fairy Lake Botanical Garden Shenzhen Guangdong 《东北亚地学研究》2011,(2)
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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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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Reservoir Volcanic Rocks: Geology and Geochemistry, the Mesozoic Non-Marine Songliao Basin, NE China
Pujun Wang Zhiqiang Feng Frank Mattern Xuanlong Shan Wanzhu Liu Rihui Cheng Chunguang Qiu Huafeng Tang Yan Zhang Quanlin Li Nuan Wen 《世界地质(英文版)》2003,6(2)
The reservoir volcanic rocks in Songliao Basin include the Lower Cretaceous (Klyc Form., 114～135 Ma,acidic rocks) and the Upper Jurassic (J3hs Form., 145～158 Ma, intermediate rocks). Vesicles coupled with faults make the volcanic reservoir spaces which do not as badly getting worse with buried depth as those of sediments generally doing. The flood rhyolites of the Lower Cretaceous cover ca. 100 000 km2 with relict thickness from 100 m to more than 1000 m. They are high-silica, rich in aluminum and potassium, high REE contents with large negative Eu anomalies,thus believed also be formed by the large-scale sialic crust partial-melting. The andesitic rocks of the Upper Jurassic are rich in Al and K, but with lower REE contents and minor negative Eu anomalies, as well as dispersal patterns of HREE.They are believed to be produced by progressively shallower partial-melting where the fractionation of garnet and/or zircon may be involved. The most probable heat sources provided for the long-lasting volcanisms in the Songliao Basin is the subduction of the Okhotsk plate. 相似文献
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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 modern 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-Myonchon 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-bearing 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
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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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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
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辽宁北票鸟化石群国家级自然保护区，地层主要包括金岭寺群上部土城子组和热河群下部义县组。保护区鸟类化石群保存完好，仅“核心区”２ｋｍ２就共采出鸟化石约８００枚，已鉴定出６属８种，创下了古鸟类研究史上鸟化石数量最多、鸟化石层位最多、埋藏密度最大的纪录，同时它们与７门１８纲２７类化石共存。保护区的鸟类化石、被子植物化石对其起源和早期演化等研究具有重要意义。建议国家有关方面向联合国教科文组织申报辽宁北票鸟化石群国家级自然保护区为世界文化遗产或重要科学遗址。 相似文献