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Zuni-Bandera Field and McCarty's Lava Flow Field

Location: 
35° N, 108° W, Cibola County
Type: 
Holocene scoria cones, shield volcanoes, spatter cones and lava flows
Age: 
3 ka to 0.8 Ma
Significance: 
Youthful volcanic field; the McCartys lava flow is one of the youngest and longest lava flows on the continent.
Composition: 
Alkali basalt, hawaiite, tholeiite cones, craters, and fissures.

 

Geological Overview

 

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. A an inflated pahoehoe type lava flow,  it is  40 km long and retains characteristic surface glass (tachylite), and other millimeter-scale features 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 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 the inflation pits near the south end of the McCartys lava flow field. 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

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