109 / 2022-02-19 17:30:59

Identification of Milankovitch cycles and calculation of net primary productivity of paleo-peatlands using geophysical logs of coal seams

paleo-peatlands,carbon accumulation rate,net primary productivity (NPP),Milankovitch cycle

Individual coal seams formed in peatlands represent sustained periods of terrestrial carbon accumulation and a key environmental indicator attributed to this record is the rate of carbon accumulation. Determining the rate of carbon accumulation requires a measure of time contained within the coal. This study aimed at determining this rate via the identification of Milankovitch orbital cycles using spectral analysis. Spectral analyses of geophysical data from thick coal seams identify the significant signals of variations in ash content. The results showed that the variations in ash content of the coal shows Milankovitch period parameters, and then the period of coal deposition can be calculated. Further considering the carbon loss during coalification, the long-term average carbon accumulation rate and net primary productivity (NPP) of paleo-peatlands in coal seam can be obtained. This article mainly elucidates the procedures of the paleo-peatland productivity analysis with three case studies and their controlling factors on NPP of paleo-peatlands.