中国科学院南京地质古生物研究所机构知识库

The Naqing section in South China is a representative carbonate slope succession in the eastern Paleo-Tethyan realm. It encompasses four global stratotype section and point (GSSP) candidates for the Carboniferous Period. High-resolution magnetic susceptibility measurements through the section have variations that correlate with lithological cycles of lime mudstone, wackestone, and packstone. Astronomical calibration of similar to 3 m sedimentary cycles to a 405 k.y. orbital eccentricity cycle period aligns other significant, shorter sedimentary cycles to periods recognizable as short orbital eccentricity (136 k.y., 122 k.y., and 96 k.y.), obliquity (31 k.y.), and precession (22.9 k.y. and 19.7 k.y.). The orbital eccentricity has long-period modulations with 2.4 m.y., 1.6 m.y., and 1.2 m.y. periods, and the obliquity has a 1.2 m.y. modulation cycle. The astronomical calibration indicates durations of 7.6 m.y., 8.1 m.y., 8.5 m.y., 2.87 m.y., and 4.83 m.y. for the Serpukhovian, Bashkirian, Moscovian, Kasimovian, and Gzhelian Stages, respectively. The calibrated durations of the 25 conodont zones collectively indicate a 33.9 m.y. time scale. Biochronological correlation of the Paleo-Tethyan and pan-Euramerican records significantly refines the global chronostratigraphy for the Serpukhovian Stage and the Pennsylvanian subsystem. This new Paleo-Tethyan astronomical time scale opens a new window for understanding the late Paleozoic icehouse world.