Paleozoic–Mesozoic terrestrial total organic carbon and organic carbon isotope database

Studies of the terrestrial carbon cycle commonly rely on geochemical proxies such as total organic carbon (TOC) and the organic carbon isotopic composition (δ13Corg). However, terrestrial TOC and δ13Corg data are widely dispersed across the literature and lack a unified compilation, limiting large-scale synthesis and cross-comparison. Here, we present a global, standardized dataset of TOC and δ13Corg measurements derived primarily from terrestrial sedimentary facies: Paleozoic–Mesozoic Terrestrial Total Organic Carbon and Organic Carbon Isotope Database (PM-TOCI). The dataset compiles 66 583 individual data points (49 014 TOC and 17 569 δ13Corg) from 619 publications, spanning the Devonian to Cretaceous (419–66 Ma). Each entry is accompanied by 37 standardized metadata fields, covering geographic information, stratigraphic age, lithology, and depositional facies, thereby enabling consistent filtering, comparison, and reuse across spatial and temporal scales. This dataset is intended to facilitate future data-driven studies of terrestrial organic carbon accumulation, paleoclimate variability, source rock assessment, and long-term carbon cycle dynamics, as well as the link between carbon cycle and biotic evolution. The dataset is openly accessible at https://doi.org/10.5281/zenodo.20486580 (Tian et al., 2026).