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Introduction > Potash Deposit

The Potash Deposit


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Covering 600 square miles in southern Navajo and Apache counties, the potash deposit is located from 700 to 2,000 feet below the ground surface. It is east of Holbrook and south of Interstate 40, extending across parts of southern Navajo and Apache counties. The thickest parts of the deposit are beneath the Petrified Forest National Park and in surrounding areas.

The deposit is in beds, or horizons, sandwiched between layers of other evaporite minerals. Remaining after sea water flooded the area and then evaporated, the evaporites were deposited in the Upper Supai Formation during the Permian age, millions of years ago.

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The evaporite layers contain halite (sodium chloride, or common table salt). There are also gypsum and anhydrite. Potassium is found primarily in sylvite, but also in sylvinite, carnallite and polyhalite.

The Area Today

The potash horizons are on the northern side of the Holbrook salt basin, which covers 3,500 square miles at the southern edge of the Colorado Plateau, just north of the Mogollon Rim. Today the Holbrook Basin underlies a rural, high desert area located between the forested White Mountains and the White Mountain Apache Reservation on the southern side and Navajo Nation to the north. While the potash deposit is located only in Navajo and Apache counties, the salt basin extends further, into Coconino county to the west and New Mexico to the east. It is bordered by the towns of
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Town of Snowflake from Temple Hill
Holbrook, Joseph City, Winslow, Sanders, Springerville, and Heber. Except for small towns and villages, much of the area is sparsely settled by families living on large parcels, often 40 acres, or tribal land, surrounded by undeveloped grazing land.

Petrified Forest National Park

The richest parts of the deposit are beneath the Petrified Forest National Park. In 2004, the park boundary was expanded as authorized by Congress in the Petrified Forest Expansion Act of 2004, more than doubling the size of the park. The addition lands include state trust, private and BLM land. Due to funding delays, purchases of the addition lands didn’t begin until 2011, and most of the addition lands still are not under the administrative jurisdiction of the National Park Service.

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Petrified Forest National Park
Mineral rights within the original park boundary are owned by the National Park Service and mining there is prohibited, but mining within the addition lands is a possibility. Naturally, environmental impacts of mining in and near the park are a significant concern to many people. The National Parks Conservation Association is taking a lead role in pursuit of these issues.

Outside the new park boundary, there are sections managed by the BLM and state trust land managed by the Arizona State Land Department, as well as privately owned parcels and Navajo, Hopi and Zuni lands.


For More Information

Arizona Has Potash by Steven L. Rauzi, Arizona Geological Survey

Evaporite Deposits of the Permian Holbrook Basin by Peirce and Gerrard (source for the diagrammatic cross-section shown above)

Petrified Forest National Park: General Management Plan Amendment and Environmental Assessment (source for the Subsurface Mineral Ownership map shown below)

Petrified Forest National Park: Park Boundary Expansion

Potash and Related Resources of the Holbrook Basin by Steven L. Rauzi, Arizona Geological Survey (source for the map shown above)
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Petrified Forest
Subsurface Mineral Ownership


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Page Updated: 11-14-2012 Site Map To comment on the content of this page, click on the link below:
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