Paleoclimate record in the Nubian Sandstone Aquifer, Sinai Peninsula, Egypt

Abstract

Sixteen groundwater samples collected from production wells tapping Lower Cretaceous Nubian Sandstone and fractured basement aquifers in Sinai were analyzed for their stable isotopic compositions, dissolved noble gas concentrations (recharge temperatures), tritium activities, and 14C abundances. Results define two groups of samples: Group I has older ages, lower recharge temperatures, and depleted isotopic compositions (adjusted 14C model age: 24,000–31,000 yr BP; δ18O: − 9.59‰ to − 6.53‰; δ2H: − 72.9‰ to − 42.9‰; < 1 TU; and recharge T: 17.5–22.0°C) compared to Group II (adjusted 14C model age: 700–4700 yr BP; δ18O: − 5.89‰ to − 4.84‰; δ2H: − 34.5‰ to − 24.1‰; < 1 to 2.78 TU; and recharge T: 20.6–26.2°C). Group II samples have isotopic compositions similar to those of average modern rainfall, with larger d-excess values than Group I waters, and locally measurable tritium activity (up to 2.8 TU). These observations are consistent with (1) the Nubian Aquifer being largely recharged prior to and/or during the Last Glacial Maximum (represented by Group I), possibly through the intensification of paleowesterlies; and (2) continued sporadic recharge during the relatively dry and warmer interglacial period (represented by Group II) under conditions similar to those of the present.

Structural Controls on Groundwater Flow in Basement Terrains: Geophysical, Remote Sensing, and Field Investigations in Sinai

“…1) reveals structural control on groundwater flow. The south-north groundwater flow (Abouelmagd et al 2014) in the NSAS is intercepted by orthogonal (east-west-trending) dextral shear zones, the most prominent of which is the Themed shear zone (TS) and the Sinai Hinge Belt (SHB) (Moustafa et al 2013) (Fig. 1).…”

Global Isotope Hydrogeology―Review

“…Pertaining to this specific example, an approach better suited for isolating and estimating late‐Pleistocene temperatures is the comparison of late‐Holocene versus late‐Pleistocene groundwater noble gas concentrations (Mazor, ). The noble‐gas‐based paleotemperature reconstruction approach has been applied to estimate past temperatures in dozens of aquifer systems around the world (e.g., Andrews & Lee, ; Mazor & Verhagen, ; Heaton et al, ; Phillips et al, ; Andrews et al, ; Stute & Deák, ; Fontes et al, ; Stute, Clark, et al, ; Stute, Forster, et al, ; Clark et al, , ; Beyerle et al, ; Stute & Talma, ; Edmunds et al, ; Elliot et al, ; Weyhenmeyer et al, ; Condesso de Melo et al, ; Huneau et al, ; Beyerle et al, ; Guendouz et al, ; Lehmann et al, ; Kulongoski et al, ; McMahon et al, ; Plummer et al, ; Zuber et al, ; Kloppmann et al, ; Edmunds & Smedley, ; Edmunds et al, ; Kennedy & Genereux, ; Klump et al, ; Kreuzer et al, ; Osenbrück et al, ; Kulongoski et al, ; Blaser et al, ; Morrissey et al, ; von Rohden et al, ; Wieser et al, ; Varsányi et al, ; Corcho Alvarado et al, ; Szocs et al, ; Abouelmagd et al, ; Seltzer et al, ; Mihajlov et al, ; Saadi et al, ; Darling et al, ). More frequent intercomparisons of noble gas concentrations and fossil groundwater δ 18 O values may help to decouple influences of late‐Pleistocene to late‐Holocene warming from deglacial shifts to other hydroclimatic processes.…”

Assessment and Comparison of TMPA Satellite Precipitation Products in Varying Climatic and Topographic Regimes in Morocco

“…( [19,[40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59]; among others) has far outweighed those studying the accuracy, uncertainty, and validation of TMPA data ( [13,18,24,45,60,61]; among others). Even less research has been conducted on the viability of TMPA rainfall products as an adequate substitute for field gauges in data sparse and arid to semi-arid environments [11,18]; arguably the area most critically in need of satellite rainfall.…”