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中国近海早第三纪海侵层序及地层对比 总被引：1，自引：0，他引：1
彭世福 《海洋地质与第四纪地质》1992,(1)
中国近海各盆地,据古生物群及沉积特征,在早古新世为陆相沉积,至中晚古新世时为第Ⅰ海侵期。早始新世时为海退期,至中晚始新世为第Ⅱ海侵期。早、中渐新世时为海退期,晚渐新世为第Ⅲ海侵期。在论证地层时代时结合海侵的划分,提出新的见解。海相夹层可作为地层对比的重要标志层。 相似文献
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通过对辽东湾高分辨率浅地层剖面声学地层与典型钻孔沉积地层的对比分析,揭示了研究区晚第四纪MIS5以来的地层层序。辽东湾高分辨率浅地层剖面自下而上划定的6个声学地层单元(SU5、SU4、SU3、SU2、SU12、SU11)与钻孔岩芯划分的6个沉积地层单元(DU5、DU4、DU3、DU2、DU12、DU11)具有良好的对应关系。分别与MIS4期、MIS2期低海面时期的沉积间断密切相关的两个层序界面R5、R3,将辽东湾识别出的地层单元自下而上划分为3个层序(SQ3、SQ2、SQ1)。其中SQ3仅识别出上部的海侵体系域与高水位体系域,对应MIS5期海平面相对较高时期的滨浅海相沉积(DU5);SQ2自下而上由低水位体系域(MIS4期的河流相与河道充填相沉积(DU4))与海侵体系域(MIS3期早中期滨海相沉积(DU3))组成;SQ1自下而上包括低水位体系域(MIS2期的河流相与河道充填相沉积(DU2))、海侵体系域(全新世早中期滨海相沉积(DU12))高水位体系域(全新世高海面以来的浅海相沉积(DU11))。研究区的海侵体系域厚度较薄且变化较小,分布广泛,而低水位体系域厚度与横向分布均变化较大。 相似文献
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渤海海峡及周边海域浅地层结构及地层声速的拾取 总被引：2，自引：0，他引：2
通过系统分析渤海海峡及周边海域的高分辨率浅地层剖面与3口钻孔的资料,将研究区地层自上而下划分为T0、T1、T2、T3、T4、T5、T6、T7、T8共9个反射界面及SU11、SU12、SU13、SU2、SU3、SU41、SU42、SU43、SU5共9个声学地层单元,SU1地层单元对应全新世海相沉积,其底界为一海进侵蚀面,削蚀对应晚更新世晚玉木冰期陆相沉积的SU2地层单元。SU3地层单元对应晚更新世晚玉木间冰期的海相沉积,通过侵蚀间断面与上覆SU2呈不整合接触。SU41地层单元对应晚更新世早玉木冰期晚期的陆相沉积,SU42地层单元对应晚更新世早玉木亚间冰期的海相沉积,与上覆SU41呈侵蚀不整合接触,SU43地层单元对应晚更新世早玉木冰期早期的陆相沉积,其顶界面为海进侵蚀面,与下伏地层呈不整合接触,SU5对应晚更新世玉木—里斯间冰期的海相沉积。对比分析浅地层剖面地层单元与钻孔沉积地层,确定了研究区海底面之下不同地层单元对应的平均声学速度,为后续的地层层序的研究奠定了基础。研究区"海侵-海退-海侵-海退-高水位"的沉积过程,决定了地层平均声速随深度自下而上呈现由高-低-高-低的变化模式。 相似文献
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福州市马尾地区第四纪地层划分及海相层分析 总被引：1，自引：0，他引：1
通过对该区钻孔剖面贡料,结合~(14)C、古地磁、孢粉及微体古生物等资料综合分析研究,对该区第四纪地层提出划分意见和自第四纪晚期以来,地层中存在着典型两期海侵所形成的海相层。 相似文献
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本文根据岩性特征、沉积旋回、接触关系、孢粉和微体古生物等资料,对大小凌河地区的第四纪地层进行初步研究,在此基础上探讨第四纪以来的沉积物及其特征,并分析晚第四纪以来的海相地层与海侵特征。 相似文献
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晚第四纪长江三角洲高分辨率层序地层学的初步研究 总被引：24，自引：3，他引：24
根据钻孔资料分析了长江三角洲冰后期层序的构成：古河谷内由河床相，浅海相－河口湾相组成，海侵面在滞留沉积与潮坪堆积物之间，最大海侵面位于浅海相和前三角洲泥质层中，古河间地层层序包含滨海相，浅海相和潮坪相，其海侵面与层序界面重合，最大海侵面在浅海泥质层中，在古河谷和古河间的沉积相组合不同，但二者同在一个海侵海退旋回中形成，属同一层序。 相似文献
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根据在日照近岸海域施工的地质钻孔和浅地层剖面测量资料,对比南黄海已有钻孔成果,系统地开展日照近岸海域晚更新世以来地层结构特征识别和沉积环境演化重建。结果表明:日照近岸海域沉积地层中见含有有孔虫化石的第二海相层,形成年代介于34.3~41.4 cal.ka B.P.,对应MIS3的暖湿阶段,该层位可能与古三角洲有关。沉积层从上往下分别为:滨海相细砂混杂泥质沉积层(命名为DU1沉积单元);河流-河口相粉砂质黏土夹粗砂、粉砂层(DU2沉积单元);浅海相粉砂质黏土夹粗砂层(DU3沉积单元);河流-湖泊相粗砂夹黏土层(DU4沉积单元)。晚更新世以来日照东部南黄海海域主要经历了2~3次显著的海侵和海退,各区域因条件不同表现有所差异:日照近岸浅水区主要表现为两次海侵和海退,东部深水区主要表现为三次海侵和海退,由于地势高低和侵蚀破坏等原因,总体表现为从离岸深水区域向近岸浅水区域海相地层厚度逐渐减少的趋势,部分地层出现尖灭消失。 相似文献
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通过对琼州海峡东西口高分辨率浅地层剖面的解释,结合14 C年龄数据,分析结果表明:浅地层剖面上的R1反射界面指示琼州海峡的完全开启,其下为海峡完全开启之前的低能海相沉积,表现为一套无层理的相对均一的地层,其上为海峡完全开启之后的潮流三角洲沉积,表现为一套层理发育的进积地层,海峡贯通前后,底流发生剧烈变化,导致该界面上下地层沉积结构明显不同;琼州海峡完全开启的时代为距今8 000a左右,归因于该区的全新世海侵。 相似文献
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中国东部晚更新世以来的海水进退 总被引：19，自引：4，他引：19
我国东部滨海平原及其以东的浅海陆架,是第四纪冰川时期海岸线往复迁移的地带.要掌握海水的进退边界及反复过程,必须在沉积层序学和年代学的广泛研究基础上,依据古滨线沉积和残留地貌标志,与世界典型地区的海面变化模式进行对比,才能获得冰川性海面变化及构造型海面变化在我国东部海面升降及海水进退过程中互相影响、相互消长的时空表现. 相似文献
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In the marine environment, stability of the glacier terminus and the location of subglacial streams are the dominant controls on the distribution of grounding-line deposits within morainal banks. A morainal bank complex in Muir Inlet, Glacier Bay, SE Alaska, is used to develop a model of terminus stability and location of subglacial streams along the grounding line of temperate marine glaciers. This model can be used to interpret former grounding-line conditions in other glacimarine settings from the facies architecture within morainal bank deposits.The Muir Inlet morainal bank complex was deposited between 1860 A.D. and 1899 A.D., and historical observations provide a record of terminus positions, glacial retreat rates and sedimentary sources. These data are used to reconstruct the depositional environment and to develop a correlation between sedimentary facies and conditions along the grounding line.Four seismic facies identified on the high-resolution seismic-reflection profiles are used to interpret sedimentary facies within the morainal bank complex. Terminus stability is interpreted from the distribution of sedimentary facies within three distinct submarine geomorphic features, a grounding-line fan, stratified ridges, and a field of push ridges. The grounding-line fan was deposited along a stable terminus and is represented on seismic-reflection profiles by two distinct seismic facies, a proximal and a distal fan facies. The proximal fan facies was deposited at the efflux of subglacial streams and indicates the location of former glacifluvial discharges into the sea. Stratified ridges formed as a result of the influence of a quasi-stable terminus on the distribution of sedimentary facies along the grounding line. A field of push ridges formed along the grounding line of an unstable terminus that completely reworked the grounding-line deposits through glacitectonic deformation.Between 1860 A.D. and 1899 A.D. (39 years),
m3 of sediment were deposited within the Muir Inlet morainal bank complex at an average annual sediment accumulation rate of
m3/a. This rate represents the annual sediment production capacity of the glacier when the Muir Inlet drainage basin is filled with glacial ice. 相似文献
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胶州湾是海岸带研究及开发利用的热点之一,已做过大量工作(包含钻探工作),但深入的总结不足。1994年作者对胶州湾东北侧海底和海滩进行了详细钻探,获得了丰富资料。本文作一简要分析。钻探共4个剖面35个钻孔,其中11个孔位于陆域(图1)。大部分钻孔揭穿第四系至基岩强风化层,终孔直径110mm。1 岩性分析综观岩芯,自上至下,由新到老大体划分如下几层,见表1。杂填土 主要分布在近岸,厚约0.00～3.60m,层底标高-0.07～2.95m,主要由城市垃圾和建筑垃圾组成,堆积时间短,结构松散。淤泥 层厚0.80～3.50m,自岸向海逐渐增厚,层底标高-0.23～5.30m,灰… 相似文献
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南黄海中部沉积岩芯的微体古生物组合特征及古环境演化 总被引：4，自引：0，他引：4
本文分析测定南黄海中部两个沉积物柱状样中的有孔虫、介形虫和“C年代，对其微体古生物组合特征、沉积环境和地层年代进行了初步的探讨。有孔虫组合表明研究海域为近岸一浅海环境，其含量从下到上由缺失到出现近岸、浅海有孔虫，反映了沉积环境由陆相到滨岸相、浅海相环境的变迁；孢粉组合反映的古气候也同样经历了针、阔叶混交林一草原，到阔叶林或以阔叶树为主的针、落叶混交林的变化，反映出气候由冷干到暖干的特点。研究结果表明，所研究的柱状样沉积物下部形成于晚更新世晚期，上部属于全新世。 相似文献
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长江三角洲第一硬土层中微结核的矿物化学特征及其成因 总被引：4，自引：0，他引：4
长江三角洲第一硬土层是古土壤层,是长江河漫滩型沉积物,其形成经历多次沉积和成土过程.硬土层中的铁锰结核以菱铁矿、菱锰矿和褐铁矿为主,通过铁锰元素离子和矿物Eh-pH稳定关系分析,最有利于菱锰矿和菱铁矿结核生成的条件是:Eh＜0且pH＞8.成土期处于末次冰期低海面、气候寒冷干燥期,土壤的化学过程是以氧化作用为主,是褐铁矿等氧化性矿物形成时期;冰后期海相层的沉积覆盖使土壤层进入成岩阶段,土壤层的化学过程以还原作用为主,成岩过程是铁锰碳酸盐结核的主要生成期. 相似文献
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Diagenesis in the uppermost Jurassic to Lower Cretaceous deltaic sandstones and shales of the Scotian Basin is an important control on reservoir quality. Ferruginous zone (sub-oxic) marine pore-water diagenesis controls the initial formation of Fe2+-silicates that are the precursors of grain-rimming chlorite that preserves porosity. This study assesses the regional controls on the type of marine pore-water diagenesis by studying the sedimentology, mineralogy, and geochemistry of the retrogradational units and underlying progradational units in parasequences from conventional cores in two wells in different parts of the basin. Coated grains preserve a record of whether marine pore-water diagenesis below the seafloor was dominantly in the ferruginous or sulphidic geochemical zone. Four types of coated grain were distinguished, each with a different mineral paragenesis. Mineralogical and chemical evidence of ferruginous zone diagenesis includes the presence of diagenetic chlorite and siderite, and the correlation of P with Fe or Ti. Pyrite and Fe-calcite are found where the sulphidic zone is more significant than the ferruginous zone. Ferruginous zone diagenesis was common in low-sedimentation rate retrogradational sediments with low organic carbon, and in delta-front turbidites and river-mouth sandstones. Estuarine, tidal flat and prodeltaic facies that are directly supplied by riverine sediments have a lower Fe:Ti ratio than do fully marine shoreface and open shelf facies as a result of input of detrital ilmenite and its alteration products. The relative contribution of colloidal iron (hydr)-oxides appears greater in distal low-sedimentation rate environments. Where large changes in sedimentation rate occurred at ravinement surfaces, the underlying progradational rocks have evidence of ferruginous zone diagenesis, whatever their facies. Rapid upward migration of the pore-water profile resulting from the change in sedimentation rate reduced the time available for mineral products to form in the deeper pore-water zones. This study has shown that the availability of Fe and organic carbon varying in a complex manner in marine deltaic sediments, but that the resulting diagenesis by marine pore-water can be predicted from facies and paleogeographic setting. 相似文献
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为了了解南中国海南部南沙群岛陆架-陆坡区中生代地层发育情况,作者通过综合分析该海区钻井、拖网及1987年以来采集的20000多公里的多道反射地震勘探等资料,得到了对该区中生界基本特征的如下新认识:空间分布上,南沙的中生界具有从北部的郑和-礼乐隆起南缘向南增厚的趋势;沉积岩相方面,东部三叠纪时为深海相,侏罗纪为浅海与三角洲相,白垩纪为浅海-内浅海相,而往西南部中生代的海水深度有变深的趋势;中-新生代变形上,在南沙西部的曾母盆地,中生界褶皱为复式的、非协调性的,南沙中部多为舒缓褶皱,东部仅在近巴拉望海槽地带出现小幅度的褶皱。结合围区中生界及特提斯构造域的发育特征,作者提出南沙地块上的海相中生界在大地构造上归属于残留在中特提斯洋北部减薄陆缘地壳上的中特提斯期海相沉积地层,是该海域油气资源勘探不可忽视的对象。 相似文献
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PALYNOLOGICAL ASSEMBLAGES FROM THE QUATERNARY SEDIMENTS OF THE CHANGJIANG RIVER DELTA AND THE AGE OF STRATA AND PALEOGEOGRAPHY 总被引：2，自引：0，他引：2
Through the palynological research of Quaternary sediments in Changjiang River Delta, 14 spores and - pollen zones might be distinguished, reflecting the vegetation succession and climate fluctuation of Quaternary, which conforms to the climate of the world.Zones 1-9 are thought of as Pleistocene and Zones 10-14 as Holocene based on the climatic fluctuation reflected by these zones and the comparison with the climatic stage at home and abroad.The marine facies sediments of Quaternary in the Changjiang River Delta contain abundant fossil spores and pollen and have obvious characters. Because the warm and humid climate reflected by the palynological assemblages of marine facies sediments often fittes with the transgression, the curve line of the climate fluctuation of Quaternary in the Delta coincides with that of sea level changes. 相似文献