The Coyote Butte Limestone (OR085) is a geologic formation in Oregon. It preserves fossils dating back to the Sakmarian to Kungurian stages of the Permian period,Wardlaw et al., 1982, p.15 spanning an estimated 23 million years.Coyote Butte Formation at Fossilworks.orgCoyote Butte Formation at USGS The formation occurs in isolated buttes to the north; Triangulation Hill, and south; type locality and name giver Coyote Butte and Tuckers Butte, on either side of the Grindstone and Twelvemile Creeks in Crook County, Oregon.Wardlaw et al., 1982, p.14
Description The Coyote Butte Formation was first defined by Merriam and Berthiaume in 1943.Merriam & Berthiaume, 1943 The formation crops out in isolated buttes (Coyote & Tuckers) south and north (Triangulation Hill) of the Grindstone and Twelvemile Creeks in Crook County, central Oregon. The formation comprises an uncommonly unaltered and well-exposed set of Permian shallow marine and reefal limestones in the tectonically complex Permian present-day Pacific margin of western North America.Wardlaw et al., 1982, p.13
The Coyote Butte Formation is represented by isolated limestone hills ( in area), of which most appear to have the same stratigraphic and biostratigraphic sequence and appear to be right-side-up. The resistant limestone blocks stand above the surrounding rocks of the "melange." The Coyote Butte Formation represents shallow-water carbonate-platform deposition and contains a varied faunal assemblage of corals, bryozoans, algae, fusulinids, brachiopods, crinoids, and conodonts.
Paleogeographic situation The formation is dated to the Sakmarian to Kungurian stages of the Early to Middle Permian period, spanning an estimated 23 million years from 296 to 273 Ma. During these times, what is now central Oregon, was located at the edge of Pangea in the northern paleotemperate zone, at paleolatitudes of 16-18° North.
Climate
Tectonics
The hinterland of the carbonate platform where the Coyote Butte Limestone was deposited, was formed by the Arizonan and Utahan arid landscapes of a Pangea starting to break up. This occurred before the Sonoma orogeny was active in western North America and during the Alleghanian orogeny in eastern Laurentia and western Europe.
The 23 million year deposition coincided with impact of the Clearwater West crater, dated at 286.2 ± 2.6 million years ago.Bottomley et al., 1990Schmieder et al., 2014
Paleontological significance
The formation is the only discovered Paleozoic fossiliferous formation in the state of Oregon, and comprises an uncommonly unaltered and well-exposed set of Early to Mid Permian shallow marine and reefal limestones in the tectonically complex Permian present-day Pacific margin of western North America. The formation just predates Olson's Extinction; a mass extinction that occurred in the early Guadalupian of the Permian period and which predated the Permian–Triassic extinction event.Sahney & Benton, 2008
Fossil content
Among others, the following fossils have been reported from the formation:
Brachiopods
?Alexenia occidentalis Anidanthus minor Antiquatonia cooperi Calliprotonia inexpectatum Kochiproductus transversus Krotovia oregonensis ?Marginifera profundosulcata Martinia berthiaumei Probolionia posteroreticulata ?Proboscidella carinata Rostranteris sulcatumCooper, 1957 0 Spiriferella pseudodraschei Stenoscisma cf. plicatum Tiramnia semiglobosa Yakovlevia transversa
Trilobites
Proetida Phillipsiidae Cummingella (Cummingella) sp.
Rostroconchia Conocardiida Conocardiidae Arceodomus sphairikos
Gastropods Prosobranchia Acteoninidae Acteonina permiana
Polyplacophora Neoloricata Acutichitonidae Arcochiton soccus Homeochiton triangularis Gryphochitonidae Gryphochiton planoplata Lepidopleuridae ?Chauliochiton sp. Pterochiton sp. Strobilepidae Diadeloplax apiculatusHanger et al., 2000
Corals
Cystolonsdaleia berthiaumi Petalaxis occidentalis Wilsonastraea ochocoensis Protowentzelella sp.Merriam, 1942
Correlations Geologic correlations
Cisuralian Series Sakmarian formations Artinskian formations Roadian formations Wordian formations Kungurian formations Permian North America Esplanade Sandstone, Grand Canyon Arroyo Formation, Texas Road Canyon Formation, idem Waggoner Ranch Formation, idem Word Formation, idem Cherry Canyon Formation, New Mexico and Texas San Andres Formation, United States, idem Wellington Formation, Kansas and Oklahoma Orby Head Formation, Prince Edward Island Permian South America Carapacha Formation, Argentina Mangrullo Formation, Uruguay Rio Bonito Formation, Brazil Permian Africa Ganigobis Formation, Namibia Gai-As Formation, idem Huab Formation, idem Whitehill Formation, idem Permian Europe Tambach Formation, Germany Treskelodden Formation, Svalbard, Norway Arpinskaya Formation, Caucasus Gnishik Formation, idem
Faunal correlations
See also
List of fossiliferous stratigraphic units in Oregon Alsea Formation, Whitneyan fossiliferous formation in Lincoln County, Oregon John Day Fossil Beds National Monument, Late Eocene to Early Miocene sequence of mammal-rich Lagerstätten: John Day Formation, Duchesnean to Hemingfordian Clarno Formation, Bridgerian to Duchesnean Crooked River caldera, Crook County, Oregon
Sources Notes
References
Bibliography