Astronomical cycle driving of coal-bearing rock system rotations in the Permian Shihezi Formation at Renlou Coal Mine

Marine terrestrial transitional sedimentary rocks of Renlou Coal Mine are developed in coal bearing rock formations, which exhibits obvious cyclicity. These sedimentary cycles have a good correspondence with astronomical cycle signals. This paper provides a cyclic stratigraphy analysis of Renlou Coal Mine. First, the period of change of the Earth's orbital parameters from 289 to 293 Ma are determined based on the algorithm of Laskar J and Waltham. The theoretical period ratio of Milankovitch's cycles during this depositional period is also calculated. Second, the GR logging data from the four boreholes of the Renlou Mine (S1–S4) are analysed for cyclothem stratigraphy by Acycle software. Finally, a floating astronomical dating scale was established with S1 borehole 1007.93 m at 293 Ma as an anchor point by using 405 ka long eccentricity for astronomical tuning. The results show that the coal-bearing rock systems of the Permian Upper and Lower Shihezi Formations in Renlou Coal Mine are obviously controlled and driven by Milankovitch cycles. The cycle parameters are close to the Permian astronomical orbital cyclic cycle. The study of the mechanism of the cyclostratigraphy is of great significance for exploring the mechanism and prevention of geological hazards in mines.