Recognition of Diagenetic Sandstone in the Jibal ad Dughum Area, Southeast of Ar Riyadh, Saudi Arabia
Mohammed A. Ali, Abdullah I. Nabhan, and Sami S. Maddah
Five samples were collected from diagenetic sandstone with unusual surface features at Jibal ad Dughum, 40 km east southeast of Ar Riyadh. The samples were studied in the SGS laboratories in Jeddah, using a polarizing microscope and chemical analyses. They consist almost entirely of quartz grains, cemented by opaque mineral (hematite and goethite) and some clay. The chemical composition of the rock is SiO2 60.23 percent, Fe2O3 30.43 percent and Al2O3 2.03 percent. The unusual surface features, which resemble ropes on tracks and knobs, are taken to be the result of silica solution and precipitation phenomena in a desert environment.
Ali, M.A., Nabhan, A.I., and Maddah, S.S., 2010, Recognition of diagenetic sandstone in the Jibal ad Dughum area, southeast of Ar Riyadh, Saudi Arabia: Saudi Geological Survey Open-File Report SGS-OF-2010-9, 8 p., 7 figs. 1 table.