LINK<\/strong><\/a><\/p>\n\n\n\n“On the night of June 22, 1931 at 4\u2009h 30\u2009min, a fireball was seen in the vicinity of Malotas, Argentina. During the atmospheric trajectory (southwest to northeast), it experienced several fragmentation events. After the fall, a piece was given to Professor Juan A. Olsacher (National University of C\u00f3rdoba City, Argentina), who collected some further pieces. One of those samples was officially classified as an H5 ordinary chondrite termed Malotas. The present work focuses on the study of another two pieces rediscovered recently in the Museo de Mineralog\u00eda y Geolog\u00eda Dr. Alfred Stelzner in Cordoba City, Argentina. The first piece turned out to be an achondritic meteorite termed Malotas (b). Petrographic features, chemical composition, and oxygen isotopes point to a monomict basaltic eucrite belonging to the Stannern-trend chemical subgroup of eucrites. The occurrence of anorthitic plagioclase veins in clinopyroxene, veinlet apatite, irregular-shaped pockets of silica and troilite and porous silica signal metasomatism and thermal annealing before a late thermal event took place after brecciation. The latter was possibly recorded in the nominal U\/Th-4He ages of 1.2\u20133.4\u2009Ga detected in this work, whereas nominal K-Ar gas retention ages are within the range 3.5\u20134.2\u2009Ga and may have escaped late thermal modifications. The second piece is classified as an L5 chondrite. The different cosmic ray exposure ages of 3, ~50, and 27\u2009Ma determined for the H5 and L5 chondrites and the eucrite samples, respectively, might signal a common fall as a result of the breakup of a polymict meteoroid.”<\/p>\n","protected":false},"excerpt":{"rendered":"
Marcela E. Saavedra, Julia Roszjar, My E. I. Riebe, Mar\u00eda E. Varela, Shuying Yang, Munir Humayun, Ryoji Tanaka, H. Busemann MAPSFirst Published: 17 November 2022 LINK “On the night of June 22, 1931 at 4\u2009h…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[35,54,7,47],"tags":[1823,5,1838,103,6413,1807,1832],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/31575"}],"collection":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=31575"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/31575\/revisions"}],"predecessor-version":[{"id":31576,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/31575\/revisions\/31576"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=31575"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=31575"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=31575"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}