Abstract:
Jebal Remah volcano is one of huge but very poorly known tephra cones exposed on the basalt province ofHarra El-Jabban. Detailed investigations indicate that this volcano is topographically distinct and structurally well-developed. It consists of voluminous air-fall scoria, arranged in three distinct horizons; namely lower black lapillihorizon, middle banded yellow horizon and upper brown blocky horizon. Each horizon consists of friable, loose and wellbedded ejecta. Agglutination and lithification are limited to the upper horizon. A comparison among the volcanicsuccessions of three horizons show different volcanic features that nevertheless retain a comparable overall characterfrom one horizon to another. In spite of some similarity in the type of ejecta, actually these differ in total thickness,number of beds and internal stratification. This dissimilarity within volcanic successions of the volcano support theoverall increase in fluidity, temperature and decrease in volatile content of the magma with the time. Thus, volcanoshows a complete range of thermal facies. The studied volcano appears to have resulted from one prolonged eruptivephase. Its volcanic activity consisted of a series of discrete explosion intervals, separated by quiet periods. Field criteriaindicate that the volcano is of strombolian type of volcanicity and resulted in a magmatic fragmentation mode.
