天山第四纪冰川擦痕特征及分布规律

STRIA DISTRIBUTION AND SUBGLACIAL PROCESSON EROSIONAL LANDFORM IN TIANSHAN MOUNTAINS

根据冰蚀痕迹的统计数据 ,着重讨论了天山高山地区冰岩界面形成过程和冰川擦痕分布规律。典型的冰碛岩一般有擦面和擦痕。冰川槽谷的横剖面上 ,从侧部向中部 ,擦痕密度逐渐增大 ,槽谷的谷壁向谷底的转折处是擦痕密度由小转大的突变点 (拐点 ) ,反映了磨蚀作用不断增强。而冰坎的擦痕密度则呈现较大的波动。冰坎迎冰面的粗大擦痕密度远比槽谷中的擦痕密度大。羊背石从顶部到侧部 。

Based on the data of glacial striation measurement from alpine glacial areas in Tianshan Mountains,the process at ice and bedrock interface was considered in the paper.Field measurement shows that density of striation increases gradually from both sides to centre section of troughs.It indicates that abrasion increases and plucking decreases from trough walls to centre bed.There is a sudden changing point from trough walls to centre bed,at which the stria density changes from a few to tens per meter.The scale of striation size is greater at glacial bars than at trough bottom.The erosional features are fairly regular on roche mountonnee.The long and straight stria often appers on top of roche mountonnee,crescentic fractures,short stria and cracks on head- on side.