A PRE-GLACIAL d13C ANOMALY IN SVALBARD: IMPLICATIONS FOR THE NUMBER, CAUSES AND CORRELATION OF NEOPROTEROZOIC GLACIATIONS
Taking into account strikingly similar sedimentological and geochemical features in likely coeval cap dolostones (e.g. Dracoisen, Nyborg, Keilberg, Nuccaleena, Ravensthroat, Noonday), we propose a new correlation scheme for the Neoproterozoic glaciations. We correlate tillite pairs in Svalbard, Greenland and Death Valley with single glacigenic formations in Scotland (Port Askaig), Norway (Smalfjord), Namibia (Ghaub), Australia (Elatina), and Canada (Ice Brook). Deposits associated with the older Chuos-Rapitan-Sturtian glaciation are absent in most North Atlantic basins and Death Valley, but associated cap carbonates can generally be identified. A younger glaciation is represented by tillites in Norway (Mortenses), Scotland (Loch na Cille/Macduff), and the Avalon Terrain (Gaskiers/Squantum). In Norway, this glaciation is preceded by highly 13C-depleted carbonates and deep incision into underlying strata (up to 400 m). These features suggest correlation with the paleovalley beneath the Stirling Quartzite in Death Valley, which overlies the isotopically negative Johnnie Rainstorm Member (Corsetti and Kaufman, in press).