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| 借助137Cs估算滇池沉积量 | |
| 引用本文： | 张燕,彭补拙,陈捷,吕俊杰.借助137Cs估算滇池沉积量[J].地理学报,2005,60(1):71-78. |
| 作者姓名： | 张燕 彭补拙 陈捷 吕俊杰 |
| 作者单位： | 1. 南京大学城市与资源学系,南京,210093 2. 中国科学院南京土壤研究所土壤与农业可持续发展国家重点实验室,南京,210008 |
| 摘 要： | 根据137Cs测量值和具体区位判断,滇池流域土壤与湖泊沉积物中的137Cs是世界与中国核试验生成物叠加的结果,由此在滇池沉积物中识别出1954年、1963年、1976年、1986年几个特定年份的沉积层(时标)。计算不同时标间的沉积物质量,可求出不同时段单位面积上的年均沉积质量,不同湖区该值有差别,但符合湖心沉积低于湖岸的湖泊沉积规律。又参照滇池流域地貌、物源供给、湖盆形态及采样点等,借助GIS方法将滇池湖区划分为远岸湖心区(I)、近岸湖心区(II)、湖西区(III)、湖东区(IV)和湖南区(V),并计算各区底面积;然后将面积与年均沉积质量相乘,得到不同时段各区域的年均沉积总量1954~2003年与I~V区对应的年均沉积总量(104t/a)分别是6.85、8.90、8.43、9.82和5.91,滇池外海的总沉积量为39.91×104t/a。这些结果与当地实情吻合,与他人的研究结果也非常一致。 |
| 关 键 词： | 137Cs时标 年均沉积量 沉积区 滇池 |
| 收稿时间： | 2004-07-14 |
| 修稿时间： | 2004年7月14日 |
Evaluation of Sediment Accumulation in Dianchi Lake Using 137Cs Dating |
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| ZHANG Yan,PENG Buzhuo,CHEN Jie,LU Junjie.Evaluation of Sediment Accumulation in Dianchi Lake Using 137Cs Dating[J].Acta Geographica Sinica,2005,60(1):71-78. | |
| Authors: | ZHANG Yan PENG Buzhuo CHEN Jie LU Junjie |
| Institution: | 1. Department of Urban and Resources Science, Nanjing University, Nanjing 210093, China; 2. State Key Laboratory of Soil Sustainable Agriculture, Institute of Soil Sciences, CAS, Nanjing 210008, China |
| Abstract: | Based on the 137Cs activity and the specific geographical location of the Dianchi Basin, the 137Cs in the soil of Dianchi Basin and in the sediment of Dianchi Lake are derived from both the fallout of the world nuclear tests and that of China nuclear tests. Therefore, some sediment layers in special years, such as 1954, 1963, 1976 and 1986, can be identified by special distribution of 137Cs activity in the sediment cores. The mean annual accumulation mass of sediment per unit area (sediment accumulation rate) for a specific period can be calculated based on the accumulation mass of the various periods. The mean annual accumulations are diverse in different parts of the Dianchi Lake. But it is well agreed with the fact that sediment accumulation in the center of the lake is smaller than that of the lakeside. Then according to the shape of the lake, landforms of the lake basin, sources of sediment and other factors, Dianchi Lake is divided into five zones: central lake zone far from bank (I), central lake zone close to bank (II), western lake zone (III), eastern lake zone (IV) and southern lake zone (V). And using Geographic Information System (GIS), area of each zone is calculated. The total amounts of mean annual sediment accumulation of each zone for various periods is obtained by area of zone multiplying the sediment accumulation rate. The mean annual total amounts of sediment accumulations of the above five zones are 0.0572, 0.0925, 0.1249, 0.1095, and 0.0842 g/cm2a, respectively. |
| Keywords: | Cs dating sediment accumulation rate sediment zone Dianchi Lake |
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