[Objective]Milankovitch cycles affect the Earth's climate system and organic carbon burial by regulating the Earth's astronomical orbital parameters.In addition to the conventional astronomical cycles that regulate the cli-mate system through linear processes,there are"unconventional"astronomical cycles that regulate the climate sys-tem through a series of"non-linear"positive or negative feedback processes,such as the 170 kyr obliquity amplitude modulation(AM)cycle.Previous studies have demonstrated the modulating effect of the 170 kyr cycle on organic car-bon burial in the middle to high latitudes of the Earth during the Mesozoic-Cenozoic.However,owing to the lack of accurate astronomical solutions and high-resolution geological records,the 170 kyr cycle has rarely been reported in the Paleozoic.[Methods]In this study,the total organic carbon content and natural gamma logging data of the Early Permian Lucaogou Formation in the Junggar Basin were analyzed with cyclostratigraphy,which concluded that the Lucaogou Formation has preserved short eccentricity,obliquity,and precession cycles.[Results and Discussions]The astronomical tuning results based on the short eccentricity cycle show that the deposition duration of the Lucao-gou Formation is～2.8 Myr,and the sedimentary rate is estimated at 9.1 cm/kyr.In addition to conventional astro-nomical cycles,the 170 kyr cycle was found in detrended data series and their obliquity AM series,which is the first systematic exploration of the 170 kyr cycle in a Paleozoic terrestrial basin.[Conclusions]Based on the strong obliqui-ty signals,this 170 kyr cycle likely originates from the s3-s6 obliquity AM cycle.It can affect organic carbon burial by modulating water circulation processes in the middle to high latitudes of the earth during the Early Permian.Further-more,the threshold response effect in sedimentary basins amplifies the 170 kyr AM cycle in the obliquity cycle and appears in the geological record.
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