| Summary |
The Reynolds Limestone Member of the Bluefield Formation is a thin (4 to 22 meters thick), extensive carbonate unit found throughout West Virginia. It is correlative, at least in part, with the driller's "Little Lime" and is a useful subsurface stratigraphic marker. Petrographic analysis indicates that the Reynolds Limestone Member is composed of three shoaling upward sequences. The lithologies in each sequence include, in ascending order, biomicrosparites (packstones) and biomicrosparrudites (packstones) rich in echinoderms, bivalves, brachiopods, and bryozoans; micrites (mudstones), argillaceous biomicrosparites (wackestones) and calcareous shales rich in peloids, brachiopods, bivalves, and gastropods; and dolostones or biolithites. The shoaling upward sequences developed on a broad, shallow shelf dominated by terrigenous clastic sediments. A rise in sea level resulted in the initiation of carbonate sedimentation. The subsequent development of shallowing upward sequences in any given area was dependent upon variations in water depth, subsidence, rate of terrigenous sediment influx and the change in topographic relief. Subsurface straigraphy demonstrates a topographic high perpendicular to the outcrop pattern in Fayette and Greenbrier Counties. This feature subdivides the study area into 2 sub-basins, affecting sedimentation and the development of the sequence in each area. Surface stratigraphy indicates that transitional sedimentation (dolostones or algal lithites) was restricted to the Clayton and Raines Corner sections, suggesting that the topographic high extended through Summers and Monroe Counties. |
