Carbondale Group Explained

Carbondale Group
Type:Geological group
Prilithology:Shale, Siltstone
Otherlithology:Sandstone, Coal
Subunits:
  • Dugger Formation
  • Petersburg Formation
  • Linton Formation
Underlies:McLeansboro Group
Overlies:Raccoon Creek Group
Region:Illinois Basin
Country:United States
Namedfor:Carbondale, Illinois
Age:Middle Pennsylvanian

The Carbondale Group is a Middle Pennsylvanian aged unit found in the Illinois Basin. This geologic unit is made up of siliciclastic rock and coal beds.[1]

Description

The Carbondale is made up of mostly siliciclastic lithology. There are several coal beds as well as well as some limestone member units. Some coal beds are commercially viable and a number of mines extract coal from this geologic unit.

Stratigraphy

Dugger formation

The Dugger formation is at the top and therefore the youngest of the group. This formation contains more sandstone and serves as an aquifer for domestic use.[2]

Petersburg Formation

The Petersburg formation also contains sandstone members that are used as aquifers.

Linton Formation

The Linton Formation is a geologic formation in Indiana. It is the lower formation in the Carbondale Group, and includes six named members, "which, in ascending order, are the Seelyville Coal, Coxville Sandstone, Colchester Coal, Mecca Quarry Shale, Velpen Limestone, and Survant Coal Members, and unnamed units of sandstone, shale, and clay".[3]

It preserves fossils dating back to the Carboniferous period.

The Linton Formation was first named on a United States Geological Survey coal investigations map in 1950.[4] The type locality is along the tributaries of Lattas Creek, approximately 4 miles north of Linton, Greene County, Indiana.

Notes and References

  1. Hatch . Joseph R. . Affolter . Ronald H. . 2002 . Resource assessment of the Springfield, Herrin, Danville, and Baker coals in the Illinois Basin . Professional Paper . 10.3133/pp1625d . 2330-7102. free .
  2. Jackson . Robert F. . 1971 . HYDROLOGY OF THE PRINCIPAL AQUIFERS IN VIGO AND CLAY COUNTIES, INDIANIA . State of Indiana Department of Natural Resources, Division of Water . 34.
  3. Web site: Linton Formation . Indiana Geologic Names Information System . Indiana Geological and Water Survey . 28 June 2021.
  4. Wier . C. E. . Geology and coal deposits of the Jasonville quadrangle, Clay, Greene, and Sullivan Counties, Indiana . U.S. Geological Survey Coal Investigations Map . C1.