| 引用本文: | D.Eisma,孙顺才,X.Song,E.Thomasse.云南洱海现代沉积研究.湖泊科学,2000,12(1):25-37. DOI:10.18307/2000.0105 |
| D. Eisma,S. Sun,X. Song,E. Thomasse.Sedimentation in Erhai Lake, Yunnan Province, China. J. Lake Sci.2000,12(1):25-37. DOI:10.18307/2000.0105 |
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| 云南洱海现代沉积研究 |
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D.Eisma1, 孙顺才2, X.Song3, E.Thomasse1
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1.Netherlands Institute for Sea Research, Texel, and Department of SedimentoLogy, Institute of Earth Sciences, Utrecht University, The Netherlands;2.中国科学院京地理与湖泊研究所, 南京210008;3.云南省地质研究所, 昆明650011
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| 摘要: |
| 洱海是位于云南省境内较大的但相对较浅的断陷湖泊(水深小于20m)根据1990-1993年对该湖现代沉积的研究,结果表明,湖泊沉积物主要来自西部相对高2000m以上的山地,东部为低矮石灰岩山地,物源较少,南北两条入湖河流亦是重要的物源供应区.湖区沉积物主要是由粉砂质粘土组成,来自山地的粗碎屑物质则大量的堆积于此地,三角洲、扇三角洲及滨湖地带,沉积速率在过去 13000年中平均为0.2cm a-1,相当于全湖平均每年堆积约600 t a-1,这个量也相当于 1992年 2月湖中悬浮物总量.这也表明丰富的陆源供给(雨季降雨,植被破坏和地震等),并说明了持续浅水湖泊的存在.湖泊沉积作用也受到内部因素影响而复杂化,如湖流作用使沉积物重新分布并扩展至整个湖底在现代沉积物中,水下滑坡和滑塌尚少见.对沉积物化学分析表明,其反映了周边岩石和土壤组成,包括生物成因的成份(主要是植硅石).沉积物微量元素相对较丰,可能系土壤渗漏、污染或细粒沉积物携带所致. |
| 关键词: 洱海 现代沉积 |
| DOI：10.18307/2000.0105 |
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| Sedimentation in Erhai Lake, Yunnan Province, China |
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D. Eisma1, S. Sun2, X. Song3, E. Thomasse1
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1.Netherlands Institute for Sea Research, Texel, and Deportment of sedimentology, Institute of Earth Sciences, Utrecht University, The Netherlands;2.Nanjing Institute of Geography and Limnology, CAS, Nanjing 210008, P. R. China;3.Geological Institute of Yunnan Province, Kunming 6S0011, P. R. China
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| Abstract: |
| Erhai Lake in S.W.Ghina is a large, shallow (<20m deep) rift lake.Sediment supply comes mainly from the mountains west of the lake that reach a relative height of 2000m.Supply from the east, a relatively low limestone country, is small.Two rivers supply sediment from north and south.Bottom deposits are predominantly silty mud;coarse material supplied from the mountains has been deposited on broad terraces, deltas, delta-fans, and nearshore in the lake.Deposition rates during the past 13000 years have been low, on the average 0.2 cm a-1, which is equivalent to about 600 t a-1, over the entire lake and is of the same order as the amount of suspended sediment present in February 1992.This points to storage of sediment on land during periods of relatively large supply (period of large rainfall, destruction of vegetation, or earthquakes) and it explains the continuing existence of the shallow lake.Average sediment deposition may have varied by a factor of 2 or 3 at most.Currents redistribute the sediment over the lake floor in flat beds extending over almost the entire lake.There is very little evidence of slumping or sliding.The composition of the sediment reflects the composition of the rocks and soils in the source areas with an additional biogenic component(mainly diatom opal).There is a relative abundance of trace elements, which may be the result of leaching on land, pollution and/or the fine grain of the sediment. |
| Key words: Erhai Lake sedimentation |
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