Geologic Formations

a smooth flat band of lava rock winds through mounds of chunky black lava rock into the distance
This flat ribbon of basalt was once a river of lava that cut through the chunky slow-moving flows on either side.

NPS Photo

The 3 young lava fields found in Craters of the Moon National Monument and Preserve range in age from 15,000 years to 2000 years. Craters of the Moon lava field, the largest of the three fields found along the Great Rift, is made up of about 60 lava flows and 25 volcanic cones that cover 618 square miles. It provides outstanding examples of how molten basaltic rock can solidify into various types of lava. The basic types include block lava (very dense and formed into angular blocks), aa lava (a rough, jagged surface), and pahoehoe lava (a smooth, ropy, or billowy surface). Visitors can also see vents, fissures, cinder cones, lava tubes, lava bombs, spatter cones, tree molds, rafted blocks, and many other volcanic features and structures.

Below is a link to a detailed geologic map of the Craters of the Moon lava fields:

Geologic Map of the Core Visitation Area of Craters of the Moon National Monument and Preserve

 

Last updated: August 19, 2021

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Mailing Address:

Craters of the Moon National Monument and Preserve
P.O. Box 29

Arco , ID 83213

Phone:

208 527-1300

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