A new classification scheme for sedimentary cycle orders based on astronomical orbital cycles: a case study of Es4scs in Well Niuye 1, Dongying Depression

Abstract Cycle classification of fine-grained sedimentary strata is currently an active area of research in sedimentology. However, the correlation between different orders of sedimentary cycles and astronomical orbital cycles remains unclear, which restricts the quantitative development of high-frequency sequence stratigraphy. This study focuses on the Chunshang Sub-member of the Upper Es 4 (Es 4 scs ) strata of Well Niuye 1 in the Dongying Depression, Jiyang Depression, Bohai Bay Basin. Based on sedimentological, geochemical, and conventional well-logging data, combined with the Fischer plot method, we conducted a multi-scale classification of sedimentary cycles in fine-grained strata and established a new scheme correlating orbital cycles with cycles of various orders. This study proposed the concepts of the shorter-term base-level cycle and the sixth-order sub-parasequence, and systematically established the correspondence between astronomical orbital cycles and sedimentary cycles of different scales. This scheme provides a quantitative framework for calibrating sedimentary cycles against astronomical orbital cycles.