The relationship between the Neoproterozoic Noonday Dolomite and the Ibex Formation: New observations and their bearing on 'snowball Earth'

Several interpretations of the new observations are possible. The erosional unconformity upon which the Ibex is deposited may be glacio-eustatic in origin, the basal conglomerate would represent glaciogenic ice rafted debris, and the overlying dolostone is a classic cap carbonate (noted atop many Neoproterozoic glacial deposits worldwide). Combined with the record from underlying units, the Death Valley succession would then unambiguously record three discrete Neoproterozoic ice ages with cap carbonates in a single succession. Alternatively, the sequence boundary could represent local tectonic activity rather than glacioeustacy.