700 to 694 Ma Olumi Sumbi large igneous province emplaced in the middle Sturtian cryochron

The Sturtian Snowball Earth cryochron (ca. 717–660 Ma) was the Earth’s longest glaciation, yet mechanisms for its persistence remain debated. We report high‑precision ID‑TIMS baddeleyite U–Pb ages of 700.6 ± 9.5 Ma and 694.0 ± 2.0 Ma for the Olumi dolerite dyke swarm (Gabon) and Sumbi dolerite sills (DRC), defining a previously unrecognized ca. 700–694 Ma Olumi–Sumbi large igneous province (LIP). Paleomagnetic constraints for the Olumi dyke indicate low‑latitude emplacement, placing the Congo Craton near the equator. Together with the ca. 719 Ma Franklin LIP, these tropical LIPs may have contributed to both initiating and sustaining the Sturtian glaciation. Episodic magmatism might have driven transient warming and deglaciation via volcanic CO2 emissions, followed by efficient chemical weathering of fresh mafic rocks, which enhanced CO2 drawdown and restored global ice cover. This suggests that tropical emplacement of LIPs during the Sturtian Snowball Earth cryochron might have strongly impacted the dynamics of the Earth’s longest glaciation. “Previously unrecognized ca. 700–694 Ma Olumi–Sumbi large igneous province with low‑latitude emplacement may have contributed to both initiating and sustaining Earth's longest glaciation, the Sturtian glaciation, shown using baddeleyite uranium-lead ages and paleomagnetic constraints.”