摘要
通过分析南黄海辐射沙脊群苦水洋海域铁板沙11DT06钻孔的沉积相序列、^14 C测年数据、粒度特征及其沉积环境意义,并与该海域北翼潮流通道11DT01孔、里磕脚11DT02孔对比,重建了MIS 3阶段以来苦水洋海域的环境演变过程.铁板沙11DT06孔自上而下揭示了4个沉积序列：S1（潮流沙脊层）、S2（潮滩层）、S3（陆相硬黏土层）和S4（高潮滩层）.MIS 3阶段以来苦水洋海域经历了潮滩（ca.44～25ka BP）、洪泛平原（陆相硬黏土层,ca.25～12ka BP）、滨岸沼泽与潮滩（ca.12～7ka BP）和水下沙脊-潮流通道（ca.7ka BP至今）等一系列环境演变过程.铁板沙潮流沙脊主要由细砂和粉砂质细砂组成,而MIS 3阶段与早全新世的潮滩沉积主要由黏土质粉砂和粉砂质黏土组成,分选性总体都较差,基本都为正偏态,表明沉积物粒度分布都存在细尾部分,这正是潮流沉积物的一大特点,与洪泛平原相的硬黏土层存在明显差异,指示了主控沉积动力环境的不同.苦水洋海域三个钻孔测试获得的11个AMS 14 C和2个OSL测年数据显示了海陆交互作用强烈地区测年结果的复杂性与不确定性.
Based on the analysis of sedimentary facies,^14 C dating results,characteristics of grain size and its environmental implication of core 11DT06,which is in the Kushuiyang area of radial sand ridge field,southern Yellow Sea,and stratigraphic correlation between core 11DT06 and adjacent cores（i.e.,core 11DT01 and 11DT02）,we reconstructed the progression of environmental changes in the Kushuiyang area since MIS 3.Core 11DT06 revealed four sedimentary sequences from top to bottom（i.e.,S1,tidal sand ridge layer;S2,tidal flat layer;S3,terrigenous stiff mud layer;S4,upper tidal flat layer）.The Kushuiyang area experienced a series of environmental changes mainly controlled by sea level changes since MIS 3,which included tidal flat（ca.44～25ka BP）,river flood plain（terrigenous stiff mud layer,ca.25～12ka BP）,coastal marsh and tidal flat（ca.12～7ka BP）,and subaqueous sand ridge-tidalchannel（ca.7ka BP to present）environments.The Tiebansha tidal sand ridge（i.e.,the site of core 11DT06）was mainly composed of fine sand and silty fine sand,while the MIS 3and early Holocene tidal flat deposits were mainly composed of clayey silt and silty clay.These deposits generally had poor sorting and positive skewness,showing that there was fine sediments in the grain size distribution,which was a major feature of tidal sediments.These characteristics of grain size parameters were obviously different between tidal sediments and stiff mud layers of river flood plain facies,indicating the discrepancy in terms of dynamic sedimentary environments.Eleven AMS 14 C and two OSL dating results of three cores in the Kushuiyang area showed the complexity and uncertainty of late Quaternary datings recovered from the intensive land-sea interaction areas again.
出处
《南京大学学报（自然科学版）》
CAS
CSCD
北大核心
2014年第5期564-575,共12页
Journal of Nanjing University（Natural Science）
基金
国家重大科学研究计划项目(2013CB956503)
国家海洋局海洋公益性行业科研专项(201005006)
国家自然科学基金(40776023
41371024)
国家建设高水平大学公派研究生项目(2011619035)
关键词
辐射沙脊群
潮流通道
环境演变
14
C测年
光释光测年
南黄海
radial tidal sand ridge field
tidal channel
environmental change
14 C dating
OSL dating
southern Yellow Sea
