TRAVERSING THE CATSKILLS SUCCESSION, BOTTOM TO TOP: APPROACH AND CHALLENGES

The Catskill Mountains comprise >mile thickness of Mid to Late Devonian-age terrestrial strata. Oldest terrestrial rocks, west of the Hudson River, are uppermost Marcellus age (early Givetian). Little biostratigraphic data is available to constrain the succession above that. Strata atop Slide Mountain, highest Catskills peak, are estimated to be mid-Frasnian.

Past studies through the Catskills succession (e.g., petrography, palynology, sedimentology, paleobotany) concentrated on well-exposed intervals, or scattered localities. No study and analyses had systematically traversed the entire vertical stack of terrestrial rocks.

To resolve this, the route with the best continuity through the Catskill succession was determined (Greene and Ulster cos.), and sampling initiated. Two overlapping segments traverse the terrestrial rocks bottom to top. A long, lower segment follows a creek and trail from the Hudson Valley to Hunter Mountain. A second, shorter segment to the southwest follows a trail to the top of Slide Mountain. An overlap of unknown thickness connects the two segments. Total length of the transect is ~56 km.

Transect fieldwork the first years indicated various problems, including extensive cover in some intervals (especially of fine-grained strata), and the inability to determine vertical stratigraphic position mountain-to-mountain. Subsequent use of LiDAR maps (1-2 m-resolution) indicate best sampling and visibility of the succession occur off-trail, along ridges descending northern mountainsides. Some issues, chiefly correlation of sampling positions mountain-to-mountain, remain.

Sandstones and dark olive to black mudstones are ideally collected at 100 to 150 m intervals, and conglomerates when encountered. Samples are large (generally ~2-5 kg), to provide for slabs and thin sections, with abundant material for additional analyses now (e.g., ongoing detrital zircon dating, XRF, and palynology) and into the future.

Surveys across the top of the Catskill Escarpment (~Platte Clove to North-South Lake/Sunset Rock) indicate the Twilight Park Member consists of several conglomerates, up to six meters or thicker, vertically spaced ca. 18-30 meters apart. The cause of this recurring pattern is unclear, but could be related to eustatic changes of base level, among other processes.