Dataset for 'Sedimentary 17O-nitrate evidence for Phanerozoic aridity and humidity oscillations in South China' in Geophysical Research Letters

Climate changes are known to have been a key regulator of the biodiversity in Earth’s history. However, the dry-humid degrees and alternating patterns throughout the Phanerozoic remain largely unconstrained. In this study, we report high contents (2.4 ± 3.8 mg N kg-1) and 17O anomalies (11.0 ± 7.4 ‰) of nitrate (NO3-) in the early Cambrian black shale from South China, likely caused by atmospheric NO3- intrusion under dry climates that followed tectonic uplift. By developing new methods to quantify aridity indices (AI, 0.06 ± 0.08) in combination with observational data with paleoclimate models, we reconstructed the historical AI variations. Our analyses revealed three significant dry-to-humid transitions which include Cambrian-Ordovician to Silurian-Permian, Permian-Triassic boundary to middle Triassic-early Jurassic, and Jurassic-Paleogene to Neogene. This study quantitatively unlocked the Phanerozoic climate changes in South China, offering important evidence for understanding the co-evolution of ecological and climatic systems in Earth’s history.