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鄱阳湖湖滨沙山垄状地形的成因
  • ISSN号:0375-5444
  • 期刊名称:地理学报
  • 时间:0
  • 页码:331-338
  • 语言:中文
  • 分类:P9[天文地球—自然地理学]
  • 作者机构:[1]南京大学地理与海洋科学学院,南京210093
  • 相关基金:国家自然科学基金项目(40771023;40401006) 致谢:江西省气象科学研究所徐为民提供沙岭风场数据.
  • 相关项目:鄱阳湖地区沙山的风沙堆积过程的年代学研究
中文摘要:

江西星子县沙岭沙山位于鄱阳湖湖滨,临湖一侧发育顺盛行风方向延伸的垄状地形。研究从地貌学、沉积学和年代学的角度分析了垄状地形的成因。按照目前的风场计算出的沙丘走向与合成输沙方向近于垂直,说明这些垄状地形不是纵向沙丘。垄状地形内部发育平行层理,缺少滑动面,则进一步表明垄状地形并非沙丘。对垄状地形之间的沟谷形态观察后发现,这些沟谷与前丘上槽形风蚀坑形态颇为相似,且沙山的环境具备发育槽形风蚀坑的基本条件,所以我们将垄状地形之问的沟谷视为槽形风蚀坑。为确定风蚀坑的形成时代,我们在沙山上风区、下风区边缘选取了6个剖面,测得的28个光释光年龄显示,构成垄状地形的沙层堆积于约20kaBP以前的末次冰期。据此我们推测在冬季风最强的阶段(18—14ka BP),沙山由以前的风沙堆积转变为风沙侵蚀,产生了槽形风蚀坑。相邻槽形风蚀坑之间的条状突起就构成了垄状地形,因此星子县沙岭沙山临湖一侧的垄状地形属于风蚀地貌。

英文摘要:

Sand hills are mainly composed of aeolian sands developed along the north shore of the Poyang Lake. The sand hill at Shaling is situated in Liaohua town of Xingzi county. The relative height of this sand hill is about 100 m and it covers an area of about 10 km2. Ridgslike landform develops on the side facing the Poyang Lake. These ridges trending to merge downwind parallel to the prevailing wind and were assumed to be the sand ridge (longitudinal dune). Although the ridge lines are relatively straight, both the space between contiguous ridges and the length of ridge are different from each other. Based on the wind data measured between 2005-10 and 2006-09, we calculate the bedform trend (132°) with maximum gross normal transport and resultant transport direction (42°) using Trend program. The result demonstrates that only transverse dunes can develop under present wind regime which might be similar to those when ridgelike landform formed because Shaling region is controlled by the funnel effect. Sand mining along the shore expose sections that reveal the sediment structure of the ridgelike landform. Some ridges are composed of two layers, i.e. the surface layer and the interior layer. The surface layer (about several tens of centimeters in thickness) shows massive structure, while the interior layer shows parallel bedding truncated by the former on both sides of the ridge. This structure indicates the slideface is absent within these ridges, and that these ridges are of erosion landform instead of accumulation landform. The erosion postdates the deposition of the interior layer and predates the deposition of the surface layer. Optically Stimulated luminescence (OSL) dating is carried out on 6 sections. 28 OSL ages show that aeolian sand deposited extensively on the sand hill about -20 ka BP and formed the interior layer. The thicker surface layer in the downwind region only began to deposit at -0.2 ka BP. Therefore, we conclude that the ridges on the sand hill belong to erosion landform. Sin

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期刊信息
  • 《地理学报》
  • 北大核心期刊(2011版)
  • 主管单位:中国科学院
  • 主办单位:中国地理学会 中国科学院地理科学与与资源研究所
  • 主编:刘昌明
  • 地址:北京安外大屯路甲11号
  • 邮编:100101
  • 邮箱:acta@igsnrr.ac.cn
  • 电话:010-64889295
  • 国际标准刊号:ISSN:0375-5444
  • 国内统一刊号:ISSN:11-1856/P
  • 邮发代号:2-109
  • 获奖情况:
  • 国家双奖期刊,中国科学院优秀期刊一等奖
  • 国内外数据库收录:
  • 俄罗斯文摘杂志,荷兰文摘与引文数据库,美国工程索引,日本日本科学技术振兴机构数据库,中国中国科技核心期刊,中国北大核心期刊(2004版),中国北大核心期刊(2008版),中国北大核心期刊(2011版),中国北大核心期刊(2014版),中国北大核心期刊(2000版)
  • 被引量:64517