NEOPROTEROZOIC EARTH HISTORY AS WRITTEN IN NAMIBIA

Namibia houses an exceptional archive of Neoproterozoic rocks and it is little wonder that Paul Hoffman, together with his students and colleagues, discovered there a geological equivalent of the Rosetta Stone to use to conjure the snowball Earth hypothesis. The outstanding exposures of the Neoproterozoic Otavi Group in the Kaokoveld region of northwest Namibia in particular were key, preserving a record of two, variably developed Cryogenian glaciations in the Chuos and Ghaub formations. Since then, those climatic mileposts and their respective cap carbonates, the Rasthof and Keilberg-Maieberg formations, along with the associated chemostratigraphic profiles, became and remain central to ideas about the nature of the Cryogenian – Ediacaran Earth system. This talk builds on that legacy and will present several of the many findings of the more than two decades of collaborative work that my colleagues and I have undertaken to document the geology of Neoproterozoic successions throughout Namibia. The talk will focus on data and observations obtained in the northern and eastern portions of the Otavi Group and its basinal equivalents, linking those to the more intensely studied, largely platformal portions of the outcrop belt that fringe the basement-cored Kamanjab Inlier. Combining the work of Paul Hoffmann and his students with ours reveals a more complete and complex tectonostratigraphic record of the Cryogenian – Ediacaran time slice in northern Namibia than shown previously. We think that these findings are of significance in helping enhance understanding of this hallmark interval of Earth history.