Deployment of a novel field stable isotope analyzer: trials on fumaroles at Solfatara volcano, Campi Flegrei, Italy.
Abstract
Volcanic degassing is the primary mechanism by which carbon is transferred from Earth's interior to the atmosphere—making extensive monitoring of Earth's volcanoes essential to understanding the planet's total carbon budget. Determining the 13CO2/12CO2 ratio in emissions can reveal if the carbon was mantle or crust derived, allowing researchers to model carbon pathways among Earth's deep reservoirs. The Laser Isotope Ratiometer (LIR) is a new instrument specialized in measuring the ratio of stable isotopes of a given molecule. The current system has been developed and demonstrated for 13C:12C (δ13) analysis in CO2, with high precision (0.3 per mil in 10 seconds), in real time, and in a compact and robust package to allow deployment in-situ. The instrument underpinning architecture includes features such as drifts cancellation techniques and on-board calibration for autonomous operation and enhanced stability and accuracy. The LIR brings simplicity to stable isotope analysis, whether in the field or in a laboratory environment. The instrument's design originated as part of a European Space Agency programme to demonstrate the LIR for application in planetary landers. Overall the design offers compactness, robustness and precision without the need for a skilled operator or consumables and owing to a novel dual laser approach, the system offers far greater stability over a wide temperature range. Supported by an instrumentation grant from the Sloane Foundation Deep Carbon Observatory, a first field deployment of the LIR was conducted at the Solfatara volcano, Campi Flegrei, Italy, to trial the in situ, real-time measurements of 13CO2/12CO2 ratios in fumaroles. The instrument operated very well in the field and proved to be extremely resilient to dirty samples. A systematic bias of -1 per mil was observed in comparison to the reference measurements made in the laboratory by isotopic ratio mass spectrometry, which was traced back to fractionation in long sampling intake tubing.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.V43B3160L
- Keywords:
-
- 1040 Radiogenic isotope geochemistry;
- GEOCHEMISTRYDE: 1041 Stable isotope geochemistry;
- GEOCHEMISTRYDE: 1094 Instruments and techniques;
- GEOCHEMISTRYDE: 5494 Instruments and techniques;
- PLANETARY SCIENCES: SOLID SURFACE PLANETS