天山和阿尔泰山冰碛物显微结构特征

采用薄片法对新疆阿尔泰山哈纳斯河流域和天山乌鲁木齐河源区冰上融出碛、冰下融出碛和滞碛的显微结构特征进行了分析。冰上融出碛的显微结构的主要特征是:次棱角状和破裂状表面特征、点支撑和边支撑结构、异向组构、不规则大孔隙;冰下融出碛显微结构的主要特征是:次棱角状和次圆状以及碎裂表面特征、点支撑和边支撑以及镶嵌和悬浮结构、微旋转和微叶理以及粉沙团块构造、定向组构、规则的圆孔隙和扁孔隙;滞碛显微结构的主要特征是:次棱角状和次圆状以及碎裂状表面特征、悬浮结构和镶嵌结构、微旋转和微叶理以及粉沙团块构造、定向组构、规则圆孔隙。不同冰碛显微特征的成因与冰川冰和冰碛产生的静压力、冰川的运动和冰碛介质以及由此引起的冰下磨蚀、压碎、剪切等过程有关。

MICROFABRIC STUDY OF TILL AT MOUNTAINS TIANSHAN AND ALTAY

Based on analysis of thin section, this paper discusses the microfeatures of till, including superglacier till, subglacier till and lodgement till, from Halasi River Catchment, Altay Mountain and the source of Urumqi River, Tianshan Mountain. The main microfeatures of surperglacier till are: subangular and cracked surface textures, particle-supported and edge-supported microtextures, allo-orientation microfabrics, and irregular large voids. The main microfeatures of subglacier till are: subangular, subrounded and crushed surface textures; particle-supported, edge-supported, morsaic and matrix-supported microtextures; microfoli-ation, microorientaion and silt inclusion microstructures; orientationmicrofabrics; regular round and ellipsoid voids. The main microfeatured of lodgement till are: subangular, sub-rounded and crushed surface textures; matrix-supported and morasic microtextures; mi-croorientation, microfoliation and silt inclusion microstructures; orientation microfabrics and regular round viods. The microfeatures of different till are related directly to the icestatic pressing, ice movement, abrasion, crushing, as well as the characterictics of fragments.