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- Title
CHAPTER 3: UPPER FRASNIAN AND FAMENNIAN STRATIGRAPHY IN WESTERN NEW YORK STATE.
- Authors
SMITH, GERALD J.; JACOBI, ROBERT D.
- Abstract
The upper Frasnian and Famennian Devonian stratigraphy in central and western New York State is comprised of the upper Frasnian West Falls and Java groups and the Famennian Canadaway, Conneaut, and Conewango groups. The Devonian stratigraphic correlation chart compiled by Rickard (1975) has been the general standard for the Frasnian and Famennian section in central and western New York. However, Rickard’s (1975) chart predates sequence stratigraphy, more sophisticated biostratigraphic and δ13Corg studies, and the recognition of numerous faults that offset the “layer-cake” stratigraphy. Our detailed field studies at over 2,000 sites that involved sedimentology, sequence stratigraphy, structure, and ichnology promoted the identification and tracing of key marker beds in central and western New York State. These studies encouraged a revision and refinement of the units and correlations that were represented in the Rickard (1975) stratigraphic chart. Revisions to Rickard’s (1975) Devonian stratigraphic chart include: abandoning the Perrysburg and Forty Bridge formations; reinstating units that Rickard (1975) omitted in his compilation, including the South Wales, Canaseraga, Rushford, Machias and Cuba formations, as well as the Salamanca Member; and proposing new East Sixtown, Gorge Dolomitic, Higgins, and West Lake members of the Caneadea Formation. We revised seven other units; fifteen units remain unchanged. A consequence of this new stratigraphy is a more robust depositional history for the Upper Devonian in central and western New York State. The Upper Devonian stratigraphic units of New York State record the transition from deeper-water shales and turbidite sandstones to terrestrial sands and shales as the Acadian Foreland Basin filled and the shoreline moved farther westward through time. The westward march of the shoreline was not steady, however, and was controlled by the usual interplay of 1) basin subsidence and fault block motion, 2) sediment supply, and 3) eustatic variation. The last of the Devonian black shale deposition occurred in the Frasnian/Famennian. The Frasnian is typified by offshore deposition, including turbidities. In contrast, the sedimentary structures and ichnofacies observed indicate the Famennian stratigraphy represented a shallower, offshore-to-nearshore depositional environment. The occurrence of storm influenced/modified bedding becomes ubiquitous in units of the upper Canadaway, Conneaut, and Conewango groups. Exposures of the Conneaut and Conewango typically are comprised of the thicker, fine sandstone packets. Fewer outcrops upsection result in less definitive correlations. Correlations in the Conneaut and Conewango are dependent on the presence of marker beds that contain distinctive lithologies such as red shales and beds containing white quartz pebbles.
- Subjects
NEW York (State); RED beds; BLACK shales; STRATIGRAPHIC correlation; SEQUENCE stratigraphy; GRABENS (Geology); DEVONIAN Period; SEDIMENTARY structures
- Publication
Bulletins of American Paleontology, 2023, Issue 407/408, p47
- ISSN
0007-5779
- Publication type
Article
- DOI
10.32857/bap.2023.407.03