Universität zu Köln

Voigt, Claudia ORCID: 0000-0003-2124-9684, Herwartz, Daniel ORCID: 0000-0003-3604-8295, Dorador, Cristina and Staubwasser, Michael ORCID: 0000-0002-5892-1115 (2021). Triple oxygen isotope systematics of evaporation and mixing processes in a dynamic desert lake system. Hydrol. Earth Syst. Sci., 25 (3). S. 1211 - 1229. GOTTINGEN: COPERNICUS GESELLSCHAFT MBH. ISSN 1607-7938

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Abstract

This study investigates the combined hydrogen deuterium and triple oxygen isotope hydrology of the Salar del Huasco, an endorheic salt flat with shallow lakes at its centre that is located on the Altiplano Plateau, N Chile. This lacustrine system is hydrologically dynamic and complex because it receives inflow from multiple surface and groundwater sources. It undergoes seasonal flooding, followed by rapid shrinking of the water body at the prevailing arid climate with very high evaporation rates. At any given point in time, ponds, lakes, and recharge sources capture a large range of evaporation degrees. Samples taken between 2017 and 2019 show a range of delta O-18 between 13.3 parts per thousand and 14.5 parts per thousand, dexcess between 7 parts per thousand and 100 parts per thousand, and O-17-excess between 19 and -108 per meg. A pan evaporation experiment conducted on-site was used to derive the turbulence coefficient of the Craig-Gordon isotope evaporation model for the local wind regime. This, along with sampling of atmospheric vapour at the salar ( -21.0 +/- 3.3 parts per thousand for delta O-18, 34 +/- 6 parts per thousand for d-excess and 23 +/- 9 per meg for O-17-excess), enabled the accurate reproduction of measured ponds and lake isotope data by the Craig-Gordon model. In contrast to classic delta H-2- delta O-18 studies, the O-17-excess data not only allow one to distinguish two different types of evaporation - evaporation with and without recharge - but also to identify mixing processes between evaporated lake water and fresh flood water. Multiple generations of infiltration events can also be inferred from the triple oxygen isotope composition of inflow water, indicating mixing of sources with different evaporation histories. These processes cannot be resolved using classic delta H-2- delta O-18 data alone. Adding triple oxygen isotope measurements to isotope hydrology studies may therefore significantly im- prove the accuracy of a lake's hydrological balance - i.e. the evaporation-to-inflow ratio (E / I) - estimated by water isotope data and application of the Craig-Gordon isotope evaporation model.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Voigt, Claudia UNSPECIFIED orcid.org/0000-0003-2124-9684 UNSPECIFIED Herwartz, Daniel UNSPECIFIED orcid.org/0000-0003-3604-8295 UNSPECIFIED Dorador, Cristina UNSPECIFIED UNSPECIFIED UNSPECIFIED Staubwasser, Michael UNSPECIFIED orcid.org/0000-0002-5892-1115 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-582805
DOI:	10.5194/hess-25-1211-2021
Journal or Publication Title:	Hydrol. Earth Syst. Sci.
Volume:	25
Number:	3
Page Range:	S. 1211 - 1229
Date:	2021
Publisher:	COPERNICUS GESELLSCHAFT MBH
Place of Publication:	GOTTINGEN
ISSN:	1607-7938
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language AQUEOUS SALT-SOLUTIONS; PAMPA DEL TAMARUGAL; HYDROGEN ISOTOPES; STABLE HYDROGEN; ATACAMA DESERT; WATER; PRECIPITATION; FRACTIONATION; VARIABILITY; PHYTOLITHS Multiple languages Geosciences, Multidisciplinary; Water Resources Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/58280