α铀系测年对洞穴碳酸盐沉积物中碎屑岩物质影响的祛除研究

The Removal of the Disturbance of the Clastic Rock Material from Cave Carbonate Sediments in Alpha U-series Dating Method

洞穴碳酸盐沉积物常因为含有碎屑岩物质,而导致测年精度下降,甚至导致测年失败。通过对干扰物的X射线荧光分析,发现Mg、Ca、P、Si、Al等元素含量尤其高,其矿物组成可能为方解石、磷酸盐、硅酸盐、铝盐、粘土矿物、石英、云母类。通过改进化学流程,在化学处理过程中将含量高的P、Al、Si元素祛除,提高了测量精度,说明此改进有利于含碎屑物质的洞穴碳酸盐沉积物的α铀系年龄研究。

As cave carbonate sediments usually contain some clastic rock materials, the accuracy of the alpha U-series dating may decrease, which even leads to the failure of the U-series dating. X ray fluorescence analysis reveals that such elements as Mg, Ca, P, Si and A1 are especially high in the disturbing materials, and the mineral compositions of these elements may be calcite, phosphate, silicate, aluminum salt, clay materials, quartz and mica. The authors changed the chemical process, removed the high level elements like P, A1, Si, and improved the accuracy of the measurements. The results obtained by the authors can improve the research on cave carbonate sediments which contain clastic rock materials.