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Table 5 Geology and geochemistry of water bearing formation and watershed affecting groundwater wells

From: Rock-water interaction processes based on geochemical modeling and remote sensing applications in hyper-arid environment: cases from the southeastern region of Egypt

Well no. Aquifer Water-bearing formation
Lithology Geochemistry and/or mineralogy
1 Alluvial Alluvial sediments composed of sand, mud, and basement rock fragments in gravel and sand sizes Rock fragments of basement and mixture of watershed rocks; their geochemistry are identified in the following columns. In addition, carbonate minerals are dolomite, calcite, Mg-calcite, and aragonite. Siliciclastic minerals are quartz, K-feldspars, and plagioclase, with minor heavy minerals and clays (SiO2, CaO, Al2O3, and MgO)
2
3
4
5 Alluvial sediments and sabkha deposits Evaporates minerals include (gypsum, halite, anhydrite). Carbonate minerals are dolomite, calcite, Mg-calcite, and aragonite. Siliciclastic minerals are quartz, K-feldspars, and plagioclase (SiO2, CaO, SO3, MgO and Al2O3)
6
7 to 11 Alluvial sediments composed of sand, mud, and basement rock fragments The same as mentioned in well numbers 1and 2
12 to 19 Nubian Sandstone Sandstone with iron-ore beds, shale, and silt intercalation Ferruginous sandstone and ironstone. The mineralogy includes goethite magnetite, quartz, illite, halite, kaolinite, dolomite, and vesuvianite. Abundant SiO2, Fe2O3, Al2O3, Cao, and MgO
20 to 23 Coarse to medium fluviatile sandstone
24 Fractured basement Ophiolitic metagabbro SiO2, Al2O3, CaO, Fe2O3, MgO, Na2O
25
26 Older gray granite High SiO2, TiO2, CaO, NaO2,and P2O5 and low K2O and FeO, with abundant trace elements of Ba and Rb
27 Metasediments Abubdant SiO2, Al2O3, CaO, Fe2O3, MgO, Na2O
28 to 35 Acid volcanics Include rhyolite, rhyodacite, and dacite. High concentrations of SiO2, Na2O, Fe2O3, K2O, Zr, Nb, and Y but low in MgO, CaO, Cr, Ni, Sr, Ga, and V
36 Ophiolitic serpentinite and talc carbonate Include magnizite, chromite, dolomite, talc, iron oxides (geothite, hematite, magnitite). Abundant Al2O3, SiO2, Feo, TiO2, CaMg(Co3)2, CaCO3, and Fe-Ti oxides
37
Well no. Aquifer The geology along the water flow path to the wells
Lithology Geochemistry and/or mineralogy
1 Alluvial Older gray granite High SiO2, TiO2, CaO, NaO2, and P2O5 and low K2O and FeO, with abundant trace elements of Ba and Rb (R1)
2 Metamorphic rocks Included gneiss (abundant: SiO2, Al2O3, Cao, Fe2O3, MgO, Na2O, K2O) and schist (are composed mainly of quartz + garnet+ muscovite + biotite + plagioclase ± chlorite ± opaque; abundant: SiO2, Al2O3, Cao, Fe2O3, MgO, Na2O, TiO2), and amphibolites (the same as schist) (R2)
3 Metagabbro, metasediments Abundant (SiO2, Al2O3, CaO, Fe2O3, MgO, Na2O) (R1)
4
5 Sabkha deposits included clay, sand, and evaporates Evaporates minerals include gypsum, halite, and anhydrite. Carbonate minerals are dolomite, calcite, Mg-calcite, and aragonite. Siliciclastic minerals are quartz, K-feldspars, and plagioclase (SiO2, CaO, SO3, MgO, and Al2O3)
6
7 to 11 Metasediments, ophiolitic basic metavolcanics, Tertiary olivine basalt Metasediments: high Al2O3, CaO, Fe2O3, MgO, TiO2, Ni, V, and Cr; low SiO2, Na2O, Rb, Ba, Sr, Zr, and Y, where Tertiary olivine basalt composed of plagioclase, augite, and olivine (SiO2, TiO2, K2O, MgO) (R1, R3)
12 to 23 Nubian Sandstone Sandstone with iron-ore beds, shale, and silt intercalation Ferruginous sandstone and ironstone. The mineralogy includes goethite magnetite, quartz, illite, halite, kaolinite, dolomite, and vesuvianite. Abundant SiO2, Fe2O3, Al2O3, Cao, MgO (R4)
24 Fractured basement Ophiolitic serpentine and talc carbonate Include magnizite, chromite, dolomite, talc, and iron oxides (geothite, hematite, magnitite). Abundant Al2O3, SiO2, Feo, TiO2, CaMg(Co3)2, CaCO3, and Fe-Ti oxides (R1)
25
26 Acid volcanic Include rhyolite, rhyodacite, and dacite. High concentrations of SiO2, Na2O, Fe2O3, K2O, Zr, Nb, and Y but low in MgO, CaO, Cr, Ni, Sr, Ga, and V (R5)
27 Metamorphic rocks The same like well number 2
28 to 35 Acid volcanic and metasediments Acid volcanic (the same as well number 26) Metasediments (the same as well number 4)
36 Older gray granite and acid volcanic Older gray granite (the same as well number 1)
Acid volcanic (the same as well number 26)
37
  1. The geochemistry of the studied rocks is obtained from different sources as follows: (R1)—Hassan (2015), (R2)—Abd El-Naby and Frisch (2006), (R3)—Khalil (1997), (R4)—Farouk et al. (2015), (R5)—Shahin et al. (2016)