The lherzolitic shergottite Grove Mountains 99027: Rare earth element geochemistry

Abstract

is widespread in non-poikilitic regions, occurring interstitially between olivine and pyroxene grains. It is the main REE carrier in GRV 99027 and has relatively higher REEs (200-1000 × CI) than that of other lherzolitic shergottites. A REE budget calculation for GRV 99027 yields a whole rock REE pattern very similar to that of other lherzolites. It is characterized by the distinctive light REE depletion and a smooth increase from light REEs to heavy REEs. REE microdistributions in GRV 99027 strongly support the idea that all lherzolitic shergottites formed by identical igneous processes, probably from the same magma chamber on Mars. Despite many similarities in mineralogy, petrography, and trace element geochemistry, subtle differences exist between GRV 99027 and other lherzolitic shergottites. GRV 99027 has relatively uniform mineral compositions (both major elements and REEs), implying that it suffered a higher degree of sub-solidus equilibration than the other three lherzolites. It is notable that GRV 99027 has experienced terrestrial weathering in the Antarctic environment, as its olivine and pyroxenes commonly display a light REE enrichment and a negative Ce anomaly. Caution needs to be taken in future chronological studies.

Petrography, mineralogy, and geochemistry of lunar meteorite Sayh al Uhaymir 300

“…Both synthetic (NBS) and natural mineral standards were used, and matrix corrections were based on ZAF procedures (Armstrong 1982). The rare earth element (REE) and trace element concentrations were measured in situ on individual grains of olivine, pyroxenes, plagioclase, apatite, and impact-melt glass with the Cameca-6f ion microprobe at Arizona State University, using procedures described in Hsu et al (2004). An O − primary ion beam of 1-4 nA was accelerated to −12.5 KeV.…”

Localized shock melting in lherzolitic shergottite Northwest Africa 1950: Comparison with Allan Hills 77005

“…NWA 1950 is one of seven lherzolitic shergottites: Allan Hills (ALH) 77005 (McSween et al 1979), Lewis Cliff (LEW) 88516 (Gleason et al 1997), Yamato (Y-) 793605 (Ikeda 1997), Grove Mountain (GRV) 99027 (Hsu et al 2004), GRV 020090 (Russell et al 2005), and NWA 2646 (Bunch et al 2005), representing the first sample of this type recovered outside of Antarctica. NWA 1950 was originally described as a plagioclase-bearing ultramafic cumulate rock consisting of olivine, low-and high-Ca pyroxene, and plagioclase (transformed to maskelynite by shock metamorphism) (Russell et al 2004).…”

Expanding the application of the Eu‐oxybarometer to the lherzolitic shergottites and nakhlites: Implications for the oxidation state heterogeneity of the Martian interior

“…c Melt REE data for ALH 77005 and MIL 03346 from this study. Melt data for the other meteorites is as follows: LEW 88516 (Dreibus et al 1992); Y 793605 (Warren and Kallemeyn 1997); GM 99027 (Hsu et al 2004); Nakhla, Lafayette, Y 593/749 (Dreibus et al 2003); NWA 817 (Sautter et al 2002).…”