Hydrothermal origin of hexagonal CaAl₂Si₂O₈ (dmisteinbergite) in a compact type A CAI from the Northwest Africa 2086 CV3 chondrite

Abstract

3&). We infer that dmisteinbergite, together with the other secondary minerals, formed by replacement of melilite as a result of fluid-assisted thermal metamorphism experienced by the CV chondrite parent asteroid. Based on the textural appearance of dmisteinbergite in NWA 2086 and petrographic observations of altered CAIs from the Allende meteorite, we suggest that dmisteinbergite is a common secondary mineral in CAIs from the oxidized Allende-like CV3 chondrites that has been previously misidentified as a secondary anorthite.

Refractory inclusions in carbonaceous chondrites: Records of early solar system processes

“…; Fintor et al. ). The secondary minerals plot along mass‐dependent fractionation line with slope 0.5 and Δ 17 O of −2.6 ± 2.6‰ (average ±2 SD ) that corresponds to composition of aqueous fluid of the Allende meteorite parent asteroid.…”

“…The mineralogy and O-isotope compositions of the CH CAI-bearing chondrules are similar to those of the CH porphyritic chondrules without relict CAIs ). Choi et al 2000;Krot et al 2000Krot et al , 2010cHua et al 2005;Cosarinsky et al 2008;Jogo et al 2011;Fintor et al 2014). The secondary minerals plot along mass-dependent fractionation line with slope 0.5 and D 17 O of À2.6 AE 2.6& (average AE2SD) that corresponds to composition of aqueous fluid of the Allende meteorite parent asteroid.…”

Case study of chondrule alteration with IR spectroscopy in NWA 2086 CV3 meteorite

“…Although being an often analyzed meteorite type, several questions are unanswered in this group. Alteration in CV chondrites occasionally happened at high water/rock ratios (Zolensky et al, 1993), and while most CV meteorites belong to the petrographic type 3 (McSween, 1977) with little or no metamorphic and water related alteration, some signatures could also be present there related to hydration and interaction with water (Beck et al, 2010;Fintor et al, 2014). Thermal metamorphism happening at very low level in this type (Bonal et al, 2006), as well as their potential connection to CK chondrites (Weisberg et al, 2006) should be analyzed, with emphasis on the formation conditions (Quirico et al, 2011) that also requires more detailed work.…”

“…The aim of this work is to analyze the alteration of a chondrule in the NWA 2086 CV3 type chondrite with a special method: contact measurements with ATR detector on a Fourier Transform Infrared Spectrometer; the findings might have implications on other carbonaceous chondrites, including their alterations (Fintor et al, 2013). Although being an often analyzed meteorite type, several questions are unanswered in this group.…”

Shock heterogeneity and shock history of the recently found ordinary Csátalja chondrite in Hungary

“…Al though in clas si cal Earth sci ences this method is al ready used, for cos mic ma te ri als it has been less com monly employed. In this work we ana lyse typ i cal me te or ite min er als, includ ing shock-al tered ones, in or der to dem on strate some useful ca pa bil i ties of FTIR ATR and also the lim its of this method, by com par ing in fra red ob ser va tions with better es tab lished Raman mea sure ments for phase iden ti fi ca tion and char ac te r iza tion (Fintor et al, 2014). The aim be sides the meth od olog i cal test ing is to char ac ter ize the shock de for ma tion and es ti mate for ma tion con di tions, the ex tent of small-scale het er o ge ne ity, and to re con struct a shock his tory of this me te or ite.…”