CIMARRON- Dark, dense to vesicular volcanic rock 50 to 85 +/- feet thick forming cap rock of Black Mesa.
State Oklahoma
Name Basalt
Geologic age Pliocene
Lithologic constituents
Igneous > Volcanic > Mafic-volcanic > Basalt (Flow)
Comments Raton Basalt: Is oldest (of three) basaltic to latiandesitic effusive rock unit mapped in western part of Raton-Clayton volcanic field, Colfax Co, NM in Las Vegas-Raton basin. Caps highest and longest mesas in area. Includes many sheets of lava; vents are generally no longer marked by cinder cones. Analyzed specimens are olivine basalts, alkali basalts, a few trachy-basalts, and latibasalts. Rocks are medium to dark gray or black, very hard, and in part vesicular; some have silvery sheen on fresh break, aptly owing to fine diktytaxitic texture; are visibly porphyritic (typically olivine is the only phenocryst), but some flows have phenocrysts or xeno-crysts of other minerals; altered olivine phenocrysts appear as red or brown specks. Petrography and petrochemistry described. K-Ar ages range from 3.5 to 4.0 m.y. Age is Pliocene. (Scott, 1991).
NGMDB product
Counties Cimarron