Terrestrial ecosystem response to Early Cretaceous global environmental change: A calibrated, high-resolution Aptian record from Northeast China

Abstract

Extensive studies of Aptian oceanic anoxic events and carbon cycle perturbations have significantly advanced our understanding of marine responses to global climate change. However, further exploration of possible volcanism–climate–environment linkages is hindered by the scarcity of continuous, well-documented terrestrial records. In an attempt to address this gap, the Yanshan Scientific Drilling Project extracted a 1497.5 m core from the shale-dominated, lacustrine, Jiufotang Formation in the Kazuo Basin of Northeast China. High-precision U-Pb geochronology of two interlayered tuffs yielded depositional ages of 121.05 ± 0.32 Ma and 117.359 ± 0.031 Ma, and a Bayesian age-depth model for the lower half of the formation. An astrochronological model based on δ¹³C_org and major element chemostratigraphy has suggested a duration of 9.03–9.14 Ma for the entire core, from 121.05 to 121.30 to 111.91–112.20 Ma. A 75.2 m core interval with unequivocal correlation to the oceanic anoxic event (OAE) 1a was identified by carbon isotope stratigraphy, which has a calibrated onset at 120.2 Ma and a total duration of ca. 450 kyr. Our results highlight the potential of lacustrine strata in recording at high-resolution the marine-correlated carbon cycle changes and in deciphering the drivers and mechanisms of climate change across the marine and terrestrial realms.