Twin Peaks quarry (Rillito Cement Plant quarry; Rillito Quarry), Twin Peaks, Amole District, Tucson Mts, Pima Co., Arizona, USAi
|Regional Level Types|
|Twin Peaks quarry (Rillito Cement Plant quarry; Rillito Quarry)||Quarry|
|Twin Peaks||Group of Peaks|
|Amole District||Mining District|
|Tucson Mts||Mountain Range|
|Latitude & Longitude (WGS84):||32° 21' 20'' North , 111° 11' 26'' West|
|Latitude & Longitude (decimal):||32.35556,-111.19056|
|USGS MRDS Record:||10060229|
|Köppen climate type:||BSh : Hot semi-arid (steppe) climate|
Ref.: Wilson, E.D. & G.H. Roseveare (1949), Arizona Nonmetallics, A Summary of Past Production and Present Operations, 2nd. Edition (revised), Arizona Bureau of Mines Bull. 155: 13.
Keith (1969): 389, 390, and 397.
Keith, Stanton B. (1974), AZ Bur. of Geol. & Min. Technology, Geol. Survey Br. Bull. 189, Index of Mining Properties in Pima County, AZ: 103 (Table 4).
Elevatorski, E.A. (1978), Arizona Industrial Minerals, Arizona Department of Mineral Resources, Minerals Report No. 2: 49.
Directory of Active Mines in Arizona, Arizona Department of Mineral Resources (1983), Sep. 1983.
Kupferman, S.A. (1987) The Geology of Cement Raw Materials: Pacific Southwest, in: Peirce, H.W., editor, Proceedings of the 21st. Forum on the Geology of Industrial Minerals: Arizona Bureau of Geology and Mineral Technology, Geological Survey Branch Special Paper 4: 37-43.
Phillips, K.A. (1987), Arizona Industrial Minerals, 2nd. Edition, Arizona Department of Mines & Minerals Mineral Report 4, 185 pp.
Peirce, H. Wesley (1990), Arizona Geological Survey Industrial Minerals card file.
Phillips, K.A., Beard, R.R., Niemuth, N.J., and Bain, D.R. (1991) Active Mines in Arizona – 1992: Arizona Department of Mines and Mineral Resources Directory 39, 20 pp.
Houser, B.B. (1992) (editor) Industrial Minerals of the Tucson Area and San Pedro Valley, Southeastern Arizona: Tucson, Arizona. Arizona Geological Society Field Trip, April 4-5, 1992, Guidebook, 55 pp.: 23-36.
Arizona Bureau of Mines file data.
MRDS database Dep. ID file #10060229, MRDS ID #TC10196; and, Dep. ID #10210571, MAS ID #0040190433.
A limestone and shale quarry located in South-central sec. 26, T.12S., R.11E, 2 miles NE of Avra. Owned and operated at times, or in part, by the Arizona Portland Cement Co. division of the California Portland Cement Co.
Mineralization is folded and faulted Mississippian Escabrosa, Horquilla Limestone, and Pennsylvanian-Permian Naco Group limestone. The limestone is typically siliceous and contains zones of dolomitic limestone, quartzite, and siltstone. The limestone contains sufficient silica that no additional source of silica is needed for Portland cement production. The Horquilla limestone typically consists of fine-grained, light yellowish gray limestone interbedded with shaley or silty limestone. The Escabrosa limestone consists of white to light gray limestone in the upper and middle parts of the formation and light to dark gray dolomite and limestone in the lower section. The Martin formation consists mostly of very fine- to fine-grained, laminated to thin-bedded, and medium-dark gray to olive-gray dolomite.
Workings include a quarry operation. More than 14,000,000 tons of rock have been mined for cement manufacture.
Material that is too high in silica or more than 6% MgO is crushed, sized, and sold as aggregate. The limestone is used at the Rillito cement plant, which has an annual capacity of 1.1 million tons.
The quarry is 5 miles from the plant, which is at 32-24-49N, 111-08-16W (SEC 5, T12S, R12E). Production capacity is 1.1 million short tons of cement per year. The deposit is selectively mined to produce a low magnesia, controlled-silica limestone.
Regions containing this locality
|North America Plate||Tectonic Plate|
|Sonoran Desert, North America||Desert|
List of minerals for each chemical element
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
|Quaternary - Miocene|
0 - 23.03 Ma
|Cenozoic sedimentary rocks|
Age: Cenozoic (0 - 23.03 Ma)
Lithology: Sedimentary rocks
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. 
|Olenekian - Ediacaran|
247.2 - 635 Ma
|Paleozoic sedimentary rocks|
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.