Shock vaporization/devolatilization of evaporitic minerals, halite and gypsum, in an open system investigated by a two-stage light gas gun

TL;DR

This study introduces a new experimental method to investigate how evaporitic minerals like halite and gypsum vaporize or devolatilize under shock impacts, shedding light on volatile release processes on Mars.

Contribution

A novel two-valve experimental technique was developed to study impact shock effects on evaporitic minerals in an open system without contamination.

Findings

Halite vaporizes at 31 GPa during impact.

Gypsum devolatilizes at 11 GPa, releasing volatiles.

Impact shocks could have contributed to Martian volatile history.

Abstract

Dry lakebeds might constitute large volatile reservoirs on Mars. Hypervelocity impacts onto ancient dry lakebeds would have affected the volatile distribution on Mars. We developed a new experimental method to investigate the response of evaporitic minerals (halite and gypsum) to impact shocks in an open system. This technique does not result in chemical contamination from the operation of the gas gun. The technique is termed the two-valve method and the gun system is located in the Planetary Exploration Research Center, Chiba Institute of Technology, Japan. We detected the vaporization of halite at 31 GPa and devolatilization from gypsum at 11 GPa, suggesting that impact-induced volatile release from dry lakebeds has periodically occurred throughout Martian history. The vaporization of halite deposits might have enhanced the production of perchlorates, which are found globally on Mars. The water loss from gypsum possibly explains the coexisting types of Ca-sulfates found in Gale Crater.