Topography of sinuous rilles in the Harbinger Mountains region of the moon

Five sinuous rilles occur in mare basalts in the Harbinger Mountains region of the Moon. Complete and accurate topographic data, now available for the first time, make possible a detailed topographic study of these rilles. Rille length ranges from 12 to 79 km and width from 0.8 to 4.8 km. Depth varies from 100 to 300 m and the rilles appear to become shallower to the north. The southern ends of the rilles are characterized by circular to elongate depressions that occur on a 30 km in diameter dome of probable volcanic origin. Longitudinal profiles show that the rille floors have a northward slope of less than one degree. This slope is consistent with the general slope of the surrounding mare surface. Structural studies indicate that slope rather than the regional structural pattern is the dominant factor controlling rille direction. Topographic data lend support to the theory that the rilles were formed as lava channels or tubes.     

Geophysical Constraints on the Hydrogeologic and Structural Settings of the Gulf of Suez Rift-Related Basins: Case Study from the El Qaa Plain,Sinai, Egypt

Groundwater has been identified as one of the major freshwater sources that can potentially meet the growing demands of Egypt’s population. Gravity data (from 381 ground gravity stations) were collected, processed, and analyzed together with the available aeromagnetic (800 line-km) data to investigate the hydrogeologic and structural settings, areal distribution, geometry, and water storage of the aquifers in El Qaa coastal plain in the southwest Sinai Peninsula, and to assess their longevity given projected extraction rates. Findings include (1) complete Bouguer anomaly and total magnetic intensity maps show two connected sub-basins separated by a narrow saddle with an average basin length of 43 km and an average width of 12 km; (2) two-dimensional modeling of both gravity and magnetic data indicates basin fill with a maximum thickness of 3.5 km; (3) using anomalous residual gravity, the volume of water in storage was estimated at 40–56 km³; and (4) progressive increases in extraction rates over time will deplete up to 40 % of the aquifers’ volume in 200–230 years and will cause the water quality to deteriorate due to seawater intrusion in 45 years. Similar geophysical exploration campaigns, if conducted over the entire coastal plains of the Red Sea and the Gulfs of Suez and Aqaba, could assist in the development of sound and sustainable management schemes for the freshwater resources in these areas. The adopted techniques could pave the way toward the establishment of sustainable utilization schemes for a much larger suite of similar aquifers worldwide.