Constraining the Origin of Earth’s Water with Isotope Tracers in Astromaterials

Project Overview

Much of what has been inferred about the origin and evolution of water in the solar system comes from measurements of the hydrogen and oxygen (H and O) stable isotope compositions of bulk meteorites and other astromaterials. Yet, considerable uncertainty remains about the origin of the Solar System's water (and thus Earth's) and whether it came from water-rich chondritic meteorites that coalesced in the inner solar system, or those that formed further out, in the region of the gas giant planets. Limitations in previous techniques to analyze hydrogen and oxygen isotopes in these materials lead to H and O commingling from different minerals and organic matter into bulk pools, severely limiting interpretations. In this project we have developed Lawrence Livermore National Laboratory's unique TGA-IRIS (thermogravimetric analyzer + isotope ratio infrared spectroscopy) analytical capability to measure mineral-specific water and hydroxl-bound H and O isotope compositions in meteorites. Using the TGA-IRIS analytical system and methods developed during this project, we made preliminary measurements of the delta deuterium and delta oxygen-18 (δ²H and δ¹⁸O) values of mineral hydration water in iron oxide and phyllosilicate minerals in the Murchison carbonaceous chondrite meteorite.

Mission Impact

This research supports the Laboratory's nuclear, chemical, and isotopic core competency and helps establish Livermore as the premier laboratory in the world for measuring the abundances and isotopic compositions of water in extraterrestrial samples. With this investment, the Laboratory is uniquely situated to acquire NASA funding and measure the samples from asteroid sample return missions in 2023.

Publications, Presentations, and Patents

Oerter, E., Garenne, A., Singleton, M., Alexander, C., 2019. "Hydrogen and Triple Oxygen Stable Isotope Composition of Water in Hydrated Carbonaceous Chondrites." American Geophysical Union Fall Meeting, San Francisco. LLNL-ABS-784359.

Oerter, E., Singleton, M., Alexander, C., 2019. "Hydrogen and Triple Oxygen Stable Isotope Composition of Water in Hydrated Carbonaceous Chondrites." Goldschmidt Geochemistry Conference, Barcelona, Spain. LLNL-PRES-786697.