Lessons from the Foreland Basin: Northern Appalachian Basin Perspectives on the Acadian Orogeny

TitleLessons from the Foreland Basin: Northern Appalachian Basin Perspectives on the Acadian Orogeny
Publication TypeBook Chapter
Year of Publication2010
AuthorsVer Straeten, CA
EditorTollo, RP, Bartholomew, MJ, Hibbard, JP, Karabinos, PM
Book TitleFrom Rodinia to Pangea: The Lithotectonic Record of the Appalachian Region
Series TitleMemoir
Series Volume206
PublisherGeological Society of America
CityBoulder, Colorado
KeywordsAcadian orogenesis, Devonian, Foreland basin rocks, New York, northern Appalachian Basin, Upper Silurian

Foreland basin rocks of the northern Appalachian basin in New York and adjacent areas contain a significant Upper Silurian to Devonian record of Acadian orogenesis. Sediment composition, stratal geometry, stratigraphic anomalies, and distribution of volcanic air-fall tephras through time and space provide insights into patterns of tectonism and quiescence, uplift and unroofing, tectonically induced basin flexure, and explosive volcanism in the orogenic belt. Herein, I combine a literature review and new data to examine several aspects of the foreland basin fill and their implications. Established models of Acadian-related impacts on the foreland, including tectophase development, are tested against a more refined high-resolution stratigraphy. Some sedimentary patterns are cyclic; others evolve through time. Initial study of synorogenic conglomerates across 40 m.y. of sedimentation sketches an unroofing history of the orogen. Stratigraphic anomalies delineate a flexural history interpreted directly from the rock record: topographic features in the foredeep migrate toward the craton in tectonically active intervals and toward the orogen during quiescent intervals. In addition, the forebulge undergoes cyclic uplift and leveling. These results differ from predictions in existing models of foreland basin kinematics. Preserved air-fall tephras reflect a history of explosive volcanism along the orogen. Comparisons of igneous rocks from the foreland and orogen portray a larger picture of Lower Emsian magmatism. Finally, I summarize the chronology of foreland basin signatures of orogenesis. Data and interpretations presented here should be compared with the record of Acadian orogenesis from the mountain belt in order to better determine causation and outline a more detailed synthesis of the Acadian orogeny.