|Geology of the County
In Jackson County, water is obtained from consolidated sedimentary
rocks ranging in age from Devonian and Mississippian to Pennsylvanian,
and from unconsolidated Quaternary sediments. The Devonian New Albany
shale, 400 million years old, was formed when the deep sea floor became
covered with an organic black muck. The muck is now hard black shale
(an oil shale) which is one of the most distinctive of all geologic
formations in Kentucky. The Mississippian sandstones and siltstones
are the result of a great influx of mud, silts, and sands brought in
by rivers and streams from uplands many miles to the northeast and deposited
as a great delta. The Mississippian limestone found in Jackson County
was deposited 350 million years age in the bottom of a warm, shallow
sea. At the end of the Mississippian, 320 million years ago, the seas
receded and sediments of the Pennsylvanian were deposited. The warm
climate of the Pennsylvanian grew extensive forests and great coastal
swamps at the edges of water bodies. Marine waters advances and receded
many times which produces many layers of sandstone, shale, and coal.
Vegetation of all sorts fell into the water and was buried under blankets
of sediments, which over long geologic time were compressed into coal.
Geologic Formations in the County
Interbedded clay shales, siltstones, and sandstones
Coals, sandstones, and shales
For more information, see the definitions of geologic terms and rock descriptions, a geologic map of the county, a summary of the geology of Kentucky, and a discussion of fossils and prehistoric life in Kentucky.