Shiprock

Shiprock is the remains of an extinct volcano in the U.S. state of New Mexico. Shiprock is composed of fractured volcanic breccia and black dikes of igneous rock. It is the erosional remnant of the throat of a volcano. The exposed rock was probably formed 2,500–3000 feet (750–1,000 meters) below the Earth's surface, but exposed after millions of years of erosion. Radiometric dating of the rock shows that the volcanic rocks solidified about 27 million years ago. Shiprock is in the northeastern part of the Navajo Volcanic Field. El Capitan in Monument Valley is another prominent volcanic neck in this field. References