周笑笑^1,2,,
陈秀玲^1,2,3,,,
范逸飞^1,2,
卢欣^1,2,
陈晓薇²
1. 福建师范大学湿润亚热带山地生态国家重点实验室培育基地, 福建 福州 350007
2. 福建师范大学地理科学学院, 福建 福州 350007
3. 福建师范大学地理研究所, 福建 福州 350007

基金项目: 福建省自然科学基金项目(批准号: 2019J01259)和福建师范大学创新团队项目(批准号: IRTL1705)共同资助


详细信息

作者简介: 周笑笑, 女, 28岁, 硕士研究生, 全球变化与第四纪研究, E-mail: 1453007473@qq.com

通讯作者: 陈秀玲, E-mail: xiulingchen@163.com

中图分类号: P595;P534.63⁺2

收稿日期:2021-02-28
修回日期:2021-05-20
刊出日期:2021-09-30

Discussion on the sedimentary environment and provenance of surface sediment in Luoyuan Bay offshore of Fujian Province

ZHOU Xiaoxiao^1,2,,
CHEN Xiuling^1,2,3,,,
FAN Yifei^1,2,
LU Xin^1,2,
CHEN Xiaowei²
1. Key Laboratory of Humid Subtropical Eco-geographical Processes of the Ministry of Education, Fujian Normal University, Fuzhou 350007, Fujian
2. School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, Fujian
3. Institute of Geography, Fujian Normal University, Fuzhou 350007, Fujian


More Information

Corresponding author: CHEN Xiuling,E-mail:xiulingchen@163.com

MSC: P595;P534.63⁺2

--> Received Date: 28 February 2021
Revised Date: 20 May 2021
Publish Date: 30 September 2021


摘要
摘要:东亚大陆边缘近岸泥质物源研究对于认识地球表生过程、物质循环以及气候变化等问题十分关键，但目前对沿岸半封闭型海湾的物质来源研究还尚不深入。本研究以东亚大陆边缘浙闽泥质区罗源湾为研究区，通过对罗源湾表层沉积物粒度组成的分析发现，罗源湾表层沉积物粒度组成以粉砂为主，各粒度参数分区明显，湾内西北部近岸潮滩颗粒较细，湾内顶部、东部潮汐通道附近和东南部大部分区域颗粒较粗。粒度参数也表明罗源湾大部分区域沉积环境较稳定，湾内顶部、潮流通道与东部潮滩连接处水动力较强。对罗源湾与闽江、起步溪以及长江表层沉积物的稀土元素特征参数、配分模式进行对比发现，罗源湾表层沉积物δEu、UCC配分模式与闽江和起步溪相差甚远，而与长江表层沉积物更为接近。结合判别函数（DF）、微量元素比值判别图以及La/Yb-REE关系图解分析结果表明，罗源湾表层沉积物主要来自浙闽沿岸流携带的包括长江沉积物、长江口杭州湾沉积物在内的泥质沉积物，以及波浪和潮汐对周边基岩的剥蚀产生的碎屑物质。此外，罗源湾顶部入港溪流在洪水期产生的洪冲积物对湾的顶部也有一部分的物质贡献。
关键词: 罗源湾/
粒度/
微量元素/
沉积环境/
物源

Abstract:Luoyuan Bay is located on the northeastern coast of Fujian Province, approximately 50 km away from the mouth of Minjiang River. It is a typical semi-closed bay with a large belly and a small mouth. It is connected to the East China Sea through the entrance at the southeast corner. The channel width is approximately 2 km. The Fujian and Zhejiang coastal current flows along the east of Luoyuan Bay, and the coastal material can be exchanged with the bay via the tidal channel. There are no large rivers in Luoyuan Bay, only a few small streams at the top. Luoyuan Bay is located in the middle of the Zhe-Min uplift zone, surrounded by tectonic mountains and hills mainly composed of glutenite and granite.
70 sediment samples were collected from the bottom of the Luoyuan Bay, 8 sediment samples were collected from the river surface in the Minjiang River Basin, and 17 sediment samples were collected from the top of Luoyuan Bay. The particle size analysis of the collected samples showed that the proportions of clay, silt and sand in the surface sediments of Luoyuan Bay are 29.82%, 66.61% and 3.57%, based on the Folk's classification system. In this paper, the average particle size, clay content, and sorting coefficient are selected as three grain-size characteristic parameters, and the Luoyuan Bay is divided into three types of sedimentary areas using the system cluster analysis method. Zone Ⅰ is distributed in the depths of the northwestern of Luoyuan Bay. Zone Ⅱ is distributed on the top tidal of Luoyuan Bay, near the eastern tidal channel and most of the southeastern region of the bay. Zone Ⅲ is scattered on the top tidal flat and the junction of the eastern tidal channel and the southeast tidal flat of Luoyuan Bay. The analysis results of trace elements and rare earth elements in surface sediments of Luoyuan Bay showed that the surface sediments of Luoyuan Bay are relatively close the Yangtze River, Hangzhou Bay and mud area off Zhejiang-Fujian coast, while different from the surface sediments of Minjiang River and Qibuxi. The DF discriminant function shows that the DF of surface sediments Luoyuan Bay is the smallest when the surface sediments of Yangtze River are used as end members. The La/Yb-REE diagram shows that the surface sediments of Luoyuan Bay are concentrated in the intersection of granite, basalt and sedimentary rocks. The results of this analysis revealed that the surface sediments of the Luoyuan Bay are mainly carried by the coastal current of Zhejiang and Fujian, including the surface sediments of the Yangtze River, Hangzhou Bay, and the mud area off Zhejiang-Fujian coast, and the detrital materials produced due to the erosion of the surrounding bedrock caused by waves and tides. In addition, the material contribution to the top of the Luoyuan Bay is partly due to the alluvial deposits created by the inflow streams during the flood period.
Key words:Luoyuan Bay/
grain-size/
trace elements/
sedimentary environment/
provenance



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