局所分析法による先カンブリア時代微化石および炭質物の化学分析

抄録

Morphologically preserved microfossils are direct evidences of existence of life on Earth. However, it is usually insufficient to identify microfossils using morphological analysis alone because of their simple morphology and small size. Chemical analysis of the carbonaceous matter is necessary in order to fully understand its origin and characteristics. In situ analysis of Precambrian microfossils and carbonaceous matter preserved in petrographic thin sections is a powerful tool for analyzing their chemical composition. Interpretation of analytical techniques reveals elemental, isotopic, and molecular compositions on nanometer-to-micrometer scales, and enables us to examine spatial relationships between individual morphological structures and the surrounding minerals. This chemical information is used to assess the syngenicity and biogenicity of the individual microfossil-like structures. This review explores examples of in situ analytical techniques applied to Precambrian microfossils, microfossil-like structures, and carbonaceous matter.