Diagenetic barite nodules in Ordovician and Devonian shales of the Appalachian Basin

Conference · Tue Jan 01 04:00:00 EST 1985 · Geol. Soc. Am., Abstr. Programs; (United States)

OSTI ID:6651460

Clark, S H.B.

Barite nodules are present in shales of the miogeosynclinal Appalachian basin at numerous localities from western New York to northeastern Tennessee. The association of barite with large sedimentary exhalative sulfide deposits worldwide and the similarity of the geologic settings of the Appalachian nodule occurrences and the bedded barite deposits in Nevada and Arkansas have led to speculation about the possible existence of economic deposits of these types in rocks of the Appalachian basin. Diagenetic nodules occur in Middle Ordovician shales in northeastern Tennessee and southern Virginia; in Devonian shales in western Virginia, West Virginia, and Pennsylvania and in Upper Devonian shale in New York. The nodules typically are in the lower parts of shale sequences deposited slowly in stagnant marine environments and in units that contain concretionary to lenticular layers of limestone. Barite also occurs filling fractures in septaria and in cavities in fossils. The associations of barite nodules with carbonate concretions or layers and sulfides and indications from fossils of sporadically oxygenated bottom conditions suggest that local variations in Eh-pH conditions associated with aerobic-anaerobic boundaries and (or) decay of organic matter could have resulted in dissolution and reprecipitation of barium. The lack of a geochemical halo of increased barium content in the shales also suggests derivation of barium primarily from local sources, without significant enrichment from exhalative hydrothermal fluids.

• Research Organization: Geological Survey, Reston, VA (USA)
• OSTI ID: 6651460
• Report Number(s): CONF-8510489-
• Conference Information: Journal Name: Geol. Soc. Am., Abstr. Programs; (United States) Journal Volume: 17
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580300* -- Mineralogy
Petrology
& Rock Mechanics-- (-1989)
580400 -- Geochemistry-- (-1989)
ALKALINE EARTH METAL COMPOUNDS
APPALACHIAN MOUNTAINS
BARITE
BARIUM COMPOUNDS
BARIUM SULFATES
CHEMISTRY
DEPOSITION
DEVONIAN PERIOD
DIAGENESIS
GEOCHEMISTRY
GEOLOGIC AGES
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
MINERALIZATION
MINERALOGY
MINERALS
MOUNTAINS
ORDOVICIAN PERIOD
ORIGIN
OXYGEN COMPOUNDS
PALEOZOIC ERA
PETROGENESIS
PRECIPITATION
ROCKS
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
SEPARATION PROCESSES
SHALES
SULFATE MINERALS
SULFATES
SULFIDE MINERALS
SULFUR COMPOUNDS