Print this pageInitiation of the Arbuckle Platform in the Slick Hills, Oklahoma
DONOVAN, R. NOWELL
Late Cambrian (Franconian) transgression involved (i) transgression, (ii) the transgressed surface, (iii) eustatic sea level changes, and (iv) tectonic adjustments. Basal Reagan and Honey Creek Formations (the Timbered Hills Group) pass into the Fort Sill Formation (Arbuckle Group). The Reagan is constructed of alluvium, tidal sandbars and green shale heterolithics; topmost Reagan is glauconitic. The Honey Creek consists of cyclic alternations of quartz sandstones and detrital grainstones. Abundant lime mud defines the base of the Arbuckle Group. The lower Fort Sill displays shallowing-upward cycles; the top of the Formation (locally dolomitized) displays massive algal boundstones. The succeeding Signal Mountain Formation is dominated by "below wave base" facies. The transgression inundated a hilly rhyolitic land surface; the resulting archipelago persisted until the end of Fort Sill deposition. Clear waters around islands were colonized by carbonate organisms. Facies variation is related to topography; lee- and windward carbonate facies are preserved. Eustatic variations are recorded by meter-scale cycles in the Honey Creek and Fort Sill Formations. The sequence shows two grand cycle boundaries, one low in the Honey Creek (associated with slight angular unconformity due to compaction around rhyolite terrain). The other constitutes the Fort Sill/Signal Mountain boundary. Tectonic definition of the Southern Oklahoma aulacogen is recorded by aberrant variations in the size and type of siliciclastic grains, facies changes that record increasing water depth and increase in the thickness of grand cycle packages.