Abstract
The manganese deposits of Egypt are logged in many different localities in the Eastern Desert. Several manganese deposits were exploited by open cast mining excavation in the Red Sea coastal plain, particularly in the area covering from south-west of Halayeb Village to around the flood–plain of Wadi Elba north-east of Abu Ramad. Our study discussed the manganese deposits in twelve areas named as wadi Bashoya, Oshbia, N-Gabal Toyo, El-Hebal, Mateet, Blownay, Adeeb, Sarara, Sirmatai, Aqilahuq, Eikwan and N-wadi Ajway. There are two types of manganese deposits it can occur either as massive manganese ore type or mangneferous sandstone ore type.
The area is situated at the Abu Ramad fault system which is the major belt of shearing within the NW –SE striking fault system. It forms part of Red Sea on south Eastern Desert in NW–SE direction with sub vertical dip. The deformation history attributed to Arc accretion tectonic of the Pan African Orogeny, also lies at the eastern part of North Hamizana Shear Zone.
Binary diagram between (Co + Ni) wt. % versus (As + Cu + Mo + Pb + V + Zn) wt. % display the hydrothermal origin and supported by the MnO (wt. %) Fe2O3 (wt. %) and ppm (Cu + Co + Ni) 1000 triangle diagram and also by the Mn (wt. %) Fe (wt. %) and 10*(Ni + Co + Cu) wt. % triangle diagram. These deposits are characterized by low concentration of Cu, Ni and Co. The geochemical composition of manganese ores reflect formation by chemical precipitation from hydrothermal solution but occurrence of colloform texture, oolites in the mangneferous types denote to the redeposition by sedimentation processes.
Keywords: Manganese deposits, Elba, Southern eastern desert, Mangneferous sandstone, Massive manganese
Specifications Table
| Subject | Earth science, Mineralogy and Geochemistry. |
| Specific subject area | Geochemical analysis of Elba Manganese to determine the origin of manganese. |
| Type of data | Table, Plots, Figure. |
| How data were acquired | Analysis using XRF. |
| Data format | Raw and Analysed |
| Parameters for data collection | The samples were prepared and milled in an electric agate mill, normalized, and dried on the oven to avoid humidity. 100 g are send for the geochemical analysis. |
| Description of data collection | Geochemistry dataset were determined. All figures are plotted by Ig-Pet and GCD-kit programs for the geochemical analysis |
| Data source location | Gabal Elba, southern Eastern Desert, Egypt. Our data show the manganese deposits in twelve areas named as wadi Bashoya, Oshbia, N-Gabal Toyo, El-Hebal, Mateet, Blownay, Adeeb, Sarara, Sirmatai, Aqilahuq, Eikwan and N-wadi Ajway The area is sited between longitudes 36° 02′ 30.31″ to 36° 47′ 52.40″ and latitudes 22° 04′ 03″ to 22° 28′ 27.30''. (Fig. 1) |
| Data accessibility | Data are available within this article. |
Value of the Data
|
1. Data
The data of this article provides informations on the origin of Elba manganese. Fig. 1 show Google Earth photo of the area and also sample locations and Mn occurrences. The Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7, Fig. 8, representing the geochemical analysis interpretation of the origin. Fig. 9 represent photo for the manganese outcrops in the field. Table 1 represent the nature, geology and coordination of manganese deposits and also host rocks. Table 2 represent the raw data of the major and trace element of the rocks.
Fig. 1.
Google Earth photo for Elba area and also sample locations and Mn occurrences.
Fig. 2.
Discrimination diagram between hydrothermal and supergene deposits [1].
Fig. 3.
Si/Al diagram [2] showing the hydrothermal origin.
Fig. 4.
Fe-Al-Mn triangular diagram [3] to define the Venarch Mn ore type. (ANS BIF) Field of data points of Banded Iron Formation in the Arabian–Nubian Shield, after [4].
Fig. 5.
Ternary diagram (Ni + Co + Cu) x10-Fe-Mn [5] with notronites of Aden Gulf [6].
Fig. 6.
Co/Zn versus Co + Ni + Cu diagram [7]. The Venarch samples plot in the field of deposits with the hydrothermal origin.
Fig. 7.
Fig. 8.
Co + Ni versus (V + Pb + Zn + Cu) in Wt. % after [8].
Fig. 9.
Field Photograph show the outcrop of the Elba manganese.
Table 1.
Brief description of the nature of manganese deposits.
| No | Location name | Location Co-ordination |
Nature of Mn deposits | Host Rocks | Age | |
|---|---|---|---|---|---|---|
| Latitude | Longitude | |||||
| 1 | Wadi-Bashoya | 22° 22′ 15″ | 36° 16′ 30″ | Mn Veins and lenses, Magneferous sandstone and Multi-veins and pockets | Interbedded with sandstone, conglomerate, clay, siltstone and calcareous sandstone | Miocene |
| 2 | Oshbia | 22° 21′ 50″ | 36° 16′ 57″ | Mn pockets in fractures and fault plane | Lie between mederatly high Quaternary terraces, clay, siltstone and calcareous sandstone | Quaternary-Miocene to Post Miocene |
| 3 | North Gabal Toyo | 22° 23′ 15″ | 36° 11′ 00″ | Mn veins and horizontal beds with calcite | Clay, siltstone and sandstone | Middle Miocene |
| 4 | El-Hebal | 22° 26′ 30″ | 36° 06′ 23″ | Mn deposits are unconformable ovelain by Miocene sediments, veinlets of calcite are associated with Mn veins | Coarse and calcereous sandstone, | |
| 5 | Mateet | 22° 19′ 15″ | 36° 25′ 34″ | Mn Veins and lenses | Lie between mederatly high Quaternary terraces and Miocene to post Miocene are represented as low hills of clay, siltstone and sandstone | Quaternary-Miocene to Post Miocene |
| 6 | Blownay | 22° 20′ 15″ | 36° 26′ 25″ | Mn pockets in fractures and fault plane and isolated lenses | ||
| 7 | Adeeb | 22° 18′ 10.30″ | 36° 28′ 34″ | Mn veins accrued near surface | Clay, siltstone and sandstone | Miocene |
| 8 | Sarara | 22° 16′ 12″ | 36° 29′ 58″ | Mn deposits are unconformable ovelain by Miocene sediments both lenses and veins along mineralized zone | Coarse and calcereous sandstone, | Middle Miocene |
| 9 | Sirmatai | 22° 15′ 32″ | 36° 30′ 00″ | |||
| 10 | Aqilahuq | 22° 07′ 15″ | 36° 39′ 58″ | Mn deposits are unconformable ovelain by Miocene sediments to post Miocene occurred as cement material inbetween conglomerate grains | Conglomerate sandstone and calcereous conglomeratic sandstone | Miocene to post Miocene |
| 11 | Ei-kwan | 22° 07′ 00″ | 36° 40′ 44″ | |||
| 12 | North wadi Ajway | 22° 07′ 09″ | 36° 40′ 44″ | within sandstone and syanogranite | ||
Table 2.
Major and trace elements of the studied rocks.
| Sample No | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Major oxides (wt. %) | ||||||||||||||||||||
| SiO2 | 20.15 | 25.78 | 49.27 | 52.03 | 40.05 | 16.40 | 10.35 | 3.15 | 9.35 | 5.23 | 10.05 | 14.11 | 15.12 | 16.35 | 5.95 | 9.05 | 7.85 | 2.35 | 1.18 | 0.59 |
| TiO2 | 0.15 | 0.18 | 1.88 | 0.10 | 0.17 | 0.27 | 0.06 | 0.07 | 0.12 | 0.07 | 0.11 | 0.03 | 0.04 | 0.80 | 0.04 | 0.10 | 0.10 | 0.02 | 0.03 | 0.02 |
| Al2O3 | 1.82 | 1.86 | 1.09 | 1.11 | 2.59 | 3.26 | 0.59 | 0.83 | 1.07 | 1.09 | 1.85 | 0.47 | 0.55 | 0.91 | 0.40 | 1.23 | 0.94 | 0.37 | 0.22 | 0.11 |
| Fe2O3 | 6.16 | 22.15 | 35.26 | 11.63 | 7.31 | 4.15 | 3.30 | 1.61 | 1.02 | 1.11 | 4.75 | 1.15 | 1.15 | 31.04 | 0.70 | 3.90 | 3.02 | 25.05 | 0.33 | 0.17 |
| MnO | 33.40 | 25.14 | 4.77 | 27.05 | 17.77 | 53.02 | 54.95 | 47.05 | 35.70 | 41.07 | 51.03 | 39.05 | 41.27 | 31.02 | 24.35 | 31.15 | 61.02 | 35.12 | 5.74 | 3.28 |
| MgO | 0.15 | 0.12 | 0.02 | 0.02 | 1.40 | 0.73 | 0.87 | 0.40 | 0.67 | 0.45 | 0.12 | 0.24 | 0.02 | 0.20 | 0.37 | 0.43 | 0.32 | 0.20 | 0.39 | 0.34 |
| CaO | 19.43 | 7.76 | 0.55 | 0.57 | 13.67 | 4.15 | 10.45 | 25.23 | 27.30 | 27.15 | 16.03 | 18.25 | 19.05 | 17.23 | 38.16 | 29.15 | 8.65 | 13.05 | 51.35 | 53.26 |
| Na2O | 0.80 | 2.05 | 0.02 | 0.01 | 1.05 | 1.15 | 0.85 | 0.57 | 1.06 | 0.95 | 0.55 | 1.25 | 0.51 | 0.46 | 0.80 | 0.58 | 0.80 | 0.55 | 0.18 | 0.05 |
| K2O | 0.91 | 0.46 | 0.25 | 0.67 | 0.62 | 2.09 | 3.21 | 1.11 | 1.02 | 1.05 | 0.95 | 0.96 | 0.51 | 0.50 | 0.60 | 0.30 | 0.82 | 0.08 | 0.10 | 0.02 |
| P2O5 | 0.08 | 0.04 | 0.02 | 0.00 | 0.02 | 0.11 | 0.07 | 0.05 | 0.05 | 0.05 | 0.08 | 0.01 | 0.01 | 0.02 | 0.03 | 0.05 | 0.04 | 0.10 | 0.02 | 0.02 |
| L.O.I | 15.57 | 13.55 | 6.06 | 6.05 | 14.57 | 12.90 | 14.13 | 19.03 | 21.62 | 20.75 | 13.12 | 23.55 | 21.03 | 19.23 | 26.51 | 22.28 | 13.45 | 15.83 | 39.95 | 41.68 |
| Elements (wt. %) | ||||||||||||||||||||
| Si % | 9.42 | 12.05 | 23.03 | 24.32 | 18.72 | 7.67 | 4.84 | 1.47 | 4.37 | 2.44 | 4.70 | 6.60 | 7.07 | 7.64 | 2.78 | 4.23 | 3.67 | 1.10 | 0.55 | 0.28 |
| Al % | 0.96 | 0.98 | 0.58 | 0.59 | 1.37 | 1.73 | 0.31 | 0.44 | 0.57 | 0.58 | 0.98 | 0.25 | 0.29 | 0.48 | 0.21 | 0.65 | 0.50 | 0.20 | 0.12 | 0.06 |
| Fe % | 4.31 | 15.49 | 24.66 | 8.13 | 5.11 | 2.90 | 2.31 | 1.13 | 0.71 | 0.78 | 3.32 | 0.80 | 0.80 | 21.71 | 0.49 | 2.73 | 2.11 | 17.52 | 0.23 | 0.12 |
| Mn% | 25.87 | 19.47 | 3.69 | 20.95 | 13.76 | 41.06 | 42.56 | 36.44 | 27.65 | 31.81 | 39.52 | 30.24 | 31.96 | 24.02 | 18.86 | 24.12 | 47.26 | 27.20 | 4.45 | 2.54 |
| Mg % | 0.09 | 0.07 | 0.01 | 0.01 | 0.84 | 0.44 | 0.52 | 0.24 | 0.40 | 0.27 | 0.07 | 0.14 | 0.01 | 0.12 | 0.22 | 0.26 | 0.19 | 0.12 | 0.24 | 0.21 |
| Na % | 0.59 | 1.52 | 0.01 | 0.01 | 0.78 | 0.85 | 0.63 | 0.42 | 0.79 | 0.70 | 0.41 | 0.93 | 0.38 | 0.34 | 0.59 | 0.43 | 0.59 | 0.41 | 0.13 | 0.04 |
| Trace elements (ppm) | ||||||||||||||||||||
| V | 1084.00 | 570.20 | 721.10 | 179.30 | 277.80 | 1311.20 | 634.60 | 330.40 | 410.20 | 368.10 | 368.10 | 559.10 | 536.40 | 353.60 | 355.00 | 415.00 | 175.00 | 1450.00 | 142.00 | 59.00 |
| Cr | 163.40 | 82.60 | 82.20 | 123.90 | 153.40 | 195.00 | 260.40 | 56.40 | 159.60 | 139.90 | 139.90 | 93.30 | 161.40 | 3742.00 | 67.30 | 121.40 | 19.80 | 93.40 | 58.80 | 56.90 |
| Co | 22.90 | 9.50 | 22.30 | 25.30 | 41.20 | 27.30 | 26.10 | 113.30 | 48.50 | 55.30 | 55.30 | 31.50 | 32.50 | 64.20 | 42.10 | 32.50 | 38.60 | 41.50 | 10.80 | 5.30 |
| Ni | 25.50 | 11.00 | 10.00 | 10.00 | 10.00 | 11.00 | 10.00 | 11.00 | 1200.00 | 14.00 | 14.00 | 11.00 | 11.00 | 12.00 | 0.90 | 0.85 | 0.90 | 0.85 | 0.90 | 0.80 |
| Cu | 15.10 | 4.50 | 3.50 | 18.00 | 47.90 | 4.20 | 6.70 | 26.20 | 8.50 | 15.50 | 15.50 | 51.00 | 24.90 | 15.10 | 0.90 | 19.70 | 23.90 | 51.00 | 0.90 | 0.90 |
| Zn | 1086.00 | 9920.00 | 1000.00 | 1457.00 | 1802.00 | 1357.00 | 1272.00 | 573.30 | 385.00 | 332.00 | 332.00 | 433.00 | 446.00 | 473.00 | 869.10 | 1151.70 | 2001.50 | 1854.40 | 704.60 | 350.20 |
| Rb | 1.00 | 0.20 | 1.20 | 2.70 | 2.60 | 3.80 | 10.80 | 2.10 | 2.80 | 1.10 | 1.10 | 24.00 | 2.70 | 6.70 | 2.20 | 3.70 | 2.30 | 1.30 | 2.10 | 2.60 |
| Sr | 3917.00 | 2329.00 | 2525.00 | 1609.00 | 1991.00 | 2534.00 | 1864.00 | 48.91 | 3349.00 | 3349.00 | 3349.00 | 2656.00 | 1563.00 | 2094.00 | 1152.00 | 875.00 | 1015.00 | 1450.00 | 445.00 | 265.00 |
| Zr | 246.00 | 163.00 | 178.00 | 106.00 | 138.00 | 178.00 | 191.00 | 347.00 | 244.00 | 250.00 | 250.00 | 189.00 | 108.00 | 163.00 | 245.00 | 125.00 | 212.00 | 45.00 | 85.00 | 55.30 |
| Nb | 1> | 1> | 1> | 1.60 | 1.00 | 1> | 8.00 | 1> | 1> | 1> | 1> | 1> | 1.00 | 0.90 | 1> | 1.50 | 1> | 3.30 | 2.20 | 2.30 |
| Mo | 28.40 | 4.70 | 6.10 | 4.30 | 3.70 | 7.20 | 4.30 | 9.70 | 9.60 | 7.10 | 7.10 | 9.10 | 9.00 | 9.40 | 8.80 | 9.60 | 7.10 | 5.40 | 4.30 | 9.00 |
| Ba | 5900.00 | 5700.00 | 4500.00 | 18000.00 | 4700.00 | 11000.00 | 6200.00 | 13000.00 | 3300.00 | 4800.00 | 4800.00 | 4300.00 | 5800.00 | 4800.00 | 9100.00 | 8500.00 | 17500.00 | 5500.00 | 445.00 | 665.00 |
| La | 1> | 317.80 | 108.90 | 84.20 | 342.20 | 1> | 1> | 206.10 | 2.00 | 1> | 1> | 1> | 91.80 | 93.10 | 1> | 1> | 1> | 107.20 | 186.10 | 76.80 |
| Yb | 3.70 | 1.30 | 1.10 | 0.50 | 0.60 | 1.20 | 1.20 | 1.40 | 1.50 | 2.10 | 2.10 | 1.60 | 1.00 | 1.20 | 2.20 | 1.40 | 1> | 2.30 | 1.80 | 1.60 |
| Hf | 16.00 | 9.70 | 10.40 | 6.10 | 7.80 | 10.20 | 12.10 | 26.00 | 17.60 | 14.70 | 14.70 | 13.40 | 6.30 | 9.30 | 7.60 | 3.90 | 7.40 | 1.00 | 2.80 | 2.70 |
| Ta | 2.80 | 0.40 | 2.30 | 2.00 | 1.60 | 2.60 | 2.10 | 2.90 | 1.40 | 1.60 | 1.60 | 1.50 | 2.00 | 2.10 | 1.50 | 2.60 | 1.60 | 2.70 | 2.90 | 2.00 |
| As | 850.00 | 870.00 | 810.00 | 770.00 | 790.00 | 810.00 | 800.20 | 793.60 | 239.10 | 1801.20 | 19683.10 | 681.20 | 820.00 | 777.00 | 301.50 | 812.00 | 865.00 | 917.00 | 780.00 | 402.00 |
| Pb | 33.30 | 7.20 | 1.00 | 320.90 | 79.60 | 45.60 | 4.50 | 194.30 | 1.50 | 1.30 | 1.30 | 1.20 | 1.20 | 13.80 | 64.10 | 139.30 | 2.50 | 54500.00 | 8.10 | 8.90 |
| Trace elements (%) | ||||||||||||||||||||
| V % | 0.11 | 0.06 | 0.07 | 0.02 | 0.03 | 0.13 | 0.06 | 0.03 | 0.04 | 0.04 | 0.04 | 0.06 | 0.05 | 0.04 | 0.04 | 0.04 | 0.02 | 0.15 | 0.01 | 0.01 |
| Co % | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.01 | 0.00 | 0.01 | 0.01 | 0.00 | 0.00 | 0.01 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
| Ni % | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.12 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
| Cu % | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.01 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.01 | 0.00 | 0.00 |
| (Co + Ni)% | 0.00 | 0.00 | 0.00 | 0.00 | 0.01 | 0.00 | 0.00 | 0.01 | 0.12 | 0.01 | 0.01 | 0.00 | 0.00 | 0.01 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
| (Co + Cu + Ni)% | 0.01 | 0.00 | 0.00 | 0.01 | 0.01 | 0.00 | 0.00 | 0.02 | 0.13 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.00 | 0.01 | 0.01 | 0.01 | 0.00 | 0.00 |
| (Co + Cu + Ni)%*10 | 0.06 | 0.03 | 0.04 | 0.05 | 0.10 | 0.04 | 0.04 | 0.15 | 1.26 | 0.08 | 0.08 | 0.09 | 0.07 | 0.09 | 0.04 | 0.05 | 0.06 | 0.09 | 0.01 | 0.01 |
| (Co + Cu + Ni)ppm/1000 | 0.06 | 0.03 | 0.04 | 0.05 | 0.10 | 0.04 | 0.04 | 0.15 | 1.26 | 0.08 | 0.08 | 0.09 | 0.07 | 0.09 | 0.04 | 0.05 | 0.06 | 0.09 | 0.01 | 0.01 |
| Zn % | 0.11 | 0.99 | 0.10 | 0.15 | 0.18 | 0.14 | 0.13 | 0.06 | 0.04 | 0.03 | 0.03 | 0.04 | 0.04 | 0.05 | 0.09 | 0.12 | 0.20 | 0.19 | 0.07 | 0.04 |
| Mo % | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
| Ba % | 0.59 | 0.57 | 0.45 | 1.80 | 0.47 | 1.10 | 0.62 | 1.30 | 0.33 | 0.48 | 0.48 | 0.43 | 0.58 | 0.48 | 0.91 | 0.85 | 1.75 | 0.55 | 0.04 | 0.07 |
| As % | 0.09 | 0.09 | 0.08 | 0.08 | 0.08 | 0.08 | 0.08 | 0.08 | 0.02 | 0.18 | 1.97 | 0.07 | 0.08 | 0.08 | 0.03 | 0.08 | 0.09 | 0.09 | 0.08 | 0.04 |
| Pb % | 0.00 | 0.00 | 0.00 | 0.03 | 0.01 | 0.00 | 0.00 | 0.02 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.01 | 0.01 | 0.00 | 5.45 | 0.00 | 0.00 |
| (As + Cu + Mo + Pb + V + Zn) % | 0.31 | 1.14 | 0.25 | 0.27 | 0.30 | 0.35 | 0.27 | 0.19 | 0.11 | 0.25 | 2.04 | 0.17 | 0.18 | 0.16 | 0.16 | 0.25 | 0.31 | 5.88 | 0.16 | 0.08 |
2. Experimental design, materials, and methods
Twenty representative samples from Elba manganese were analysed for major oxides and trace element. SiO2, TiO2, Al2O3, and P2O5 were measured by using spectrophotometer. Na2O and K2O were determined by the flame photometric technique. Fe2O3, FeO, MgO, MnO, and CaO were calculated by titration methods and LOI was determined gravimetrically at a temperature of 1000 °C. Cr, Co, Ni, Cu, Zn, Zr, Rb, Ba, Sr and V concentrations were determined using X-rays fluorescence by Philips X unique II machine. These chemical analyses were approved out at the Laboratory of Nuclear Materials Authority in Qatameia, Cairo.
2.1. Geologic setting and stratigraphy
The manganese deposits of Egypt are logged in many different localities in the Eastern Desert. Several manganese deposits were exploited by open cast mining excavation in the Red Sea coastal plain, particularly in the area covering from south-west of Halayeb Village to around the flood–plain of Wadi Elba north-east of Abu Ramad. The deposits are lenticular bodies filling faults and fractures within the Tertiary marine sediments of the Red Sea.
Our study discussed the manganese deposits in twelve areas named as wadi Bashoya, Oshbia, N-Gabal Toyo, El-Hebal, Mateet, Blownay, Adeeb, Sarara, Sirmatai, Aqilahuq, Eikwan and N-wadi Ajway.
Late Proterozoic granodiorite rocks occurs in the Hebal area which lies in north-west of Wadi Kiraf and south east of Wadi Diit. These rocks intruded within the metavolcanics and metagabbros rocks; and also intruded by basic volcanic dykes swarm with general NW – SE trend.
The Middle Miocene is represented by two formations, Gabel Al-rusas formation (conglomeratic sandstone and shale, rare marle and limestone bands) and Abu-Dabbab formation (thick, massive anhydrate and gypsum beds intercalated with marle, silty clay, sandstone and dolomitic limestone).
The Pliocene composed essentially of Sermatai Formation (grey clay, sandstone, and conglomerate) with manganese pockets.
Manganese occurs in sedimentary rocks of Miocene age in some sites within Halaib area. It occurs as fracture fillings in igneous rocks especially, granites. Manganese minerals befall either in veins or interchanging in the Miocene conglomerates. The mineralogy of the ore includes pyrolusite, psilomelane and cryptomelane adding to irregular goethite and hematite. The gangue minerals consist of quartz, calcite and barite.
All data of geology and stratigraphy and also the nature of manganese deposits are briefly represented in Table 1. There are two types of manganese deposits it can occur either as massive manganese ore type or mangneferous sandstone ore type.
-
•
Mangneferous ore type which described by highest average values of SiO2 >20%, Fe2O3 >5.5%, Al2O3 >2% lowest average values of MnO (28%) and LOI (8.56%), less in resistance and associated with calcite.
-
•
Massive manganese ore type which described by the highest average contents of MnO (50.5%) and LOI (16.8%) and lowest values of Fe2O3 (3.9%), SiO2 < 20% and Al2O3 <1% accorded with mangneferous ore.
The trace elements of the two types mostly Sr, Pb, V, Ba, Zn and Cu which are remarkably of high values while Zr, Ni, Cr, Co, Mo, y and Li are less concentrated.
2.2. Geochemistry and identification of the origin of Elba manganese deposits
The geochemical composition of manganese ores (Table 2) reflect formation by chemical precipitation from hydrothermal solution but occurrence of colloform texture, oolites in the mangneferous types mean to the redeposition by sedimentation processes. Binary diagram between (Co + Ni) wt. % versus (As + Cu + Mo + Pb + V + Zn) wt. % (Fig. 2) [1] display the hydrothermal origin and supported by Si versus Al binary diagram (Fig. 3) [2]. Also by using Al (wt. %), Fe (wt. %), Mn (wt. %) ternary diagram (Fig. 4) [3], and Mn (wt. %), Fe (wt. %), ppm (Cu + Co + Ni)*10 ternary diagram (Fig. 5) [5]. Co/Zn versus Cu + Co + Ni (ppm) binary diagram (Fig. 6) [7] also SiO2 (wt. %) versus Al2O3 (wt. %) (Fig. 7) [2,7]. and finally, (Co + Ni) wt. % versus (V + Pb + Zn + Cu) wt. % (Fig. 8) [8] all are reflect the hydrothermal origin of Elba manganese deposits.
An epigenetic low temperature origin was suggested by Ref. [11] based on the predominance of stable higher oxides of manganese and absence of manganese silicates, carbonates and sulphides, which replicate near–surface deposition of the ore. According to the chemical composition particularly the ratio of Mn, Fe and the concentration of Cu, Co and Ni, iron–manganese deposits can be genetically categorized into three major types which reflect their depositional processes lie hydrogenic, hydrothermal and digenetic [12], Fig. 5, Fig. 7, Fig. 8.
2.3. Structural analysis
The area is positioned at the closeness of Abu Ramad fault system that is major belt of shearing within the NW –SE striking fault system with sub vertical dip. The deformation history of the area is accredited to Arc accretion tectonic of the Pan African Orogeny, also the area deceits at the eastern part of North Hamizona Shear Zone which is abroad zone of deformation [9]. Several transverse fractures perpendicular to the Red Sea and linear magnetic anomalies parallel to the Red sea are related deep, seated dikes [10]. Bedding and laminations are mainly detected in the metavolcanics, Miocene deposits and Post Miocene sediments. The beds are nearly horizontal sometimes are dipping few degree towards the NE.
The structural elements of the area basically pronounced as the following:-
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•
Fractures include joints and faults, most of them extend parallel to major fault, and they have mainly ENE–WSW, NW –SE, E-W and NS trends.
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•
Faults are rejuvenated during various tectonic cycles most of them have left lateral movement. Most of the major wadies, sloping towards the Red Sea are controlled by ENE direction faults from crossed and parallel system. The ENE trending normal faults form graben delimitated from S by Aigan plain and Gabal Sol Hamed (Fig. 1). The surface of this graben is mainly serene of highly weathered rocks. The strike slip movement of ENE fault evacuated the mineralized manganese zone parallel to the Red Sea shore line. The Quaternary NW normal faults are cutting across the alluvial deposits and along the coastal plain.
Acknowledgments
The first author is grateful to Shalaten Mineral Resource Company for helping during geologic field work. He also, thanked his wife for continuous support and his baby Sela.
Conflict of Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
References
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