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

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

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