| 临夏盆地晚中新世以来的风沙沉积及环境意义 |
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| 引用本文： | 王建力,方小敏.临夏盆地晚中新世以来的风沙沉积及环境意义[J].地理科学,2000,20(3):259-263. |
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| 作者姓名： | 王建力 方小敏 |
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| 作者单位： | 1. 西南师范大学地理系重庆 400715
2. 兰州大学地理科学系甘肃兰州730000 |
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| 基金项目： | 中国科学院“九五”青藏研究项目!（KZ951－A1－204－02－01），国家自然科学基金项目!（49871010）的资助。 |
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| 摘 要： | 对临夏盆地１５Ｍａ以来地层中的石英砂所作的扫描电镜分析表明，风成砂一直存在，并在８Ｍａ和６～５Ｍａ时含量最高。最大颗粒的平均粒径在（１．５～３．６）／２．６Ｍａ达０．４ｍｍ，３．６～２．６Ｍａ之后显著下降。前者表明３．６～２．６Ｍａ以前，近源风沙作用一直存在，并在８Ｍａ和６～５Ｍａ达到最盛；后者表明第四纪以来，远源风沙沉积盛行，可能反映了青藏高原在３．６～２．６Ｍａ急剧隆丐和与之相关的大气环流的发
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| 关 键 词： | 青藏高原 石英砂 大气环流 中新世 风沙沉积 |
| 文章编号： | 1000-0690(2000)03-0259-05 |
Eolian Sand Deposition and Its Environmental Significance inLinxia Basin Since Middle Miocene |
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| WANG Jian-li,FANG Xiao-min.Eolian Sand Deposition and Its Environmental Significance inLinxia Basin Since Middle Miocene[J].Scientia Geographica Sinica,2000,20(3):259-263. |
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| Authors: | WANG Jian-li FANG Xiao-min |
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| Abstract: | Atotal of 55 samples were taken from the Tertiary red earth and Quaternary lacustrine deposits and loess for Linxia Basin for the analysis of quartz type and content using electron probe microanalyzer. The eolian sand contents appeared two high values at about 8Ma and 6-5Ma respectively. The mean size of quartz grains was about 0.4mm during the 15-3. 6/2. 6 Ma period and dropped down to 0.1mm dramatically after 3. 6-2. 6Ma. These results mean the eolian deposition reached its maximum at 8 Ma and 6-5 Ma respectively. Since the Quaternary, the local eolian deposition was decreased significantly and disappeared which was replace by dust deception from far source, suggesting the uplift of Qinghai-Xizang Plateau and the change of air circulation. |
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| Keywords: | Qinghai-Xizang Plateau Quartz sand Eolian deposition Air circulati |
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