Multiple carriers of Q noble gases in primitive meteorites

TL;DR

This study provides experimental evidence that the primordial noble gases in meteorites are likely contained in two subcomponents, sulfides and carbonaceous phases, revealing their formation conditions and behavior.

Contribution

It offers the first direct experimental evidence linking meteoritic sulfides to phase Q noble gases, suggesting a dual-component nature of the carrier.

Findings

Noble gases in sulfides show behavior similar to phase Q gases.

In situ decay of iodine in sulfides reproduces observed Xe isotopic excess.

Sulfides formed at high temperature, recording chondrule formation conditions.

Abstract

The main carrier of primordial heavy noble gases in chondrites is thought to be an organic phase, known as phase Q, whose precise characterization has resisted decades of investigation. Indirect techniques have revealed that phase Q might be composed of two subphases, one of them associated with sulfide. Here we provide experimental evidence that noble gases trapped within meteoritic sulfides present chemically- and thermally-driven behavior patterns that are similar to Q-gases. We therefore suggest that phase Q is likely composed of two subcomponents: carbonaceous phases and sulfides. In situ decay of iodine at concentrations levels consistent with those reported for meteoritic sulfides can reproduce the 129Xe excess observed for Q-gases relative to fractionated Solar Wind. We suggest that the Q-bearing sulfides formed at high temperature and could have recorded the conditions that prevailed in the chondrule-forming region(s).