Phreatomagmatic (hydrovolcanic) structures are rare in the Golan Heights, probably due to the deep groundwater table in most of this area. The volcanic deposits in the Pleistocene complex of Mt. Avital document a shift from an initial period of dry strombolian eruptions to wet phreatomagmatic explosions. We present a new map of the volcanic complex Mount Avital at a scale of 1:10,000 and an analysis of the deposit distribution and sequence of events that led to the dry-wet transition. Dry activity commenced at the southern part of the complex (pouring of the 'En Zivan basalt and buildup of the Avital cinder cone) and then migrated to the west (Avital basalts) and north (Bental cinder cone). The transition to wet activity occurred during the terminal stages of the buildup of the Bental cone and it concentrated in two vents at the central part of the complex. The reason for this transition is attributed to the diversion of the Quneitra creek eastwards into the Quneitra Valley, which caused an increase in the level of Lake Quneitra and the infiltration of its water into the magma conduit. This could be facilitated by a decrease in magma pressure in the conduit due to an intense magmatic activity. The phreatomagmatic activity was frequently interrupted by low water:melt eruptions that produced fine-grained scoria, which erupted from a small scoria cone where the access of water was restricted. The phreatomagmatic activity was followed by collapse in the southern and central areas of the complex, which produced the central depression of the Avital complex.
ASJC Scopus subject areas
- Earth and Planetary Sciences (all)