Recently, a research team focusing on the Late Paleozoic at the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS)—consisting of Associate Professor ZHENG Quanfeng, Professor WANG Yue, Assistant Professor HUANG Xing, and Professor CHEN Bo—collaborated with Nanjing Normal University, China University of Mining and Technology, and Nanjing University to conduct a high-resolution sedimentological, fusuline biostratigraphic, and inorganic carbon isotope stratigraphic study of the Chuanshan–Chihsia formations at the Kongshan section in Nanjing. Based on regional and global correlations, this team reconstructed a high-resolution glacioeustatic sea-level curve spanning the Asselian to middle Kungurian stages, thereby elucidating the evolution of the Late Paleozoic Ice Age (LPIA) during the early Permian.
This study has been published in the international journal Palaeogeography, Palaeoclimatology, Palaeoecology.
Since the beginning of the Phanerozoic Eon, Earth has experienced four major icehouse periods: the end-Ordovician, Late Devonian, Late Paleozoic, and Cenozoic ice ages. Among them, the LPIA was the most extensive and long-lasting, profoundly influencing environmental and biological evolution on Earth. However, its termination age has long been debated, with proposed timings ranging from the mid-Sakmarian to the Artinskian, late Guadalupian, and even late Lopingian.
During major icehouse intervals, large volumes of surface water are stored in continental or alpine glaciers at high latitudes or altitudes, thereby reducing global seawater volume and maintaining sea level at a long-term low stand. At the same time, Milankovitch orbital cycles drive alternating cold and warm phases, causing periodic glacier advance and retreat and resulting in high-frequency, globally synchronous sea-level fluctuations. These long- and short-term changes in sea level, known as glacioeustasy, provide a key geological indicator for reconstructing the onset, evolution, and disappearance of ancient ice ages.
The study shows that the Chuanshan Formation (Asselian to early Artinskian) was deposited in a shallow-water carbonate shoreface environment, whereas the overlying Chihsia Formation (middle–late Artinskian to middle Kungurian) formed in a deep-water carbonate shelf setting. This lithofacies transition records a rapid and significant transgression during the middle–late Artinskian.
Detailed sedimentological analysis reveals that the Chuanshan Formation is characterized by numerous meter-scale depositional cycles, each comprising lower subtidal deposits and upper subaerial-exposure or intertidal deposits, indicating prominent high-frequency sea-level oscillations. However, these cycles abruptly disappear in the Liangshan Member of the basal Chihsia Formation. Up-section, the Chihsia Limestone becomes uniformly composed of deep-shelf bioclastic limestones, reflecting a marked weakening—and eventual disappearance—of high-frequency sea-level fluctuations.
Inorganic carbon isotope values correlate closely with lithofacies: intertidal or subaerial exposure facies typically yield δ¹³C values below 1‰, whereas subtidal deposits generally exceed 2‰. These patterns suggest that isotopic variations were mainly controlled by the relative influence of meteoric and marine diagenesis, making them a reliable proxy for relative sea-level changes.
Regional and global correlations indicate that both the high-frequency sea-level fluctuations from the Asselian to early Artinskian and the major transgression in the middle–late Artinskian are globally recognizable phenomena. The 19 high-frequency cycles identified in the Asselian-Sakmarian Chuanshan Formation have an average periodicity of ~463 kyr, closely matching the long-eccentricity Milankovitch cycle, supporting an orbital forcing origin for these fluctuations.
Taken together, the relative sea-level changes recorded in the Chuanshan–lower Chihsia formations at Kongshan can be confidently interpreted as glacioeustatic signals driven by the waxing and waning of continental ice sheets. This allows reconstruction of the LPIA evolution during the early Permian, including: (1) an ice maximum during the Asselian–early Sakmarian; (2) a brief warming during the mid-Sakmarian; (3) a final ice maximum from the late Sakmarian to early Artinskian; and (4) a rapid, great deglaciation during the middle–late Artinskian.
The middle–late Artinskian deglaciation effectively marks the termination of the Late Paleozoic Ice Age, during which continental ice sheets nearly completely disappeared, with only limited alpine glaciers persisting into the late Permian.
This study provides the first high-resolution, multi-scale evidence of glacioeustatic sea-level changes from South China, delineating the complete transition of the LPIA from peak glaciation to final demise, offering crucial geological insights into Earth's late Paleozoic climate evolution.
This research was supported by the National Natural Science Foundation of China.
Reference: Zheng, Q.F.*, Wang, Y.*, Huang, X, Chen, B, Wu, H.P., Yuan, D.X., Wang, X.D., Shen, S.Z., 2025. Artinskian great deglaciation: Glacioeustasy evidence from South China. Palaeogeography, Palaeoclimatology, Palaeoecology, 679: 113310. https://doi.org/10.1016/j.palaeo.2025.113310.
Fig. 1 Outcrop photograph of the upper Chuanshan Formation showing meter-scale cyclic deposits at the Kongshan section in Nanjing (A), and representative images of major lithofacies on polished slab (B) and in thin sections (C–D).
Fig. 2 Integrated stratigraphic column of the Kongshan section in Nanjing, showing chronostratigraphy, lithostratigraphy, lithofacies associations (LFA), sedimentary environments (Sed. Env.), sedimentological log, inorganic carbon isotopes, and relative sea-level changes.
Fig. 3 Comparison of sea-level changes, relative global continental ice-volume variations, glacial history, and atmospheric CO₂ partial pressure during the Asselian to middle Kungurian stages of the Cisuralian Series (Early Permian).
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