Toltec Divide Area Gypsum deposit, Winslow, Winslow Mining District, Navajo Co., Arizona, USAi
|Regional Level Types|
|Toltec Divide Area Gypsum deposit||Workings|
|Winslow||- not defined -|
|Winslow Mining District||Mining District|
A former gypsum occurrence/mine located in secs. 15, 16 & 21, T19N, R15E, G&SRM, 0.3 km (0.2 mile) ENE of LeChee and 5.2 km (3.3 miles) WNW of Winslow, astride the Coconino County line along Interstate highway 40, on National Forest land.
Mineralization is a surface, sedimentary gypsum deposit. The ore body is 1.22 meters thick. Ore occurs irregularly and is hosted in Permian red sandstone and Late Triassic shale of the Moenkopi Formation, and is comprised of almost alabaster-like gypsum on surface and veinlets of satin spar with a slight greenish tinge. The gypsum beds are flat-lying and overlay red shale and underlie green shale. The deposit extends nearly 5 miles south from the railroad in a belt that is more than 1 mile wide in places. Produced during the period 1909-1914. Operated by the Acme Cement and Plaster Co. and the Navajo Gypsum and Fertilizer Co. The USGS MRDS database stated accuracy for this location is 2,000 meters. Local rocks include rocks of the Moenkopi Formation. NOTE: Deposit extends into Coconino County.
There was considerable production. The quarry is worked out. Material was shipped tom California for cement, plaster and agricultural use.
The grade and amount of resources remain unknown.
Regions containing this locality
|North America Plate||Tectonic Plate|
|Colorado Plateau, USA||Plateau|
Select Mineral List TypeStandard Detailed Strunz Dana Chemical Elements
Commodity ListThis is a list of exploitable or exploited mineral commodities recorded at this locality.
1 valid mineral.
Rock Types Recorded
Select Rock List TypeAlphabetical List Tree Diagram
Detailed Mineral List:
| ⓘ Gypsum|
Formula: CaSO4 · 2H2O
Description: As a bed 4 inches to 4 feet thick, avg. 18 inches.Occurs as a bed in red shale & sandstone of Moencopi formation (includes satin spar variety).
Reference: Galbraith, F.W. & Brennan (1959), Minerals of AZ: 60.; Stone, R.W. (1920), Gypsum deposits of the United States, USGS Bulletin 697: 51-52.; Keith, S.B. (1969), Gypsum, in USGS & Arizona Bureau of Mines, and U.S. Bureau of Reclamation 1969, Mineral and water resources of Arizona, Arizona Bureau of Mines Bulletin 180.
| ⓘ Gypsum var: Selenite|
Formula: CaSO4 · 2H2O
Description: Mined as large plates in upper member Permian Supai Formation.
Reference: Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 242; Peirce, H.W. & T.A. Gerrard (1966), Evaporite deposits of the Permian Holbrook Basin, AZ, 2nd. Symposium on Salt. Northern Ohio Geological Soc., Inc. 1: 1-10; Stone, R.W. (1920), Gypsum deposits of the US, USGS Bull. 697: 51; Galbraith, F.W. & Brennan (1959), Minerals of AZ: 60.
List of minerals arranged by Strunz 10th Edition classification
|Group 7 - Sulphates, Chromates, Molybdates and Tungstates|
|ⓘ||Gypsum||7.CD.40||CaSO4 · 2H2O|
|ⓘ||var: Selenite||7.CD.40||CaSO4 · 2H2O|
List of minerals arranged by Dana 8th Edition classification
|Group 29 - HYDRATED ACID AND NORMAL SULFATES|
|ⓘ||Gypsum||220.127.116.11||CaSO4 · 2H2O|
|Unclassified Minerals, Mixtures, etc.|
|ⓘ||var: Selenite||-||CaSO4 · 2H2O|
List of minerals for each chemical element
|H||ⓘ Gypsum||CaSO4 · 2H2O|
|H||ⓘ Gypsum (var: Selenite)||CaSO4 · 2H2O|
|O||ⓘ Gypsum||CaSO4 · 2H2O|
|O||ⓘ Gypsum (var: Selenite)||CaSO4 · 2H2O|
|S||ⓘ Gypsum||CaSO4 · 2H2O|
|S||ⓘ Gypsum (var: Selenite)||CaSO4 · 2H2O|
|Ca||ⓘ Gypsum||CaSO4 · 2H2O|
|Ca||ⓘ Gypsum (var: Selenite)||CaSO4 · 2H2O|
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
|Early Jurassic - Late Triassic|
174.1 - 237 Ma
|Mesozoic sedimentary rocks|
Age: Mesozoic (174.1 - 237 Ma)
Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529. 
|Carnian - Anisian|
227 - 247.2 Ma
Age: Triassic (227 - 247.2 Ma)
Stratigraphic Name: Moenkopi Formation
Comments: Original map source: Arizona Geological Survey, DI-8 Geologic Map of Arizona, Digital Spatial data for the Geologic Map of Arizona, v. 3.0, edited by S.M. Richard and S.M. Kneale, 2002, 10 p., 2 DOS HD disks. Arc/INFO export file (.e00) format, scale 1:1,000,000.
Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052. 
|Middle Triassic - Early Triassic|
237 - 251.902 Ma
|Holbrook and Moqui Members, undivided|
Age: Triassic (237 - 251.902 Ma)
Stratigraphic Name: Holbrook Member; Moqui Member
Description: Reddish-brown, slope-forming, alternating sequence of claystone, siltstone, and sandstone (McKee, 1954). Includes large- to medium-scale trough-crossbedding and abundant cusp-type ripple marks that testify to isolated fluvial-channel origin of the Holbrook Member; meander channels of the Holbrook Member are easy to recognize on 1:24,000-scale color aerial photographs between Winslow and Leupp. Commonly also includes sandstone and siltstone beds of the Moqui Member, making it an undivided map unit. Includes interbedded thin-bedded limestone, conglomeratic sandstone lenses, and gypsiferous siltstone and numerous gypsum veins in the Moqui Member. Thickness, about 25 to 37 m (80 to 120 ft)
Comments: Moenkopi Formation (Middle? and Lower Triassic)—Red, slope-forming, fine-grained, thin-bedded, shaley siltstone and sandstone. Includes the following two subunits, in ascending order: the lower massive sandstone member, and the undivided Holbrook and Moqui Members. The lower massive sandstone member also includes the Wupatki Member of the Moenkopi Formation (McKee, 1954) because it generally is less than 4.5 m (15 ft) thick and pinches out in southwest quarter of quadrangle just west of Winslow (sheet 1). Overall, unit has unconformable contact with the underlying Kaibab Formation (Pk), representing regional Permian–Triassic unconformity. Thickness, 67 m (220 ft)
Reference: Billingsley, G.H., D. Block, and M. Hiza Redsteer. Geologic map of the Winslow 30’ × 60’ quadrangle, Coconino and Navajo Counties, northern Arizona. U.S. Geological Survey Scientific Investigations Map 3247.