GEOLEX

Summary of Citation: Dockum

Publication:
Cummins, W.F., 1890, The Permian of Texas and its overlying
   beds, IN First-fourth annual report of the Geological Survey
   of Texas, 1889-1892: Geological Survey of Texas Annual Report,
   v. 1, p. 185-200

Usage in Publication:
Dockum Beds

Modifications:	Geologic Province:	Dominant Lithology:
Named	Permian basin	Sandstone Conglomerate Clay

Summary:
Named for Dockum, western edge of Dickens Co, TX in Permian basin. No type locality designated. Unconformably overlies the Double Mountain Beds (new, of Permian age); unconformably underlies Blanco Canyon Beds (new, "of much more recent date than the Cretaceous which is found at the foot of the Staked Plains [Llano Estacado] farther southward."). The Trinity sands of the Cretaceous are missing; instead, overlying the Permian beds are pieces of conglomerate and large pebbles of white quartz; these fragments increase in size to west--author found the source beds for this material near Dockum, and named them Dockum Beds. Dockum consists of conglomerate sandstone and red clay. The conglomerate contains many silicified trunks of trees, some of great length. In the red clay above the conglomerate are fossil remains of large reptiles. In the upper sandstone are many casts of a Unio [pelecypod] provisionally called UNIO DOCUMENSIS. The sandstone is everywhere full of scales of mica. Formation lies along the foot of the Staked Plains in a narrow belt. Occurs extensively in vicinity of Dockum, Dickens Co, TX. Thickness of the formation in this vicinity is about 150 ft. These beds extend under the Staked Plains. They were traced up Blanco Canyon to the falls of the White River, where they pass out of sight under the overlying strata. Jura-Trias? in age. [Some information also from Dumble, E. T., Report of the State Geologist, same volume, p. xv-lxxv.]

Summary of Citation: Dockum

Publication:
Gould, C.N., 1907, Geology and water resources of the western
   portion of the Panhandle of Texas: U.S. Geological Survey
   Water-Supply Paper, 191, 70 p.

Usage in Publication:
Dockum group*

Modifications:	Geologic Province:	Dominant Lithology:
Revised	Amarillo arch Palo Duro basin

Summary:
Revised; raised to group rank to include the Trujillo formation (new, upper) and the Tecovas formation (new, lower) in the Panhandle of TX on the Amarillo arch and in the Palo Duro basin. Unconformably overlies the Permian Quartermaster formation and unconformably underlies the Tertiary. Ranges from 82 ft thick on West Amarillo Creek to 410 ft thick on the North Branch of Cita Creek. Presence of vertebrates stated. Mapped (geologic map) as an undivided unit along Palo Duro Creek and its tributaries in Randall Co, TX in the Palo Duro basin and along the Canadian River and its tributaries in Potter and Oldham Cos, TX on the Amarillo arch. Cross sections; measured sections. Of Triassic age.

Summary of Citation: Dockum

Publication:
Parker, B.H., 1933, Clastic plugs and dikes of the Cimarron
   Valley area of Union County, New Mexico: Journal of Geology,
   v. 41, no. 1, p. 38-51

Usage in Publication:
Dockum group

Modifications:	Geologic Province:	Dominant Lithology:
Revised	Sierra Grande uplift

Summary:
Upper contact revised in that Dockum underlies the vari-colored shales and marls of the newly named Sloan Canyon formation or unconformably underlies pink to white, massive, cross-bedded sandstone of the Exeter sandstone, depending on the locality. Sloan Canyon-Dockum contact concealed. In prior reports, Sloan Canyon rocks were thought to belong to the Morrison formation. Name Dockum applied to the 400+ ft thick maroon to purple conglomerate, sandstone, shale sequence interbedded near base with white sandstone that form the lowest exposures in the Cimarron valley in Union Co, NM on the Sierra Grande uplift. Dockum assigned to Triassic?. Stratigraphic chart.

Summary of Citation: Dockum

Publication:
McLaughlin, T.G., 1954, Geology and ground-water resources of
   Baca County, Colorado: U.S. Geological Survey Water-Supply
   Paper, 1256, 232 p.

Usage in Publication:
Dockum group*

Modifications:	Geologic Province:	Dominant Lithology:
Overview	Anadarko basin

Summary:
In Baca Co, CO in the Anadarko basin, Dockum group [undivided in this report] includes all rocks between Taloga formation and Entrada sandstone. Crops out in Carrizo Creek, Cimarron River, and Two Butte Creek. Believed to pinch out eastward a short distance beyond, Point of Rocks, Morton Co, KS in the Anadarko basin. Maximum thickness observed is 50 ft. Base not exposed. Lithology varies. In southwest part of county includes variegated shale, clay, siltstone, and lesser amounts of sandstone and conglomerate. In southeast part of county, beds are predominantly red and sandier, very fine to coarse grained, well sorted, friable, loosely cemented. In northwest part of county beds are mostly dark red to maroon siltstone, sandstone, and gray limestone. The sandstone is hard, quartzitic, fine to coarse grained. One of the limestone beds is crinkly. Geologic map. Cross section. Of Triassic age.

Summary of Citation: Dockum

Publication:
Baldwin, Brewster and Muehlberger, W.R., 1959, Geologic studies
   of Union County, New Mexico: New Mexico Bureau of Mines and
   Mineral Resources Bulletin, no. 63, 171 p.

Usage in Publication:
Dockum group

Modifications:	Geologic Province:	Dominant Lithology:
Revised Overview	Sierra Grande uplift

Summary:
Exposures in Dry Cimarron valley, Union Co, NM on Sierra Grande uplift divided into Baldy Hill formation (new name) at base, Travesser formation (new), Sloan Canyon Formation, and Sheep Pen sandstone at top. Previous workers applied name Dockum to lower red beds (Baldy Hill and Travesser), and called upper rocks Sloan Canyon and Sheep Pen; upper part of Dockum therefore revised in this report to include two younger formations. Lower contact of Dockum not exposed. Dockum was gently folded and eroded before deposition of Exeter sandstone. [Sheep Pen-Exeter contact not distinct at some localities.] Baldy Hill exposed near T32N, Rs32 and 33E and has been recognized in subsurface; Sloan Canyon and Sheep Pen are of local extent; Travesser exposed continuously eastward of T32N, R32E. Is of Late Triassic age (vertebrates). Thought to correlate with Wingate sandstone and upper part of Chinle formation of AZ.

Summary of Citation: Dockum

Publication:
Barnes, V.E., 1967, Geologic atlas of Texas, Lubbock Sheet;
   Halbert Pleasant Bybee memorial edition: University of
   Texas-Austin, Bureau of Economic Geology, 1 sheet, scale
   1:250,000

Usage in Publication:
Dockum Group

Modifications:	Geologic Province:	Dominant Lithology:
Overview	Palo Duro basin Permian basin	Sandstone Clay Shale Conglomerate

Summary:
Is Triassic group mapped in mostly continuous, southward-broadening belt below Caprock Escarpment in west-central part of map sheet in southwest Motley Co, TX (Palo Duro basin) and in western Dickens, southeast and southern Crosby, southeast Lubbock, southeast Lynn, Garza, and western Kent Cos, TX (northeastern Permian basin). Overlies Quartermaster Formation (Permian); overlain by Antlers Sand (Lower Cretaceous). Map unit described as sandstone, clay, shale, and conglomerate. Sandstone, fine- to coarse-grained quartz, micaceous silty, thin-bedded to massive, cross-bedded, well indurated, greenish gray, brownish red. Clay, sandy, silty, reddish brown. Shale, sandy, locally calcareous, indistinctly bedded, various shades of red, green, gray, yellow. Conglomerate of various colored chert pebbles common in lower part; basal conglomerate also contains quartz, sandstone slabs, and petrified wood. Thickness 400+/-ft, locally absent in Motley Co, TX.

Summary of Citation: Dockum

Publication:
Barnes, V.E., 1976, Geologic atlas of Texas, Hobbs Sheet; William
   Battle Phillips memorial edition: University of Texas-Austin,
   Bureau of Economic Geology, 1 sheet, scale 1:250,000

Usage in Publication:
Dockum Group

Modifications:	Geologic Province:	Dominant Lithology:
Overview	Permian basin	Shale Sandstone Siltstone Limestone Gravel

Summary:
Is Triassic group mapped undivided in Eddy and Lea Cos, NM and Andrews, Midland, and Martin Cos, TX (Permian basin). Overlies Dewey Lake Redbeds (Permian); overlain by Antlers Sand (Lower Cretaceous). Map unit described as shale, sandstone, siltstone, limestone, and gravel; mostly shale, micaceous, thin-bedded, variegated; thickness up to 300 ft. Map explanation shows Dockum Group correlative with Chinle Formation (above) and Santa Rosa Sandstone (below) as mapped elsewhere in map sheet. In NM part of map sheet, Chinle Formation mapped in eastern part, Santa Rosa Sandstone mapped in western part, and Dockum Group undivided mapped in southern and western part, as well as in TX. [Chinle and Santa Rosa are formations in the Dockum Group.]

Summary of Citation: Dockum

Publication:
Barnes, V.E., 1983, Geologic atlas of Texas, Tucumcari Sheet;
   Henryk Bronislaw Stenzel memorial edition: University of
   Texas-Austin, Bureau of Economic Geology, 1 sheet, scale
   1:250,000

Usage in Publication:
Dockum Group

Modifications:	Geologic Province:	Dominant Lithology:
Overview	Sierra Grande uplift Palo Duro basin Amarillo arch

Summary:
Is Upper Triassic group with 3 formations mapped separately in this sheet in northeast NM and TX Panhandle (Sierra Grande uplift, Palo Duro basin, and Amarillo arch). Mapped formations are (descending): Chinle Formation--shale, siltstone, sandstone, limestone, and mudstone; Trujillo Formation--conglomerate, sandstone, and shale; and Tecovas Formation--shale, clay, siltstone, and sand. Overlies Quartermaster Formation (Permian); overlain by Exeter Sandstone (Upper Jurassic).

Summary of Citation: Dockum

Publication:
Chatterjee, Sankar, 1986, The Late Triassic Dockum vertebrates;
   their stratigraphic and paleobiogeographic significance,
   Chapter 10, IN Padian, Kevin, ed., The beginning of the age
   of dinosaurs; faunal change across the Triassic-Jurassic
   boundary: Cambridge, UK, Cambridge University Press, p.
   139-150

Usage in Publication:
Dockum Formation

Modifications:	Geologic Province:	Dominant Lithology:
Revised Overview	Permian basin

Summary:
This continental redbed sequence in the Permian basin of eastern NM and western TX was deposited unconformably on Upper Permian and is overlain by Cretaceous, Tertiary, or Quaternary sediments. Ranges in thickness from 70-700 m. A fauna was found in a quarry in Garza Co, TX that includes taxa previously unknown in the Triassic of North America. Age of Dockum thought to extend from late Carnian to early Norian. Reinstated as a formation. Divided into (ascending): Tecovas Member (formerly of formation rank), Trujillo Member (formerly of formation rank), and Cooper Member, a new name replacing use of Chinle Formation of Dockum Group in TX and NM. The name Chinle should not have been used for the upper part of the Dockum because Chinle is equivalent to all of the Dockum--a thought published in several earlier papers. Also Santa Rosa Sandstone should not be considered part of the Dockum. A fossil skull found in the basal bed of the Santa Rosa in the Tucumcari area has long been known from the Holbrook Member of the Moenkopi Formation in AZ. Dockum has phytosaur fossils of Late Triassic age. NICROSAURUS fauna found in Cooper Member in Garza Co and PARASUCHUS found in Tecovas Member. Stratigraphic diagrams.

Summary of Citation: Dockum

Publication:
Staatz, M.H., 1986, Geologic map of the Pine Buttes quadrangle,
   Colfax County, New Mexico: U.S. Geological Survey Geologic
   Quadrangle Map, GQ-1591, 1 sheet, scale 1:24,000

Usage in Publication:
Dockum Formation*

Modifications:	Geologic Province:	Dominant Lithology:
Areal limits	Las Vegas-Raton basin

Summary:
Mapped as a unit of formation rank and of Late Triassic age in central part of Temple Dome in secs 1, 2, 11 and 12, T26N, R26E, Colfax Co, NM in Las Vegas-Raton basin. Is the oldest formation in the quad; only upper part is present. Underlies Exeter Sandstone.

Summary of Citation: Dockum

Publication:
Lucas, S.G., Hunt, A.P. and Hayden, S.N., 1987, The Triassic
   System in the Dry Cimarron Valley, New Mexico, Colorado, and
   Oklahoma, IN Lucas, S.G., and Hunt, A.P., eds., Northeastern
   New Mexico: New Mexico Geological Society Guidebook, no. 38,
   p. 97-117

Usage in Publication:
Dockum Group

Modifications:	Geologic Province:	Dominant Lithology:
Not used

Summary:
Application of term "Dockum Group" rejected for the Baldy Hill, Travesser, and Sloan Canyon Formations, and Sheep Pen Sandstone in the Dry Cimarron valley of Union Co, NM. Name Dockum has been applied, according to these authors, to rocks of various lithologies and to rocks that represent various amounts of Triassic time. Also, Dockum as it was used in Union Co included strata not equivalent to the Dockum of TX.

Summary of Citation: Dockum

Publication:
Finch, W.I., 1988, Description of the principal reference section
   for the Santa Rosa Formation, IN Finch, W.I., ed., Principal
   reference section for the Santa Rosa Formation of Middle and
   Late Triassic age, Guadalupe County, New Mexico: U.S. Geological
   Survey Bulletin, 1804-A, p. 1-10

Usage in Publication:
Dockum Group*

Modifications:	Geologic Province:	Dominant Lithology:
Age modified	Palo Duro basin

Summary:
Basal formation of Dockum Group, the Santa Rosa Sandstone redescribed as Santa Rosa Formation because of its mudstone and conglomerate content in addition to sandstone. Age of Santa Rosa changed from Late Triassic to Middle and Late Triassic on basis of an amphibian skull of Anisian age in the lower sandstone member near Dilia, Guadalupe Co, NM. Plant fossils of Carnian age identified in mudstone member at principal reference section of Santa Rosa at N1/2 sec 1, T8N, R21E and SE1/4 SE1/2 sec 36, T9N, R22E and nearby, Guadalupe Co, NM. Report area is in the Palo Duro basin.

Summary of Citation: Dockum

Publication:
Lucas, S.G. and Hunt, A.P., 1989, Revised Triassic stratigraphy
   in the Tucumcari basin, east-central New Mexico, IN Lucas,
   S.G., and Hunt, A.P., eds., Dawn of the age of dinosaurs in
   the American southwest: New Mexico Museum of Natural History,
   p. 150-170

Usage in Publication:
Dockum Group or Formation

Modifications:	Geologic Province:	Dominant Lithology:
Not used

Summary:
Term not used for Upper Triassic rocks as a group or formation in San Miguel and Guadalupe Cos in east-central NM, Palo Duro basin; was not defined precisely. Term Chinle Formation not used because Upper Triassic rocks of east-central NM were deposited in a separate basin from the Chinle Formation of the Colorado Plateau. The Upper Triassic sequence formerly assigned to the Chinle or Dockum is divided into (ascending): Garita Creek (new), Trujillo (term used in preference to Cuervo, a name coined 65 years after the Trujillo), Bull Canyon (new), and Redonda (raised in stratigraphic rank to formation). Nomenclature chart.