宇宙成因<sup>21</sup>Ne暴露测年方法的初步建立及检验

Abstract

The stable cosmogenic isotope ²¹Ne provides an extremely powerful tool for surface exposure dating, because of its extremely wide exposure dating range, requirement for comparatively small samples (about 0.2-1.0 g), and relatively simple sample preparation process. Furthermore, in addition to quartz, ²¹Ne analysis is applicable to many other types of silicate, such as pyroxene, olivine, and biotite. Cosmogenic ²¹Ne has become a significant geochronological technique in Quaternary geology; however, because of the high resolution required to separate the ⁴⁰Ar²⁺ peak from that of ²⁰Ne⁺ in mass spectrometry, the development of the cosmogenic ²¹Ne exposure dating technique in China is still in its early stages. A measurement procedure has been established in our laboratory for cosmogenic ²¹Ne dating based on improvement of the purification system of the mass spectrometer by adding a cryogenic pump. A highly enriched ²¹Ne standard material (CREU-1) and an alluvial fan surface sample from Longshou Shan, Inner Mongolia, China, were analyzed, and the data from these two samples have demonstrated the feasibility of our ²¹Ne analytical procedure for quartz. The establishment of this neon analytical procedure provides a promising tool for the development of a cosmogenic ²¹Ne dating method for use in many fields, such as Quaternary geology and active tectonics.