Paxton Cone, New Mexico 



Volcanoes have been an active force in 

 northwestern New Mexico for the past 

 four million years, beginning with the first 

 violent eruption of Mount Taylor. Some 

 590 square miles of lava between the Zuni 

 Mountains and Acoma now provide a mu- 

 seum of volcanic phenomena. This arid, 

 inhospitable area is known as El Malpais, 

 "the badlands." Part of the land is private, 

 part is managed by the National Park Ser- 

 vice, and part is managed by the Bureau of 

 Land Management. A small area falls 

 within Cibola National Forest. 



Paxton Cone, on the National Forest 

 land, was created between 10,000 and 

 40,000 years ago, when an eruption sent a 

 river of lava northeastward down Zuni 

 Canyon. Lying about thirty miles south- 

 west of the present-day community of 

 Grants, the cone built up from cinders that 

 fell around the eruption orifice. The lava 

 that flowed northeast was thick and tarlike; 

 it solidified leaving very rough, sharp sur- 

 faces and an intricate network of fissures. 

 This type of lava is called aa (the word is 

 Hawaiian). 



Cinder cones are only one of four vol- 

 cano types found in the Malpais area. The 



by Robert H. Mohlenbrock 



most violent, exemplified by long-extinct 

 Mount Taylor, is the stratovolcano, which 

 ejects material into the upper atmosphere. 

 When it last erupted. Mount Taylor sent 

 tons of lava, cinders, ash, and steam into 

 the air as its crater walls fell inward to 

 form a caldera. Less violent are shield vol- 

 canoes, broad, flat volcanoes that often re- 

 lease their energy through several orifices. 

 Shield volcanoes usually can be recog- 

 nized by multiple craters at the top. Fi- 

 naUy, basalt cones, with wide, steep-sided 

 craters, erupt rapidly and send out a rather 

 thin-textured lava that cools to a smooth or 

 somewhat ropy surface. This type of lava, 

 referred to as pahoehoe, is the most com- 

 mon in El Malpais. 



At higher elevations, where conditions 

 are relatively cool and moist, the Malpais 

 area is forested with well-developed conif- 

 erous trees. Douglas firs and ponderosa 

 pines are found at elevations between 

 7,000 and 8,900 feet, along with a lower 

 layer composed primarily of Rocky 

 Mountain juniper. Douglas firs, which re- 

 quire more moisture, are found mainly on 

 northern slopes and on rough lava where 

 rainwater tends to accumulate in the fis- 



Douglasfirs and ponderosa pines grow on Paxton Cone, above, 

 which erupted between 10,000 and 40,000 years ago. Left: Claret 

 cup cactus and yellow-flowered pericome cling to the volcanic rock. 



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