In addition to the isotopic and geochronologic data which were collected from various published sources, groundwater samples for Cl-36 dating were collected in the Egyptian part from Siwa area, surroundings, Qattara Depression, west Farafra and north Behariya by the author. Two 750-ml polyethylene bottles of each sample were filled for Cl-36 analysis. The collected samples were prepared for accelerator mass spectrometry (AMS) analysis of 36Cl by precipitation and purification of AgCl. Chlorine-36 was measured at the PRIME laboratory of Purdue University (Elmore and Phillips, 1987).
Figure 2 shows the locations of the isotopic (δ2H and δ18O) data which were used in the current study and plotted along the global meteoric water line (GMWL) of …show more content…
This region is characterized by a steep increase of the annual rainfall (summer rains from July to September) from 150 mm/year at their northern margin to more than 350 mm/year at the southern margin. Groundwater samples were collected by Gröning et al., (1993) and analyzed for H and O isotopes in both areas. Darfur has δ18O, which varies between -10.99 and 4.73‰, while δD ranges between -81.7 and 42‰; Kordofan has δ18O, which varies between -11.26 and 14.57‰, while δD ranges between -80.5 and 81.1‰ (Fig. 3). The stable isotopic data show three different groups of the groundwater: the first group is of paleowaters, which formed from the pluvial wet period; the second group is of modern groundwater due to infiltration water, showing δD and δ18O values similar to low latitude precipitation; the third group represents the mixing between the two groups. The greater the amount of modern precipitation and Nile water seepage, the greater the contribution from modern recharge and the less depleted the isotopic compositions become. Water samples were collected in the area around Dongola east and west of the Nile River. The water samples indicate a strong mixing of modern Nile water to the local groundwater, as Nile River is used for irrigation and for flooding the fields and these samples show also a strong evaporation effect due to the shallow depth to groundwater (Vrbka et al., 2008). …show more content…
Hydrogen and oxygen isotopic analyses were carried out for groundwater samples at different areas by many workers (Sonntag et al., 1978; Sultan et al., 1997; Sturchio et al., 2004; Patterson et al., 2005). The isotopic compositions of the Western Desert groundwater samples are similar over large areas and through various depths in the aquifer. δD and δ18O values range from -81 to -72‰ and from -1.9 to -10.6‰, respectively (Fig. 3). These waters show highest depletion in isotopic compositions compared to other areas in Egypt reflecting the paleowaters, which formed deposited by intensified paleo-westerlies in previous cold and wet climatic
Figure 2 shows the locations of the isotopic (δ2H and δ18O) data which were used in the current study and plotted along the global meteoric water line (GMWL) of …show more content…
This region is characterized by a steep increase of the annual rainfall (summer rains from July to September) from 150 mm/year at their northern margin to more than 350 mm/year at the southern margin. Groundwater samples were collected by Gröning et al., (1993) and analyzed for H and O isotopes in both areas. Darfur has δ18O, which varies between -10.99 and 4.73‰, while δD ranges between -81.7 and 42‰; Kordofan has δ18O, which varies between -11.26 and 14.57‰, while δD ranges between -80.5 and 81.1‰ (Fig. 3). The stable isotopic data show three different groups of the groundwater: the first group is of paleowaters, which formed from the pluvial wet period; the second group is of modern groundwater due to infiltration water, showing δD and δ18O values similar to low latitude precipitation; the third group represents the mixing between the two groups. The greater the amount of modern precipitation and Nile water seepage, the greater the contribution from modern recharge and the less depleted the isotopic compositions become. Water samples were collected in the area around Dongola east and west of the Nile River. The water samples indicate a strong mixing of modern Nile water to the local groundwater, as Nile River is used for irrigation and for flooding the fields and these samples show also a strong evaporation effect due to the shallow depth to groundwater (Vrbka et al., 2008). …show more content…
Hydrogen and oxygen isotopic analyses were carried out for groundwater samples at different areas by many workers (Sonntag et al., 1978; Sultan et al., 1997; Sturchio et al., 2004; Patterson et al., 2005). The isotopic compositions of the Western Desert groundwater samples are similar over large areas and through various depths in the aquifer. δD and δ18O values range from -81 to -72‰ and from -1.9 to -10.6‰, respectively (Fig. 3). These waters show highest depletion in isotopic compositions compared to other areas in Egypt reflecting the paleowaters, which formed deposited by intensified paleo-westerlies in previous cold and wet climatic