Bulk and In-situ Chemical Analysis of Meteorite Berduc, an L6 Chondrite

Abstract

We present a detailed study of petrography, mineralogy, mineral chemistry and bulk chemistry of the Berduc L6 ordinary chondrite, which fell in 2008 in Colonia Berduc, Argentina. Modal abundance of the constituent phases is similar to the other L6 chondrites. The preserved phases of oxide and sulphide point towards a low-grade thermal metamorphism in Berduc parent body. Presence of melt veins and evidence of element redistribution in constituent phases indicate Berduc underwent localised melting processes, due to shock loading (S4). Further, highly volatile elements are depleted as compared to CI-chondrite. The heating process in Berduc parent mass took place in an open environment allowing volatiles to get lost from the system at low temperatures. These conditions enabled the preservation of pristine non-silicate assemblages. The fact that the bulk REE and refractory elements in Berduc are akin to that of the CI-chondrite, indicates that they were not mobilised from Berduc parent mass. The unfractionated pattern exhibited by the refractory and moderately volatile trace elements resembles that of an unequilibrated ordinary chondrite. Berduc parent body seems to have had a particular behaviour, as an open system allowing a substantial loss of the highly volatile elements and as a closed-system during and after the peak thermal metamorphism.