In the Seven Springs area (Qigequan area) western Qaidam basin, the Quarternary glacialploughed deformation beddings in the yellow—brown calcareous sandstone and calcareous mudstone bearing conglomerate are developed. Among which, the large ones may be up to 2m in thickness for an individual bed within it, and remarkably complicated in shape as illustrated especially by the pipelike and sheathlike deformation bedding, and rodlike and tabular structures. Otherwise, the lithology of the outwash is very complex as well, containing not only claystone, claystone bearing conglomerate, calcareous and argillaceous sandstone but also conglomerate, and among which a kind of argillaceous conglomerate is specific and the coarsegrained deposition—moraine surface induced by glacier are scratched clearly by the glacier. According to the sporopollen analysis, the outwash is formed in the Quatenary, and more possible in Pleistocene that is analogous to the Quaternary ice age, though the definite period is yet to be ascertained. The evidence of Quaternary outwash in the Mangai depression of western Qaidam basin is unequivocal and may therefore of important significance for the study of Quaternary ice age and related Qinghai—Xizang(Tibet) Plateau research in terms of formation and evolution, paleoclimate and paleogeography. Moreover, the outwash discussed herein demonstrates unambiguous evidence that the Qinghai—Xizang(Tibet) Plateau in Quaternary is not mantled by a whole icecap.