热带地理 ›› 2016, Vol. 36 ›› Issue (3): 374-387.doi: 10.13284/j.cnki.rddl.002844

• 论文 • 上一篇    下一篇

珠江口万顷沙晚第四纪沉积及古环境重建

余少华1,陈 芳1,谢叶彩2,周 洋1,吴 聪1,陈炽新1,龙 桂2   

  1. (1.国土资源部海底矿产资源重点实验室,广州海洋地质调查局,广州 510075;2.广东省地质调查院,广州 510080)
  • 出版日期:2016-05-05 发布日期:2016-05-05
  • 通讯作者: 谢叶彩(1977―),女,广东仁化人,高级工程师,主要研究方向为第四纪地质,(E-mail)xieyecai@foxmail.com。
  • 作者简介:余少华(1987―),女,湖北枝江人,博士,主要从事第四纪孢粉研究,(E-mail)yuyushaohua@foxmail.com
  • 基金资助:
    中国地质调查项目(1212011220528);国家青年自然科学基金(41506049);国土资源部海底矿产资源重点实验室开放基金(KLMMR- 2014-A-02)

Paleoenvironment Reconstruction and Sedimentary Record in the Wanqingsha Area of the Pearl River Estuary

YU Shaohua1,CHEN Fang1,XIE Yecai2,ZHOU Yang1,WU Cong1,CHEN Chixin1,LONG Gui2   

  1. (1.Guangzhou Marine Geological Survey,Key laboratory of Marine Mineral Resources of Ministry of Land and Resources, Guangzhou 510075,China;2.Guangdong Geologic Survey Institute,Guangzhou 510080,China)
  • Online:2016-05-05 Published:2016-05-05

摘要: 选取位于珠江口万顷沙ZK316-2钻孔进行孢粉、硅藻和岩性等分析,重建了珠江口晚更新世以来的海侵海退旋回和古环境特征。孢粉和硅藻分析表明:晚更新世期间该区域主要经历了一次大的海侵海退,期间有2次小的海平面波动。晚更新世地层海相特征明显,孢粉组合指示了温暖湿润的气候环境,其植被以南亚热带常绿林为主,孢粉组合以青冈属、蕈树属、金缕梅科等亚热带种属为主,期间出现的海桑属推测为滨海相沉积,指示了当时海平面的位置。晚更新世的海相沉积尽管14C测年结果为老于30 ka左右,但经过区域孢粉组合、硅藻特征、海平面高度等因素的综合对比分析后认为:下部海相层的年代更可能属于MIS 5期,而期间2次短暂的低海面记录可能与5b和5d海平面波动有关。钻孔上部13.9 m以上为全新世2 232 cal. a B.P.以来的沉积,孢粉分析表明植被仍以亚热带常绿林为主,但人类干扰因素的禾本科、松属、芒箕和火灾记录(炭屑)大量增加,指示了沿海人类活动增强和大规模农业的发展,这与全新世晚期海平面下降和三角洲的快速加积作用基本同步进行。

关键词: 珠江口岸, 孢粉, 硅藻, 海平面变化, 晚第四纪, 人类活动

Abstract: In order to reconstruct the eustatic change and paleoenvironment of the estuary of Pearl River since the late Pleistocene, the Core ZK 316-2, which is located in the Wanqingsha district of the Pearl estuary, was chosen to carry on pollen analysis combining with diatom and lithological analyses. Results of diatom and pollen analyses as well as lithological analysis showed that the late Pleistocene experienced a large sea level transgression and regression and two smaller eustatic changes. During the transgression period in the late Pleistocene the pollen assemblages indicated warm and rainy climate, when vegetation was dominated by south sub-tropical Asian evergreen forest, including sub-tropic pollen types Cyclobalanopsis, Altingia, and Hamamelidaceae, etc. The appearing of Sonneratia in this period was deduced from the littoral face, and it represented the altitude of relative sea level. Although the dating year from 14C results in this oceanic layer was more than 30 ka, the regional pollen assemblages and diatom signals as well as the altitude of global sea level demonstrated that the deposition in the transgressive period during the late Pleistocene was more likely from MIS5, and the two shorter low sea level records probably corresponded to 5b and 5d. The upper layer of the core (less than 13.9 m in depth) was deposited since 2 232 cal. a B.P., and the pollen analysis demonstrated that the vegetation was still dominated by the subtropical evergreen forest, when the climate was colder and dryer during this period as compared with that in the transgressive period of the late Pleistocene. The flourishing of Poaceae, Pinus and Dicranopteris as well as fire records (charcoal) which indicated the anthropogenic disturbance during this period indicated that human activities and cultivated agriculture bloomed, almost synchronizing with the regression of sea level and deposition of the Pearl River delta.

Key words: the Pearl River estuary, pollen analysis, diatom analysis, sea level change, late Quaternary, human activities