Sedimentary Characteristics of Relict Deposits on the Western South Yellow Sea

来源 :Journal of Ocean University of China | 被引量 : 0次 | 上传用户:hlp2009
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
Integrated studies of vertical sedimentary sequences, grain sizes, and benthic foraminifera and ostracoda, in combination with AMS 14C dating, and 210Pb and 137Cs analysis were carried out in three vibracores taken from the area of relict deposits on the western South Yellow Sea. The relict sands, which are about 0.4 m thick, overlie on the Early Holocene coastal marsh or tidal flat deposits with an evident erosional interface in between. The middle and upper parts or sometimes the whole of the relict sands have been reworked under the modern dynamic environment. The sedimentation rate varies between 0.20–0.30 cm year-1. The relict sands show a bimodal grain-size distribution pattern in frequency curves, with a sharp peak in the coarse fraction between 3Φ and 4Φ and a secondary peak in the fine fraction of about 7Φ. Of the benthic foraminiferal and ostracod assemblages, the reworked relict sands are characterized by the mixing of the nearshore euryhaline shallow-water species and deeper water species. The erosional interface at the bottom of the relict sands is considered as a regional ravinement surface formed during the transgression in the Early Holocene due to shoreface retreating landwards. The relict sands were accumulated on the ravinement surface during the transgression in the deglaciation period as lag deposits after winnowing and reworking by marine dynamic processes. And the secondary peak of fine fraction in the frequency curve for the relict sands suggests the input of fine-grained sediments during the reworking process. As the conclusion, the relict sands in the study area are interpreted as a type of reworked relict sediments. Integrated studies of vertical sedimentary sequences, grain sizes, and benthic foraminifera and ostracoda, in combination with AMS 14C dating, and 210Pb and 137Cs analysis were carried out in the area of ​​relict deposits on the western South Yellow Sea. The relict sands, which are about 0.4 m thick, overlie on the Early Holocene coastal marsh or tidal flat deposits with an evident erosional interface in between. The middle and upper parts or sometimes the whole of the relict sands have been reworked under the modern dynamic environment. The sedimentation rate varies between 0.20-0.30 cm year-1. The relict sands show a bimodal grain-size distribution pattern in frequency curves, with a sharp peak in the coarse fraction between 3Φ and 4Φ and a secondary peak in the fine fraction of about 7Φ. Of the benthic foraminiferal and ostracod assemblages, the reworked relict sands are characterized by the mixing of the nearshore euryhaline shallow-water species and deeper water species. The erosional interface at the bottom of the relict sands is considered as a regional ravinement surface formed during the transgression in the Early Holocene due to shoreface retreating landwards. The relict sands were accumulated on the ravinement surface during the transgression in the deglaciation And the secondary peak of fine fraction in the frequency curve for the relict sands suggests the input of fine-grained sediments during the reworking process. As the conclusion, the relict sands in the study area are interpreted as a type of reworked relict sediments.
其他文献
随着现代社会的发展,日趋社区化的进程,幼儿园已成为社区内的一个有机成员,幼儿园的生存与发展既明确地是为社区全体成员服务的,又明显地受社区内全体成员及其环境的影响.
期刊
公民享有基本政治权利,监督权则是现代法治国家赋予公民的一项基本权利。宪法上的公民监督权,即公民监督国家机关及其工作人员活动的权利,它与公共权力同时产生,是一种原生性的权
【中图分类号】G633.955【文献标识码】A 【文章编号】2095-3089(2016)03-0218-01  美术学科是义务教育的一门必修的艺术教育课程,美术教学是向学生传授美术基础知识和基本技能,对提高学生的审美能力,陶冶高尚情操 ,对培养良好的德意行十分有益。 美术教育工作者在教学方法上要积极进行改革,努力探索美术教学的新路子,激发学生对美术学习的兴趣。亲其师信其道,有了良好的学习情绪任何
为探究吕家坨井田地质构造格局,根据钻孔勘探资料,采用分形理论和趋势面分析方法,研究了井田7
思想政治工作是事业单位解放员工思想、实现企业长久健康发展的政治依托。本文针对我国当前事业单位思想政治工作中存在的问题进行分析,对新时期的的思想政治工作的开展提出了
本次实验,首先,实验从学生个体微观视角出发,利用问卷调查和文献法相结合的方法,通过涉及多方面包括生活学习以思想上的问题的设置,全面而又有针对性的反映当代大学生的寝室
近年来,随着我国教育体制改革的不断深入,中小学德育教育取得了一定成效,但其中仍存在德育课程目标碎片化、内容抽象化、课程实施片面化等诸多问题.2016年5月,山东省教育厅组
前阵子耳朵里时常很诡异地萦绕着一种声音,确切地说是歌声,很多孩子的合唱,音调起伏,百转千回,就像它的歌词:“山青青,水碧碧,高山流水韵依依”。
数学是小学中的基础学科,数学中最重要的便是思维逻辑能力,拥有一定的思考能力才能解决问题。因此,帮助学生建立一定的独立思考能力,才能提升学生的数学能力。本篇文章主要讨