28 Paleozoic Events and Processes: Sedimentary Geology, Paleontology, and Geochemistry

The focus of this session is short- to long-term geologic, paleobiologic, and geochemical events and processes, recorded in Paleozoic sedimentary rocks.

Monday, 23 March 2026
3:25 PM - 5:30 PM
CCC, Room 27

Sedimentology and Preliminary Chitinozoan Biostratigraphy of the Glenerie Formation (Hudson Valley, New York State)

Paper number: 28-3
Program: Technical Sessions
Time: 4:10 PM – 4:30 PM

Authors

Abstract

Partly correlative with the Oriskany Sandstone, the Glenerie Formation is a cherty limestone (Goldring 1943; Chadwick 1944; Ver Straeten 1995, 2003) comprised of well-sorted, brachiopod-dominated biosparites and biosparudites (Hodgson 1970) with sandy/shaly interbeds. After over a century of paleontologic research focused on macrofauna, neither the sedimentology nor the biostratigraphy of the Glenerie have been investigated. This preliminary report offers sedimentologic observations and interpretations along with an initial chitinozoan biostratigraphy.

Planar bedding is common in Glenerie grainstones with some imbrication of brachiopod valves, but the coarseness of the bioclasts commonly obscures internal stratification. Two partly overlapping, sheet-like biostromes (15-20 cm thick) of ramose bryozoan bafflestone extend across several tens of meters in the Rt. 9W road cut adjacent to the Glenerie type section. This road cut also displays dm-scale herringbone cross stratification, some of which includes fine-grained drapes over slip faces. These structures are interpreted as tidal bundles, suggesting that at least portions of the Glenerie sediments were deposited as tidal sand waves on a ramp/open shelf under an asymmetric tidal regime. Paleocurrent direction is predominantly southward with fewer cosets directed northward, though some trough cross strata appear oriented east-west. Some finer grained beds show vague asymmetrical ripples with cross lamination, also consistent with transport under tidal currents.

Reliable biostratigraphic data remain sparse to absent from the late Lochkovian through early Eifelian stages in the Appalachian Standard Succession (New York State). Preliminary samples from two outcrops of the Glenerie Fm. in the Hudson Valley have yielded specimens of Eisenackitina aranea (Urban, 1972), Margachitina sp., and Ramochitina cf.gilbertsoni (Wood, 1974). E. aranea and R. gilbertsoni are species originally described from the Middle Devonian of Iowa and Ohio, and they range from the early Eifelian to the early Givetian. Long thought to be Pragian in age, it now appears that the Glenerie is of Eifelian age. If confirmed, this age would constrain the overlying Esopus and Schoharie formations to the Eifelian as well, consistent with Eifelian conodonts reported from the overlying Onondaga Formation. These preliminary findings suggest that much of the Pragian and Emsian stages may be absent from the Standard Succession. An extensive sampling campaign is planned to refine this tentative biostratigraphy.

Geological Society of America Abstracts with Programs. Vol. 58, No. 2

doi: 10.1130/abs/2026NE-411192

© Copyright 2026 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.