The Brentwood Member of the Bloyd Formation (Morrowan, Pennsylvanian) in northwestern Arkansas contains stratigraphic sequences deposted by tropical storms in middle shelf environments. The deposits are confined to shallow channels incised by strong unidirectional currents into an interval of shale deposited during fair weather conditions. Complete storm sequences reflect initial bottom currents of high competency that declined through time and were succeeded by wave generated oscillatory activity. The storm succession consists of an erosion surface followed by a basal pebble conglomerate, massive grainstone and packstone, whole-fossil wackestone, hummocky cross-strata and a swell lag of platy crinoidcalyxes. As storm activity ceased, fairweather deposits of middle shelf clay blanketed the storm sequences.
Jones, Kimberley R. and Zachry, Doy L.
"Storm Dominated Channel Sequences on a Shallow Marine Shelf: Morrowan of Northwest Arkansas,"
Journal of the Arkansas Academy of Science: Vol. 48
, Article 18.
Available at: http://scholarworks.uark.edu/jaas/vol48/iss1/18