Apatite from NWA 10153 and NWA 10645—The Key to Deciphering Magmatic and Fluid Evolution History in Nakhlites

Birski Birski,Majzner Majzner,Sláma Sláma,Słaby Słaby,Zagórska Zagórska,Kozub-Budzyń Kozub-Budzyń,Kocjan Kocjan,Wirth Wirth,Liszewska Liszewska,Chatzitheodoridis Chatzitheodoridis

doi:10.3390/min9110695

Abstract

Apatites from Martian nakhlites NWA 10153 and NWA 10645 were used to obtain insight into their crystallization environment and the subsequent postcrystallization evolution path. The research results acquired using multi-tool analyses show distinctive transformation processes that were not fully completed. The crystallization history of three apatite generations (OH-bearing, Cl-rich fluorapatite as well as OH-poor, F-rich chlorapatite and fluorapatite) were reconstructed using transmission electron microscopy and geochemical analyses. Magmatic OH-bearing, Cl-rich fluorapatite changed its primary composition and evolved toward OH-poor, F-rich chlorapatite because of its interaction with fluids. Degassing of restitic magma causes fluorapatite crystallization, which shows a strong structural affinity for the last episode of system evolution. In addition to the three apatite generations, a fourth amorphous phase of calcium phosphate has been identified with Raman spectroscopy. This amorphous phase may be considered a transition phase between magmatic and hydrothermal phases. It may give insight into the dissolution process of magmatic phosphates, help in processing reconstruction, and allow to decipher mineral interactions with hydrothermal fluids.

Highlights

Martian meteorites are the only source of material from Mars, so they are crucial for deciphering the magmatic evolution of the planet and the geochemical effects of fluid activity in deep and surfaceMinerals 2019, 9, 695; doi:10.3390/min9110695 www.mdpi.com/journal/mineralsMinerals 2019, 9, 695 reservoirs [1]
We primarily focused on apatites, which are volatile-bearing minerals of the NWA 10153 and NWA 10645 nakhlites, to understand their crystallization environment and postcrystallization evolution path
EPMAComposition results showed that minerals of the apatite group from both NWA 10645 and NWA

Summary

Introduction

Minerals 2019, 9, 695 reservoirs [1] These meteorites are divided into three main groups, shergottites, nakhlites, and chassignites, often denoted as SNC. They can provide information regarding the Martian mantle and volcanism, the geochemical effects of fluid activity on the Martian surface, atmospheric composition, liquid water, and potential environments for life [2,3,4,5,6,7,8,9,10,11,12,13]. Nakhlites were ejected from Mars by a single impact event at 11 ± 1.5 Ma [14,16,20,21], potentially from a crater at 130.799◦ E, 29.674◦ N in the Elysium Mons region [18]

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