Source of paleo-groundwater in the Emirate of Abu Dhabi, United Arab Emirates: evidence from unusual oxygen and deuterium isotope data

摘要: Paleo-groundwaters of 6000 years BP from the Liwa water-table sand dune aquifer in Rub al Khali and Gachsaran artesian carbonate aquifer, on coast Emirate Abu Dhabi (UAE), exhibit normal δ2H/δ18O slopes, modest δ18O increases, large negative deuterium excess “d” (Liwa aquifer: 2.19‰ VSMOW d = –15; 3.16‰ –28) compared to local Shamal precipitation (0.05‰ 7). This unusual isotopic signature is hypothesized result re-evaporation continental runoff Red Sea catchment basin. It postulated that this water flowed onto surface Indian Ocean providing a moisture source for monsoon dominated during this, last wet period area 5000 9000 BP. Carbonate precipitation, forming speleothems, travertines, tufas, lacustrine, capillary-zone deposits, subsequently record signature. rock thus by source, rather than environmental conditions deposition normally assumed control As consequence, re-evaluation paleo-climateδ18O data may be necessary time southern Arabia.