STUDY OF METALS AND SULFIDE BY ELECTRON MICROSCOPY OF THE PACULA METEORITE

The composition and textures of sulfide and metal phases have been examined in Pacula meteorite, using backscattered electron imaging and quantitative electron microprobe analysis with scanning electron microscopy. Pacula fell in 1881, at Hidalgo State, Mexico. Pacula is an ordinary chondrite L6, with Fe-Ni metal phases (kamacite, taenite, martensite and tetrataenite), sulfide troilite, include the presence of metallic Cu, irregular troilite grains within metallic Fe-Ni, polycrystalline trolite and tetrataenita, plessite, metal and troilite veins, large troilite nodules (10 mm) and small blebs of metallic Fe-Ni and troilite. Its Co content in kamacite varies significantly from 0.5 to 1.0 wt%. Microstructural criteria that indicate high shock stage S4-S5 Based on the observed eutectic textures; it can deduce a cooling rate of at least of 988 degrees C. By other hand, a slow cooling of 300 degrees C is indicated by the tetrataenite margins around the taenite crystals.