Modern classification of the Alfianello, Monte Milone, and Siena historical meteorites

Abstract

New microchemical and mineralogical data of three historical Italian falls (Alfianello, Monte Milone, and Siena meteorites) are presented here. These three meteorites have been scarcely studied and are amenable to being reinvestigated to update/confirm their classification, in particular looking for possibly overlooked shock features. A petrographic thin section containing fragments of the selected meteorites was provided by the Natural History Museum of the University of Firenze (Firenze University Museum System) and has been studied by optical and electron microscopy (FE-SEM), and electron microprobe (FE-EMPA). The data collected led to the following classification: Alfianello: L6, S5, W0; Monte Milone: L5, S1, W0-1; Siena: breccia LL 3-6, S1, W0- 1. Unlike previous studies, our new investigations revealed that the Alfianello sample displays the presence of ringwoodite (high-pressure polymorph of olivine), whereas the presence of maskelynite (diaplectic glass after plagioclase) was confirmed.