Hicks Dome REE-Th prospects (Henry Hamp; Jr. No. 1 Oil Test Well; and other prospects), Hicks Dome, Hicks, Hardin Co., Illinois, USA
|Latitude & Longitude (WGS84):||37° 31' 56'' North , 88° 22' 20'' West|
|Latitude & Longitude (decimal):||37.53221,-88.37216|
|Other regions containing this locality:||Illinois-Kentucky Fluorspar District, Illinois/Kentucky, USA|
Commodities (Major) - Thorium, Fluorine-Fluorite, REE
Development Status: Occurrence
Structure: New Madirio Fault Zone, 38th Parallel Lineament, Hicks Dome - An Incipient Cryptovolcanic Structure
Host Rock: Sedimentary Breccia
The dome-shaped structure, approximately 14.5 km (9 mi) in diameter, was formed by the displacement of sedimentary rocks at least 1,200 m (3,940 ft) upward above an alkaline intrusion at depth. More than 600 m (1,970 ft) of sedimentary rocks, mostly limestone, were pushed up by the explosive intrusion of magmatic fluids. A hole drilled near the apex of the dome (Brown and others, 1954) intersected a mineralized breccia at a depth of 490 m (1,607 ft), which continues to the bottom of the hole at 897 m (2,944 ft). Mineralization in the breccia contains thorium and rare earth elements, tentatively identified as residing in monazite, and is found in association with florencite, a cerium-aluminum phosphate; gangue minerals are fluorspar, calcite, quartz, minor pyrite, and traces of sphalerite and galena.
8 valid minerals.
Rock Types Recorded
Select Rock List TypeAlphabetical List Tree Diagram
Entries shown in red are rocks recorded for this region.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
|Famennian - Givetian|
358.9 - 387.7 Ma
|New Albany Shale, Blocher Shale, Sylamore Sandstone, Selmier Shale, Sweetland Creek Shale, Grassy Creek Shale, Saverton Shale, and Louisiana Limestone|
Age: Devonian (358.9 - 387.7 Ma)
Comments: Thickness from stratigraphic columns: New Albany Sh (0-460’) in southern Illinois (south of 40 degrees north latitude); New Albany Fm (0-300’) in northern Illinois (north of 40 degrees north latitude). Based on the stratigraphic columns, the New Albany Shale in southern Illinois is part of the Knobs Group and is comprised, from oldest to youngest, of the Sylamore Ss, "Hardin", Blocher Sh, Selmier Sh, Sweetland Creek Sh, Grassy Creek Sh, Saverton Sh, Louisiana Ls, Glen Park, and Hannibal Sh, and the New Albany Fm [sic] in northern Illinois is comprised, from oldest to youngest, of the Sylamore Ss, Grassy Creek-Sweetland Creek Sh undiff, Saverton Sh, and Hannibal Sh. [Oil well drillers' terms shown in quotation marks.] [*Note that the description of the map unit DMna in the map legend does NOT include the Mississippian-age Glen Park and Hannibal Shale -- they are mapped as a separate unit, Mk. The GIS (Esri shapefile IL_Geologic_Units_500K_2005_Py) uses 'Dmna ' to represent just the Devonian part of the New Albany Shale.]
Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052. 
TRACE, R.D., 1960, SIGNIFICANCE OF UNUSUAL MINERAL OCCURRENCE AT HICKS DOME
USGS Open File report 2010-5220.