【摘要】 柴达木盆地西部发育了第四纪冰川冰水与湖泊沉积,其重要特点是在黄褐色的钙质砂砾和含砾钙质泥岩中发育了大量的大型冰川刨耕变形层理及相关的杆状、板状和冰凌铸模构造,大型变形层理单个层系的最大厚度可达两米;其形态非常复杂,其中的管状、鞘状变形层理及杆状、板状构造更具特点;冰水沉积的岩性也非常复杂,既有粘土岩,又有含砾粘土岩,钙泥质砂砾岩,还有砾岩;其中有种粘土砾很有特点。孢粉分析表明,其形成时代为第四纪,极有可能为更新世,与中国西部的第四纪冰期形成时代相同,但具体期次尚不能确定。柴西第四纪冰川与冰水沉积证据充分,对于研究中国第四纪冰期及青藏高原的形成演化、古气候、古地理具有重要意义。更多还原

【Abstract】 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.更多还原