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1.
闽东北沿海晚第四纪海侵与海面变动   总被引:4,自引:0,他引:4  
闽东北沿海是福建乃至全国晚第四纪海面变化研究比较薄弱的地区之一。本文根据该区的钻孔岩芯和地表露头沉积相及测年资料的综合分析,揭示了闽东北沿海晚更新世以来的海侵和海面变动;晚更新世约90-80kaBP,70-60kab0,40-39kaBP和34-22kaBP发生4次海侵;全新世海侵在约12kaBP已开始,此后海面有过多次波动,其中约在距今6ka和3ka前出现过明显高于现今海面位置的高海面,海侵范围  相似文献   

2.
晚更新世末期东亚季风活动与陆架区沉积环境变迁   总被引:3,自引:0,他引:3  
从距今18000年的最后冰期最盛时期到距今10000年开始的全新世海侵,全球气候发生过急剧的变化。位于亚洲东部的古季风活动也经历了盛衰变化。大量的钻孔及浅地层剖面分析资料已经证实,冰期最盛时期陆架区古季风活动加强,陆架出现了沙漠环境与黄土沉积。当冰期结束,气候转暖,冬季风减弱之际,南黄海陆架及长江三角洲一带的沙漠与黄土分布范围也随之缩小,原先的沙漠活动区变成了黄土分布区,也就是所谓硬粘土沉积区。随着古季风活动的进一步衰退和海面的不断升高,来自陆架区的东北风变为冷湿气流。长江三角洲地区和陆架上出现了有利于沼泽发育的环境,全新世海侵把泥炭层淹没。陆架区晚更新世末期以来的地层中出现沙层、硬粘土和泥炭层的沉积序列,即“三元沉积结构”,是古季风盛衰过程的最好记录。  相似文献   

3.
湄洲岛海岸地貌的发育受海洋动力和断层活动双重控制。东部以海岸侵蚀为主,形成海蚀崖、海蚀平台、海蚀壕沟等地貌,在岬角间,形成海滩堆积;西部以堆积为主,形成淤泥质海滩,海蚀作用相对比东部弱。东峤断裂控制了台地和丘陵的分布,断裂东盘抬升形成丘陵,西盘下降形成台地。受北西—南东走向的仙游—郊尾断层左行运动影响,湄洲岛北部向西移动,南部向东移动,使岛的轮廓呈"S"形态。福建沿海在距今0.7—0.6万年前发生海侵时,湄洲岛处于断块抬升环境,就岛的局地范围,处于低海面;在0.4—0.3万年前福建沿海海侵达到高峰时,湄洲岛的海侵经历了两个阶段,第一阶段为水动型海侵,第二阶段为地动型海侵。  相似文献   

4.
湖南天门山牛蹄塘组底部沉积环境分析   总被引:3,自引:0,他引:3  
通过实地考察湖南张家界(大庸)天门山一带寒武系牛蹄塘组底部的岩性、结构及化石,并结合地球化学指标来探讨牛蹄塘组底部的沉积环境.牛蹄塘组的岩性自下而上为:磷块岩或硅质岩-磷结核层或砾岩-硅质页岩或泥灰岩-矿层-碳质页岩;含他形结构重晶石的层位与贵州、湖南等地喷流沉积成因重晶石矿床的层位一致.页岩的LaN/CeN比值为1.27,Ce/Ce*比值为0.87,属于大陆边缘的范围;而硅质岩的LaN/CeN是3.19,Ce/Ce*为0.33,则不属于正常大陆边缘的比值范围.硅质岩与页岩的Ua(Ua=Utotal-Th/3)分别为4.53及63.54.牛蹄塘组底部是大陆边缘陆棚到陆架的沉积环境,为一个海侵的过程.其地化环境从富氧到缺氧,期间经历了至少两次的热液活动.  相似文献   

5.
良渚先民受自然环境的制约和经济生活模式的决定,连片成串地集中分布于长江三角洲南部平原,良渚早中期的温干气候和适宜环境使良渚文化空前繁荣,但在距今4000年左右突然消亡.作者通过研究,发现在距今4100年左右存在明显的降温事件,降温使农作物歉收,食物匮乏,在部落间引起连绵战争,使良渚文化走向衰弱.而距今3600年左右的海平面升高,在长江三角洲南部平原发生沟谷海侵,地下水位升高,太湖湖泊体系迅速扩张,引起大洪水,导致良渚文化消亡.  相似文献   

6.
引言第四纪时期,我国海岸发育的过程是相当复杂的。海岸构造局格始于中生代的燕山运动和第三纪的喜马拉雅运动,而现代海岸线的外貌,则经历了第四纪的海陆变迁,直至距今6,000年左右才逐渐形成的。更新世全球性气候出现多次冷暖交替,相应地发生了几次冰期与间冰期更替,导致冰川型海面升降,冰期时海面下降,发生海退,间冰期时海面回升,则发生海侵。与此同时,海洋底部  相似文献   

7.
苗军  李红霞  魏建成 《科技资讯》2012,(29):23+25-23,25
贺兰山地区奥陶纪地层发育良好,特征显著。依据形成时间,其岩石地层序列自下而上划分为马家沟组,米钵山组2个组级岩石地层单位;出露于贺兰山中一南段,隶属华北西缘地层分区和祁连一北秦岭地层分区。笔者认为奥陶纪初期,海侵进一步扩大,海侵范围几乎含盖整个本区,形成了以碳酸岩盐为主的台地相沉积。后期沉积环境发生了明显变化,以碎屑岩,泥岩为主夹薄层灰岩,砾屑灰岩,角砾岩,属次深海大陆斜坡沉积。从岩石地层.地层层序,沉积相及沉积环境相演化序列总体看来,反映了一个海侵沉积序列演化规律。  相似文献   

8.
引言第四纪时期,我国海岸发育的过程是相当复杂的。海岸构造局格始于中生代的燕山运动和第三纪的喜马拉雅运动,而现代海岸线的外貌,则经历了第四纪的海陆变迁,直至距今6,000年左右才逐渐形成的。更新世全球性气候出现多次冷暖交替,相应地发生了几次冰期与间冰期更替,导致冰川型海面升降,冰期时海面下降,发生海退,间冰期时海面回升,则发生海侵。与此同时,海洋底部  相似文献   

9.
以珠江河口三角洲为例,论述了三角洲的概念和范围、全新世海侵最大时的古海岸位置与海水入侵范围、全新世海侵结束后三角洲发展和环境变化特点及其与古代人类活动遗迹分布的关系,并对珠江三角洲的模式问题进行讨论.  相似文献   

10.
南流江三角洲沉积特征及其环境演变   总被引:6,自引:2,他引:6       下载免费PDF全文
南流江三角洲钻孔记录揭示,三角洲全新世沉积陆上部分有三角洲平原相、三角洲前缘相、前三角洲—浅海相、河床相依次迭覆的特征,水下部分有三角洲前缘相、前三角洲─—浅海相、河床相依次迭覆的特征。该三角洲大体经历了全新世早期─—海侵阶段、全新世中期─—稳定阶段和全新世中晚期─—海退阶段。南流江主河道自明代初(距今约600年)开始,从东部周江逐渐向西部变迁至七星岛附近入海。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

15.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

16.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

17.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

18.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

19.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

20.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

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