Studio petrografico-mineralogico delle meteoriti Alfianello e Trenzano cadute nella provincia di Brescia nellla seconda meta' del 1800.

Petrographic-Mineralogical study of Alfi anello and Trenzano meteorites fall in the province of Brescia in the second half of 1800. A news scientifi c investigation is carried out in conjunction with the historical research on the two famous meteorites Trenzano and Alfi anello stored at the Museo Civico di Scienze Naturali of Brescia. The new petrographic and mineralogic study pointed our some petrographic features that appeared incompatible with the previous offi cial classifi cation (H6). This led to a revision work (FIORETTI et al., 2007) which indicates that Trenzano meteorite is an H5 chondrite with a shock stage S2 and alteration W0. A single-crystal XRD study performed on a suite of six orthopyroxene grains of Trenzano meteorite indicates a cooling rate of about 100 °C/kyr at a closure temperature (Tc) of 522±13 °C which provides new information on the thermal history of the parent body. Our petrographic and mineralogic investigation confi rms the classifi cation of the meteorite Alfi anello reported in the Catalogue of Meteorites (GRAHAM et al., 1985) as L6 ordinary chondrite, shock stage S5 and alteration W0.