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Hopi Buttes volcanic field, Hopi Buttes Mining District, Navajo Co., Arizona, USAi
Regional Level Types
Hopi Buttes volcanic field- not defined -
Hopi Buttes Mining DistrictMining District
Navajo Co.County

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Latitude & Longitude (WGS84):
35° 28' 3'' North , 110° 11' 29'' West
Latitude & Longitude (decimal):
Nearest Settlements:
Indian Wells255 (2011)11.9km
Dilkon1,184 (2011)14.9km
White Cone817 (2011)18.9km
Tees Toh448 (2011)19.7km
Seba Dalkai136 (2011)23.5km

Hopi Buttes volcanic field is a monogenetic volcanic field located on the Colorado Plateau mostly on the Navajo Reservation around the town of Dilkon in northeastern Arizona north of Holbrook.

The volcanic field covers an area of approximately 965 square miles (2,500 km2) and contains about 300 maars and diatremes.

The Hopi Buttes dominate the landscape north of Holbrook, Arizona, commonly rising to heights of 180 meters above the surrounding countryside. The buttes are underlain by individual diatremes, or in some cases by a complex of diatremes. Some sediment-filled diatremes also crop out as inconspicuous low hills (some may also be buried beneath the alluvium). The diatremes erupted into the late Miocene-early Pliocene Hopi Lake. No region in the world is known to contain a greater density of diatremes than the Hopi Buttes, where more than 300 diatremes occur within about 2500 km2. The diatremes of the Hopi Buttes are somewhat unique; they, along with few others, most notably the Miocene diatremes of the Schwabian Alb, formed maars in which lacustrine sediments accumulated. These lacustrine sediments were the hosts for syngenetic uranium mineralization. The funnel-shaped vents are filled with limburgite tuff and tuff breccia, agglomerate, monchiquite dikes, necks, and flows, fine-grained clastic and carbonate rocks, and blocks of sedimentary rocks, especially the Wingate Sandstone, derived from the vent walls.

The erosional exposure of the deposits varies with those in the eastern portion exhibiting the shallowly eroded maar deposits and those in the western portion the more deeply eroded feeder diatremes. The maars result from explosive interaction of the hot diatreme material with the groundwater system and result in a mixture of volcanic tuff material and sediments of the Miocene–Pliocene lacustrine sediments of the Bidahochi Formation. In the western portion of the field the buttes consist of the feeder diatremes of monchiquite and nepheline syenite magmas.

Most of the volcanic activity occurred between 8.5 and 6 million years ago, with the most recent dated at 4.2 million years ago.

The late Miocene-Pliocene Hopi Buttes volcanic field contains at least 300 maar and diatreme features in an area of 1800 km2. Phreatomagmatic explosions involved the interactions of monchiquitic to nephelinitic magma with groundwater, lake water, or liquefied sediments from the underlying Bidahochi Formation. These maars produced craters within the underlying strata that then increased in size due to subsidence of unstable crater walls. The field relations between marginal deposits, maar crater deposits, and country rock both inside and outside of the crater link deformation of sediments with processes occurring during and due to an eruption.

At least 23 vents are exposed within approximately 51 km2 of the First Flat Mesa area in the north-central Hopi Buttes. Locally these vents provide well-preserved exposures of marginal deposits, maar crater deposits, and country rock. These units provide critical geologic constraints regarding the vertical and lateral facies changes that occur proximal to the vent. Ten volcanic facies, three limestone facies, and one marl facies have been described and provide spatial and temporal information about processes and interactions that occur within and adjacent to the vent during a phreatomagmatic eruption. A majority of these facies suggest magma interaction with water-saturated sediment which created explosive eruptions that produced juvenile lapilli, blocks and bombs, and clasts of country rock that were recycled within the vent or dispersed away from the vent by base surges or fallout. These consist of massive lapilli tuff to moderately bedded lapilli tuff that typically contains blocks and bombs up to 2-3 meters. Where vents occur within close proximity, saturated sediments filling one crater may break the wall between them and slump from one vent into the neighboring vent as it is erupting. Some eruptions began phreatomagmatically, used up the available water, and became magmatic, producing scoria deposits that filled in the craters. Crater-lake facies suggest that most of the material removed by the eruption was deposited outside of the crater, allowing water to fill the crater and deposit limestone. Crater-lake facies are not found in vents where scoria deposits are found, although occasionally lapilli and ash are found within the limestone, from a nearby vent eruption and depositing volcanic material into the lake. Facies descriptions and interpretations provided information used to produce an eruptive model for the vents within the study area.

Regions containing this locality

North America PlateTectonic Plate
Colorado Plateau, USAPlateau
Navajo Nation Indian Reservation, USAReservation
Hopi-Navajo Indian Reservations, Colorado Plateau, Apache; Navajo and San Juan Cos., Arizona & Utah, USA

Select Mineral List Type

Standard Detailed Strunz Dana Chemical Elements

Commodity List

This is a list of exploitable or exploited mineral commodities recorded at this locality.

Mineral List

1 valid mineral.

Detailed Mineral List:

Formula: Na(AlSi2O6) · H2O
Description: Occurs in mafic volcanic rocks.
Reference: Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 108; Williams, H. (1936), Pliocene volcanics of the Navajo-Hopi country, Geol. Soc. Am. Bull.: 47: 111-172;Tschernich, R. (1992): Zeolites of the World, 64

List of minerals arranged by Strunz 10th Edition classification

Group 9 - Silicates
Analcime9.GB.05Na(AlSi2O6) · H2O

List of minerals arranged by Dana 8th Edition classification

Group 77 - TECTOSILICATES Zeolites
Zeolite group - True zeolites
Analcime77.1.1.1Na(AlSi2O6) · H2O

List of minerals for each chemical element

H AnalcimeNa(AlSi2O6) · H2O
O AnalcimeNa(AlSi2O6) · H2O
Na AnalcimeNa(AlSi2O6) · H2O
Al AnalcimeNa(AlSi2O6) · H2O
Si AnalcimeNa(AlSi2O6) · H2O

Regional Geology

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

0 - 0.0117 Ma

ID: 3375005
Mixed alluvium and eolian deposits

Age: Anthropocene (0 - 0.0117 Ma)

Description: Gray, light-red, and brown clay, silt, and fine- to coarse-grained sand interbedded with lenses of pebbly gravel. Deposits on Newberry and Ives Mesas (sheet 1) contain white, angular to subangular chert fragments locally derived from the Owl Rock Member of the Chinle Formation. Deposits within Hopi Buttes (sheet 2) contain black, white, and gray, angular to subrounded volcanic fragments locally derived from nearby volcanic outcrops. Unit has accumulated by both alluvial and eolian processes, resulting in interbedded sequence of thin-bedded, mixed clay, silt, sand, and small gravel, typical of young fluvial (Qa1, Qa2) and eolian (Qd, Qes) deposits. Subject to sheet-wash erosion during wet conditions and accumulation of eolian-sand deposits during dry conditions. Commonly overlies young fluvial and eolian surficial deposits (Qf, Qf1, Qf2, Qf3, Qa1, Qa2) and often is overlapped by young or fresh eolian-sand deposits (Qd, Qes). Supports light to moderate growths of grass, cactus, and small high-desert shrubs. Thickness, 1 to 6 m (3 to 20 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. [200]

2.588 - 5.333 Ma

ID: 3187166
Cenozoic sedimentary rocks

Age: Pliocene (2.588 - 5.333 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. [154]

Zanclean - Tortonian
3.6 - 11.62 Ma

ID: 2766775
Pliocene to late Miocene basaltic rocks

Age: Neogene (3.6 - 11.62 Ma)

Description: Mostly dark, inconspicuously flat, low-lying or mesa-forming basalt deposited as lava flows. Rocks included in this unit are located almost entirely in the large volcanic fields south and west of Flagstaff, in smaller fields in northwesternmost Arizona, and in the Hopi Buttes volcanic field on the Navajo and Hopi Indian Reservations north of Holbrook. Original volcanic landforms have been obscured by erosion. (4-8 Ma)

Comments: Chiefly Hopi Buttes, "Rim basalts", volcanic fields in northwesternmost Arizona 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.

Lithology: Major:{basalt}

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. [133]

Data and map coding provided by, used under Creative Commons Attribution 4.0 License


Sort by

Year (asc) Year (desc) Author (A-Z) Author (Z-A)
Williams, H. (1936), Pliocene volcanics of the Navajo-Hopi country, Geological Society of America Bulletin: 47: 111-172.
Wenrich, Karen J. and Mascarenas, Joseph F. (1982 a), Diatremes of the Hopi Buttes, Arizona: Chemical and statistical analyses, USGS Open File Report 82-740.
Wenrich, Karen J. and Mascarenas, Joseph F. (1982 b), Maps showing uranium-bearing diatremes of the Hopi Buttes, Arizona, Miscellaneous Field Studies Map Series number 1310. (ISBN 0607808578; DOI 10.3133/mf1310)
Tschernich, R. (1992): Zeolites of the World: 64.
Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd. ed.: 108.
Zelawksi, Mallory (2010), The Hopi Buttes volcanic field, Northern Arizona University, Flagstaff, Arizona, Arizona Geology:40(1) (Spring).
Zelawski, Mallory (2010), Marginal deposits of maar volcanoes in the First Flat Mesa area of the Hopi Buttes volcanic field, Navajo Nation, Arizona [Masters Thesis]: Northern Arizona University.
Zelawski, Mallory and Ort, Michael H. (2010), Maar margins in the Hopi Buttes Volcanic Field, Navajo Nation, Arizona: Field mapping yields interpretation of maar volcano proximal facies: GSA Abstracts with Programs: 42(5).
Zelawski, Mallory, Map of the Volcanic Geology of the First Flat Mesa Area, Hopi Buttes (Tsézhin Bií), Navajo Nation, Arizona (Award # G09AC00135), Michael H. Ort, Principal Investigator, Mallory Zelawski, Recipient.
Hopi Buttes volcanic field, Wikipedia.
Geo-Ecological Study of Historic and Prehistoric Land Use in the Hopi Buttes area, Navajo Nation, Arizona, USGS

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