Sentinel Plain volcanic field

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Sentinel Plain volcanic field, also called the Sentinel-Arlington volcanic field, is a small group of volcanoes in Arizona. It is a monogenetic volcanic field, meaning each volcano erupts only once. The rocks are alkali basalt and were formed about 3.3 to 1.3 million years ago in the Basin and Range Province of the western United States. The highest point is about 160 meters (520 feet).