State by State
- Specimen Number
The specimen is an irregular mass of vesicular basalt with multiple lobes. It's very fine grained, almost glassy, which is consistent with the lobes indicating surface/edge flow and rapid cooling. An "aa" appearance.
Igneous. Volcanic. Basalt. Vesicular.
- Location & Occurrence
Identified by staff from survey at New Mexico Tech as a young lava flow, either from the Zuni Bandera volcanic field or the Carrizozo Malpais lava flow near Carrizozo. This is extensional rift volcanism, alkalic and tholeitic in composition, is associated with the Rio Grande Rift.
- Geological Age
~5000 years old if it's Carrizozo. Likely Holocene in age.
The Carrizozo is one of the the largest in volume and most well-preserved lava flows on earth, being only about 5000 years old. The fows are up to 15 m thick over an area of ~330 km2 with a volume of 4.3 km3.
Link to State Geological Map from USGS. Link to New Mexico Bureau of Geology and Mineral Resources. Link to Carrizozo Flow.