Geologic evidence for an icehouse Earth before the Sturtian global glaciation

• DOI: 10.1126/sciadv.aay6647
• Publication Date: 2020-06-10T23:18:43Z
• Authors: Scott A. MacLennan; Michael P. Eddy; Arthur J. Merschat; Akshay K. Mehra; Peter W. Crockford; Adam C. Maloof; C. Scott Southworth; Blair Schoene
• Keywords: 13. Climate action; 01 natural sciences; Research Articles; 0105 earth and related environmental sciences

Snowball Earth episodes, times when the planet was covered in ice, represent most extreme climate events Earth's history. Yet, mechanisms that drive their initiation remain poorly constrained. Current models require a cool to enter state. However, existing geologic evidence suggests had stable, warm, and ice-free before Neoproterozoic Sturtian global glaciation [ca. 717 million years (Ma) ago]. Here, we present eruption ages for three felsic volcanic units interbedded with glaciolacustrine sedimentary rocks from southwest Virginia, USA, demonstrate glacially influenced sedimentation occurred at tropical latitudes ca. 751 Ma ago. Our findings are first of teetering on edge several Earth.