Basinwide stratigraphic synthesis and sequence stratigraphy, upper Pragian, Emsian and Eifelian stages (Lower to Middle Devonian), Appalachian Basin

Abstract

A new synthesis of the Lower to Middle Devonian (upper Pragian, Emsian and Eifelian) succession across the Appalachian Basin has been developed by high resolution event and sequence stratigraphic analysis. The correlation of numerous marker beds and a hierarchy of cycles in the interval of the Oriskany Sandstone to lower Hamilton Group provide a refined picture of the depositional patterns, faunal changes, formation to member-level (and finer) relationships, and sea-level trends. The succession begins above the Wallbridge Unconformity, or its correlative conformity, which lies beneath the Oriskany Sandstone, not above it as previously thought. The new sequence-stratigraphic framework of Oriskany to lower Hamilton strata comprises nine ‘third order’ stratigraphic sequences (cycles), though an interval of some 25 million years. At a coarse scale, the eustatic Pragian to Eifelian sea-level curve for Euramerica of Johnson et al. (1985) shows broad variance with the Appalachian curve, reflecting the regional influence of the Acadian orogeny. However at the finer sequence-scale, the Euramerican sea-level trends are recognizable in the Appalachian Basin succession.

Geochemistry and depositional history of the Union Springs Member, Marcellus Formation in central Pennsylvania

“…(Shamokin Mbr. of the Marcellus Formation; Cooper, 1930;Ver Straeten, 2007) and is generally characterized in well logs by a pronounced increase in the gamma ray signature (Figure 1). The contact between the Onondaga Formation and the Union Springs Mbr.…”

“…The upper Eifelian and lower Givetian (388-390 million years) Marcellus Formation comprises of organic-and pyrite-rich black to dark gray shale intervals that are separated by a sequence of limestone, shale, and sandstone of variable thicknesses (Rickard, 1975;Lash and Engelder, 2011;Kohl et al, 2014). Although the Marcellus Formation has been elevated to subgroup status in New York State (Ver Straeten, 2007), the Marcellus Formation in Pennsylvania is divided into three members (Kohl et al, 2014).…”

Lithofacies and Sequence Stratigraphy of the Middle Devonian Marcellus Formation for a Cored Well in Clearfield County, Pennsylvania Using Core Analysis Methods

“…The stratigraphic terminology for the Marcellus Formation is convoluted due to facies variations across the basin and a long history of study. (Sexton, 2011, Ver Straeten, 2007, Ver Straeten and Brett, 2006, Lash and Engelder, 2011 approximately between 390 ± 0.5 and 388.1 ± 2.6 Ma, as suggested by Kaufmann (2006), while Parrish (2013) predicted an earlier deposition between Emsian and Eifelian age. The lower Marcellus/Union Springs Member, in western New York, is described as a highly organic, calcareous, dark-gray to black mudstone containing skeletal lags (Sageman et al, 2003).…”

“…Lithologic subdivisions for the Middle Devonian Eifelian to Givetian Strata from ver Straeten (2004 and2007), Milici and Sweezy (2006), and Kohl et al (2014). Calibrated time scale derived from Kaufman (2006) and third order depositional sequences from Brett et al (2011) and ver Straeten (2007). The stratigraphic nomenclature used in this study is on the far right (modified from Kohl, 2014) .5.…”

Outcrop Lithostratigraphy and Petrophysics of the Middle Devonian Marcellus Shale in West Virginia and Adjacent States

“…The Marcellus shale has been reported to maintain this same character from east-central Pennsylvania to as far south as Bluefield, Virginia (Woodward, 1943). The Marcellus Shale of western New York has been elevated to subgroup status and contains two distinct formations, the Union Springs and the Oatka Creek (Ver Straeten, 2007).…”