The Buritizal meteorite: classification of a new Brazilian chondrite

Abstract On August 14, 1967, the reporter Saulo Gomes, working at TV Tupi, went to a small city in the State of São Paulo called Buritizal to investigate reports of a meteorite fall and write a newspaper report. He actually recovered three fragments of the meteorite at a small farm. In 2014, he donated one of the fragments to the Museu Nacional of the Universidade Federal do Rio de Janeiro (MN/UFRJ). We named this meteorite Buritizal and studied its petrology, geochemistry, magnetic properties and cathodoluminescence with the intent to determine the petrologic classification of the meteorite. In this manner, the Buritizal meteorite is classified as an ordinary chondrite LL 3.2 breccia (as indicated by lithic fragments). The meteorite consists of ~ 2% of metallic Fe,Ni and many well-defined chondrules with ~ 0.8 mm in average diameter. An ultramafic ferromagnesian mineralogy is predominant in the meteorite, represented by olivine, orthopyroxene, clinopyroxene, Fe-Ni alloy, troilite and glass. The total iron content was calculated as 20.88 wt%. Furthermore, the meteorite was classified as weathering grade W1 and shock stage S3. Buritizal is the 25th observed meteorite fall recovered in Brazil, of 70 meteorites known from Brazil. Thus, the study of the Buritizal meteorite is very important and relevant for the Brazilian scientific community.摘要 1967年8月14日，供职于图皮电视台（TV Tupi）的记者绍洛·戈麦斯（Saulo Gomes）前往巴西圣保罗州小城布里蒂萨尔（Buritizal），调查当地有关陨石坠落的报道并撰写新闻稿件。他最终在一处小型农场中回收了三块陨石碎片。2014年，他将其中一块碎片捐赠给里约热内卢联邦大学国家博物馆（Museu Nacional da Universidade Federal do Rio de Janeiro，MN/UFRJ）。我们将该陨石命名为布里蒂萨尔（Buritizal），并对其开展岩石学（petrology）、地球化学（geochemistry）、磁学性质及阴极发光（cathodoluminescence）研究，旨在确定该陨石的岩石学分类。经研究，布里蒂萨尔陨石被归类为普通球粒陨石（ordinary chondrite）LL 3.2角砾岩，该分类可通过岩屑碎片分析得到佐证。该陨石含约2%的铁镍金属合金，以及大量平均直径约0.8毫米的轮廓清晰的球粒。陨石以超镁铁质铁镁矿物组合为主，矿物组成包括橄榄石、斜方辉石、单斜辉石、铁镍合金、陨硫铁（troilite）及玻璃相。总铁含量经计算为20.88 wt%（重量百分比）。此外，该陨石的风化等级为W1，冲击阶段为S3。布里蒂萨尔是巴西境内第25颗被观测到坠落并回收的陨石，而目前已知的巴西陨石共计70颗。因此，对布里蒂萨尔陨石的研究对巴西科学界具有重要的学术价值与现实意义。