GSA Today
Volume 21, Number 3 (March 2011)

About the cover:
The sharply outcropping cap carbonate at the base of the Nafun Group above the Marinoan glacial epoch (ca. 635 Ma) in the Jabal Akhdar, Oman. The area is characterized by several tectonic events that turned the shown stratigraphy upside down. Photo courtesy Daniel Figi. See “The case for a Neoproterozoic Oxygenation Event: Geochemical evidence and biological consequences,” p. 4–11.

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