Use of the Deicke and Millbrig K-bentonites to resolve Middle Ordovician stratigraphic problems in the central Appalachians
- Univ. of Cincinnati, OH (United States). Dept. of Geology
It well known that numerous K-bentonite beds occur in Middle Ordovician strata in eastern North America. Two of these beds, the Deicke and Millbrig, have been correlated on a regional scale and have proven to be excellent time lines between the southern Appalachians and the upper Mississippi Valley. The purpose of this study is to extend the correlation of these two beds through the Central Appalachians (southern Virginia into central Pennsylvania) and to use them to investigate regional changes in carbonate and clastic facies. The Deicke and Millbrig can be correlated by chemical fingerprinting using whole rock chemical and mineralogical analyses. The immobile trace elements (Yb, Dy, Sc, Lu, Zr, and etc.) serve as effective discriminators when grouped in a hierarchical assemblage by discriminate function analysis. Distinctive mineral assemblages include labradorite as the principle plagioclase in the Deicke and andesine as the principle plagioclase in the Millbrig. Interpretation of Middle Ordovician stratigraphy in the central Appalachians has been hampered in the past by structural and facies complications. Both the Deicke and Millbrig have been correlated in this study from southern Virginia along strike northward into central Pennsylvania. Both the Deicke and Millbrig occur within the platform carbonates of the Eggleston Fm. at Hagan, Virginia, the shallow ramp carbonates of the Oranda Fm. at Strasburg and Mauzy, Virginia, the lower Martinsburg black shale and turbidite facies at Martinsburg, West Virginia, and the slope carbonates of the New Enterprise Member of the Salona Fm. in central Pennsylvania. This study supports the work done by Rosenkrans (1963) that dealt with the correlation of K-bentonites in the central Appalachians.
- OSTI ID:
- 5579516
- Report Number(s):
- CONF-9303211--
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Journal Name: Geological Society of America, Abstracts with Programs; (United States) Vol. 25:2; ISSN GAAPBC; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
Similar Records
Correlation of the Ordovician Deicke and Millbrig K-bentonites between the Mississippi Valleyand the southern Appalachians
Middle Ordovician carbonate ramp deposits of central Appalachians
Related Subjects
580000* -- Geosciences
APPALACHIAN MOUNTAINS
BENTONITE
CHEMISTRY
CLAYS
COMPARATIVE EVALUATIONS
DEVELOPED COUNTRIES
EVALUATION
GEOCHEMISTRY
GEOLOGIC AGES
GEOLOGIC FORMATIONS
GEOLOGY
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
MATERIALS
MINERALOGY
MOUNTAINS
NORTH AMERICA
ORDOVICIAN PERIOD
PALEOZOIC ERA
PENNSYLVANIA
STRATIFICATION
STRATIGRAPHY
USA
VIRGINIA
WEST VIRGINIA