樊耘畅¹,
丁旋^1,,,
樊加恩¹,
印萍²,
李秋子¹,
王天昊¹,
王晨¹
1. 中国地质大学(北京)海洋学院, 北京 100083
2. 青岛海洋地质研究所, 山东 青岛 266071

基金项目: 国家海洋地质调查项目"长江口等海岸带综合地质调查"（批准号：DD20160145）、中国-东盟海上合作基金项目"长江三角洲与红河三角洲全新世沉积演化对比研究"和中国地质大学（北京）2017大学生创新创业训练项目（批准号：201711415082）共同资助


详细信息

作者简介: 樊耘畅, 男, 21岁, 本科生, 海洋科学专业

通讯作者: 丁旋, E-mail:dingx@cugb.edu.cn

中图分类号: P736.22⁺1, P736.22⁺3

收稿日期:2018-02-05
修回日期:2018-03-20
刊出日期:2018-05-30

A preliminary study on the variability in ¹⁴C date of different benthic foraminifera from the muddy coast of Zhejiang and Fujian in the East China Sea

Fan Yunchang¹,
Ding Xuan^1,,,
Fan Jia¹,
Yin Ping²,
Li Qiuzi¹,
Wang Tianhao¹,
Wang Chen¹
1. School of Marine Sciences, China University of Geosciences(Beijing), Beijing 100083
2. Qingdao Institute of Marine Geology, Qingdao 266071, Shandong


More Information

Corresponding author: Ding Xuan,E-mail:dingx@cugb.edu.cn

MSC: P736.22⁺1, P736.22⁺3

--> Received Date: 05 February 2018
Revised Date: 20 March 2018
Publish Date: 30 May 2018


摘要
摘要:底栖有孔虫是浅海陆架区钻孔岩芯¹⁴C测年的良好材料，但由于其个体细小，为了获得足够的样品量，常常采用不区分属种和大小的混合壳体样品，不利于高分辨率的古环境研究。本研究选择东海陆架浙闽沿岸泥质区的两个钻孔沉积物样品，对其中不同的底栖有孔虫属种壳体化石分别进行¹⁴C测年，结果显示同一沉积物样品中不同的底栖有孔虫属种壳体化石¹⁴C年龄值存在差异，以Quinqueloculina spp.壳体¹⁴C年龄最老，其次是Ammonia comperessiuscula壳体，最年轻的分别为Elphidium spp.壳体和Bolivina cochei壳体。从底栖有孔虫的生态习性和壳体的结构特征等方面分析推测，同层位不同底栖有孔虫属种壳体年龄差异，不能简单地用它们生活时壳体和所处的微生境水体同位素交换来解释；不同属种有孔虫壳壁构造不同可能是产生壳体化石¹⁴C年龄差异的原因。建议为地质钻孔建立高分辨率年代地层挑取底栖有孔虫AMS ¹⁴C测年样品时，尽量选择相同的属种，或微生境相同、个体大小相近、壳壁厚度和壁孔大小密度近一致的类别，以降低属种不同对测年结果产生的影响，为海岸带高分辨率的古环境研究提供高精度的测年数据。
关键词: 沉积物样品/
底栖有孔虫/
AMS ¹⁴C测年/
微生境/
有孔虫壳壁构造

Abstract:Benthic foraminiferas from sediment cores are ideal materials for ¹⁴C dating in the shallow continental shelf areas. Usually, mixed benthic foraminiferal shells of different species and sizes from the sediment are picked out to obtain sufficient weight for ¹⁴C dating. In this study, two holes D03(121°47'56″E, 27°53'42″N; water depth 42 m, long 41.2 m) and D05(121°36'22″E, 27°20'53″N; water depth 57 m, long 40.4 m) were drilled on the muddy coast of Zhejiang and Fujian in the East China Sea shelf. Samples of different benthic foraminiferal species picked from two sedimentary samples at 31.05~31.11 m of Hole D03 and at 12.80~12.87 m of Hole D05 were analyzed for ¹⁴C dating. The results show that different benthic foraminiferal species from the same sediment units yielded different ¹⁴C ages. The ¹⁴C age of Quinqueloculina spp. was found to be the oldest, Ammonia comperessiuscula relatively yonger, and Elphidium spp. and Bolivina cochei were the youngest.
The observed ¹⁴C age differences were interpreted with reference to the benthic foraminiferal microhabitats and the characteristics of shell structure. The water isotope exchange process between the shell and their microhabitat is thought to be less likely the main cause for the age difference. Instead, the characteristic shell structures of foraminiferal taxa used in the study may be responsible for the ¹⁴C age difference.
In order to reduce the impact of the different foraminiferal species on ¹⁴C dating and provide the high precision chronological constraints for coastal zone paleoenvironmental study, it is recommended to use benthic foraminiferal shells from the same genus or species, or taxon that have similar microhabitats, size, wall thickness and pore pattern for AMS ¹⁴C analyses.
Key words:sedimentary samples/
benthic foraminifera/
AMS ¹⁴C/
microhabitat/
foraminiferal shell construction



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