Abstract

The geothermal resources of Saudi Arabia are mainly located in the southwestern parts associated with a series of volcanic rocks and ridges. Jizan area is considered as one of the most promising geothermal targets which are characterized by the presence of a number of structural related hot springs with a surface temperature range of 46 to 79°C at the surface. This work mainly aims to throw light on the possible potentiality of these resources at Jizan area, through analyzing the available satellite images and interpreting the geothermometer data. A number of Landsat and Spot satellite images, which cover the study area, are analyzed. The drainage pattern, digital elevation model and the prevailing structural elements are all interpreted. Three main thermal anomalies are recognized (Al Ardah, Al Khouba and Bani Malik), and more closely located to the east, away from the coastal plain in areas of high and complicated topographic nature, and originating from hard crystalline rocks. The general slope decreases notably westward from 45° in the high hill areas to 1° near the sea coast. The prevailing drainage patterns are mainly denderitic, running seaward and associated with up to four seaward-oriented coastal basins. A geo-thermometer based study (Silica, Na, K and Mg) was performed by analyzing the different water samples collected from the different studied hot springs and adjacent water wells to determine the subsurface formation temperature, heat flow and water type. Much higher thermal regimes are recognized in the localities occupied by the hot springs as compared with other surrounding areas. Maximum values up to 152°C and 210 mW/M² are recorded for the subsurface temperature and heat flow respectively. The studied hot springs are promised and needs to be further investigated and accessed by additional geophysical methodologies.

Key words: Hot springs, geothermal, land sat, geothermometers, Saudi Arabia.