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通过对北海外沙泻湖CK10 钻孔岩芯进行硅藻、有孔虫、孢粉的综合分析, 发现全新世地层中有8 个硅藻组合带,5 个孢粉组合带和5 个有孔虫组合。结合14C测年资料与沉积物特征, 认为该泻湖全新世地层可划分为早全新世、中全新世、晚全新世。植被演替为混有落叶阔叶林的亚热带常绿阔叶林→亚热带常绿林→亚热带、热带常绿阔叶林→混杂有中、北亚热带落叶阔叶林的南亚热带季风雨林→南亚热带常绿阔叶林。气候演变依次为热湿偏凉干→热湿→炎热潮湿→热湿偏凉→热湿。沉积相发展顺序为河漫滩相→河口沼泽相→河漫滩相→河口沼泽相→河口湾相→泻湖相→河口湾相→泻湖相。 相似文献
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鲁东南滨海平原全新世海进地层研究 总被引：1，自引：2，他引：1
本文主要根据对钻孔样品的粒度分析、矿物分析、微体古生物分析、孢粉分析及14C测年资料,探讨了鲁东南滨海平原地区全新世海进地层的划分和对比、沉积特征、沉积古地理环境及其演变规律.在早全新世阶段,该区处于滨海环境,广泛发育了下全新亚统滨海沼泽相沉积层;中全新世时,该区遭受海侵,为河口湾、滨岸沉积环境,发育了中全新亚统海陆过渡相沉积层;自晚全新世以来,该区成为冲积海积平原环境,上全新亚统陆相沉积层得以发育形成. 相似文献
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依据南海低纬地区SA09-040孔高分辨率的孢粉记录,自下至上划分了4个孢粉组合带。从孢粉成分的变化,重建了22.25ka B P以来的植被与气候变化历史。结果表明:孢粉主要来源于婆罗洲和周围岛屿,孢粉1带(22.25～16.6ka B P),低山雨林植被发育,为暖热气候,从测年时间看,当时为末次冰期晚期。孢粉2带(16.6～10.82ka B P,为末次冰消期),植被以热带低山雨林和低地雨林为主,针叶的松数量较多,当时的气温比现在低。孢粉3带(全新世早期,10.82～6.43ka B P),植被以热带低山雨林和低地雨林为主,针叶松属数量减少,气温比前期升高,海平面也上升。孢粉4带(全新世中晚期,6.43ka B P至今),全新世中期为炎热、湿润的气候环境,全新世晚期可能与婆罗洲现今的植被景观相近,为热、湿的气候环境。 相似文献
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台湾海峡晚更新世以来的高分辨率地震地层学研究 总被引：2，自引：1，他引：1
基于4 530 km高分辨率单道地震数据和钻孔资料,采用高分辨率地震地层学的方法,对台湾海峡晚更新世以来的地层进行了划分,自上而下共识别出R0、R1、R2、R3、R4等5个主要反射界面,分别对应海底、3 ka BP前后高海平面、最大海泛面、海侵面和 Ⅰ 型层序界面,并以此划分出4个地层单元:晚全新世浅海-滨海沉积A,中全新世浅海沉积B,早全新世海侵沉积C,晚更新世陆相河流沉积D。在海平面变化的作用下,海峡地区先后发育低水位沉积D（低位体系域）,海侵沉积C （海侵体系域）、高水位沉积B和A（高位体系域）。研究了台湾海峡的典型地震相,提出了关于台中浅滩（云彰隆起）处的楔状沉积体的新观点,认为该楔状体为全新世中期以来形成的三角洲沉积受波浪和潮流作用改造而形成的潮流沙脊,其物质主要来源于台湾。识别出了晚更新世和早全新世古河道沉积,海平面变化和地势高低是其形成时间差异的主要因素。 相似文献
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通过对辽东湾北部LH01孔柱状岩芯样品进行粒度、孢粉、有孔虫和测年多项环境指标测试,探讨了辽东湾北部晚更新世24ka BP以来的古环境演变。LH01孔沉积环境经历了晚更新世晚期河湖相沉积—全新世早期海陆交互相沉积—全新世中期浅海相沉积—全新世晚期河口滨海相沉积;气候经历了晚更新世晚期冷较干—晚更新世晚期凉稍润—新仙女木降温—全新世早期凉稍润—全新世中期温暖较润—全新世中期温暖较干—全新世晚期温较干的变化;LH01孔在大约7.5ka BP发生了盘山海侵。 相似文献
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对上海地区晚第四纪钻孔地层中的孢粉以及较高分辨率测年资料进行了分析.根据孢粉组合恢复了6个植被演替以及古气候期,和该区的海水进退吻合很好.研究发现,120～96 ka B.P.间处于里斯冰期末期,沉积物粗,孢粉稀少;96～84 kaB.P.间处于里斯一玉木问冰期,孢粉以落叶栎一松一枫香一常绿栎一栲为主,气候温暖略湿,海平面上升;84～64 kaB.P.间处于早玉木冰期,气候寒冷,孢粉稀少,海水退出本区;64～20]kaB.P.间处于玉木问冰期,孢粉组合以落叶栎-栗-麻栎-常绿栎-栲-蒿-水龙骨为主,常绿树种大量出现,气候温暖湿润,海平面回升,其中37～34 kaB.P.间气候稍微变凉;22～10 kaB.P.间为末次冰盛期,孢粉含量以及种类稀少,主要以针叶树种和耐干草本植物为主,反映气候冷凉干燥,海水全面退出本区;10 kaB.P.以来,气候开始转暖,尤其进入全新世大暖期后,孢粉以落叶栎-松-常绿栎-禾本科为主. 相似文献
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中国东部沿海平原第四系层序类型 总被引：26，自引：0，他引：26
据渤海湾西岸、长江三角洲地区钻孔资料,确定在构造沉降背景下形成的中国东部沿海平原第四系见两类层序。超过0.10Ma周期的大洪泛事件,分别发生在约2.60、0.8、0.5(?)和0.15Ma前后,相当于层序地层的水进体系域,在天津北部平原系华北盆地北边缘山体周期性隆升,在长江一线是附近低山丘陵周期性隆升的表现,反映沿海平原环境变化对西部构造-气候旋回的响应。MIS5以来沿海出现受全球海面变化控制的3期10ka级海侵,结合海域研究可以确定MIS1期间出现完整的海侵-海退层序,沿海平原10ka开始的全新世沉积为高位体系域,7～10ka基底泥炭作为最大海进面,在下切河谷内可见14C测年早于10ka的泥炭。 相似文献
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福建沿海全新世高温期的气候与海面变化 总被引：1，自引：3，他引：1
本文综合分析了福建沿海全新世高温期的孢粉资料和海平面变化资料,建立了气温和海平面变化曲线.结果表明,8ka,B.P.前为气温和海平面上升期,8ka,B.P.以来为高温期和高海平面期,海平面升降与气温升降几乎同步. 相似文献
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通过分析辽河三角洲获取的长41.4m的ZK2孔岩心的岩性、粒度、有孔虫丰度及分子标志物等资料的基础上,结合精确的测年数据、海面变化等资料,并与其他钻孔资料分析对比,构建了辽河三角洲晚更新世33ka BP以来的年代地层框架,将ZK2孔自下而上划分为U1-U4这4个沉积相段:U1为河道相,U2为河漫滩相,U3为海相(全新世海侵)和U4为上三角洲平原相。U3段的海相沉积自下而上又可进一步分为U3~1、U3~2、U3~3、U3~4、U3~5 5个沉积层,分别对应了河口湾相、浅海相、前三角洲相、三角洲前缘相、下三角洲平原相(潮坪相)。沉积物的粒度、有孔虫及生物标志物BIT等指标在不同沉积环境中出现了较为明显的变化,且变化趋势相似,揭示了辽河三角洲晚更新世33ka BP以来的海平面变化的沉积历史,其中U3段沉积物(15.75~2.65m)沉积连续,地层完整,测年数据可靠,较完整地反映了辽河三角洲9 100cal.a BP以来全新世海侵期的沉积历史。 相似文献
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对南海北部B106站柱状剖面进行了高分辨率孢粉与藻类研究,部分样品作了AMS14C年代测定。根据孢粉成分的变化将南海B106站从下至上划分了3个孢粉组合带,依次为:1带(294~194 cm)以Pinus-Quercus(常绿)-Gramineae-Polypodiaceae-Pterdium-Dicranopteris为主孢粉带;2带(194~94cm)以Pinus-Quercus(常绿)-Polypodiaceae-Pteridium-Dicranopteris为主孢粉带;3带(94~4 cm)以Pinus-Polypodiaceae-Pteridium-Quercus(常绿)-Dicranopteris为主孢粉带。并相应恢复了南海北部11 000 aBP以来3个植被、气候、古环境演替阶段,结合AMS14C测年资料,对B106站柱状地层时代划分作了讨沦,为南海古气候、古环境演变研究提供了科学依据。 相似文献
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全球海岸生态系统正遭受气候变化及人类活动带来的威胁, 本文基于沙坝-潟湖系统海岸典型剖面形态, 通过设计实施动床波浪水槽试验, 定量研究了侵蚀浪条件下沉水植被对该系统海岸冲淤的影响。结果表明: 沉水植被明显削弱了沙坝前坡波浪破碎区前缘的波高增大幅度, 并使坝后波高衰减; 植被作用使波浪反射和透射系数减小、耗散系数增大; 侵蚀浪作用下, 沙坝坝顶冲刷较明显, 潟湖内呈淤积趋势, 海岸前丘受波浪冲刷呈陡坎形态。植被影响下沙坝和前丘区域最大侵蚀厚度均减小; 植被可减少沙坝净侵蚀量、潟湖内淤积量及离岸输沙量, 对海岸前丘有较好的保护作用。 相似文献
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High resolution (HR – sparker) and very high resolution (VHR – boomer) seismic reflection data acquired in shallow water environments
of the Roussillon coastal area are integrated to provide an accurate image of the stratigraphic architecture of the Quaternary
deposits. The complementary use of the two systems is shown to be of benefit for studies of shallow water environments. The
HR sparker data improved the landward part of a general model of Quaternary stratigraphy previously established offshore.
They document an incised valley complex interpreted as the record of successive late Quaternary relative sea-level cycles.
The complex is capped by a polygenetic erosional surface developed during the last glacial period (>18 ky) and variably reworked
by wave ravinement during the subsequent post-glacial transgression. The overlying transgressive systems tract is partly preserved
and presents a varying configuration along the Roussillon coastal plain. The VHR boomer data provide information on the architecture
of the uppermost deposits, both in the near-shore area and in the lagoon. These deposits overlie a maximum flooding surface
at the top of the transgressive systems tract and constitute a highstand systems tract composed of two different architectural
elements. In the near-shore area, a sandy coastal wedge is subdivided into a lower unit and an upper unit in equilibrium with
present day dynamics. In the Salses-Leucate lagoon area, the sedimentary architecture is highly complex due to the closure
of a former embayment and the formation of the present beach barrier. 相似文献
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对取自台湾浅滩西北部福建东山岛外的浅钻ZK2孔进行了包括AMS14C测年、粒度、微体古生物、碎屑矿物和黏土矿物等分析。结果表明该孔地层中存在两个明显的海相层和其间的两个陆相层,顶部的海相层为全新世高海平面以来形成的被现代潮流作用改造的现代沉积和残留沉积混合体;底部陆相层为MIS4期低海平面时期形成的河流沉积;中间的细粒沉积层又可划分为下部形成于MIS3期的以潟湖、潮坪和盐沼交替出现的海相沉积层,以及上部形成于MIS3期末到盛冰期出露水面之前的陆上沟谷充填沉积;台湾海峡南部在MIS3期之后发生了明显的构造沉降过程,但是在末次盛冰期海峡南部仍然出露水面之上形成了沉积间断面。本文研究内容为今后在台湾浅滩西北边缘到福建东南近岸区深入开展沉积学、地层学及古环境演化研究提供了新的参考。 相似文献
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Liang Zhou Xiaomei Xu Yaping Wang Jianjun Jia Yang Yang Gaocong Li Changliang Tong Shu Gao 《海洋学报(英文版)》2021,40(11):162-175
The relationship between storm activity and global warming remains uncertain. To better understand storm–climate relationships, coastal lagoon deposits are increasingly being investigated because they could provide high-resolution storm records long enough to cover past climate changes. However, site-specific sediment dynamics and high barriers may bias storm reconstructions. Here, we aimed to investigate these factors through the reconstruction of five distinct storm records (XCL-01, XC-03, XC-06, XC-07, XC-08) from different water depths in a lagoon with a high barrier (i.e., Xincun Lagoon of Hainan Island). Sediment cores were characterized using high-resolution grain size and XRF measurements, to identify storm events. These data were coupled with a numerical simulation to obtain bed shear stress data with high-spatial resolution to better understand storm-induced sediment transport mechanisms. 210Pb dating and Pb pollution chronostratigraphic markers indicated that the chronology of the storm deposit sequences of the cores span the period between 117 a and 348 a. The grain size and XRF results indicated numerous, highly variable and short-duration fluctuations, suggesting that storm-induced coarse-grained sediments were deposited at these core sites. The inconsistent storm events recorded in these cores suggest that these sites have different preservation potentials for storm deposits. However, the consistence between storm sediment records and historical documents for Core XCL-01 indicates that high-barrier lagoons could provide long-term storm event records with high preservation potential. 相似文献
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Silvia Albarracín Javier Alcántara-Carrió Andrés Barranco María José Sánchez García Ángela Fontán Bouzas Jorge Rey Salgado 《Geo-Marine Letters》2013,33(2-3):217-223
The focus of this study is the analysis of coastal sand barriers and associated coastal lagoons on the inner continental shelf of the Gulf of Valencia (western Mediterranean), based on two W–E seismic profiles recorded seaward of the Albufera de Valencia coastal lagoon. Seismic facies identified include a number of coastal sand barriers with landward lagoons draped by contemporary continental shelf deposits. The barrier systems have been grouped into two sedimentary systems tracts, the older one corresponding to a prograding/aggrading highstand systems tract involving at least four paleo-coastal sand barrier/lagoon systems, followed landward by a transgressive systems tract comprising three such systems. All the systems have been allocated a Tyrrhenian age, the formation of individual barrier systems having been associated with successive sea-level stillstands, and their present-day position being explained by the very high regional subsidence rate. In summary, this study demonstrates that the Quaternary stratigraphic record of the Gulf of Valencia inner continental shelf is composed of littoral sand facies, in particular coastal sand barrier and lagoon deposits. These findings are in agreement with corresponding observations on other continental shelves of the western Mediterranean, showing that the formation of coastal sand barriers was a characteristic feature of this region during the Quaternary. 相似文献
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A. Pacheco J.J. Williams Ó. Ferreira E. Garel S. Reynolds 《Estuarine, Coastal and Shelf Science》2011
This paper derives local formulae to estimate bed roughness and suspended transport and present a method to calculate net sediment transport at tidal inlet systems, combining field data and a range of well established empirical formulations. To accomplish this, measurements spanning a spring-tidal cycle of mean water levels, waves, near-bed flow turbulence and bed forms were obtained from the Ancão Inlet, Ria Formosa lagoon system, Portugal. High-resolution hydrodynamic data were gathered using acoustic equipments and by measuring sediment properties (grain-size diameter and bed form dimensions) under fair-weather conditions. The results compared favourably with available direct and indirect field observations of sediment transport rates. The approach appears to be robust and widely applicable and so can be applied to the same conditions in any tidal inlet system. This is of particular importance when attempting to understand sediment transport at inlet mouths, and has practical applications in a range of coastal engineering and coastal management areas concerned with navigation safety, coastal erosion, ecosystem health and water quality. The study discusses the applicability of the method on evaluating system flushing capacity, giving important insights on multiple inlet evolution, particularly with regard to their persistence through time. The methodological framework can be applied to assess the long-term stability of single- and multiple-inlet systems, provided that estimates of sediment storage at ebb-tidal deltas are available and sediment transport estimates during storm events are statistically considered. 相似文献