Rhyacian intermittent large igneous provinces sustained Great Oxidation Event: Evidence from North China craton

Abstract

To better understand the sustaining mechanism of the Great Oxidation Event (GOE), strata and igneous suites especially large igneous provinces (LIPs) during the GOE's late stage, known as the Lomagundi-Jatuli event (LJE), in the eastern North China craton (NCC) are investigated and reviewed. New results approve a span of ca. 200 Ma for the LJE-traced strata, including the lower Gaofan Group during 2270–2185 Ma, the lower-middle Sanchazi-Machollyong groups during 2185–2125 Ma and the lower-middle Hutuo Group during 2125–2025 Ma. The entirety of the LJE of the NCC intermits and spatially correlates with the emplacement of LIPs at ca. 2220 Ma, ca. 2185 Ma, ca. 2145 Ma, ca. 2120 Ma, ca. 2090 Ma, and ca. 2060 Ma during a global LIP peak of 2250–2050 Ma. These igneous suites are featured by subaqueous-extrusions, with prominent volcaniclastics and volcanic ashes (tuffs), which enhanced nutrient elements' input (such as Co, Ni, and V). The igneous suites have thus potentially contributed to keep the primary bioproductivity and then the accumulation of organic matters in the sediments and oxygenation-status of atmosphere. The end of this period was partly coincident with and closely followed by the arising of subduction system and orogenic processes during 2050–1800 Ma, which were responsible for the forming of major graphite-ore deposits followed by melting and converting of buried organic carbon into carbon dioxide. A blooming of arc magmatism and weathering of exhumed arc roots and orogens while a retreating of LIPs during 2050–1800 Ma might have elevated recyclability of organic carbon during high-temperature metamorphism and back into Earth surface via arc magmatism, favoring the causally termination of the GOE-LJE.