DEVONIAN TERRESTRIAL STRATA, NEW YORK, APPALACHIAN BASIN, AND EASTERN NORTH AMERICA

Devonian terrestrial strata are found in 18 areas of eastern North America, from the Hampshire Fm. in Virginia and West Virginia to East Greenland and Ellesmere and adjacent islands, far north of Arctic Circle.

Devonian terrestrial strata occur in three areas in New York State, mostly in eastern to east-central New York’s Catskill Mountains region. This comprises about 9.5% of the area of the state. Two smaller areas occur northwest of New York City, and along the southwestern border with Pennsylvania. Devonian terrestrial strata in New York and across the Appalachian Basin remain a little-known frontier.

In the Hudson Valley, eastern New York, the transition from marine to terrestrial strata occurs in lower Eifelian, upper Marcellus-age strata, ~388 Ma. Two packages of terrestrial rocks are known in Pennsylvania: the Lochkovian Andreas Redbeds (Helderberg Group, early Early Devonian), and the Catskill Formation, interpreted to first occur sometime within the Frasnian (lower Upper Devonian). In the Maryland-Virginia-West Virginia outcrop belt, there is little time control on the oldest Devonian terrestrial. Using the Becker et al. (2020) time scale, which would roughly be on the order of 370 Ma (uppermost Frasnian, lower Upper Devonian), in Maryland; and in West Virginia roughly on the order of 375 Ma. Notably, the author found multiple apparent, dateable airfall volcanic tephras at the marine-terrestrial transition zone at a site in West Virginia.

A recent large-scale synthesis of Devonian terrestrial strata is found in the last volume, last chapter of Devonian of New York (Ver Straeten, 2003). This extended paper examines the Devonian terrestrial in New York State, chiefly in the Catskill Mountains. The paper also provides overviews of the sedimentary geology and paleobiology literature, applicable in many areas, and future possible work.

Dennis Terry and Chuck Ver Straeten are starting a Devonian Terrestrial Research Group, examining all and any geological and paleobiological aspects of the system, This will include the marine-terrestrial transition, fluvial channel and flood plains, lacustrine and palustrine settings, etc., their paleosols, stratigraphy, correlations (e.g., biostratigraphy, high resolution geochronologic age dates, 3d lidar), faunas and floras, climate, etc.