Dating recent lava flows
A thousand years ago, the landscape in and around Sunset Crater Volcano National Monument was different than it is today.
The prominent cinder cone had not yet formed and the stark lava flows had yet to pour onto the surface.
Volcanism began approximately 6 million years ago in the western part of the field and has since migrated eastward producing over 600 volcanic vents.
Activity culminated with the eruption of Sunset Crater Volcano (Figure 2) just over 900 years ago.
More recent paleomagnetic studies show the onset of the eruption occurred between AD 1040 and AD 1100 (Ort et al., 2002). (2008b) Mineralogy of Fumarole Deposits at Sunset Crater Volcano National Monument, Northern Arizona: Rocks and Minerals, 83 (6) p.534-544.
Thus, the eruption that formed Sunset Crater Volcano may have begun several years later than originally estimated and continued for a much shorter time, perhaps as little as a month or two, or as long as a few years (Ort Regardless of the date, eruptive activity began along a 10 km (6 mi) long NE-SW trending fissure that produced a series of coeval vents including Sunset Crater, Rows of Cones, Gyp Crater, and Vent 512. This fissure eruption ended shortly after it began as activity became focused on the northern end of the fissure. Strombolian eruption built Sunset Crater Volcano and blanketed an area of at least 2000 km2 with cinders. The Sinagua were the ancestors of the Pueblo Indians of the Four Corners area, including the Hopi Indians, who refer to them as Hisatsinom (those who lived long ago). The lives of these people were profoundly changed in the late 11th century when a volcano was born. Holocene scoria cone and lava flows at Sunset Crater, northern Arizona: Geological Society of America Centennial Field Guide – Rocky Mountain Section393-397.