ANOTHER LOOK AT THE GASKIERS FORMATION OF NEWFOUNDLAND AND THE NATURE OF EDIACARAN GLACIATION

Newly discovered paleosols in the Gaskiers Formation of Newfoundland provide a new perspective on its paleoenvironment, and are evidence that it was not a deep submarine tillite, nor the first highly oxidized deep-sea floor, nor a “cap carbonate” from extreme geochemical perturbation of the global ocean by “Snowball Earth” conditions. Discovery of oxidized paleosols and revaluation of sedimentary facies and stratigraphic relationships now suggest reinterpretation as a coastal plain with glacial moraines in the forearc basin of a continental volcanic arc, like that of modern Japan. Ediacaran paleosols of the Gaskiers Formation lack large root traces, but show soil profile differentiation (clay enrichment and depletion of alkali and alkaline earth elements at the expense of feldspar and rock fragments) and diagnostic soil structures (blocky peds, argillans, sepic plasmic fabric). These paleosols are evidence of a humid temperate climate and marked marine regression accompanying Gaskiers Glaciation of the early Ediacaran (580 Ma). Geochemical weathering trends in the paleosols, especially phosphorus depletion, are characteristic of biologically active soils. Ediacaran microbial earth ecosystems may have been responsible for filamentous disruption of bedding in the paleosols.