Stable Isotope Analysis – Measuring δ¹⁷O in Water by CRDS

The lab only accepts samples that are ready for δ¹⁷O measurement (filtered, no chemicals added, do not require pretreatment).

Stable Isotope Analysis Cost

Beta Analytic provides δ¹⁷O water analysis on a standalone basis or in conjunction with δ¹⁸O and δD measurements for a fee using a cavity ring-down spectrometer (CRDS).

To request for a formal quotation, please let us know the number of water samples for analysis and the billing information of the paying institution.

Submittal – Please use this online form. For details on how to collect and submit water samples, please see our Radiocarbon Dating Groundwater page.

If you have any questions about your sample, please contact the lab.

Why Measure δ¹⁷O in Water?

Triple isotopic variability reveals more information about environmental conditions than dual isotopic tools alone. For example, deuterium excess in water – interpreting the variability of protium to deuterium isotopes in relation to δ¹⁸O from meteoric waters has been used to enhance the interpretation of humidity and its effects on the fractionation of water isotopes. Since many geological materials (evaporite minerals) do not incorporate H into their structural components, the use of deuterium excess has its limits as an environmental proxy, few materials can produce meaningful results (Li et al., 2015).

Oxygen has the potential to be a triple isotopic tool that can reveal additional information about evaporation and condensation oxygen systematics among many oxygen-bearing materials. Δ¹⁷O (δ¹⁸O v. δ¹⁷O) or the variability of ¹⁷O and ¹⁸O to ¹⁶O has only recently been recognized to have the potential as an additional proxy as the precision of isotopic analysis has increased. Current research has been focused on understanding Δ¹⁷O variability in modern meteoric waters as baseline investigations to relate results of Δ¹⁷O to other materials.

Beta Analytic’s Capabilities

The lab’s current CRDS is capable of determining the δ¹⁷O ((¹⁷O/¹⁶OUNKN/¹⁷O/¹⁶OSTD-1)*1000) values of water vapor at a precision of +/- 0.8 ‰ or better as well as determine a ¹⁷O-excess value (also referred to as Δ¹⁷O).

The ¹⁷O-excess value is defined as the deviation from an expected relationship in ¹⁷O/¹⁶O and ¹⁸O/¹⁶O ratios (Li et al., 2015). The CRDS measures both the δ¹⁷O and δ¹⁸O and the software calculates the ¹⁷O-excess.

The data are used to suggest information regarding the conditions in which the phase change occurred. Did water evaporate in a climate that was arid or humid or at a high elevation or low elevation? Δ¹⁷O data can refine conditions further by the addition of condensation and evaporation effects on fractionation.

Evaporation has been found to vary both δ¹⁸O and Δ¹⁷O values whereas condensation has been found to only significantly shift δ¹⁸O values. Suggesting that δ¹⁷O and δ¹⁸O values covary at different rates with evaporation and condensation.

Reference:

Li, S., Levin, N. E., & Chesson, L. A. (2015). Continental scale variation in ¹⁷O-excess of meteoric waters in the United States. Geochimica et Cosmochimica Acta, 164, 110-126.

Beta Analytic Webinars: