Triple oxygen isotope systematics in evaporitic lake settings
This page lists all metadata that was entered for this dataset. Only registered users of the CRC1211DB may download this file.
Feature
Request download
Citation
Citation Options
Identification
| Title: | Main Title: Triple oxygen isotope systematics in evaporitic lake settings |
| Description: | Abstract: The precise analysis of 17O/16O and 18O/16O ratios of H2O allows the distinction of equilibrium and kinetic aspects of isotope fractionation during evaporation, which becomes increasingly kinetic as relative humidity decreases. According to the classic Craig-Gordon model, the isotopic composition of evaporating water is primarily a function of the isotopic composition of atmospheric vapor and inflowing water, and relative humidity. While both, the δD-δ18O and the δ17O-δ18O system, measurably respond to evaporation, relative humidity may be more robustly quantified from the latter. Here, we explore the usefulness of the triple oxygen isotope system, complemented by hydrogen isotope data, to determine fundamental processes governing the general hydrologic balance of water reservoirs. We investigated natural water bodies in three different regions: Sistan Oasis (Iran) [1], Salar de Llamará (Atacama Desert, N-Chile) [2], and Salar de Huasco (Altiplano, N-Chile). All three environments are characterized by low annual precipitation amounts (< 150 mm·a-1), low relative humidity (30-40%) and high evaporation rates (> 1200 mm·a-1). They are endorheic lake systems, but their hydrologic balance differs substantially. While the Sistan Oasis has been a sink-only system since it was flooded over a decade prior to sampling, the Salar de Llamará and the Salar de Huasco are source-sink systems. The Salar de Llamará is situated in the hyperarid core of the Atacama Desert (< 2 mm·a-1 precipitation) at near-constant average day-time humidity. It is only recharged by groundwater sourced from an aquifer of distal origin. The Salar de Huasco is located on the semiarid Altiplano. This system is affected by groundwater, streams, and seasonally distributed short events of precipitation and meltwater injection. Evaporation is extreme, but relative humidity and temperature are highly variable throughout the year. Various water samples were analysed for their triple oxygen and hydrogen isotope composition by IRMS. The dataset is complemented by major ion concentration data. Results were compared with theoretical evaporation trajectories modelled using local environmental parameters. The evaporation trajectory for Sistan Oasis data was modelled using a simple pan evaporation model, since the oasis only receives sporadic flooding. In contrast, Salar de Llamará and Salar de Huasco are continuously fed by groundwater. Thus, a recharge evaporation model was used. Isotope data from the study sites at Sistan Oasis and Salar de Llamará are in good agreement with modelled evaporation trajectories reflecting average local relative humidity. Data from the Salar de Huasco scatter moderately around the modelled trajectory. The Salar de Huasco is a complex evaporative environment. The main lake receives inflow from two perennial streams and possibly other seasonal point sources. During intervals of low discharge, smaller ponds emerge at the main lake’s margin that are cut off from recharge as evaporation continues to lower the lake level. A number of additional chains of ponds and lakes with increasing salinity up to terminal ponds in the salar’s interior extend from various perennial and seasonal point sources along the basin margin. In the northwestern corner, one such system is also fed by meltwater originating from local winter snow. Our sampling was conducted in a fashion to representatively capture the variety of hydrologically different settings. Considering the complexity of the hydrological system at the Salar de Huasco the scatter of isotope data around the modelled recharge evaporation trajectory can be explained by the interaction of three fundamental processes. In general, recharged ponds follow the trendline depending on their actual ratio of evaporation and inflow. The isotopic composition of ponds that are affected by episodic injection of meltwater or seasonal precipitation are shifted below the evaporation trajectory along a mixing trend. Ponds that were cut off from recharge show elevated δ18O values and approach a simple pan evaporation trajectory. Distinguishing of these different hydrological processes is made possible by triple oxygen isotope analysis. In the classic δD-δ18O system, trajectories for pan and recharge evaporation as well as mixing may not be easily resolved. REFERENCES [1] J. SURMA, S. ASSONOV, M. J. BOLOURCHI, AND M. STAUBWASSER, Triple oxygen isotope signatures in evaporated water bodies from the Sistan Oasis, Iran, Geophys. Res. Lett. 42 (2015) 20. [2] J. SURMA, S. ASSONOV, D. HERWARTZ, C. VOIGT, AND M. STAUBWASSER, The evolution of 17O-excess in surface water of the arid environment during recharge and evaporation, Sci. Rep. 8 (2018) 4972. |
Responsible Party
| Creators: | Claudia Voigt (Author), Daniel Herwartz (Author), Jakub Surma (Author), Michael Staubwasser (Author) |
| Contributor: | Claudia Voigt (Contact Person) |
| Funding Reference: | Deutsche Forschungsgemeinschaft (DFG): CRC 1211: Earth - Evolution at the Dry Limit |
| Publisher: | CRC1211 Database (CRC1211DB) |
| Publication Year: | 2019 |
Topic
| CRC1211 Topic: | Climate |
| Related Subproject: | D3 |
| Subjects: | Keywords: Paleoclimate Proxies, Stable Isotope Geochemistry |
| Geogr. Information Topic: | Environment |
File Details
| Filename: | 2019_IAEA_Symposium_Isotope_Hydrology_Talk.pdf |
| Data Type: | Text - Text |
| File Size: | 2.6 MB |
| Date: | Issued: 23.05.2019 |
| Mime Type: | application/pdf |
| Data Format: | |
| Language: | English |
| Status: | In Process |
Constraints
| Download Permission: | Only Project Members |
| General Access and Use Conditions: | According to the CRC1211DB data policy agreement. |
| Access Limitations: | According to the CRC1211DB data policy agreement. |
| Licence: | [CRC1211DB] Data policy agreement |
Geographic
Specific Information - Presentation
| Presenter: | Claudia Voigt |
| Presentation Date: | 23rd of May, 2019 |
| Presentation Type: | Talk |
| Event: | IAEA - International Symposium on Isotope Hydrology |
| Event Type: | Conference |
| Event Location: | Vienna |
| Event Duration: | 20th of May, 2019 - 24th of May, 2019 |
| Event Website: | https://www.iaea.org/events/international-symposium-on-isotope-hydrology-2019 |
Metadata Details
| Metadata Creator: | Claudia Voigt |
| Metadata Created: | 27.05.2019 |
| Metadata Last Updated: | 27.05.2019 |
| Subproject: | D3 |
| Funding Phase: | 1 |
| Metadata Language: | English |
| Metadata Version: | V50 |
Metadata Export
| Metadata Schema: |
Dataset Statistics
| Page Visits: | 201 |
| Metadata Downloads: | 0 |
| Dataset Downloads: | 2 |
Dataset Activity
Feature
DownloadBy downloading this dataset you accept the license terms of [CRC1211DB] Data policy agreement and CRC1211DB Data Protection Statement
Adequate reference when this dataset will be discussed or used in any publication or presentation is mandatory. In this case please contact the dataset creator.
Adequate reference when this dataset will be discussed or used in any publication or presentation is mandatory. In this case please contact the dataset creator.
