Bentonitic clay deposit, Winslow, Winslow Mining District, Navajo Co., Arizona, USAi
|Regional Level Types|
|Bentonitic clay deposit||Occurrence|
|Winslow||- not defined -|
|Winslow Mining District||Mining District|
A bentonite occurrence located in sec. 11, T20N, R17E, G&SRM, 21.9 km (13.6 miles) NE of Winslow, on private land.
Local rocks include rocks of the Chinle Formation.
Regions containing this locality
|North America Plate||Tectonic Plate|
|Colorado Plateau, USA||Plateau|
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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. 
201.3 - 237 Ma
|Petrified Forest Member|
Age: Late Triassic (201.3 - 237 Ma)
Stratigraphic Name: Petrified Forest Member
Description: Purple, blue, light-red, red-purple, and gray-blue, slope-forming mudstone and siltstone, interbedded with white to yellow-white, coarse-grained, lenticular sandstone. Includes lenticular alluvial stream-channel features that exhibit large-scale, low-angle trough-crossbedding. Petrified logs and petrified-wood fragments are common in white or yellow-white sandstone beds. Blue and red claystone beds weather into rounded hills or slopes that have rough, puffy, popcorn-like surfaces owing to swelling clay. Contact with the underlying Shinarump Member (^cs) is gradational and is arbitrarily placed at lithologic and topographic change from claystone and siltstone slopes of unit to coarse-grained conglomeritic sandstone ledges of the Shinarump Member. Thickness, 107 to 131 m (350 to 430 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. 
|Norian - Carnian|
208.5 - 237 Ma
Age: Late Triassic (208.5 - 237 Ma)
Stratigraphic Name: Chinle Formation
Description: Colorful mudstone, such as in the Painted Desert, and less abundant lenses of sandstone and conglomerate, deposited by a large river system. This unit typically is eroded into badlands topography and contains clays that are prone to shrinking and swelling. (210-230 Ma)
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.