石学法, 刘升发, 乔淑卿, 刘焱光, 方习生, 吴永华, 朱志伟. 东海闽浙沿岸泥质区沉积特征与古环境记录[J]. 海洋地质与第四纪地质, 2010, 30(4): 19-30. DOI: 10.3724/SP.J.1140.2010.04019
引用本文: 石学法, 刘升发, 乔淑卿, 刘焱光, 方习生, 吴永华, 朱志伟. 东海闽浙沿岸泥质区沉积特征与古环境记录[J]. 海洋地质与第四纪地质, 2010, 30(4): 19-30. DOI: 10.3724/SP.J.1140.2010.04019
SHI Xuefa, LIU Shengfa, QIAO Shuqing, LIU Yanguang, FANG Xisheng, WU Yonghua, ZhU Zhiwei. DEPOSITIONAL FEATURES ANG PALAEOENVIRONMENTAL RECORDS OF THE MUD DEPOSITS IN MIN-ZHE COASTAL MUD AREA,EAST CHINA SEA[J]. Marine Geology & Quaternary Geology, 2010, 30(4): 19-30. DOI: 10.3724/SP.J.1140.2010.04019
Citation: SHI Xuefa, LIU Shengfa, QIAO Shuqing, LIU Yanguang, FANG Xisheng, WU Yonghua, ZhU Zhiwei. DEPOSITIONAL FEATURES ANG PALAEOENVIRONMENTAL RECORDS OF THE MUD DEPOSITS IN MIN-ZHE COASTAL MUD AREA,EAST CHINA SEA[J]. Marine Geology & Quaternary Geology, 2010, 30(4): 19-30. DOI: 10.3724/SP.J.1140.2010.04019

东海闽浙沿岸泥质区沉积特征与古环境记录

DEPOSITIONAL FEATURES ANG PALAEOENVIRONMENTAL RECORDS OF THE MUD DEPOSITS IN MIN-ZHE COASTAL MUD AREA,EAST CHINA SEA

  • 摘要: 2007-2009年执行"我国近海海洋综合调查与评价"专项过程中,对东海闽浙沿岸泥质区进行了系统的底质调查,取得表层沉积物样品2 949个、柱状沉积物样品148个。基于上述样品的研究,得到以下认识:(1)以6.5 Φ粒径为界线详细划分出泥质区的分布范围,主要位于26°~29°N之间,水深90 m以浅的区域。(2)粒径趋势分析结果表明泥质区现代沉积物总体趋势是由东北向西南运移,但研究区的两侧又稍有不同,均表现出明显的向外偏转趋势;南部闽江河口外沉积物运移模式大致表现为由河口向周围呈散射状的输运趋势,最北影响可到27°N附近。(3)泥质区黏土矿物可明显划分为2个组合区,Ⅰ区覆盖了从长江口到南部闽江口外的大片海域,富集伊利石(平均含量为64%),沉积物主要来自于长江;Ⅱ区主要集中在闽江口附近的小区域,富集高岭石和绿泥石(两者平均含量之和为50%),推断其沉积物可能主要来自于闽江。(4)常量元素的R型因子分析表明闽浙沿岸泥质区沉积主要以陆源碎屑沉积为主,伴有少量生物沉积。(5)利用210Pb法测试了研究区百年来沉积速率,结果表明闽浙沿岸泥质区近百年来沉积速率介于0.79~3.34 cm/a之间,平均值为1.97 cm/a,属于东海次高沉积强度区,明显低于长江口泥质区沉积速率。(6)对闽浙沿岸泥质区南部的MZ01孔进行了综合分析,恢复了中全新世以来泥质区的古环境演变过程,识别出10次极值事件,可能主要由东亚冬季风的增强所引起,推测中全新世以来泥质区东亚冬季风演化过程大致可以分为4个阶段:8 400~6 300 aBP为季风较强且波动期、6 300~3 800 aBP为季风较弱且稳定期、3 800~1 400 aBP为季风高波动期、1 400 aBP以来为季风稳定增强期。

     

    Abstract: During the systemic investigation carried out in the Min-Zhe coastal mud area in 2007-2009 by the "Project on Coastal Investigation and Research", 2949 surface sediment samples and 148 gravity cores were collected. The following results have been achieved based on the detailed study of the samples:(1) As defined by the mean grain size finer than 6.5Φ, the Min-Zhe coastal mud area is distributed between 26°N and 29°N, with a water depth less than 90 m. (2) Gao-Collins grain size trend analysis was carried out to delineate the net sediment transport patterns of the mud area. It indicates that the sediments were mostly transported from northeast towards southwest. The sediments off the Minjiang River mouth were moved in a radiated pattern from the river mouth, upto the area around 27 N as the farthest. (3) The clay minerals in the Min-Zhe coastal mud area could be partitioned into two classes. RegionⅠdistributed from the Yangtze River estuary to the area off the Minjiang River is characterized by high content of illite (64% on average), indicating a provenance from the Yangtze River. Region Ⅱ, located in the Minjiang River estuary, is characterized by high content of kaolinite and chlorite (sum of the two averages 50%), suggesting the source of sediments possibly coming from the Minjiang River. (4) R-factor analysis of macroelements reveals that the mud area is dominated by terrigenous detrital materials instead of biological and marine chemistry materials. (5) The210Pb data from seven gravity cores demonstrates that the sedimentation rates change between 0.79 and 3.34 cm/a, with 1.97 cm/a on average. It is lower than the figure from the mud area around the Yangtze River estuary. (6) Based on the environmentally sensitive grain size, clay mineralogy, macroelement assemblages and AMS14C dating data of the Core MZ01 from the Min-Zhe coastal mud area, 10 extreme values corresponding to contemporaneous cooling events could be recognized since mid-Holocene, and the extreme values are likely to be caused by the enhancement of the East Asia winter monsoon. Furthermore, it is deduced that the East Asia winter monsoon could be divided into four stages, i.e., 8 300~6 300 aBP, strong and unstable; 6300~3800 aBP, strong but stable; 3 800~1 400 aBP, weak and unstable; and after 1 400 aBP, weak but stable.

     

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