Becraft Formation

The Becraft Formation is a coarse limestone with occasional thin interbedded shale layers. Individual limestone beds within the formation range from 5 to 15 centimeters in thickness, while the shale horizons are up to 3 centimeters thick. Chert nodules are found near the top of the formation.[5] The limestone which constitutes the bulk of the formation is pinkish grey in color and contains abundant invertebrate fossils including brachiopods and crinoids.[6] The Becraft is a grainstone in Dunham classification.[7] Recently the Helderberg Group, of which the Becraft Formation is a member, has been investigated as a possible geologic seal for subsurface carbon dioxide sequestration efforts.[8]

The Becraft Formation was likely deposited in a shallow, high-energy marine environment similar to the depositional environment of the Coeymans Formation which underlies the Becraft within the Helderberg Group. After the mountain building events of the Taconic Orogeny around 440 million years ago, the eastern edge of North America became a passive margin. During this period in the Early Devonian, much of the Appalachian Basin was flooded with seawater producing a shallow, tropical marine environment. The Becraft Formation was deposited as part of a carbonate platform which developed within this basin prior to the onset of the Acadian orogeny in the Middle Devonian.[9]