摘要
长江三角洲是研究古海岸沉积环境演化的理想区域。选取长江三角洲平原一支长岩芯钻孔上部55 m层位的沉积物进行光释光(optically stimulated luminescence,OSL)测年研究。根据沉积物粒度特性,在实验前处理过程中,提取100~200μm或63~100μm粗颗粒石英矿物进行OSL测年。测年样品的预热坪与剂量恢复实验表明选择180℃作为预热条件较为合适,石英OSL信号衰退曲线以快组分为主。条件实验结果、等效剂量分布以及各测片的循环比、热转移等方法学层面的实验结果表明,OSL测年技术对该孔的沉积物测年具有适应性和可靠性。通过年代—深度关系模型,建立该段地层中全新世以来的年龄框架。依据该孔的年代地层序列并结合前人工作,探讨全新世以来长江三角洲的沉积演化。
Yangtze River delta is an ideal region for studying paleoenvironmental evolution.In the first part,research objective was collected five samples from the upper 30 m of a drill hole in the Yangtze River delta plain to demonstrate the potential of optically stimulated luminescence(OSL)dating method in coastal/delta zone.On the basis of the size characteristic of the core sediments,the single aliquot regenerative dose(SAR)was applied to coarse(63-100μm or 100-200μm)grained quartz extracts to measure equivalent dose(D e)in pretreatment.Preheat plateau tests and dose recovery tests showed that 180℃as preheat was very suitable for OSL dating measurement.The quartz OSL signal decay curves proved that the fast component was the main component of OSL signal.It was analyzed the suitability and reliability of OSL by the spread in measured equivalent doses,experimental results under optimal conditions laboratory dose and recycling ratio as well as recuperation from the methodological viewpoint.These indicated that the OSL protocol can provide a trustable chronological framework for this core.A chronological framework since the middle Holocene of this stratium was established on the basis of the modelling age-depth.Finally,the characteristics and process of the Yangtze River Delta paleoenvironmental evolution were discussed according to chronostratigraphy of the core and previous work.
作者
申江
常华进
曹广超
刘洪舟
SHEN Jiang;CHANG Hua-jin;CAO Guang-chao;LIU Hong-zhou(Qinghai Provincial Key Laboratory of Physical Geography and Environmental Process,College of Life and Geographical Science,Qinghai Normal University,Xining,810008,China;State Key Laboratory of Lake Science and Environment,Nanjing Institute of Geography and Limnology,Chinies Academy of Sciences,Nanjing,210008,China;College of Resources Environment and Tourism,Hubei University of Arts and Science,Xiangyang,441053,China)
出处
《盐湖研究》
CAS
CSCD
2020年第4期29-40,共12页
Journal of Salt Lake Research
关键词
长江三角洲
石英
光释光测年
全新世
Yangtze River delta
Quartz
Optically stimulated luminescence(OSL)
Holocene
