Mineralogy and Genesis of Zeolites of Gedarif Area, Eastern Sudan

Amygdaloidal, cavity- and vein-filling zeolites in basaltic rocks from the Gedarif area in the eastern Sudan have been studied in some detail by optical microscope and X R D techniques combined with field observations. This show that basalt experienced two paragenetic stages with respect to their texture and mineralogy. Stage 1 alteration, which occurred in response to the burial of basaltic rocks and their interaction with heated groundwater, is characterized by the formation of low-temperature zeolite facies minerals in vesicles (amygdales) containing mainly fine- grained zeolite minerals (natrolite, stilbite, chabazite, analcime and thomsonite). Stage 2 mineralization occurred due to an activity of hydrothermal solutions that formed large crystals of natrolite, stilbite, chabazite, analcime and mesolite, associated frequently with quartz (Geodes quartz), calcite and semi gemstones. © 2022 Institute of Physics Publishing. All rights reserved.