Spatio-Temporal Distribution of Marine Siliceous Deposits during the Permian and Triassic

The Permian Chert Event (PCE) and the Early Triassic Chert Gap (ETCG) are regarded as anomalous episodes of siliceous deposition, responding to significant tectonic, climatic, and environmental changes during the transition from the latest Paleozoic to the earliest Mesozoic. To comprehensively examine the temporal and spatial distribution patterns of marine chert related sediments and contest the PCE and ETCG scenarios, we have established a Permian-Triassic marine cherty deposits database (bedded chert, chert nodules, cherty limestone, and cherty mudstone/shale), which includes 1,027 records of 215 lithology units. The results show that: (1) The PCE is heavily biased towards intensive sampling in the low-latitude Tethyan realms, while the overall spatial extent of siliceous deposition during the middle-late Permian did not exhibit significant changes compared to earlier ages; (2) The ETCG has been misinterpreted at the stage level, as the records of bedded chert, chert nodules, and cherty mudstone/shale present successive deposition throughout the Permian and Triassic, but to the absence of chert nodules from the Early Triassic; (3) Siliceous deposits started occur in the high-latitude regions of the Southern Hemisphere from the Lopingian (late Permian) to the Triassic, representing a significant spatial expansion which had been previously overlooked. Thus, we present a comprehensive view of the spatio-temporal evolution of global chert-related sediments during the Post-Paleozoic Great Warming, providing valuable insights for predicting oceanic depositional responses to ongoing and future climatic changes.