The origin, occurrence and distribution of water and volatiles in nominally anhydrous minerals
EMSL Project ID
51905
Abstract
Nominally anhydrous minerals such as olivine and pyroxene constitute most of the major rock forming minerals. As a result, these phases are abundant in crustal and mantle rocks on Earth, as well as samples from the Moon, Mars, and the asteroid belt. They are also some of the first minerals to crystallize out of a melt, allowing them to record the earliest stages of a rock's formation and evolution. Recent work has shown that these 'anhydrous' phases can incorporate more water than previously thought (< 5,000 part per million), establishing a new reservoir for water and volatiles in a wide range of rocks throughout the Solar System. This is critically important on Earth, as the nominally anhydrous minerals are critical for the development of hydrous minerals (such as clays) and soils, which evolve from the alteration and breakdown of these abundant mineral phases and drive the release of elements critical for life, such as N, S, Cl, F and H. On the Moon, anhydrous minerals in ancient (>4 billion-year-old) rocks may preserve evidence of the abundance and composition of the earliest water, providing new insights into the origin of water on Earth. Despite this importance, very little work has focused on the mechanisms responsible for the incorporation of water and volatiles into phases such as pyroxene and olivine. Here, we propose to analyse a range of nominally anhydrous minerals in lunar samples to 1) determine the mechanisms responsible for hosting water and volatile species within the mineral lattice of pyroxene and olivine, and 2) provide new insights into the composition of ancient water on the Earth and Moon. The abundance and composition of water in nominally anhydrous minerals will be measured by NanoSIMS following published protocols, with the most water-rich phases being selected for nanoscale chemical and structural analysis utilising coupled atomic force microscopy (AFM), transmission electron microscopy (TEM), and atom probe tomography (APT). Understanding the mechanisms responsible for volatile inclusion in nominally anhydrous minerals is critical for the accurate interpretation of measured abundances and isotopic compositions, much of which is based upon the assumption of closed system behaviour following crystallization. By utilising lunar samples to address this major knowledge gap we will also produce a wide array of volatile data from ancient samples on the Moon, facilitating more accurate modelling of the origin and evolution of water in the inner Solar System. The challenging analytical approach proposed here hinges on the correlation of structure and chemistry across a wide range of length scales (from atoms to planets), and would be unachievable without the support of EMSL.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2021-10-01
End Date
2024-02-02
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)
Team Members