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The Cleveland Shale, also referred to as the Cleveland Member of the Ohio Shale, is a Late Devonian (Famennian) shale geologic member in the eastern United States.
The remainder of the Cleveland Shale generally consists of a relatively hard, organic rich oil shale. It has both an upper and lower part.
In northeast Ohio, the member does not appear east of the Grand River. Measurements taken in northeast Ohio show the Cleveland Shale to be to thick. It is thickest around the Rocky River north of Berea, Ohio, and thins to the east, west, and south.
The Cleveland Shale is found in east-central Kentucky. In east-central Kentucky, the Cleveland Shale is more uniform in thickness, ranging from , and increases in thickness toward the east.
The unit is also present in West VirginiaRyder, R.T., Swezey, C.S., Crangle, R.D., Jr., and Trippi, M.T., 2008, Geologic cross section E-E'
It is the regional equivalent of the Hangenberg Black Shale and the Bakken Shale.
Faunal list follows Carr and Jackson (2008) and Carr (2018).
The upper 2.5 m of the Cleveland Shale has been chemostratigraphically correlated with the Hangenberg Event and the type stratigraphy in Germany, suggesting that the Cleveland Shale preserves the second of the two mass extinction events that together comprise the late Devonian extinction
The contact between the Chagrin Shale and Cleveland Shale has been described as interbedding. This feature is interpreted as having been caused when two different depositional environments (in this case, the oxygenated sea which laid down the Chagrin Shale and the anaerobic sea rich in organic matter which laid down the Cleveland Shale) moved repeatedly back and forth over the same area. Geologist Horace R. Collins called the boundary area intercalated, but it is unclear what meaning he intended.
Different hypotheses have been suggested as the cause of the regional, irregular contact between the Cleveland Shale and Bedford Formation. Charles E.B. Conybeare has noted that the Cleveland Shale is siltier in the east and more calcareous in the west. He hypothesized that this indicates that silt flowed into the sea from east to west. Current eroded the Cleveland Shale and then laid down new sediment in the gullies which became the Bedford Formation. Jack C. Pashin and Frank R. Ettensohn proposed a variation on this hypothesis. They note that the region containing the Cleveland Shale was undergoing uplift when the Bedford Formation was being deposited. This likely led to exposure and erosion of the Cleveland Shale, with sediment which became the Bedford Formation filling in these Gully. They also observe that there is evidence of (the intrusion of deformable Cleveland Shale upward into the more brittle Bedford Formation), as well as intertonguing. Baird et al. note that the Cleveland Shale also tilts downward to the south. They suggest that this caused overstepping, rather than intertonguing.
/ref> and in southwest Virginia,Ryder, R.T., Trippi, M.H., and Swezey, C.S., 2015, Geologic cross section I-I'
/ref> where it is mapped as the Cleveland Member of the Ohio Shale.
Stratigraphic setting
The Cleveland Shale (or Cleveland Member) is a sub-unit of the Ohio Shale Formation. The Chagrin Shale underlies the Cleveland Shale. The Bedford Shale generally overlies the Cleveland Shale, with a sharp distinction between the two. In west-central Ohio, more than of Bedford Shale may lie above the Cleveland Shale. In places, red and grey shale may intertongue (interlock) with the Cleveland Shale extensively. In far eastern Ohio, the Bedford Shale thins by more than . Where the Cussewago Shale is also present, the Bedford Shale is usually less than and may be locally absent. In some areas, the Cleveland Shale is described as or Unconformity overlaid gradationally by Berea Sandstone and sharply by Berea Sandstone.
Paleobiota
Exceptional marine animal are found in the member. The Cleveland Shale is generally considered to be fossil-poor, but there are exceptions. The basal pyrite layer contains petrified wood and fossilized fish bones. The lower part is famous for its extensive and well-preserved fossil Chondrichthyans (including Cladoselache), , Placodermi, and palaeoniscinoids ray-finned fishes. The giant predatory placoderms Dunkleosteus, Gorgonichthys, Gymnotrachelus, Heintzichthys, and five species (including the type specimen) of Titanichthys were all discovered in the Cleveland Shale. The Cleveland Shale is classified as a konservatte-lagerstatten, which means it often preserves complete body fossils. Typical early shark preservation includes soft tissue outlines and impressions, fin rays, gill musculature, cartilage, and stomach contents. Placoderms in the Cleveland Shale typically do not show any good soft-tissue preservation.
Placodermi
All placoderms in the Cleveland Shale are Arthrodira.
Bungartius B. perissus A medium-sized Mylostomatidae with a relatively low and narrow skull and a presumably Durophagy diet. Callognathus C. regularis A rare possible Selenosteidae based on small jaw plates. "Coccosteus" "C." cuyahogae A rare Coccosteomorphi of uncertain affinities, based on a single jaw plate. Not necessarily a close relative of more complete and better-described species of Coccosteus. Diplognathus D. mirabilis A somewhat large Aspinothoracidi with narrow serrated jaws. Dunkleosteus D. terrelli A very large Dunkleosteidae with a massive bite force and an apex predator niche. The most famous placoderm in general, as well as one of the largest and most common fish in the Cleveland Shale. Previously considered a species of Dinichthys. Glyptaspis G. verrucosa
A rare arthrodire of uncertain affinities, known from a few roughly-textured belly plates. Gorgonichthys G. clarki A very large aspinothoracid, similar in size and ecology to Dunkleosteus. Previously considered a species of Dinichthys. Gymnotrachelus G. hydei A selenosteid with a low, broad skull and small tooth-like denticles along the jaw. Heintzichthys H. gouldii An aspinothoracid with a boxy skull. Previously considered a species of Dinichthys. Hlavinichthys H. jacksoni An aspinothoracid. Holdenius H. holdeni An aspinothoracid similar to Heintzichthys, though with a deeper jaw. Hussakofia H. minor A small dunkleosteid with a very short, deep jaw. Mylostoma M. eurhinus A mylostomatid with a very broad skull. M. newberryi M. variabile Paramylostoma P. arcualis A small selenosteid with a narrow skull. Selenosteus S. brevis A small selenosteid with a broad skull. Stenosteus S. angustopectus A small selenosteid similar to Selenosteus, with a broad skull. S. glaber Titanichthys T. agassizi A very large Filter feeder mylostomatid based on multiple species, some of which may be synonyms. The second most common placoderm in the Cleveland Shale after Dunkleosteus terrelli. Titanichthys hussakofi was formerly known as Brontichthys clarki. T. attenuatus T. clarkii T. hussakofi T. rectus Trachosteus T. clarki A rare possible selenosteid known from a few armor fragments.
Chondrichthyes
Other undescribed Chondrichthyes (cartilaginous fish) from the Cleveland Shale include a cladoselachian, a cochliodont, a Eugeneodontida, a Hybodontiformes, Stethacanthidae (including a new species of Stethacanthus), Sphenacanthus, and several additional forms represented by unique head and fin spines. A conference abstract by Hlavin (1972) briefly mentioned associated assemblages of teeth ( Orodus sp.) and fin spines ( Ctenacanthus vetustus); Zangerl (1981) suggested that each assemblage represented an early hybodont with Orodus-like teeth and ctenacanth-like spines.
Cladoselache C. acanthopterygius A common shark-like predator with large eyes, cladodont teeth, a broad mouth at the front of the head, a robust dorsal fin spine, a streamlined body, and a tall caudal fin with wide keels on the tail stalk. Ecologically similar to Isurus, though not closely related to any modern shark. Potentially a Symmoriiformes (close to Stethacanthus) and/or an early Holocephali (distantly related to modern Chimaera). Many Cladoselache species have been named based primarily on subtle variation in fin structure, though some will likely turn out to be invalid or synonymous upon reinvestigation. The two most frequently mentioned species are C. fyleri (the type species, which is rather small) and C. kepleri (a larger species). C. brachypterygius C. clarki C. desmopterygius C. eastmani C. fyleri C. kepleri C. magnificus C. newberryi C. pachypterygius Ctenacanthus C. concinnus A ctenacanthiform shark with many named species, some of which appear to be synonymous with others. Some ctenacanth species named from the Cleveland Shale are based on fin spines ( C. compressus, C. clarki, C. vetustus), while others ( C. concinnus, C. terrelli, C. tumidus) are based on cladodont teeth. Specimens preserving both teeth and fin spines demonstrate that C. concinnus, C. compressus, and C. clarki are probably all the same species, with C. concinnus taking priority. As a result, C. concinnus is regarded as the Cleveland Shale ctenacanth with the best-preserved specimens (formerly referred to the spine-based species). C. tumidus may be the largest shark in the member based on the size of its teeth. C. terrelli C. tumidus C. vetustus? Diademodus D. hydei A possible Phoebodontidae with a distinct rostrum, small fins, and minute many-cusped teeth. Monocladodus M. clarki A Cladoselachidae very similar to Cladoselache. Primarily distinguished by some of its cladodont teeth being single-cusped, though multi-cusped teeth are also present in the jaw. There is disagreement over whether it should be treated as a valid distinct genus or not. Orodus O. spp. (x3) At least three undescribed species of Orodontidae known from broad crushing teeth. Complete Orodus specimens from Late Carboniferous Indiana have a long body and small fins. Phoebodus P. politus A phoebodontid known from small teeth with three main cusps. Complete Phoebodus specimens from Late Devonian Morocco are similar in proportion to modern Frilled shark. Stethacanthus S. altonensis A Stethacanthidae symmoriiform with cladodont teeth, extensive denticles on the head and an unusual "spine-brush complex". S. carinatus Tamiobatis T. vetustus A ctenacanthiform shark preserving both skull cartilage and cladodont teeth.
Osteichthyes
Other undescribed Osteichthyes (bony fish) from the Cleveland Shale include a new species of Kentuckia and an unnamed Mesopoma-like palaeoniscoid.
Kentuckia K. hlavini A palaeonisciform Actinopterygii (ray-finned fish). Proceratodus P. wagneri A lungfish. The only sarcopterygian (lobe-finned fish) currently recorded from the Cleveland Member. Tegeolepis T. clarki A palaeonisciform actinopterygian.
Age
The Cleveland Shale is approximately 362.6 to 360.1 million years old, daing to the very latest part of the Devonian period, the Famennian, (2026). 9780128243602 ISBN 9780128243602 based on biostratigraphy from conodonts and plant spores. The Cleveland Shale extends all the way to the Hangenberg Event that ended the Devonian but does not reach the very end of the Devonian period. Unlike the Permian-Triassic extinction and Cretaceous-Paleogene extinction the Devonian-Carboniferous boundary does not correlate with the mass extinction event at the end of this period. The Bedford Shale and Berea Sandstone represent Devonian layers that post-date the Devonian-Carboniferous extinction but were deposited on top of the Cleveland Shale, and encompass some of the recovery fauna otherwise typical of the Carboniferous in the aftermath of the Hangenberg Event.
Interpretation of depositional environments
The Cleveland Shale is likely the regional expression of the Dasberg Event, a major extinction event that occurred near the end of the Devonian period.
The Cleveland Shale is interpreted as having accumulated in an anaerobic environment. Evidence exists to suggest that the Cleveland Shale was laid down during the Dasberg event, an Upper Famennian extinction event that devastated land-based flora and marine-based fauna. This led to a significant drop in marine oxygen (an anoxic event) and atmospheric carbon dioxide,
and then a brief Glacial period. The global environment recovered, only to suffer another extinction, the Hangenberg event, close to the Devonian-Carboniferous boundary. While the Cleveland Shale was being deposited, extensive organic matter from the land was swept into the sea then lying over Ohio. Although there is dispute over how deep this sea was, the Dasberg event meant that oceans could support few to no bottom-dwelling animals. This explains why the Cleveland Shale largely lacks fossils of benthic organisms and has a high carbon content that colors the shale very dark gray to black.
Economic geology
The high organic content of the Cleveland Shale makes it eminently suitable for the formation of fossil fuels. One 1981 study found that the Cleveland Shale can yield an average of of petroleum per of rock. The Cleveland Shale also contains cannel coal and "true" coal, although neither in great quantity.
See also
Bibliography
Categories: Stratigraphy Of Ohio, Stratigraphy Of Kentucky, Devonian System Of North America, Devonian Pennsylvania, Famennian Stage, Devonian Ohio, Devonian Kentucky, Shale Formations Of The United States, Open Marine Deposits, Source Rock Formations, Formations, Devonian Southern Paleotemperate Deposits, Lagerstätten, Fossiliferous Stratigraphic Units Of North America, Paleontology In Ohio, Geologic Members Of The United States
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