Correlation of Middle Devonian Hamilton Group-equivalent strata in east-central North America: Implications for eustasy, tectonics and faunal provinciality
Published:January 01, 2007
A. J. Bartholomew, C. E. Brett, 2007. "Correlation of Middle Devonian Hamilton Group-equivalent strata in east-central North America: Implications for eustasy, tectonics and faunal provinciality", Devonian Events and Correlations, R. T. Becker, W. T. Kirchgasser
Download citation file:
An integrated approach, involving nearly all available biostratigraphic data, event and sequence stratigraphy, has been utilized in correlation of the Middle Devonian (latest Eifelian–Givetian) Hamilton Group and equivalent strata in north-central North America. This approach permits high-resolution correlation of strata equivalent to the Oatka Creek (upper Marcellus), Skaneateles, Ludlowville and Moscow Formations from New York into sections bordering the Michigan Basin in Ontario, Canada, as well as southern Michigan, northern Ohio and Indiana, USA. Most member and submember-scale units, herein slightly redefined and interpreted as 3rd and 4th order sequences, respectively, and their bounding condensed beds can be correlated regionally. Moreover, many faunal patterns also persist across this region, which, together with sequence stratigraphy, provides a bridge for correlation into the Michigan Basin. The detailed stratigraphy presented herein permits a more-resolved understanding of far-field tectonics, eustasy and biotic responses during the Middle Devonian. Allocyclic processes, primarily eustasy, played a key role in generating persistent sedimentary cycles. Episodes of rapid mud sedimentation occurred over large areas of the cratonic interior, distal to Acadian source terrains. The major Algonquin–Findlay Arch, which presently separates the Michigan Basin from the Appalachian foreland basin, was not present during deposition of these strata. Conversely, a roughly north–south trending region, running approximately through present-day Cleveland, Ohio, was first a local subsiding area during late Eifelian–early Givetian time and then underwent topographic inversion to form a local arch at which upper Hamilton units were condensed and then bevelled during the later Givetian; we infer that this feature may represent a migrating forebulge. Finally, fossil biotas do not show strong partitioning into Appalachian and Michigan basin faunal subprovinces during the early Givetian, as there appears to have been no physical barrier to migration at least in the study area. However, Hamilton-equivalent strata in the most proximal portion of the Appalachian Basin do show a relatively minor admixture of typical Michigan Basin taxa with normal Hamilton forms.
Figures & Tables
Devonian Events and Correlations
The Devonian was a peculiar period, characterized by simplified plate tectonic configurations, climatic overheating and widely flooded continents. The bloom of fishes and ammonoids, extensive reef complexes, and the conquest of land indicate major biosphere innovations, punctuated by many global events, including two of the biggest mass extinctions. The Devonian was the first system for which subdivisions were formally defined. This was achieved by significant advances in pelagic biostratigraphy. The chronostratigraphic framework and interdisciplinary techniques allow us to correlate intervals or sudden events across facies boundaries, in order to reconstruct the sedimentary and evolutionary history of the system with highest precision.
This volume honors the lifetime stratigraphic achievements of Michael Robert House (1930-2002). Based on case studies from Europe, North Africa and North America, it shows how the combination of biostratigraphy, chemostratigraphy, magnetostratigraphy, sequence stratigraphy and event stratigraphy can contribute to a much deeper understanding of both regional and global environmental change.