【摘要】 在黄河源区支流日玛曲河谷发现第四纪湖相沉积,以含砾粉砂、粉砂、粘土互层组合为特征,形成河流的第一阶地基座。通过对该剖面野外岩性观测1、4C测年分析,探讨了古湖形成时代及成因,以及古湖发育时期周围的植被与环境。研究结果发现,古湖形成于3 120aBP前后,可能属于地震堰塞湖,于640aBP以后出现决堤事件。更多还原

【Abstract】 A group of Quaternary gyttjor are discovered in Rimaqu basin in the Yellow River source area which formed the first terrace foundation,included gravel aleurite,aleurite and clay layer.The framing age,cause,vegetation and environment of the ancient dammed lake are discussed by lithological profile testing and 14C age determination.The results show that the ancient dammed lake formed about 3 200aBP,might be earthquake dammed lake,and it might burst its bank about 640aBP later.更多还原