摘要
雅丹形态特征吸引人们的长期关注,对其形态的定量描述至今仍讨论热烈且众说纷纭。通过对罗布泊地区风蚀地貌的野外调查和无人机测量,发现普遍存在雅丹共基座现象。分布在同一个基座体上的风蚀残丘称之为共基座雅丹,属于雅丹与基座体的复合。对共基座雅丹和基座体开展雅丹形态参数的测量及分析,结果表明:共基座雅丹长宽比比值集中分布于3∶1~5∶1区间,与鲸背状等流线型雅丹形态表现相似,显示单一风向侵蚀残留特征;雅丹共基座现象是风蚀切穿深一层抗风蚀相对较强的地层形成的风蚀垄岗现象,厚度不等的不同抗风蚀强度地层在垂向上交替出现和受单一风向的风蚀作用是形成该现象的重要因素;通过对雅丹共基座现象的阐释和定量分析,对完善雅丹形态测量、深化雅丹形态变化的理解以及认识差异性风蚀过程具有重要意义。
Yardang is a typical wind erosion landform which is widely distributed in the world.Because of its various forms and volatility,Yardang’s morphological characteristics attract people’s long-term attention.How to accurately and quantitatively describe the Yardang morphology has been discussed enthusiastically and with a lot of questions still remained.The Lop Nur area is located in the eastern part of the Tarim Basin in Xinjiang,China.Although there are a large number of Yardangs in the area and the morphological types are abundant,there is a lack of detailed description of the Yardang morphology in Lop Nur area.Through the field investigation of wind erosion landforms in Lop Nur area and the aerial surveying using unmanned aerial vehicle(UAV),this paper finds that there is a new morphological combination of Yardangs in the Lop Nur area-the Yardangs which have common pedestal.It is observed on the high wind erosion ridges that there are often platform surfaces on the top of the ridges.On this flat platform surfaces there are many streamlined wind erosion tiny-hills,and they are very similar to Yardang.Under the platform surfaces,the wind erosion ridges are surrounded by cliffs which is like a pedestal,then we call this part of the ridges as pedestal body.The streamlined wind erosion tiny-hills on the same platform surfaces is called the common pedestal Yardangs,and the Yardangs which have common pedestal is the combination of Yardangs and the pedestal body.The measurement and analysis of the Yardangs morphological parameters were carried out on the common pedestal Yardangs and the pedestal bodies separately.The results shows that firstly,the values of length-width(L/W)ratio of Yardangs which have common pedestal are mainly sit in the range between 3∶1 and 5∶1,very similar to the whale-back or other streamline-appearance Yardangs,showing that the common pedestal Yardangs undergoing the same wind erosion processing as the whale-back or other streamline-appearance Yardangs.They were all shaped gradually under the single-wind-direction erosion circumstance.Secondly,the Yardangs which have common pedestal are morphological combination of Yardangs.This phenomenon is essentially a wind erosion ridge-mound phenomenon when wind broke the former deep and strong wind-erosion-resistance stratum and cut it into less wind-erosion-resistance strata,and thus the strata of different thicknesses and different wind-erosion-resistance levels appeared alternately in the vertical direction which together with the single direction wind erosion produced this phenomenon as two important factors.Lastly,the measurement results shows the Yardangs which have common pedestal made the Yardang morphological characteristics become even more complex and fluctuated,especially in the description of the Yardang spatial distribution pattern.Through the interpretation and quantitative analysis,we expect this phenomenon would attract one’s attention.By taking it into consideration,analysis of Yardangs which have common pedestal may help us improve the Yardangs’morphological measurement,understand more about Yardangs development and discuss the various causes of Yardangs’morphological diversity.
作者
宋昊泽
穆桂金
林永崇
李文
唐自华
秦小光
赵雪
张磊
李康康
SONG Hao-ze;MU Gui-jin;LIN Yong-chong;LI Wen;TANG Zi-hua;QIN Xiao-guang;ZHAO Xue;ZHANG Lei;LI Kang-kang(Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences,Urumqi 830011,Xinjiang,China;Cele National Station of Observation and Research for Desert-Grassland Ecosystems,Cele 848300,Xinjiang,China;Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;Institute of Earth Environment,Chinese Academy of Science,Xi’an 710061,Shaanxi,China;University of Chinese Academy of Sciences,Beijing 100049,China;School of History and Geography,Minnan Normal University,Zhangzhou 363000,Fujian,China)
出处
《干旱区地理》
CSCD
北大核心
2020年第1期48-55,共8页
Arid Land Geography
基金
国家科技基础性工作专项(2014FY210500)
国家自然科学基金青年基金项目(41601012)资助。
关键词
雅丹
风蚀
共基座现象
罗布泊
Yardang
aeolian erosion
common pedestal phenomenon
Lop Nur