Carlile Shale facts for kids
Quick facts for kidsCarlile Shale
Stratigraphic range: Turonian
|Unit of||Colorado Group (lower); or
|Sub-units||Juana Lopez (CO, NM)
Blue Hill Shale
|Thickness||170–230 feet (52–70 m)|
|Primary||Shale, chalky to carbonaceous|
|Named for||Carlile Spring and Carlile Station, 21 mi west of Pueblo, Colorado|
The Carlile Shale is a Turonian age Upper/Late Cretaceous series shale geologic formation in the central-western United States, including in the Great Plains region of Colorado, Kansas, Nebraska, New Mexico, North Dakota, South Dakota, and Wyoming.
It is composed of marine deposits of the generally retreating phase (hemi-cycle) of the Greenhorn cycle of the Western Interior Seaway, which followed the advancing phase of the same cycle that formed the underlying Graneros Shale and Greenhorn Formation. As such, the lithology progresses from open ocean chalky shale (with thin limestones) to increasing carbonaceous shale to near-shore sandstone. There is a discontinuity between the top of the Carlile and the Niobrara sequence.
Viewing and access
West from mile 195, Interstate 70 leaves the level bench on the Fencepost limestone for low, broad residual hills of Carlile Shale. These low hills are mostly the Fairport Chalk member, its thin limestone beds making it more resistant than the Blue Hill Shale member. In the distance to the northwest, the Fort Hays Limestone escarpment is visible, the slopes of which are grass-covered Blue Hill Shale.
Taking the Yocemento Avenue Exit 153 south, Yocemento lies at the base of the Fort Hays bluffs. Between Yocemento and Ellis, Old Hwy 40 passes over grass-covered slump blocks of Blue Hill Shale. The Codell Sandstone member is not present in this part of the county. 14 miles south of Ellis, on Monroe St./Ellis Ave., a broad slope of blue-gray Blue Hill Shale is exposed; the soil in this area "blew out" during the Dust Bowl; many orange-tinted septarian boulders may be seen from the road.
Upper Turonian series Plesiosaur remains are among the fossils that have been recovered from the strata of its Blue Hill Shale Member in Kansas. The Carlile in eastern South Dakota contains shark teeth, fossil wood and leaves, and ammonites.
History of investigation
The Carlile Shale was first named by Grove Karl Gilbert for exposures at Carlile Spring, located about 21 miles (34 km) west of Pueblo, Colorado. He described it as a medium gray shale, capped with limestone or sandstone, and assigned it to the Benton Group. By 1931, William Walden Rubey and his coinvestigators had mapped it into Kansas and the Black Hills. Rubey also first assigned it to the Colorado Group. C.H. Dane assigned it to the Mancos Shale in New Mexico in 1948.
Carlile Shale Facts for Kids. Kiddle Encyclopedia.