Oxidation state of iron and Fe-Mg partitioning between olivine and basaltic martian melts

Abstract

This is the peer-reviewed, final accepted version for American Mineralogist, published by the Mineralogical Society of America.The published version is subject to change. Cite as Authors (Year) Title. American Mineralogist, in press.

Petrological Traverse of the Olivine Cumulate Séítah Formation at Jezero Crater, Mars: A Perspective From SuperCam Onboard Perseverance

“…In Figure 13, for each olivine grain, the olivine Mg# is plotted against the rock Mg#, which is the average composition of the raster in which the olivine was probed. All data from Séítah are significantly above the equilibrium line even if the greatest value for the exchange parameters (Matzen et al., 2022) is taken. This confirms that olivine is not in equilibrium with the host rock in any of the regions of the Séítah formation visited by Perseverance.…”

“…As locally established by Liu et al (2022) for the Dourbes abraded patch, olivine Mg#s are similar to the whole rock Mg#s (Figure 13). This implies that olivine is not in chemical equilibrium with a liquid that has the whole rock composition, as the exchange coefficient for Fe-Mg partitioning between olivine and basaltic melt is 0.35 (Filiberto & Dasgupta, 2011) to 0.36 (Matzen et al, 2022) for Mars. This disequilibrium is a key argument for the determination of the cumulate nature of these rocks as it implies that the olivine did not crystallize in place to form the host rock, but instead is derived from an unknown melt composition.…”

The Temperature and Composition of the Mantle Sources of Martian Basalts

“…We also test whether two individual clasts, representative of the main families of basaltic clasts (Santos et al, 2015;Wittmann et al, 2015), could be primitive basalts later remelted by impacts: a vitrophyre (Udry et al, 2014) and an alkali-rich microbasalt known as "Clast VI" (Humayun et al, 2013). composition (e.g., Matzen et al, 2022;Musselwhite et al, 2006). The olivine megacrysts in LAR 06319 and NWA 1068 have Mg# ≤ 77 (Basu Sarbadhikari et al, 2009) but were initially more magnesian (Mg# 80) and were modified by Fe-Mg diffusion (Balta et al, 2013;Collinet et al, 2017).…”

“…The most primitive depleted shergottite (Yamato (Y) 980459, nearly identical to NWA 5789; Greshake et al., 2004; Gross et al., 2011) and the most primitive enriched shergottite (Larkman Nunatak (LAR) 06319, nearly identical to NWA 1068; Barrat et al., 2002; Peslier et al., 2010) have Mg# of 66 and 58, respectively. Y 980459 contains olivine Mg# 85–86 and is thought to represent a primary melt composition (e.g., Matzen et al., 2022; Musselwhite et al., 2006). The olivine megacrysts in LAR 06319 and NWA 1068 have Mg# ≤ 77 (Basu Sarbadhikari et al., 2009) but were initially more magnesian (Mg# 80) and were modified by Fe–Mg diffusion (Balta et al., 2013; Collinet et al., 2017).…”

The temperature and composition of the mantle sources of Martian basalts

“…The most primitive depleted shergottite (Yamato 980459, nearly identical to NWA 5789; Greshake et al, 2004;Gross et al, 2011) and the most primitive enriched shergottite (LAR 06319, nearly identical to NWA 1068; Barrat et al, 2002;Peslier et al, 2010) have Mg# of 66 and 58, respectively. Y 980459 contains olivine Mg# 85-86 and is thought to represent a primary melt composition (e.g., Musselwhite et al, 2006;Matzen et al, 2022). The olivine megacrysts in LAR 06319 and NWA 1068 have Mg# ≤ 77 (Basu Sarbadhikari et al, 2009) but were initially more magnesian (Mg# 80)…”