全新世早期黄河上游积石峡大型滑坡堵江事件研究

The event of Jishixia of river block by severe landslide occurred at in the upper reaches of the Yellow River during the early Holocene

普遍认为黄河上游积石峡地区厚约30m的纹泥沉积是由于大型滑坡堵江形成的,然而,滑坡堵江时代以及堵江形成的堰塞湖纹泥沉积历时仍有争议。为了探讨研究区大型滑坡堵江时代及纹泥沉积历程,文中在纹泥底部和顶部各采集1个样品进行14C年代测定。纹泥底部样品的14C年代为9016±425 cal a B.P.,纹泥顶部样品的14C年代为7984±334 cal a B.P.。研究结果表明:黄河上游积石峡地区曾在全新世早期距今约9ka左右发生过大型堵江事件,纹泥沉积的沉积历程约为1ka,这与前人利用纹泥层厚度估算的沉积历程相吻合。该研究可为下游地区第四纪时期文明演化的研究提供一些新的参考。

It is generally considered that about 30m thick of the varve deposition in Jishixia area is due to the large landslide blocking the river in the upper reaches of the Yellow River.However,there are disputes about the time of the large landslide occurrence and the process of lake varve deposition caused by dammed river.In order to explore the process history of varve deposition at the time of large landslide blocking the river in the study area,one sample in the bottom and a sample on the top of varve deposition were collected for the 14C dating in this reasearch.The 14C dating of the sample in the bottom is 9016±425 cal a B.P..Whereas,the 14C age is 7984±334 cal a B.P.in the top of varve deposition.The results show that the time of large landslide accurred around 9016±425 cal a B.P.（the early Holocene） in Jishixia area in the upper reaches of the Yellow River.It took about 1 ka to deposit the varve sediment,which is consistent with the previous estimate about the process of deposition through thickness of varve.This research may provide some data for the research of civilization evolution in quaternary of the lower river.