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.USGS.gov: Mineral resources of the Niobrara and Carlile Formations
History of investigation The Carlile Shale was first named by Grove Karl Gilbert for exposures at Carlile Spring, located about 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.
Description The formation 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. Near the center of the seaway, currents in the remnant shallows sorted skeletal remains into a mass of calcareous sand. The contact between the Carlile Shale and the overlying Niobrara Formation is marked by an unconformity in much of the outcrop area, but where an unconformity is not discernible, the boundary is typically placed at the first resistant, fine-grained limestone bed at the base of the Niobrara Formation.
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Fossil content Upper Turonian series plesiosaur remains are among the fossils that have been recovered from the strata of its Blue Hill Shale Member in Kansas.Jstor.org: "Probable plesiosaur remains from the Blue Hill Shale (Carlile Formation)" in Kansas", Kansas Academy of Science, 2009. The Carlile in eastern South Dakota contains shark teeth, fossil wood and leaves, and ammonites. William A. Cobban and E.A. Merewether (1983), Stratigraphy and paleontology of mid-Cretaceous rocks in Minnesota and contiguous areas. USGS Professional Paper 1253.
Reptiles Crocodyliforms Crocodyliforms Genus Species Location Stratigraphic positionMaterial Notes Images TerminonarisT. cf. T. browni Russell County, Kansas.Fairport Chalk Member.A partial rostrum. A pholidosaur.
Plesiosaurs Plesiosaurs Genus Species Location Stratigraphic positionMaterial Notes ImagesMegacephalosaurusM. eulertiNear Fairport, Kansas.Fairport Chalk Member.A skull & anterior cervical material (FHSM VP-321).A pliosaurid. Plesiosauria Mitchell County, Kansas.Blue Hill Member.Portions of a rib (FHSM VP-17299). May represent a large elasmosaur or pliosaur.
Squamates Squamates Genus Species Location Stratigraphic positionMaterial Notes Images ConiasaurusC. cf. C. crassidens Russell County, Kansas.Fairport Chalk Member.2 incomplete vertebrae (FHSM VP-4418). A dolichosaurid.RussellosaurinaEllis County, Kansas.Middle of the Fairport Chalk Member.7 successive proximal caudal vertebrae (FHSM VP-17564).A russellosaurine mosasaur.
Fish Cartilaginous fish Cartilaginous fish Genus Species Location Stratigraphic positionMaterial Notes ImagesCretodusC. houghtonorumNorth-central Kansas.Blue Hill Shale.A partial skeleton consisting of 134 disarticulated teeth, 61 vertebrae, 23 placoid scales, and fragments of calcified cartilage.A mackerel shark. CretoxyrhinaC. mantelli Dixon County, Nebraska.Fairport Chalky Shale Member.A tooth (UNSM 129549). A large mackerel shark.PtychodusP. latissimusKansas.Codell Sandstone Member.3 teeth.A ptychodontid.P. mammillarisNorth of Schoenchen, Ellis County, Kansas.Fairport Chalk Member.A medial tooth (FHSM VP-15284).A ptychodontid.P. sp.Ellis County, Kansas.Blue Hill Shale Member.A tooth contained in a coprolite (FHSM VP-13325).A ptychodontid.
See also Volcanic mineralization of the Greenhorn cycle: Bentonite, sedimentary volcanic ash (named for the original Graneros/Greenhorn/Carlile classification), generally showing some weathered iron stain in the Colorado Group Pyrite, precipitation of volcanic sulfuric acid with oceanic iron as FeS2 Limonite, pyrite in limestone weathered to HFeO2 (rust stain or yellow ochre) Selenite, CaSO4 associated with Bentonite seams and ochre
Plesiosaur stratigraphic distribution
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