Geologic Implications of Aeromagnetic Data Over the Volcanic plateau, Western Yemen

الملخص

  Aeromagnetic data of the study area was reduced to the pole (RTP), spectrally analyzed, and separated into regional and local magnetic anomaly sets. These sets of magnetic anomalies are carefully analyzed and the gross structural pattern of the area is derived from the interpreted major faults and integrated boundaries of the RTP and regional anomalies. The regional trends in the area are terminated in the eastern part by  N-S trending narrow basins developed by escape blocks tectonism beneath the Dhamar – Radaa Quaternary volcanic field and the Damt geothermal site, associated with the collision of east and west Gondwana. This may explain the fumaroles at the Al Lisi active volcano and the highest mantle imprint of gases emitted at the Damt geothermal site, compared with the other geothermal fields in Yemen. The volcanic activity in this volcanic field mostly also originated by reactivating these deeper structures.
The major faults interpreted from magnetic anomalies are exactly match, in the study area, the regional faults extended from the Paleozoic Sanaa basin which may suggests that this basin is extended through the Yemeni highlands (below the Cenozoic volcanic and Mesozoic lithology) from the north of Sanaa to the area of study.
Repeated reactivation of Precambrian structures creates nets of interconnected deep faults in the area which assist the partial melting of the mantle and resulted in the widespread magmatic intrusion invaded the area, as well as in the observed geothermal activity.