Chert oxygen isotope ratios are driven by Earth's thermal evolution.

ABSTRACT: The ¹⁸O/¹⁶O ratio of cherts (δ¹⁸O_chert) increases nearly monotonically by ~15‰ from the Archean to present. Two end-member explanations have emerged: cooling seawater temperature (T_SW) and increasing seawater δ¹⁸O (δ¹⁸O_sw). Yet despite decades of work, there is no consensus, leading some to view the δ¹⁸O_chert record as pervasively altered. Here, we demonstrate that cherts are a robust archive of diagenetic temperatures, despite metamorphism and exposure to meteoric fluids, and show that the timing and temperature of quartz precipitation and thus δ¹⁸O_chert are determined by the kinetics of silica diagenesis. A diagenetic model shows that δ¹⁸O_che

SUBMITTER: Tatzel M 

PROVIDER: S-EPMC9907065 | biostudies-literature | 2022 Dec

REPOSITORIES: biostudies-literature