--> Recognition of Carbonate Eolianites and Sequence Boundaries in the Ste. Genevieve and St. Louis Limestones (Upper Mississippian), Southwestern Kansas, by F. E. Abegg; #90986 (1994).

Datapages, Inc.Print this page

Abstract: Recognition of Carbonate Eolianites and Sequence Boundaries in the Ste. Genevieve and St. Louis Limestones (Upper Mississippian), Southwestern Kansas

F. E. Abegg

Four eolian grainstones, 0.3 to 29.0 m thick, are traceable across most of the Hugoton embayment in southwestern Kansas. Eolian limestone is intercalated with subtidal limestone of the Ste. Genevieve (Chesterian) and uppermost St. Louis (Meramecian) Limestones. Eolianites typically contain peloids, ooids, and skeletal fragments plus 5 to 30 percent detrital quartz. Abundant climbing translatent stratification in inversely-graded sets 2 to 5 mm thick is diagnostic of wind-ripple sedimentation. Well-sorted, well-rounded, and abraded grains of very fine to medium sand size, without micrite or trace fossils, support the eolian interpretation. Calcretes occur below and within eolianites as indicated by scattered rhizoliths, alveolar texture, vadose pendant cements, and depleted whole-rock dgr13C values. Eolianites are nonporous due to compaction and minor cementation.

Ste. Genevieve and upper St. Louis eolianites formed as vegetated sand sheets or active dunes. Sand-sheet deposits contain scattered rhizoliths and ubiquitous climbing translatent stratification with bounding surfaces dipping at less than 15°. Dune deposits contain abundant climbing translatent stratification, common grainfall deposits, and rare grainflow units. Rhizoliths are rare to absent. Cross-stratification dips are typically less than 20° and increase upward within sets up to 0.8 m thick. Sand-sheet and active-dune deposits are interstratified in some eolian units.

Basal contacts of eolian units are regionally correlative sequence boundaries. Calcretes commonly cap underlying subtidal lithofacies, locally skeletal wackestone and packstone, and are overlain by eolianites without intervening beach or tidal-flat deposits. These relationships demonstrate a basinward shift in lithofacies and indicate that subaerial exposure resulted from a fall in relative sea level.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994