摘要:
札达盆地及周缘高山区的第四纪冰川遗迹分布广泛,类型齐全、发育连续.特征的冰碛及冰水堆积地貌有:冰水堆积平原或冰水堆积平台、冰碛丘陵等.挤压构造遗迹有:褶皱、断裂表皮构造、压坑、压裂构造、变形砾石等.ESR年代测定结果表明,冰碛形成的最大年龄为2.33Ma.依据冰碛、冰水堆积的特征、分布和形成年代等,区域冰川发育由老到新可划分出:7次冰期、6次间冰期、1次冰缘期、1次新冰期.该区是目前所知青藏高原第四纪冰川遗迹发现最多、保存最全和发育最连续的地区,为青藏高原地区的第四纪冰川演化研究、冰期的划分和对比、古气候古环境的研究,提供了重要的实际资料和依据.
Abstract:
Quaternary glacial remnants in the Zanda basin and its peripheral high mountain areas,Tibet,are widespread and continuously developed and have a complete range of types.The main glacial-eroded remnants include U-shaped valleys,knife-edge crests,horns(pyramidal peaks),firn basins,cirques,ice-scoured hills and bedrock drumlins;the till remnants are moraines,outwash deposits,glacial erratic boulders,terminal moraines,lateral moraines and medial moraines.The characteristic morainic and outwash geomorphologies include outwash plains and platforms,morainic hills.The remnants of compressional structures are folds,faults,epigenetic structures formed by faulting,press pits,pressure fractures and deformed gravels.ESR dating of moraines gives a maximum age of 2.33 Ma.According to the features,distribution and ages of the morainic and outwash deposits,seven glacial stages,six interglacial stages and one neoglacial stage of regional glacial development may be distinguished from older to younger.The Zanda basin and its peripheral high mountain areas,Tibet,are now known as a region where the most Quaternary glacial remnants are found and Quaternary glacial remnants are most completely preserved and most continuously developed on the Qinghai-Tibet Plateau.This study provides important data and grounds for the study of the Quaternary glacier evolution,division and correlation glacial stages and study of the paleoclimate and paleoenvironment in this area and the Qinghai-Tibet Plateau.
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