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1.
THE MESOZOIC QIANGTANG FORELAND BASIN IN QINGHAI—XIZANG PLATEAU,CHINANationalKeyFundamentalResearchProjects(973) (G1990 40 80 15 ) ;NSFCGeneralProjects(4980 2 0 13) 相似文献
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The well LF35-1-1 in the eastern Pearl River Mouth basin (PRMB) of the northern South China Sea revealed nnmetamorphosed Middle-Late Jurassic neritic-bathyal sediments and Cretaceous fluvial-lacustrine sediments.Three tectonic movements were identified in Late Jurassic to Early Cretaceous,late Early Cretaceous,and Late Cretaceous to Paleocene,respectively.The Late Jurassic marine facies mainly contain the hydrocarbon source and reservoir-seal assemblages,providing a main exploration target. 相似文献
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东特提斯域思茅盆地钾盐成矿研究进展 总被引：1，自引：0，他引：1
思茅盆地位于东特提斯域,其内的勐野井钾盐矿是我国唯一的前第四纪固体钾盐矿,长期以来对此钾盐矿与呵叻巨型钾盐盆地的资源量差异和成因存在着有较大争议。特别是如下几个问题:其钾盐成矿时代是晚白垩世和古新世,还是侏罗纪的争议;其物质来源还存在陆源,海源和多源的不同认识;矿床成因机理模式也悬而未决。本文在前人研究基础上,结合项目组的最新进展,对上述这些问题的进行梳理与评述认为:勐野井组地层为晚白垩世Albian-Cenomanian期,同沉积的原生钾盐也是在此时期富集成矿;钾盐成矿后期特别是约14Ma以来,受到多期次的热液流体作用,形成次生脉状钾盐:钾盐成矿物质可能以中特提斯洋侵入的海水为主,辅以陆源水体和深部流体。总结认为,思茅与呵叻等盆地在晚白垩世都是干旱沙漠环境中彼此隔绝的小湖盆,随着中特提斯洋海水自西向东的入侵,海水由思茅流向了呵叻,形成了统一的思茅-呵叻海,这个模型可以解释有关成钾物源及思茅与呵叻盆地的成钾关系。思茅盆地钾盐矿的形成和后期变化始终受到了构造活动的控制,经历了最初断陷阶段,到沉积后期受印度-欧亚大陆碰撞导致的挤压和走滑运动影响。 相似文献
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Diagenetically altered volcanic ash deposits (bentonites) found in Cretaceous terrestrial and marine foreland basin sediments have the potential to be used for chronostratigraphy and subsurface correlation across Alaska's North Slope. Detailed age and geochemical studies of these volcanogenic deposits may also shed light on the tectonic evolution of the Arctic. Though these bentonites have been previously studied, there are few published results for regional bentonite ages and geochemistry due to challenges of dating weathered volcanic ash. We analyzed mineral separates from cored bentonites recovered from wells in the National Petroleum Reserve Alaska. The analyses confirm that an intense period of volcanic ash deposition on Alaska's North Slope began by the late Albian and persisted throughout the Cenomanian, an interval of rapid progradation and aggradation in the Colville basin. These results also add to a sparse record of radioisotopic ages from the Nanushuk Formation. A bentonite preserved in delta plain sediments in the upper Nanushuk Formation dates to 102.6 ± 1.5 Ma (late Albian), while a bentonite near the base of the overlying Seabee Formation was deposited at 98.2 ± 0.8 Ma, in the early Cenomanian. The two ages bracket a major flooding surface at the base of the Seabee Formation near Umiat, Alaska, placing it near the Albian-Cenomanian boundary (100.5 Ma). Several hundred feet up-section, the non-marine Tuluvak Formation contains bentonites with 40Ar/39Ar ages of 96.7 ± 0.7 to 94.2 ± 0.9 Ma (Cenomanian), several million years older than previously published K–Ar ages and biostratigraphic constraints suggest.Major and trace element geochemistry of a sub-sample of six bentonites from petroleum exploration wells at Umiat show a range in composition from andesite to rhyolite, with a continental arc source. The bentonites become more felsic from the late Albian (∼102 Ma) to late Cenomanian (∼94 Ma). A likely source for the bentonites is the Okhotsk-Chukotka Volcanic Belt (OCVB) of eastern Siberia, a continental arc which became active in the Albian and experienced episodes of effusivity throughout the Late Cretaceous. Chronostratigraphically anomalous 40Ar/39Ar ages coincide with peaks of magmatic activity in the OCVB, suggesting that these anomalously old ages may be due to magmatic contribution of xenocrysts or recycling of detrital minerals from older volcanic events. An alternative explanation for the chronostratigraphically anomalous ages is mixing of bentonites with detrital sediment derived from unroofing and erosion of metamorphic rocks in the Brooks Range, Herald Arch, and Chukotka throughout the mid to Late Cretaceous. 相似文献
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利用储层流体包裹体确定鄂尔多斯盆地塔巴庙区块上古生界油气充注期次和时期 总被引：5，自引：1，他引：5
流体包裹体是保存在储层中的微小流体样品,包含有丰富的地质信息。通过对鄂尔多斯盆地塔巴庙区块18口井的62块流体包裹体样品进行荧光观察和显微测温,认为该区上古生界地层共发生过6期流体活动,均与油气成藏有关,并以第二期—第六期的天然气充注为主。结合埋藏史分析可知,油气成藏分别发生在距今190～150Ma的早侏罗世中期—中侏罗世晚期,150～124Ma的中侏罗世晚期—早白垩世早期,124～101Ma的早白垩世早期—早白垩世中期,101～86Ma的早白垩世中期—早白垩世中末期和86～70Ma的早白垩世中末期—早白垩世末期。其中,早侏罗世中期—中侏罗世晚期为油气充注的初始阶段,中侏罗世晚期—早白垩世早期为轻质油的主要成藏时期,中侏罗世晚期至早白垩世末为研究区内目的层天然气的主要成藏时期。 相似文献
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海拉尔盆地位于大兴安岭西侧,盆内存在多套火山-沉积岩组合.通过对海拉尔盆地Chu8井等4处火山岩样品进行的锆石LA-ICP-MS U-Pb年代学研究,探讨了海拉尔盆地火山岩的形成时代和构造背景,为盆内和邻区地层对比以及大兴安岭地区构造演化提供了依据.研究区4个火山岩样品的锆石均呈自形-半自形晶,显示出典型的岩浆生长环带,结合其高的Th/U比值(0.22~1.50),说明其属于岩浆成因.测年结果表明,海拉尔盆地布达特群确实存在时代为晚三叠世-早侏罗世(214.4±4.3 Ma)的火山岩,结合前人研究,可将盆内火山作用划分为4期:分别为中-晚石炭世基底岩浆岩(320~290 Ma);晚三叠世-早侏罗世早期布特达特群火山碎屑岩组(224~197 Ma);晚侏罗世-早白垩世早期塔木兰沟组(152~138 Ma);早白垩世晚期铜钵庙组(128~117 Ma).大兴安岭地区各期岩浆作用的地球化学特征、时空分布特征以及盆地地震剖面特征表明,中-晚石炭世基底岩浆岩(320~290 Ma)是额尔古纳-兴安地块和松嫩地块碰撞造山后的伸展背景下形成的;晚三叠世-早侏罗世早期火山岩(224~197 Ma)是古亚洲洋闭合后的伸展背景下形成的,该期火山岩的发现说明古亚洲洋构造域对大兴安岭地区的影响至少延续到早侏罗世早期(197 Ma),而该区域蒙古-鄂霍茨克洋的俯冲碰撞最早可能开始于早侏罗世以后;晚侏罗世-早白垩世早期(152~138 Ma)和早白垩世晚期(128~117 Ma)火山岩的形成均与蒙古-鄂霍茨克洋碰撞闭合后的伸展作用有关.盆内部分火山岩样品中存在古元古代-新元古代捕获的锆石,这表明额尔古纳地块和兴安地块很可能存在着元古代结晶基底. 相似文献
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山东鲁西地块断裂构造分布型式与中生代沉积-岩浆-构造演化序列 总被引：7，自引：0，他引：7
鲁西地块的断裂构造有两类不同分布型式:一类呈放射状分布, 由陡倾、基底右行韧性剪切带和盖层内复杂力学性质的断裂组成; 另一类呈环绕地块基底核部同心环状分布, 由3个主要盖层伸展拆离带组成, 主滑脱面分别位于古生界盖层与基底间的不整合面、石炭系与奥陶系之间的平行不整合面和中新生代断陷-沉积岩系与新生代火山-沉积物之间的断层。中生代构造变形样式可以分为3个层次:印支期褶皱-逆冲推覆构造、燕山中期NNE轴向的隔槽式箱状褶皱和燕山晚期NW、NNE向共轭正断-走滑断裂。相应地鲁西地块经历了3个成盆期, 即早-中侏罗世、早白垩世和晚白垩世, 这些中生代盆地在空间上的叠置导致了地块内部复杂的盆-山耦合关系。鲁西地块中生代有两个岩浆活动集中时期, 即早侏罗世(约190Ma)和早白垩世(132~110Ma)。综合沉积记录、岩浆活动和构造变形过程, 将鲁西地块中生代构造演化历史划分为6个阶段:晚三叠世挤压变形, 早、中侏罗世弱伸展作用, 中、晚侏罗世挤压变形与地壳增厚作用, 早白垩世大陆裂谷与地壳伸展作用, 早白垩世末期挤压变形与盆地反转事件和晚白垩世区域隆升。这些构造演化阶段和构造事件对研究和理解中生代构造体制和深部岩石圈动力学转换过程具有重要意义。 相似文献
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《Cretaceous Research》1995,16(5):539-558
The Cretaceous sedimentary successions of the Ionian Zone, Hellenides, western Greece, are composed of pelagic limestones intercalated with cherty layers. The micritic and biomicritic beds with abundant chert nodules and cherty horizons, which were deposited during late Tithonian to early Santonian times, belong to the Vigla Limestone Formation, while the sediments deposited during the late Santonian to Maastrichtian, formed clastic limestone beds in which chert nodules also occur sparsely.In the Cretaceous beds calpionellids, planktonic and benthonic foraminifera characteristics of the Tethyan realm, and radiolaria have been recorded. The calpionellids, together with radiolaria, colonized the entire basin during the Berriasian to early Valanginian, the latter becoming dominant during the Hauterivian to early Albian as a result of anoxia. Planktonic foraminifera first appeared in the basin during the late Albian and persisted until the Maastrichtian. The numbers decreased, however, during the Cenomanian-early Turonian interval, when radiolaria increased owing to anoxic conditions, and during the Campanian-Maastrichtian interval because the basin became shallow. During this interval larger benthonic foraminifera colonized the basin. Zonal markers have been recognized in calpionellid and planktonic foraminiferal assemblages on the basis of which two calpionellid zones are distinguished, viz. the Calpionella alpina and Calpionellopsis Zones (Berriasian-early Valanginian) along with seven planktonic foraminiferal zones, viz. the Rotalipora ticinensis, Rotalipora appenninica (late Albian), Rotalipora brotzeni (early Cenomanian), Helvetoglobotruncana helvetica (early to middle Turonian), Marginotruncana sigali(late Turonian to early Coniacian), Dicarinella concavata (late Coniacian to early Santonian) and Dicarinella asymetrica (late early-late Santonian) Zones.The anoxic conditions that prevailed in the Ionian basin during the Barremian-early Albian, Cenomanian-early Turonian and Coniacian-Santonian intervals probably arose as a result of (a) the accumulation of large amounts of organic matter because the palaeotopography of the basin periodically hindered the circulation of water from the ocean and (b) the oxygen content of the intruding oceanic waters was low. 相似文献
10.
Maher I. El-Soughier Amr S. Deaf Magdy S. Mahmoud 《Arabian Journal of Geosciences》2014,7(8):3051-3068
Palynological and palynofacies analyses were carried out on some Cretaceous samples from the Qattara Rim-1X borehole, north Western Desert, Egypt. The recorded palynoflora enabled the recognition of two informal miospore biozones arranged from oldest to youngest as Elaterosporites klaszii-Afropollis jardinus Assemblage Zone (mid Albian) and Elaterocolpites castelainii–Afropollis kahramanensis Assemblage Zone (late Albian–mid Cenomanian). A poorly fossiliferous but however, datable interval (late Cenomanian–Turonian to ?Campanian–Maastrichtian) representing the uppermost part of the studied section was also recorded. The palynofacies and visual thermal maturation analyses indicate a mature terrestrially derived organic matter (kerogen III) dominates the sediments of the Kharita and Bahariya formations and thus these two formations comprise potential mature gas source rocks. The sediments of the Abu Roash Formation are mostly dominated by mature amorphous organic matter (kerogen II) and the formation is regarded as a potential mature oil source rock in the well. The palynomorphs and palynofacies analyses suggest deposition of the clastics of the Kharita and Bahariya formations (middle Albian and upper Albian–middle Cenomanian) in a marginal marine setting under dysoxic–anoxic conditions. By contrast, the mixed clastic-carbonate sediments of the Abu Roash Formation (upper Cenomanian–Turonian) and the carbonates of the Khoman Formation (?Campanian–Maastrichtian) were mainly deposited in an inner shallow marine setting under prevailing suboxic–anoxic conditions as a result of the late Cenomanian and the Campanian marine transgressions. This environmental change from marginal to open (inner shelf) basins reflects the vertical change in the type of the organic matter and its corresponding hydrocarbon-prone types. A regional warm and semi-arid climate but with a local humid condition developed near/at the site of the well is thought to have prevailed. 相似文献
11.
Pedro Quelhas Agata Alveirinho Dias Joao Mata Donald Wayne Davis Maria Luísa Ribeiro 《地学前缘(英文版)》2020,11(1):243-263
Six new high precision U-Pb zircon ID-TIMS ages plus thirteen in situ high spatial resolution U-Pb zircon LA-MC-ICPMS ages are reported from Jurassic plutonic(metaluminous to weakly peraluminous biotite granites)and Jurassic to Cretaceous hypabyssal(dacites)rocks from Macao.Despite its relatively small area(~30 km^2),the new ages tightly constrain the Macao granitic magmatism to two periods ranging from 164.5±0.6 Ma to 162.9±0.7 Ma and 156.6±0.2 Ma to 155.5±0.8 Ma,separated by ca.6 Ma.Inherited zircons point to the existence of a basement with ages up to Paleo-Proterozoic and late Archean in the region.In addition,younger dacitic rocks were dated at 150.6±0.6 Ma and<120 Ma.U-Pb zircon ages and whole-rock REE data of Macao granites indicate that the first pulse is also represented in Hong Kong and Southeast(SE)China,while magmatism with the chemical characteristics of the second pulse seems to not be represented outside Macao.The two granitic magmatic pulses have distinct mineralogical and geochemical features that support their discrete nature rather than a continuum of comagmatic activity and suggest that the Macao granitic suite was incrementally assembled during a period of ca.9 Ma,a hypothesis also extendable to the neighboring Hong Kong region for a time lapse of ca.24 Ma.In Macao,the transition from granitic magmatism(Middle to Upper Jurassic)to the younger dacite dykes(Upper Jurassic to Lower Cretaceous)most likely corresponds to a change in the regional tectonic setting,from an extensional regime related with foundering of the subducting paleoPacific plate during the Early Yanshanian period to the reestablishment of a normal subduction system in SE China during the Late Yanshanian period. 相似文献
12.
大青山地区侏罗纪陆相沉积盆地形成、迁移及演化规律 总被引：5，自引：0，他引：5
恢复了大青山地区侏罗纪盆地的原形，并对盆地的迁移，演化规律和阶段进行了详细研究，提出石拐－老道沟株罗纪盆地是早侏罗世晚期在古生代地层岩片与北部变质岩岩片之间发育起来的东西向延展的带状盆地。古地形表现北高南低，西高东低；中侏罗世盆地范围达最大，中株罗世末期的一次燕山构造运动，使盆地的性质发生了明显的改变，由早，中株罗世的弱拉伸构造环境转变为晚侏罗世的挤压构造环境，古气候由温暖潮湿气候变为干旱气候，晚侏罗世末期，随着大规模的逆冲推覆构造的发育而结束盆地的演化历史。 相似文献
13.
The Blue Nile Basin, situated in the Northwestern Ethiopian Plateau, contains ∼1400 m thick Mesozoic sedimentary section underlain by Neoproterozoic basement rocks and overlain by Early–Late Oligocene and Quaternary volcanic rocks. This study outlines the stratigraphic and structural evolution of the Blue Nile Basin based on field and remote sensing studies along the Gorge of the Nile. The Blue Nile Basin has evolved in three main phases: (1) pre‐sedimentation phase, include pre‐rift peneplanation of the Neoproterozoic basement rocks, possibly during Palaeozoic time; (2) sedimentation phase from Triassic to Early Cretaceous, including: (a) Triassic–Early Jurassic fluvial sedimentation (Lower Sandstone, ∼300 m thick); (b) Early Jurassic marine transgression (glauconitic sandy mudstone, ∼30 m thick); (c) Early–Middle Jurassic deepening of the basin (Lower Limestone, ∼450 m thick); (d) desiccation of the basin and deposition of Early–Middle Jurassic gypsum; (e) Middle–Late Jurassic marine transgression (Upper Limestone, ∼400 m thick); (f) Late Jurassic–Early Cretaceous basin‐uplift and marine regression (alluvial/fluvial Upper Sandstone, ∼280 m thick); (3) the post‐sedimentation phase, including Early–Late Oligocene eruption of 500–2000 m thick Lower volcanic rocks, related to the Afar Mantle Plume and emplacement of ∼300 m thick Quaternary Upper volcanic rocks. The Mesozoic to Cenozoic units were deposited during extension attributed to Triassic–Cretaceous NE–SW‐directed extension related to the Mesozoic rifting of Gondwana. The Blue Nile Basin was formed as a NW‐trending rift, within which much of the Mesozoic clastic and marine sediments were deposited. This was followed by Late Miocene NW–SE‐directed extension related to the Main Ethiopian Rift that formed NE‐trending faults, affecting Lower volcanic rocks and the upper part of the Mesozoic section. The region was subsequently affected by Quaternary E–W and NNE–SSW‐directed extensions related to oblique opening of the Main Ethiopian Rift and development of E‐trending transverse faults, as well as NE–SW‐directed extension in southern Afar (related to northeastward separation of the Arabian Plate from the African Plate) and E–W‐directed extensions in western Afar (related to the stepping of the Red Sea axis into Afar). These Quaternary stress regimes resulted in the development of N‐, ESE‐ and NW‐trending extensional structures within the Blue Nile Basin. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
14.
A. Vamvaka W. Siebel F. Chen J. Rohrmüller 《International Journal of Earth Sciences》2014,103(1):103-119
Apatite fission-track (AFT) dating applied to uplifted Variscan basement blocks of the Bavarian Forest is employed to unravel the low-temperature history of this segment of the Bohemian Massif. Twenty samples were dated and confined track lengths of four samples were measured. Most samples define Cretaceous APT ages between 110 and 82 Ma (Albian to Campanian) and three samples give older ~148–140 Ma (Jurassic–Cretaceous boundary) ages. No discernible regional age variations exist between the areas north-east and south-west of the Pfahl shear zone, but >500 m post-Jurassic and post-Cretaceous vertical offsets along this and other faults can be inferred from elevation profile analyses. The AFT ages clearly postdate the Variscan exhumation history of the Bavarian Forest. Thermal modeling reveals that the ages are best explained by a slight reheating of the basement rocks to temperatures within the apatite partial annealing zone during the middle and late Jurassic and/or by late Cretaceous marine transgression causing burial heating, which affected marginal low-lying areas of the Bohemian Massif and the Bavarian Forest. Late Jurassic period was followed by enhanced cooling through the 120–60 °C temperature interval during the subsequent exhumation phase for which denudation rates of ~100 m myr?1 were calculated. On a regional scale, Jurassic–Cretaceous AFT ages are ubiquitous in marginal structural blocks of the Bohemian Massif and seem to reflect the exhumation of these zones more distinctly compared to central parts. 相似文献
15.
楚雄盆地处于中国云南省中部，位于扬子板块西南缘，南西界以红河断裂为界与哀牢山造山带相连，北西界为程海断裂，东边为绿汁江断裂。盆地基底包括结晶基底和褶皱基底双重结构。盆地内发育了中三叠世以后的沉积盖层，西部中三叠世和晚三叠世早、中期为海相沉积，晚期为海陆交互相和陆相沉积；盆地东部为陆相沉积。侏罗—白垩纪整个盆地为巨厚的陆相沉积。楚雄盆地的构造格架分为４个带：（１）哀牢山造山带；（２）褶皱逆冲带；（３）中部沉降带；（４）东部隆起带。盆地形成与演化分为六个阶段：（１）被动大陆边缘沉降阶段；（２）拉张热隆起边缘——裂谷盆地阶段；（３）沟－弧－盆系阶段；（４）残洋－周缘前陆盆地阶段；（５）走滑－拉张盆地阶段；（６）走滑－挤压－改造阶段。楚雄盆地的形成与演化体现了盆地动力学性质转化和复合，在多种动力系统作用下或经过多旋回构造阶段产生了复式盆地 相似文献
16.
Y. Mart 《Tectonophysics》1987,140(2-4):213-232
Resurgent tectonic phases superimposed their structural imprints on the continental margin of the southeastern Mediterranean. This margin underwent a complete cycle, from a margin of a marine basin in the Paleozoic, to the margin of the incipient Neo-Tethys ocean in the early Jurassic, through the margin of the mature ocean in the late Jurassic, Cretaceous, and Paleogene. It became the margin of a desiccated marine basin in the late Miocene, and finally became the margin of a rejuvenated marine basin after the Pliocene.
The margin was affected by folding, faulting and intermittent volcanism during the early Liassic, early Neocomian, late Cretaceous, Oligocene and early Miocene. The younger tectonic phases were superimposed on the older ones, reactivating them in some places and masking them in others. The geological characteristics and this complex tectonic history are masked effectively by the thick Messinian evaporitic sequence. This smoothing effect was further enhanced by the huge pile of sediments that has been deposited by the River Nile since the early Pliocene. 相似文献
17.
In order to reconstruct tectonic evolution history of the southern margin of Asia (i.e., Lhasa terrane) before the India-Asia collision, here we present a comprehensive study on the clastic rocks in the southern Lhasa terrane with new perspectives from sedimentary geochemistry, detrital zircon geochronology and Hf isotope. Clasts from the Jurassic-Early Cretaceous sedimentary sequences (i.e., Yeba and Chumulong Formations) display high compositional maturity and experienced moderate to high degree of chemical weathering, whereas those from the late Early-Late Cretaceous sequences (Ngamring and Shexing Formations) are characterized by low compositional maturity with insignificant chemical weathering. Our results lead to a coherent scenario for the evolution history of the Lhasa terrane. During the Early-Middle Jurassic (∼192-168Ma), the Lhasa terrane was speculated to be an isolated geological block. The Yeba Formation is best understood as being deposited in a back-arc basin induced by northward subduction of the Neo-Tethys ocean with sediments coming from the interiors of the Lhasa terrane. The Middle Jurassic-Early Cretaceous Lhasa-Qiangtang collision resulted in the formation of a composite foreland basin with southward-flowing rivers carrying clastic materials from the uplifted northern Lhasa and/or Qiangtang terranes. During the late Early-Late Cretaceous (∼104-72Ma), the Gangdese magmatic arc was uplifted rapidly above the sea level, forming turbidites (Ngamring Formation) in the Xigaze forearc basin and fluvial red beds (Shexing Formation) on the retro-arc side. At the end of Late Cretaceous, the Lhasa terrane was likely to have been uplifted to high elevation forming an Andean-type margin resembling the modern South America before the India-Asia collision. 相似文献
18.
库车坳陷北部白垩系沉积速率分析 总被引：1，自引：1，他引：0
库车坳陷白垩纪经历了一个相对独立的一级构造旋回,结合坳陷北部库车河白垩系剖面详细的磁性地层学结果,应用地层回剥分析方法恢复了库车坳陷白垩系时期的沉降历史,计算得到亚格列木组、舒善河组、巴西盖组、巴什基奇克组沉积速率,分别为11.5 cm/ka、2.5 cm/ka、2.9 cm/ka、1.7 cm/ka。结合裂变径迹资料和岩相古地理特征,将库车坳陷白垩系沉降历史分为四个演化阶段:（1）Berriasian中期（141.9141.2 M a）:极快速沉降;（2）Berriasian中晚期至A lb ian中晚期（141.2101 M a）,持续缓慢沉降;（3）A lb ian末期至Campan ian早期（10179.1 M a）:构造隆升,沉积剥蚀;（4）Campan ian中晚期—M aastrichtian期（79.165.6 M a）:极慢速沉降,接受沉积。早白垩世早中期沉降曲线呈“上凹”特征,反映了构造活动由早期剧烈沉降到后期减弱,最后趋于稳定的过程。该沉降过程与典型的前陆盆地挠曲沉降过程并不一致。 相似文献
19.
Daniel Paul Le Heron Micha M. Buslov Clare Davies Keith Richards Inna Safonova 《Sedimentary Geology》2008,208(1-2):45-60
The Mesozoic stratigraphy in the subsurface of the West Siberian Basin contains prolific hydrocarbon accumulations, and thus the depositional environments of marine and marginal marine Jurassic and Cretaceous age sediments are well-established. However, no information is currently available on strata of equivalent age that crop out along the SE basin margin in the Mariinsk–Krasnoyarsk region, despite the potential of these exposures to supply important information on the sediment supply routes into the main basin. Detailed sedimentological analysis of Jurassic–Cretaceous clastic sediments, in conjunction with palaeo-botanical data, reveals five facies associations that reflect deposition in a range of continental environments. These include sediments that were deposited in braided river systems, which were best developed in the Early Jurassic. These early river systems infilled the relics of a topography that was possibly inherited from earlier Triassic rifting. More mature fluvial land systems evolved in the Mid to Late Jurassic. By the Mid Jurassic, well-defined overbank areas had become established, channel abandonment was commonplace, and mudrocks were deposited on floodplains. Coal deposition occurred in mires, which were subject to periodic incursions by crevasse splay processes. Cretaceous sedimentation saw a renewed influx of sand-grade sediment into the region. It is proposed that landscape evolution throughout the Jurassic was driven simply by peneplanation rather than tectonic processes. By contrast, the influx of sandstones in the Cretaceous is tentatively linked to hinterland rejuvenation/ tectonic uplift, possibly coeval with the growth of large deltaic clinoform complexes of the Neocomian in the basin subsurface. 相似文献
20.
松辽盆地南部中生代火山岩: 锆石U-Pb年代学及其对基底性质的制约 总被引：20，自引：0，他引：20
为了确定松辽盆地南部中生代火山岩的形成时代, 本文对位于盆地南部7个钻遇中生代火山岩的岩芯样品进行了锆石LA~ICP-MSU-Pb定年.松辽盆地南部中生代含火山岩地层主要包括火石岭组和营城组, 其中火石岭组火山岩由玄武安山岩-粗安岩-粗面英安岩组成, 营城组火山岩由玄武质粗面安山岩-粗面安山岩-流纹岩组成.锆石阴极发光(CL)图像和Th/U比值显示, 所测锆石均具有岩浆成因的特点, 锆石的LA-ICP-MSU-Pb定年结果表明, 松辽盆地南部中生代火山岩形成时代介于110b133Ma, 其中火石岭组火山岩形成于129-133Ma, 即早白垩世早期, 营城组火山岩形成于110~119/Via, 即早白垩世晚期.捕获锆石的定年结果显示, 本区基底中存在中晚侏罗世(155~169Ma)、印支期(218~236Ma)、海西期(254/Via、294Ma)、加里东期(413Ma)和前寒武纪(1823/Via和2542Ma)岩浆事件, 这与基底岩石中锆石U—Pb的定年结果相吻合. 相似文献