The grandest of them all: the Lomagundi–Jatuli Event and Earth's oxygenation

The Paleoproterozoic Lomagundi–Jatuli Event (LJE) is generally considered the largest, in both amplitude and duration, positive carbonate C-isotope (? 13 C carb ) excursion Earth history. Conventional thinking that it represents a global perturbation of carbon cycle between 2.3–2.1 Ga linked directly with, part causing, postulated rise atmospheric oxygen during Great Oxidation Event. In addition to new high-resolution ? measurements from LJE-bearing successions NW Russia, we compiled 14 943 values obtained marine rocks 3.0–1.0 age selected Phanerozoic time intervals as comparator LJE. Those data integrated with sedimentology show that, contra consensus, trend LJE facies (i.e. palaeoenvironment) dependent. Throughout interval, composition open deeper settings maintained mean value +1.5 ± 2.4‰, comparable those for most contrast, C-rich are hallmark limited largely nearshore-marine coastal-evaporitic +6.2 2.0‰ +8.1 3.8‰, respectively. Our findings confirm changes archive contemporaneous dissolved inorganic pools having variable C-isotopic compositions laterally adjacent depositional settings. implications cannot be construed priori representative or planetary-scale disturbance cycle, nor direct evidence oxygenation ocean–atmosphere system. This requires rethinking models relying on concepts framing ideas search understanding genesis grandest all excursions, its timing hypothesized linkage atmosphere. Supplementary material : C–O isotope data, figure S1, tables S1–S5 dataset available at https://doi.org/10.6084/m9.figshare.c.5471815