29 Bioevents, Tectonics, and Sea-Level Change in Marine to Non-Marine Strata of Northeastern North America

Monday, 23 March 2009
10:00 AM - 12:00 PM

ENVIRONMENTAL AND ECOLOGICAL VARIABILITY OF MIDDLE DEVONIAN (GIVETIAN) FORESTED PALEOSOLS IN THE CATSKILL REGION, APPALACHIAN BASIN, NEW YORK

Paper number: 29-3
Program: Theme Sessions
Time: 10:40 AM – 11:00 AM

Authors

Abstract

The inception of forestation on the earth is inferred to have caused major reorganizations of terrestrial and marine sedimentary systems and environments, as well as of atmospheric cycling and composition. The negative atmospheric and temperature perturbation that began in the Middle Devonian (Givetian) was a global transition from greenhouse to icehouse conditions. This climatic perturbation has been attributed to the rise of forests and a series of teleconnected environmental and climatic effects. Here we describe the environmental and ecological variability of the earliest known in situ forest deposits from the Appalachian Basin. Four separate forested paleosols are described and sampled from the Manorkill Formation in the Catskill Mountains, New York. These paleosols all have in situ stump casts rooted in their underlying mineral soils; each paleosol was described both macro- and micromorphologically. At two of the forested sites, stump features were mapped laterally along bedding plane surfaces and quantified using nearest neighbor spatial analysis.

The site at Gilboa, NY is an aquic (reduced) paleo-Entisol in very fine-grained quartz sandstone. This paleosol likely formed in a swamp on a distal delta plain. The paleosol has 60 stump casts and external molds preserved in a clustered spatial distribution pattern with evident sub-population sets that represent multiple generations of growth. Location 1 along Plattekill Creek in West Saugerties, NY has a succession of two forested paleosols with 20 total stump casts. Both paleosols are weakly developed in fluvial overbank deposits, with preserved sedimentary structures. These two paleosols both have random spatial distributions and likely formed over a short period of time. Location 2 along Plattekill Creek is a forested paleosol in a well developed and well-drained paleo-Vertisol. This paleosol has significant pedal (soil) structure, gilgai formation, slickensides, argillan development and carbonate accumulation. This forested paleosol formed on a well drained “upland” floodplain position. The paleosol in East Windham, NY along New York State Route 23 is a paleo-Alfisol. This paleosol has well developed pedality, argillans and has evidence of hydromorphy in the paleosol, but is interpreted to have formed on a more upland position along a floodplain.