Factor Analysis Of The Sedimentary Textures And Fauna Of The Becraft Formation (Lower Devonian) Of New York State

Abstract

The Becraft Formation (Lower Devonian, New York State) represents a prograding carbonate shoal environment in which four distinct sedimentary textural types are developed. Type 1 is a very poorly sorted, coarse grained biosparite; Type 2, very poorly sorted biomicrudite; Type 3, poorly sorted fine grained biosparite and Type 4 is a very poorly to poorly sorted medium grained biosparite. Association of textures and assemblages of sedimentary structures suggests that textural Type 2 was deposited in an environment which was essentially unaffected by current movement. Types 1 and 4 were deposited under lower flow regime conditions and Type 3 resulted from upper flow regime conditions. Physical energy conditions in the Becraft environment are, in part, reflected by the zoarial forms of bryozoa. However, the distribution of fauna suggests that considerable lateral mixing has occurred. Two hematite-rich horizons were deposited in the Becraft as the first stage in diagenesis.