LINK<\/strong><\/a><\/p>\n\n\n\n“This study models the compositional evolution of a chondritic starting material representative of the Mesosiderite Parent Body (MSPB) under relevant pressure-temperature-redox conditions (1\u202fbar, 1800\u2013500\u202f\u00b0C, fO2\u202f=\u202fIW\u202f+\u202f1.8), focusing exclusively on the evolution of the silicate portion of the system and not on the origin or evolution of the metallic component. The modelling framework assumes crystallization within a silicate magma ocean, and explores crystallization pathways involving varying degrees of equilibrium crystallization (EC) and fractional crystallization (FC). In addition, we present new mineral-chemistry, and phase data from two mesosiderite specimens, Estherville and Mincy.
Modelling results indicate that mesosiderite silicate mineralogy can be derived from a chondritic composition through an efficient three-stage cooling sequence: 40\u201350% EC, followed by FC down to 1395\u202f\u00b0C, and then final EC of the remaining melt to 914\u202f\u00b0C, at which point crystallization is complete. The predicted modal abundances\u201469\u202fwt% pyroxenes, 26\u202fwt% plagioclase, 1.9\u202fwt% tridymite, and 1.6\u202fwt% whitlockite\u2014closely match the observed proportions in Estherville and Mincy. In both meteorites, pyroxenes and tridymites serve as robust geothermometers, stable across 870\u20131470\u202f\u00b0C. The strong agreement between modelled Mg#, Fe#, density, and fO2 with published mesosiderite values further supports a chondritic starting composition of the MSPB.
The model suggests that the MSPB mantle consisted of olivine-orthopyroxene cumulates (dunitic in character), while the lower crust was dominated by pigeonite and hypersthene, forming a pyroxenitic lithology. The upper crust was enriched in plagioclase and pyroxene, reflecting a basaltic composition. Following differentiation, the MSPB likely underwent a collisional encounter with a differentiated impactor, leading to excavation of its silicate crust, followed by brecciation, remelting, and clast metamorphism. These processes ultimately produced mesosiderite meteorites as composite breccias of MSPB-derived silicates intermixed with metallic phases contributed by the impacting body.”<\/p>\n","protected":false},"excerpt":{"rendered":"
Pipasa Layak, Nachiketa Rai, Kuljeet Kaur Marhas, Hilary Downes GeochemistryAvailable online 16 May 2026, 126426 LINK “This study models the compositional evolution of a chondritic starting material representative of the Mesosiderite Parent Body (MSPB) under…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[765,4108],"tags":[3740,4109,2660,1893,4111,6392],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/41778"}],"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=41778"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/41778\/revisions"}],"predecessor-version":[{"id":41779,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/41778\/revisions\/41779"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=41778"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=41778"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=41778"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}