Chromite and platinum group elements mineralization in the Santa Elena Ultramafic Nappe (Costa Rica): geodynamic implications
Chromitites associated with strongly altered peridotite from six distinct localities in the Santa Elena ultramafic nappe (Costa Rica) have been investigated for the first time. Santa Elena chromitites commonly display a compositional variation from extremely chromiferous (Cr/(Cr+Al)=0.81) to interme...
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| Format: | Article |
| Language: | English |
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Universitat de Barcelona (UB), Geociències Barcelona (Geo3BCN), Institut de Diagnosi Ambiental i Estudis de l'Aigua (IDAEA), Universitat Autònoma de Barcelona (UAB)
2011-11-01
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| Series: | Geologica Acta |
| Subjects: | |
| Online Access: | https://revistes.ub.edu/index.php/GEOACTA/article/view/3705 |
| _version_ | 1797654540679380992 |
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| author | F. ZACCARINI G. GARUTI J.A. PROENZA FERNANDEZ L. CAMPOS O.A.R. THALHAMMER T. AIGLSPERGER J.F. LEWIS |
| author_facet | F. ZACCARINI G. GARUTI J.A. PROENZA FERNANDEZ L. CAMPOS O.A.R. THALHAMMER T. AIGLSPERGER J.F. LEWIS |
| author_sort | F. ZACCARINI |
| collection | DOAJ |
| description | Chromitites associated with strongly altered peridotite from six distinct localities in the Santa Elena ultramafic nappe (Costa Rica) have been investigated for the first time. Santa Elena chromitites commonly display a compositional variation from extremely chromiferous (Cr/(Cr+Al)=0.81) to intermediate and aluminous (Cr/(Cr+Al)=0.54). This composition varies along a continuous trend, corresponding to calculated parental liquids which may have been derived from the differentiation of a single batch of boninitic magma with Cr-rich and (Al, Ti)-poor initial composition. Fractional precipitation of chromite probably occurred during differentiation of the boninitic melt and progressive metasomatic reaction with mantle peridotite. The distribution of platinum group elements (PGE) displays the high (Os+Ir+Ru)/(Rh+Pt+Pd) ratio typical of ophiolitic chromitites and, consistently, the platinum group minerals (PGM) encountered are mainly Ru-Os-Ir sulfides and arsenides. Textural relations of most of the platinum group elements suggest crystallization at magmatic temperatures, possibly under relatively high sulfur fugacity as indicated by the apparent lack of primary Os-Ir-Ru alloys. The chemical and mineralogical characteristics of chromitites from the Santa Elena ultramafic nappe have a strong affinity to podiform chromitites in the mantle section of supra-subduction-zone ophiolites. Calculated parental melts of the chromitites are consistent with the differentiation of arc-related magmas, and do not support the oceanic spreading center geodynamic setting previously proposed by some authors |
| first_indexed | 2024-03-11T17:00:59Z |
| format | Article |
| id | doaj.art-18a03f893bec466a87c2bbad4ad5e782 |
| institution | Directory Open Access Journal |
| issn | 1696-5728 |
| language | English |
| last_indexed | 2024-03-11T17:00:59Z |
| publishDate | 2011-11-01 |
| publisher | Universitat de Barcelona (UB), Geociències Barcelona (Geo3BCN), Institut de Diagnosi Ambiental i Estudis de l'Aigua (IDAEA), Universitat Autònoma de Barcelona (UAB) |
| record_format | Article |
| series | Geologica Acta |
| spelling | doaj.art-18a03f893bec466a87c2bbad4ad5e7822023-10-20T07:20:49ZengUniversitat de Barcelona (UB), Geociències Barcelona (Geo3BCN), Institut de Diagnosi Ambiental i Estudis de l'Aigua (IDAEA), Universitat Autònoma de Barcelona (UAB)Geologica Acta1696-57282011-11-0193-4Chromite and platinum group elements mineralization in the Santa Elena Ultramafic Nappe (Costa Rica): geodynamic implicationsF. ZACCARINI0G. GARUTI1J.A. PROENZA FERNANDEZ2L. CAMPOS3O.A.R. THALHAMMER4T. AIGLSPERGER5J.F. LEWIS6Department of Applied Geosciences and Geophysics, University of Leoben. Peter Tunner Str. 5, 8700 Leoben, Austria.Department of Applied Geosciences and Geophysics, University of Leoben. Peter Tunner Str. 5, 8700 Leoben, Austria.Departament de Cristal·lografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona (UB)C/ Martí i Franquès s/n, E–08028 Barcelona, Spain.Escuela Centroamericana de Geología, University of Costa Rica. San Pedro de Montes de Oca, 240-2060 UCR, San José, Costa RicaDepartment of Applied Geosciences and Geophysics, University of Leoben. Peter Tunner Str. 5, 8700 Leoben, Austria.Departament de Cristal·lografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona (UB)C/ Martí i Franquès s/n, E–08028 Barcelona, Spain.Department of Earth and Environmental Sciences, The George Washington University. 2029 G St. NW, Washington, D.C. 20052, U.S.AChromitites associated with strongly altered peridotite from six distinct localities in the Santa Elena ultramafic nappe (Costa Rica) have been investigated for the first time. Santa Elena chromitites commonly display a compositional variation from extremely chromiferous (Cr/(Cr+Al)=0.81) to intermediate and aluminous (Cr/(Cr+Al)=0.54). This composition varies along a continuous trend, corresponding to calculated parental liquids which may have been derived from the differentiation of a single batch of boninitic magma with Cr-rich and (Al, Ti)-poor initial composition. Fractional precipitation of chromite probably occurred during differentiation of the boninitic melt and progressive metasomatic reaction with mantle peridotite. The distribution of platinum group elements (PGE) displays the high (Os+Ir+Ru)/(Rh+Pt+Pd) ratio typical of ophiolitic chromitites and, consistently, the platinum group minerals (PGM) encountered are mainly Ru-Os-Ir sulfides and arsenides. Textural relations of most of the platinum group elements suggest crystallization at magmatic temperatures, possibly under relatively high sulfur fugacity as indicated by the apparent lack of primary Os-Ir-Ru alloys. The chemical and mineralogical characteristics of chromitites from the Santa Elena ultramafic nappe have a strong affinity to podiform chromitites in the mantle section of supra-subduction-zone ophiolites. Calculated parental melts of the chromitites are consistent with the differentiation of arc-related magmas, and do not support the oceanic spreading center geodynamic setting previously proposed by some authorshttps://revistes.ub.edu/index.php/GEOACTA/article/view/3705ChromititeSanta Elena Ultramafic NappeCosta RicaChromite compositionPGE-PGMGeodynamic setting |
| spellingShingle | F. ZACCARINI G. GARUTI J.A. PROENZA FERNANDEZ L. CAMPOS O.A.R. THALHAMMER T. AIGLSPERGER J.F. LEWIS Chromite and platinum group elements mineralization in the Santa Elena Ultramafic Nappe (Costa Rica): geodynamic implications Geologica Acta Chromitite Santa Elena Ultramafic Nappe Costa Rica Chromite composition PGE-PGM Geodynamic setting |
| title | Chromite and platinum group elements mineralization in the Santa Elena Ultramafic Nappe (Costa Rica): geodynamic implications |
| title_full | Chromite and platinum group elements mineralization in the Santa Elena Ultramafic Nappe (Costa Rica): geodynamic implications |
| title_fullStr | Chromite and platinum group elements mineralization in the Santa Elena Ultramafic Nappe (Costa Rica): geodynamic implications |
| title_full_unstemmed | Chromite and platinum group elements mineralization in the Santa Elena Ultramafic Nappe (Costa Rica): geodynamic implications |
| title_short | Chromite and platinum group elements mineralization in the Santa Elena Ultramafic Nappe (Costa Rica): geodynamic implications |
| title_sort | chromite and platinum group elements mineralization in the santa elena ultramafic nappe costa rica geodynamic implications |
| topic | Chromitite Santa Elena Ultramafic Nappe Costa Rica Chromite composition PGE-PGM Geodynamic setting |
| url | https://revistes.ub.edu/index.php/GEOACTA/article/view/3705 |
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