Sedimentary Processes of Tidal Flat and the Responses to Typhoon Events and Anthropogenic Influences in the Luoyuan Bay of China
Sedimentary Processes of Tidal Flat and the Responses to Typhoon Events and Anthropogenic Influences in the Luoyuan Bay of China
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发表时间：
2013
影响因子：
1.1
通讯作者：
Y. Xiang
中科院分区：
文献类型：
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作者：
Y. Xiang
潮滩位于陆海交界处，对台风事件和人为影响非常敏感，为了揭示区域台风事件和强烈人为影响的历史，在互花米草沼泽内和中-为了提取沉积物记录，对罗源湾潮滩上部的沉积物进行了粒度和放射性同位素测年。粒度分析结果表明，罗源湾潮滩沉积物以细粒级沉积物为主，互花米草沼泽内和潮滩中上部柱状沉积物的平均粒度分别为5.41 μm~45.00 μm和5.4 μm~68.82 μm;但是，在此情况下，互花米草沼泽内部和中部的平均沉积速率分别为1000 m/s和1000 m/s，而中部的平均沉积速率为1000 m/s。由210 Pb计算的潮坪平均沉积速率分别为1.96cm/a和1.23cm/a，但由于强烈的围垦作用，潮坪平均沉积速率由1909~1946年的0.56cm/a增加到1946~1966年的2.36cm/a，互花米草的引入使沼泽形成初期的平均沉积速率增加到5.10 cm/a，随着沼泽年龄的增加，对互花米草沼泽内部和中部的沉积物记录进行了分析，上海滩不仅记录了近170年来对罗源湾产生强烈影响的台风事件，而且还记录了20世纪50年代以来的几次大规模填海。
Situated at the junction of land and sea,tidal flat is very sensitive to typhoon event and anthropogenic influence.In order to reveal the histories of regional typhoon events and strong anthropogenic influences,two sediment cores were collected in inner Spartina alterniflora marsh and middle-upper intertidal flat in the Luoyuan Bay for sedimentary records extraction.The sediment cores were cut with 1 cm interval for grain size and radio isotope dating.The results of grain size analysis indicate that the sediment on tidal flat of Luoyuan Bay is mainly composed by fine fractions.The mean grain sizes of core sediments in inner Spartina alterniflora marsh and middle-upper intertidal flat are 5.41 μm~45.00 μm and 5.4 μm~68.82 μm,respectively;however,there are several interfaces where sediment characteristics vary obviously.The mean sedimentation rates in inner Spartina alterniflora marsh and middle-upper intertidal flat calculated from 210Pb are 1.96 cm/a and 1.23 cm/a,respectively.However,the mean sedimentation rates increased from 0.56 cm/a during 1909~1946 to 2.36 cm/a during 1946~1966 at upper intertidal flat due to strong reclamations,and the introduction of Spartina alterniflora led to the mean sedimentation rate increased to 5.10 cm/a during the early marsh formation,and with increasing of the marsh age,the mean sedimentation rate decreased to 2.83 cm/a.The sedimentary records of core sediments collected from inner Spartina alterniflora marsh and middle-upper intertidal flat not only recorded the typhoon events which brought the strong effects on the Luoyuan Bay in recent 170 years,and but also recorded the several large scale reclamation from 1950's.