Major- and trace-element compositions of indicator minerals that occur as macro- and megacrysts, and of xenoliths, from kimberlites in Northeastern Angola

In this study, we compare the major- and trace-element compositions of olivine, garnet, and clinopyroxene that occur as single crystals (142 grains), with those derived from xenoliths (51 samples) from six kimberlites in the Lucapa area, northeastern Angola: Tchiuzo, Anomaly 116, Catoca, Alto Cuilo-...

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Autores principales: Robles-Cruz, S.E., Melgarejo, J.C., Galí, S., Escayola, M.
Formato: JOUR
Materias:
Angola
Clinopyroxene
Diamond
Garnet
Kimberlite
Mantle xenoliths
Nd isotopes
Olivine
REE
Sm
Thermobarometry
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_2075163X_v2_n4_p318_RoblesCruz
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_2075163X_v2_n4_p318_RoblesCruz
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spelling todo:paper_2075163X_v2_n4_p318_RoblesCruz2023-10-03T16:39:13Z Major- and trace-element compositions of indicator minerals that occur as macro- and megacrysts, and of xenoliths, from kimberlites in Northeastern Angola Robles-Cruz, S.E. Melgarejo, J.C. Galí, S. Escayola, M. Angola Clinopyroxene Diamond Garnet Kimberlite Mantle xenoliths Nd isotopes Olivine REE Sm Thermobarometry In this study, we compare the major- and trace-element compositions of olivine, garnet, and clinopyroxene that occur as single crystals (142 grains), with those derived from xenoliths (51 samples) from six kimberlites in the Lucapa area, northeastern Angola: Tchiuzo, Anomaly 116, Catoca, Alto Cuilo-4, Alto Cuilo-63 and Cucumbi-79. The samples were analyzed using electron probe microanalysis (EPMA) and laser-ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS). The results suggest different paragenetic associations for these kimberlites in the Lucapa area. Compositional overlap in some of the macrocryst and mantle xenolith samples indicates a xenocrystic origin for some of those macrocrysts. The presence of mantle xenocrysts suggests the possibility of finding diamond. Geothermobarometric calculations were carried out using EPMA data from xenoliths by applying the program PTEXL.XLT. Additional well calibrated single-clinopyroxene thermobarometric calculations were also applied. Results indicate the underlying mantle experienced different equilibration conditions. Subsequent metasomatic enrichment events also support a hypothesis of different sources for the kimberlites. These findings contribute to a better understanding of the petrogenetic evolution of the kimberlites in northeastern Angola and have important implications for diamond exploration. © 2012 by the authors; licensee MDPI, Basel, Switzerland. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_2075163X_v2_n4_p318_RoblesCruz
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Angola
Clinopyroxene
Diamond
Garnet
Kimberlite
Mantle xenoliths
Nd isotopes
Olivine
REE
Sm
Thermobarometry
spellingShingle Angola
Clinopyroxene
Diamond
Garnet
Kimberlite
Mantle xenoliths
Nd isotopes
Olivine
REE
Sm
Thermobarometry
Robles-Cruz, S.E.
Melgarejo, J.C.
Galí, S.
Escayola, M.
Major- and trace-element compositions of indicator minerals that occur as macro- and megacrysts, and of xenoliths, from kimberlites in Northeastern Angola
topic_facet Angola
Clinopyroxene
Diamond
Garnet
Kimberlite
Mantle xenoliths
Nd isotopes
Olivine
REE
Sm
Thermobarometry
description In this study, we compare the major- and trace-element compositions of olivine, garnet, and clinopyroxene that occur as single crystals (142 grains), with those derived from xenoliths (51 samples) from six kimberlites in the Lucapa area, northeastern Angola: Tchiuzo, Anomaly 116, Catoca, Alto Cuilo-4, Alto Cuilo-63 and Cucumbi-79. The samples were analyzed using electron probe microanalysis (EPMA) and laser-ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS). The results suggest different paragenetic associations for these kimberlites in the Lucapa area. Compositional overlap in some of the macrocryst and mantle xenolith samples indicates a xenocrystic origin for some of those macrocrysts. The presence of mantle xenocrysts suggests the possibility of finding diamond. Geothermobarometric calculations were carried out using EPMA data from xenoliths by applying the program PTEXL.XLT. Additional well calibrated single-clinopyroxene thermobarometric calculations were also applied. Results indicate the underlying mantle experienced different equilibration conditions. Subsequent metasomatic enrichment events also support a hypothesis of different sources for the kimberlites. These findings contribute to a better understanding of the petrogenetic evolution of the kimberlites in northeastern Angola and have important implications for diamond exploration. © 2012 by the authors; licensee MDPI, Basel, Switzerland.
format JOUR
author Robles-Cruz, S.E.
Melgarejo, J.C.
Galí, S.
Escayola, M.
author_facet Robles-Cruz, S.E.
Melgarejo, J.C.
Galí, S.
Escayola, M.
author_sort Robles-Cruz, S.E.
title Major- and trace-element compositions of indicator minerals that occur as macro- and megacrysts, and of xenoliths, from kimberlites in Northeastern Angola
title_short Major- and trace-element compositions of indicator minerals that occur as macro- and megacrysts, and of xenoliths, from kimberlites in Northeastern Angola
title_full Major- and trace-element compositions of indicator minerals that occur as macro- and megacrysts, and of xenoliths, from kimberlites in Northeastern Angola
title_fullStr Major- and trace-element compositions of indicator minerals that occur as macro- and megacrysts, and of xenoliths, from kimberlites in Northeastern Angola
title_full_unstemmed Major- and trace-element compositions of indicator minerals that occur as macro- and megacrysts, and of xenoliths, from kimberlites in Northeastern Angola
title_sort major- and trace-element compositions of indicator minerals that occur as macro- and megacrysts, and of xenoliths, from kimberlites in northeastern angola
url http://hdl.handle.net/20.500.12110/paper_2075163X_v2_n4_p318_RoblesCruz
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