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Tokio Formation

Tokio Formation
State Arkansas
Name Tokio Formation
Geologic age Phanerozoic | Mesozoic | Cretaceous-Late
Comments Intertouging beds of gray clay and qtz. sand with some lignite and basal novaculite gravels. Approximately 300 ft. thick. Novaculite-similar to chert but characterized by dominance of microcrystalline quartz over chalcedony.
Primary rock type clay or mud
Secondary rock type sand
Other rock types coal; novaculite
Lithologic constituents
Major
Sedimentary > Clastic > Mudstone (Bed)
Sedimentary > Clastic > Sandstone (Bed)
Minor
Sedimentary > Chemical > Novaculite (Bed)
Sedimentary > Coal (Bed)
Map references
Haley, B. R., Glick, E. E., Bush, W. V.; Clardy, B. F.; Stone, C. G.; Woodward, M. B., Zachry, D.L., 1993, Geologic Map of Arkansas: U.S.Geological Survey Special Geologic Map. Scale 1:500K
Unit references
Dane,C. H.,1929, Upper Cretaceous formations of southwestern Arkansas: Arkansas Geol. Survey Bull.1, 215 pp.
Counties Clark - Hempstead - Howard - Little River - Pike - Sevier