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Triple oxygen isotope signatures in evaporated water bodies from the Sistan Oasis, Iran
Author(s) -
Surma J.,
Assonov S.,
Bolourchi M. J.,
Staubwasser M.
Publication year - 2015
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2015gl066475
Subject(s) - arid , evaporation , isotopes of oxygen , relative humidity , environmental science , δ18o , fractionation , geology , isotope , stable isotope ratio , atmospheric sciences , chemistry , geochemistry , meteorology , geography , paleontology , physics , organic chemistry , quantum mechanics
Natural samples from water bodies in the arid and semiarid environment of the Sistan Oasis, Iran, demonstrate a systematic evolution of 17 O‐excess and δ 18 O as a result of nonequilibrium fractionation during extreme evaporation. Residual water samples exhibit a significant and systematic decrease of 17 O‐excess with progressive evaporation loss, reaching values of −160 per meg over a 35‰ range of δ 18 O. Waters from heavily evaporated volume‐limited natural bodies with limited or no recharge fall on the theoretically predicted isotopic evolution curve in agreement with ambient relative humidity of 30 to 35%. Recharged water bodies appear to follow a different trend. These new results demonstrate the potential of 17 O‐excess for the estimation of evaporation loss and ambient conditions in an arid environment.