Carboniferous Algae from the Peratrovich Formation, Southeastern Alaska

Abstract

The Peratrovich Formation is exposed in the Klawak, Ladrones,Madre de Dios, Shelikof, Toti and Wadleigh Islands off the west side of Prince of Wales Island in southeastern Alaska (Armstrong 1970, Fig. 1). The total thickness of the succession is hard to assess as the base of the formation is extensively faulted. A minimum of 550 meters of carbonates can be measured in nine well-exposed sections. The whole gamut of carbonate facies is observed. In the lower part of the formation, deep-water radiolarites and spiculites are overlain by an extensive carbonate sequence (Vaskey 1982, Pinard 1982) in an island arc setting within the Cordilleran Eugeosyncline (Bamber and Mamet 1985). The succession of Foraminiferal Zones (Mamet and Skipp 1970) ranges from the late Tournaisian to the Bashkirian and indicates a mixture of North American and Tethyan fauna (Mamet and Skipp 1979). This contribution illustrates the algal microflora and its paleobiogeography based on the microfossils. We have also added some references to the Bashkirian Ladrones microflora which overlies the Peratrovich Formation.