CHAPTER 12: THE DEVONIAN TERRESTRIAL SYSTEM OF NEW YORK

Devonian terrestrial strata in NY comprise three of 18 areas in eastern North America with Lochkovian to Fammenian terrestrial strata. Lower Givetian to Frasnian terrestrial rocks of the Catskill Mountains region, ~9.5% of the area of NY State, are said to be the only Devonian succession globally where correlation between adjacent, coeval marine and terrestrial strata is possible (House, 1974), permitting analyses of events and processes active on both land and sea. Yet, nearly 230 years after initial reports on Catskills rocks, these estimated ~2.4 km- (1.5 mi-) thick, homogenous strata largely remain a geological frontier. This chapter summarizes current geological and paleobiological knowledge of the NY Devonian terrestrial system, chiefly in the Catskills, and presents new research findings by the author.

Stratigraphic studies of the Catskills terrestrial strata over the last century yielded two different stratigraphic frameworks, by Chadwick in the 1930s to 40s; and Fletcher and Rickard, in the 1960s to mid-70s. Recent work indicates that in the field this latter model is problematic. Major research foci in NY’s Devonian terrestrial in recent decades include paleobotany, petrography, fluvial systems, and terrestrial arthropods. Broader paleobiological studies, as at Red Hill, PA, arose in the 1990s. Research of greater impact is largely paleobiological and includes the first complete Eospermatopteris (“Gilboa”) tree, and discovery of two large, well-preserved forest floors, representing Earth’s oldest known forests.

Difficulties in researching NY’s Devonian terrestrial strata include: 1) lateral discontinuity of terrestrial facies; 2) lack of recognized, distinctive marker units for correlation; 3) little biostratigraphic and geochronologic control; 4) extensive cover, in sometimes rugged terrain; and 5) too few researchers.

The author’s research is multifold – to systematically gather various data (e.g., event deposits, petrography, detrital zircon dating, palynological biostratigraphy), via a top to bottom, two-part transect through the succession from the Catskill Front to Slide Mountain. One key goal for future decades is to test the existing stratigraphic model and try to ground that stratigraphy in the regional rock record better, or to develop a new stratigraphic framework.