Origin and Diagenesis of the Oriskany Sandstone (Lower Devonian, Appalachians) as Reflected in its Shell Fossils

Abstract

The quartzitic Oriskany Sandstone contains an abundance of calcitic fossil fragments and is cemented by calcite.

A high energy (beach) depositional environment is indicated by (a) rounding and sorting of quartz grains, (b) faunal restriction to few types of fossils, (c) absence of stem columnals of crinoids, indicating drift of the preserved fragile, buoyant calices into this environment, and (d) sturdy form of autochthonous brachiopods.

Diagenesis includes (a) early solution of aragonitic skeletons and redeposition as calcite cement, (b) local solution of calcitic fossils during a period of emergence, and (c) strong corrosion of quartz grains along contacts with shell surfaces during late diagenesis.