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中国沙漠 ›› 2024, Vol. 44 ›› Issue (2): 11-24.DOI: 10.7522/j.issn.1000-694X.2023.00082

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福建晋江颜厝老红砂的光释光测年及其环境指示意义

许岱玉(), 靳建辉(), 李志忠, 卫俊杰, 侯晨阳   

  1. 福建师范大学 福建省亚热带资源与环境重点实验室/地理科学学院,福建 福州 350117
  • 收稿日期:2023-03-26 修回日期:2023-05-23 出版日期:2024-03-20 发布日期:2024-03-19
  • 通讯作者: 靳建辉
  • 作者简介:靳建辉(E-mail: geojjh@fjnu.edu.cn
    许岱玉(1998—),女,江西赣州人,硕士研究生,主要研究方向为全球变化与第四纪。E-mail: xu19559155989@163.com
  • 基金资助:
    国家自然科学基金项目(41301012)

Luminescence dating of Old Red Sand in YancuoJinjiangFujian and its environmental significance

Daiyu Xu(), Jianhui Jin(), Zhizhong Li, Junjie Wei, Chenyang Hou   

  1. Fujian Provincial Key Laboratory of Subtropical Resources and Environment / School of Geographical Sciences,Fujian Normal University,Fuzhou 350117,China
  • Received:2023-03-26 Revised:2023-05-23 Online:2024-03-20 Published:2024-03-19
  • Contact: Jianhui Jin

摘要:

老红砂是全球气候变化研究的重要载体,能有效反映晚更新世以来的海岸带地貌过程和气候演化背景。囿于不可靠的测年方法,华南老红砂的形成年代及其气候环境背景问题尚未解决。为了更好地揭示华南老红砂主要的形成时段及其环境特征,本研究经野外考察后选取了位于福建晋江的颜厝老红砂剖面进行采样。在实验室选用中颗粒石英单片再生剂量法进行光释光年代测量,并对测年样品进行了粒度和地球化学元素测试。结合离散系数和化学风化指数CIA等指标对老红砂测年结果的可靠性进行了探讨。同时通过对已有的部分华南老红砂年代数据进行概率密度统计分析,探讨华南老红砂的形成年代及其气候环境背景。结果表明:(1)颜厝剖面为典型的风成砂,分选性较好,整体以中细砂为主。(2)颜厝老红砂沉积主要形成于132.85~37.22 ka,其中,在MIS5和MIS4阶段,沙丘可能因为处于活化—沉积—再活化的状态,释光信号没有得到良好的保存,因而出现了“沉积间断”的假象。MIS3阶段对应海退时期,风沙沉积速率较快,在暖湿的气候环境下,风化作用强烈。(3)受到海平面变化和冬季风强度等因素影响,高海面和低海面环境均有可能发育老红砂,但其沉积时段主要在80~30 ka,对应MIS4和MIS3阶段。

关键词: 华南沿海, 福建, 老红砂, 释光年代学

Abstract:

As one of the important materials of global climate change research, the Old Red Sand can effectively reflect the coastal geomorphological process and climate evolution background since the late Pleistocene. Limited by no reliable dating methods, the formation age and climatic background of Old Red Sand in South China have not been well solved. For that matter, this study selected the section of Yancuo Old Red Sand located in Jinjiang, Fujian Province. In the laboratory, the single aliquot regenerative-dose method of medium-particle quartz was used for luminescence age measurement, and the samples were tested for grain sizes and geochemical elements. The influence of dispersion coefficient and chemical weathering index CIA on the reliability of Old Red Sand dating results was discussed. At the same time, through the statistical analysis of probability density of some reported Old Red Sand age data in South China, the formation of Old Red Sand in South China and its environmental background were discussed. The results showed that: (1) Yancuo profile (YCR) was a typical aeolian sand dune, with good sorting, and the whole was mainly medium sand and fine sand. (2) The sedimentation of Old Red Sand in Yancuo was mainly formed during the period of 132.85-37.22 ka, among which, in the MIS5 and MIS4 stages, the sand dunes may be in the state of activation-deposition-reactivation, and the OSL signal is not well preserved, so it appears the illusion of "sedimentary disconnection". And the MIS3 stage corresponds to the regressive period, the sedimentation rate of aeolian sand is relatively fast, and the weathering degree is strong in the warm and humid climate environment. (3) Affected by sea level change and winter wind intensity, Old Red Sand deposition may occurred in both high sea level and low sea level, but its sedimentation stages are mainly occurred in 80-30 ka, corresponding to MIS4 and MIS3 stages. The sedimentary process of Old Red Sand mainly occurred in the regressive stage, when the sea level is neither high nor low. Too high or too low sea level will affect the provenance range, and then affect the accumulation process of Old Red Sand.

Key words: South China coast, Fujian, Old Red Sand, optically stimulated luminescence

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