The volcanoes and associated lava flows in this area are among the youngest eruptions in New Mexico. The lava flows are unusually long lava flows and have covered most of the broad valley between the e Zuni Mountains on the west and Cebolleta Mesa on the east.
The youngest flow, the McCartys lava flow field, is the youngest eruption in New Mexico. An inflated pahoehoe type lava flow, it is 40 km long and retains characteristic surface glass (tachylite), and other millimeter-scale features typical of fresh lava flows. The extreme northern distal end of the lava flow lies within the Rio San Jose Valley at modern day I-40. Another young lava flow of mostly aa type lava characteristics, erupted from a small basaltic cone within the Zuni Mountains flowed north through a canyon and out onto the valley of the Rio San Jose near modern day Grants and I-40. And other flows erupted from the larger cinder cones within the Zuni-Bandera volcanic field at the southern margin of the Zuni Mountains.
General geologic map of the Zuni-Bandera Field.
Aerial, low altitude view of inflation pits near the south end of the McCartys lava flow field. Note that the low areas were sunsequently flooded with lava in this scene. Some of the deep cracks visible in the surface of the lava would have required cooling of the lava for months in order to create a crust thick enough to crack to depths visible. The view is directed northward. Photo L.Crumpler
McCarty lava flow field southern edge, NM 117 (from about 20,000'). Photo L. Crumpler
Cleft in McCartys lava flow field tumulus. Photo L. Crumpler
McCartys flow field vent area (aerial). Photo L. Crumpler
McCartys vent as seen from the surface. Photo L. Crumpler
Margin of inflation plateau near the southern terminus of the McCartys lava flow field. Photo L. Crumpler
Ropy lava a few hundred meters east of the vent region. Photo L. Crumpler
Lava Tube near McCartys vent. Photo L. Crumpler
Tree trunk mold in the Bandera lava flow along the western end of the Zuni Acoma Trail. Photo L. Crumpler
Aerial view of Bandera crater, a young scoria cone (~ 10-20 Ka) on the western edge of the Zuni-Bandera volcanic field. Photo L. Crumpler
Lava channel in aa lava flows from Bandera crater (in the distance). Photo L. Crumpler
Lava tree mold. THis example is located in the Bandera flow immediately behind the visitor's center. Bandera Crater, NM. Photo L. Crumpler
View McCartys Lava Flow in a larger map