Skip to Main Content
Skip Nav Destination

Controls on development of Catskill Delta complex basin-facies

Frank R. Ettensohn
Controls on development of Catskill Delta complex basin-facies (in The Catskill Delta, Donald L. Woodrow (editor) and William D. Sevon (editor))
Special Paper - Geological Society of America (1985) 201: 65-77


Dark, commonly black, fissile shales represent the basinal facies of the Catskill Delta complex. This dark-shale facies originated in the Appalachian Basin during the Emsian (late Early Devonian) and subsequently spread beyond the Appalachian Basin thus suggesting the importance of regional controls such as paleogeography, paleoclimate, and tectonic regime. The Catskill delta debouched into a subsiding peripheral basin on the eastern margin of a nearly enclosed, equatorial sea. Enclosure prevented deep-water incursions from other water bodies and enhanced the production and concentration of organic matter. Existence in a warm, rainy equatorial belt increased organic productivity and probably formed a nearly permanent thermohaline water stratification that prevented vertical circulation and resulted in anaerobic bottom conditions. Episodes of uplift and deformational loading in the rising Acadian Mountains resulted in closely following or concomitant periods of subsidence through isostatic adjustment in the adjacent peripheral basin. Hence, episodic Acadian uplift not only formed the source of the Catskill clastic wedge, but was also responsible for forming the peripheral basin that received the wedge. Basin subsidence isolated deltaic sediments from other parts of the sea, enhanced water stratification, and augmented net transgression. Rapid aggradation of sediments in nearshore areas due to transgression and the formation of a rainshadow due to uplift in the mountains caused decreased sedimentation on the delta, while concomitant basin subsidence produced abrupt deepening, strong water stratification (bottom anoxia), and migration of clastic-deficient (dark-shale) basinal environments shoreward. During intervening periods of tectonic quiescence, subsidence eventually halted, and erosion outstripped the effects of uplift in the mountains, so that the rainshadow was destroyed and abundant clastic influx resumed. As a result, the delta prograded rapidly across former basinal environments. Decreasing subsidence, shallower water, and abundant clastic influx destroyed basinal, bottom anoxia, so that marginally- to highly-oxygenated bottom conditions resumed throughout all delta environments. Five such major cycles of dark, basinal shales alternating with coarser clastics occur in the Catskill Delta complex of the Appalachian Basin. The progressive westward migration of successive cycles reflects the westward migration of Acadian deformation and accompanying basin infilling.

ISSN: 0072-1077
EISSN: 2331-219X
Serial Title: Special Paper - Geological Society of America
Serial Volume: 201
Title: Controls on development of Catskill Delta complex basin-facies
Title: The Catskill Delta
Author(s): Ettensohn, Frank R.
Author(s): Woodrow, Donald L.editor
Author(s): Sevon, William D.editor
Affiliation: Univ. Ky, Dep. Geol., Lexington, KY, United States
Affiliation: Hobart and William Smith Coll., Dep. Geol. Surv., Geneva, NY, United States
Pages: 65-77
Published: 1985
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
Meeting name: Symposium on the Catskill Delta held at the 18th Annual Meeting of the Northeastern Section of the Geological Society of America
Meeting location: Kiamesha Lake, NY, USA, United States
Meeting date: 19830324March 24, 1983
References: 75
Accession Number: 1985-074826
Categories: Sedimentary petrology
Document Type: Serial Conference document
Bibliographic Level: Analytic
Illustration Description: illus. incl. geol. sketch map
N33°00'00" - N47°30'00", W87°00'00" - W67°00'00"
Secondary Affiliation: Pa. Geol. Surv., USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 1985
Close Modal

or Create an Account

Close Modal
Close Modal