摘要
天山中部乌鲁木齐河源区海拔3600—3900m之间的分选环是冰缘环境演化的产物。空冰斗后壁3930m发育弱分选高中心分选环,空冰斗3880m发育强烈活动的分选环,空冰斗3820m的冰坎处发育弱活动分选环,大西沟气象站西北3600—3650m发育残余的拉长的分选环。它们的海拔高度、形态、分选性、组构特点、活动性和发育时间呈现有规律的变化。根据地貌部位和古冰碛分布判断,3930m分选环系小冰期以来的产物,3880m和3600m处分选环系新冰期以来的产物,3820m处分选环系上望峰冰期以来的产物。降水丰富,一年中气温在0℃上下波动的天数较多,有利于分选环的发育。
The sorted circles between 3 600- 3 900 meters above sea level at the Head Area of Urumqi River in middle Tianshan Mountains are products of periglacial environmental evolution. At the base of the back wall in Empty Cirque, poorly sorted circles are dispersed on ground at 3 930 metres. In the middle part of the Empty Cirque, actively sorted circles are formed near the west wall at 3 880 metres. On the riegel of the Empty Cirque, unactive sorted circles developed at 3 820 meter above sea level. At north-west of Daxigou Meteorological Station, residual and extended sorted circles distribute between 3 600 and 3 650 meters. Their elevation, forms, degree of sorting, gravel fabric, mobility and forming ages show orderly variation. According to geomorphic position and tills, three groups of sorted circles with an elevation of 3 930 meters, 3 880 meters and 3 820 meters separately can be divided and they have developed since Little Ice Age, Neo-Ice Age, Late Glaciation respectively. Environmental conditions of abundant precipitation, more clay content in earth and frequent temperature fluctuation around 0℃ in a year are advantageous to the development of sorted circles.
出处
《冰川冻土》
CSCD
北大核心
1993年第3期474-480,共7页
Journal of Glaciology and Geocryology
基金
国家自然科学青年基金
中国科学院天山冰川试验站基金
关键词
分选环
空冰斗
冰缘
乌鲁木齐河源
sorted circle, sorting process, Empty Cirque, Late Glaciation, Neo-Ice Age
