Three‐dimensional sequence analysis of a subsurface carbonate ramp, Mississippian Appalachian foreland basin, West Virginia, USA

Abstract

Well-cuttings, wireline logs and limited core and outcrop data were used to generate a regional, three-dimensional sequence framework for Upper Mississippian (Chesterian), Greenbrier Group carbonates in the Appalachian foreland basin, West Virginia, USA. The resulting maps were used to document the stratigraphic response of the basin to tectonics and to glacioeustasy during the transition into ice-house conditions. The ramp facies include inner ramp red beds and aeolianites, lagoonal muddy carbonates, midramp ooid and skeletal grainstone shoal complexes, and outer ramp wackestone-mudstone, that grades downslope into laminated silty lime mudstone. The facies make up fourth-order sequences, a few metres to over 90 m (300 ft) thick. The sequences are bounded along the ramp margin by lowstand sandstones and calcareous siltstones. On the ramp, sequence boundaries are overlain by thin transgressive siliciclastics and aeolianites, and only a few are calichified. Maximum flooding surfaces on the outer ramp lie beneath deeper water facies that overlie lowstand to transgressive siliciclastic or carbonate units. On the shallow ramp, maximum flooding surfaces overlie siliciclastic-prone transgressive systems tracts, that are overlain by highstand carbonates with significant grainstone units interlayered with lagoonal lime mudstones. The fourth-order sequences are the major mappable subsurface units; they are bundled into weak composite sequences which are bounded by red beds. In spite of differential subsidence rates across the foreland basin (1 to 3 cm/k.y. up to 25 cm/k.y.), eustatic sealevel changes controlled regional sequence development. Thrust-load induced differential subsidence of fault-blocks, coupled with in-plane stress, controlled the rapid basinward thickening of the depositional wedge, whose thickness and facies were influenced by subtle structures such as arches trending at high angles as well as parallel to the margin.

Orbital forcing and Mississippian sea level change: time series analysis of marine flooding events in the Visean Windsor Group of eastern Canada and implications for Gondwana glaciation

“…However, other researchers have applied similar reasoning to deduce that glacioeustatic sea-level changes on Laurussia first appeared in the Namurian (e.g. Underlying early Asbian rocks were deposited during the transition from greenhouse to icehouse conditions according to Wynn and Read, (2008). Blake (2006) argued that the major unconformity (sea-level lowstand) which defines the Mississippian-Pennsylvanian boundary in the Central Appalachian Basin should mark the first widespread glaciation of Gondwana.…”

“…In each of these assessments, the main arguments focused on the estimated pacing of transgressive events, generally appropriate to orbital control, and the interpreted scale of sea-level rise or fall. Wynn and Read (2008), in a study of the Appalachian Basin in Virginia, presented a contrasting interpretation in which the Meramecian-Chesterian (late Asbian and Brigantian) succession was characterized by moderate-scale eustatic sea-level fluctuations marking the initial glaciation of Gondwana. Butts, 2005), based on analysis of cyclic sedimentation patterns, and supported by preservation of glaciogenic sediments of Namurian age on several continents (Isbel et al, 2003;González-Bonorino and Eyles, 1995;Fielding et al, 2008).…”

An eolian dust origin for clastic fines of Devono-Mississippian mudrocks of the greater North American midcontinent

“…2; Ettensohn et al 2022). Toward the eastern Appalachian foreland basin, carbonate strata intertongue with continental redbeds and eolianites throughout West Virginia, Virginia, and Maryland (Wynn and Read 2008;Ettensohn et al 2022). Early development of the Mauch Chunk Delta began in eastern Pennsylvania in the Meramecian (Wynn and Read 2008;Ettensohn et al 2022) (Fig.…”

Coeval versus reciprocal mixed carbonate–siliciclastic deposition, Middle Devonian Baltic Basin, Eastern Europe: implications from the regional tectonic development

“…No extensive beds of evaporites occur in the Narva succession and the proportion of evaporates decreases northward in the basin and upward through the succession. Extensively muddy deposits occur in the Mississippian Appalachian basin in West Virginia (Wynn & Read, 2008). These muddy deposits accumulated during a highstand in restricted lagoonal conditions.…”

“…Lack of open marine fossils and periodically hypersaline settings are similar to the BB. In the Mississippian succession, the periodically increased inflow of fine-grained siliciclastic material has been interpreted to be controlled by changes in climate from semi-arid to humid (Wynn & Read, 2008). However, the occurrence of evaporite fabrics throughout the retrogressive phase of the Narva succession and the suggested arid or semi-arid climate for the whole duration of deposition from adjacent areas (Marshall et al, 2007) do not explain the increase of siliciclastic material into the BB, as caused by climate changes.…”