江西庐山牧马场剖面泥砾堆积物的成因分析及年代测定

Genetic Type Analysis and ESR Dating of Quaternary Deposits along the Mumachang Profile in the Lushan Mountain in Jiangxi Province

庐山第四纪泥砾堆积物成因争论是庐山第四纪冰川争论的焦点之一。对新发现的庐山牧马场泥砾剖面进行了石英砂电镜扫描(SEM)和成因分析,并初步进行了电子自旋共振(ESR)年代测定。石英砂电镜扫描表明该剖面泥砾堆积物为冰川和流水共同作用形成,并在后期湿热化影响下导致部分化学特征明显;ESR测年数据表明该剖面形成于中更新世晚期(225.5±20)—(242.6±24)ka BP,与推测的时代(庐山冰期)基本一致。根据测试结果,作者认为庐山牧马场剖面具有第四纪冰川作用的痕迹,但其时代和规模尚有待探讨改进。

Quaternary morainic deposits in the Lushan Mountain has long been one of the controversial subjects. The authors used Scanning Electron Microscopy （SEM） to analyze the shape and texture of the quartz sand grains along the Mumachang profile, identified the genetic types, and applied Electron Spin Resonance （ESR） dating to determine their age. The SEM analysis confirms that the deposits was glacial and glaciofluvial sediments; the ESR dating indicates that it was formed at the late stage of Middle Pleistocene （225.5±20）-（242.6±24） ka BP, equivalent to the Lushan Glaciation. According to the experiment, the authors are of the opinion that there exist glacial traces in the Mumachang profile, but the timing and extent remains to be investigated and further improved.