Mega Basalt Field

The Mega Volcanic Field in southern Ethiopia is present on both sides of the 100-km-long NW-SE Mega escarpment, and covers about 1,400 km2. Franceschini et al. (2020) provides an excellent review of this field, from which most of this summary is taken. The field includes 114 monogenetic centers, primarily cinder cones and some maars; the largest maar is the 2.3-km-diameter El Sod. Uneroded lava flows often partially overly deeply eroded lava flows. Large lava flows are usually associated with cinder cones, but fissure-fed flows in the Megado area exhibit oriented spatter ramparts. One of the largest lava flows extends more than 10 km SW from the Mega escarpment and covers about 25 km2; it has a very fresh, black, glassy appearance of the surface, and minimal vegetation. Two samples analyzed by Franceschini et al. (2020) yielded 40Ar/39Ar ages of 0.116 ± 0.005 and 0.044 ± 0.008 Ma; two other samples indicated very recent Holocene ages. These are the first age dates available for this field, and are in agreement with the morphological interpretation of some young cinder cones and lava flows.