GEOLEX

Summary of Citation: Merkel

Publication:
Wrather, W.E., 1917, Notes on the Texas Permian: Southwestern
   Association of Petroleum Geologists Bulletin [now American
   Association of Petroleum Geologists], v. 1, p. 93-106

Usage in Publication:
Merkle Dolomite

Modifications:	Geologic Province:	Dominant Lithology:
Named	Bend arch	Dolomite Shale

Summary:
Named for a station on the Texas and Pacific RR, just west of exposure, Taylor Co, TX on Bend arch [Wrather misspelled town name, which is Merkel--name of this dolomite is Merkel in subsequent reports]. No type locality designated. The Merkle is traced across country and used to correlate two measured sections: first section is along Texas and Pacific RR from Abilene (Taylor Co, Bend arch) to Sweetwater (Nolan Co, Permian basin); the second section is along Double Mountain Fork of Brazos River from Flat Top Mountain (Haskell Co, Bend arch) to top of Double Mountains (Stonewall Co, Permian basin). Merkle is 7 ft thick with a 3-ft shale parting at the first section; it is 8 ft thick with a 4-ft shale parting at the second section. Contains disseminated silica and no traces of organic structure. Shallow-water sedimentary structures are beautifully preserved in the beds: fossil rain drops, sun cracks, and small ripple marks in fine sand. Merkle is characteristically ripple marked and weathers into thin plates, much after the fashion of cross-bedded sandstones. In both measured sections red clay overlies Merkle, succeeded by Blowout Mountain Sandstone (new). Merkle occurs at top of "Clear Fork Beds." Is of Permian age. Measured sections.

Summary of Citation: Merkel

Publication:
Beede, J.W. and Waite, V.V., 1918, The geology of Runnels County:
   University of Texas Bulletin, no. 1816, 64 p.

Usage in Publication:
Merkel dolomite [member]

Modifications:	Geologic Province:	Dominant Lithology:
Revised	Bend arch

Summary:
"Merkle Dolomite" of Wrather (1917) revised--name changed to Merkel (true spelling of town unit was named for) and unit included in newly named Choza formation, highest formation in Clear Fork stage [author does not use term "member", but this relationship with Choza is implied]. Merkel is highest dolomite in Choza formation. Choza formation includes the rocks from the top of the Bullwagon dolomite to the San Angelo beds of Lerch (1890). Choza consists of a series of red shales separated by groups of thin dolomite beds, some of which are fossiliferous. With the exception of the Merkel, these dolomites all disappear before reaching the Texas and Pacific RR in Taylor Co, TX (Bend arch) and their position is occupied by shales. Merkel is correlated with the Taylor Co locality by Riney [no reference given]. Thickness of Choza on the Colorado River is about 870 ft. Section measured at Choza Mountain, Coke Co, TX--barely across the Runnels Co line. There are 270 ft of shales with thin sheets of dolomitic limestone above the top of the Merkel. Generalized geologic map (not mapped separately). Measured section. Assigned to Clear Fork stage (Permian).

Summary of Citation: Merkel

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:
Merkel Dolomite

Modifications:	Geologic Province:	Dominant Lithology:
Areal limits Overview	Permian basin	Dolomite

Summary:
Is Permian unit [unranked; member?] mapped separately at top of Choza Formation (Permian) along southeastern margin of map sheet south of Brazos River in southeastern Stonewall Co, TX (northeastern Permian basin). Feathers out northeastward; is not mapped north of Salt Fork Brazos River. Dolomite is not described; thickness is not given. Choza Formation described as shale and sandstone interbedded; thickness 100 ft.

Summary of Citation: Merkel

Publication:
Barnes, V.E. (project director), 1987, Geologic atlas of Texas,
   Wichita Falls-Lawton Sheet; Alfred Sherwood Romer memorial
   edition: University of Texas-Austin, Bureau of Economic
   Geology, 1 sheet, scale 1:250,000

Usage in Publication:
Merkel Dolomite [Member]

Modifications:	Geologic Province:	Dominant Lithology:
Areal limits	Permian basin Palo Duro basin

Summary:
Area of report is north-central TX, approximately between the Brazos and Red Rivers; in this area the Choza, Vale, and Arroyo Formations of Clear Fork Group of the Colorado River Valley of TX are not distinguishable. [Author maps Clear Fork Group undivided, except for "Merkel Dolomite" and "Bullwagon Dolomite", some sandstone beds, and "Lytle Limestone". Listed in descending order: Merkel is topmost member of Choza Formation, Bullwagon is topmost member of Vale Formation, and Lytle is a middle member of Arroyo Formation, all of Clear Fork Group of the Colorado River Valley.] Merkel is described as: "light gray to white, fine grained, medium to thick bedded with solution cavities and ripple marks throughout; channeled out by San Angelo sandstones immediately west of map area; forms prominent escarpment; thickness 3-6 feet." Merkel is mapped in: Hardeman and Foard Cos, Palo Duro basin, and Knox and Haskell Cos, Permian basin. Assigned to the Leonard Series (Early Permian). Geologic map.