Ediacaran emerald mineralization in Northeastern Brazil: the case of the Fazenda Bonfim Deposit

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dc.contributor.authorSantiago, Judiron Santos
dc.contributor.authorSouza, Valmir da Silva
dc.contributor.authorDantas, Elton Luiz
dc.contributor.authorOliveira, Claudinei Gouveia de
dc.date.accessioned2024-05-17T12:02:09Z
dc.date.available2024-05-17T12:02:09Z
dc.date.issued2019
dc.description.abstractAbstract The Fazenda Bonfim emerald deposit lies within the Seridó Belt. It is a classic example of deposit formed through metasomatic interactions between Be-rich granite intrusions and Cr(± V)-rich mafic-ultramafic rocks. The setting of the emerald mineralization was built under strong strike-slip dynamics, which produced serpentinization and talcification of mafic-ultramafic host-rocks, and was followed by syn-kinematic emplacement of Be-rich albite granite, favoring hydrothermal/metasomatic processes. The structural control and lithological-contrast were fundamental to the fluid flow and the best ore-shoot geometry, developed in the S-foliation intra-plane at the contact zone (phlogopite hornfels) between mafic-ultramafic rocks and the albite granite. Subsequently, an albitization process, linked to the final-stage of magmatic crystallization, led to an overall mineralogical and chemical change of the albite granite. 207U-235Pb data revealed inheritance ages from Archean to Neoproterozoic and a crystallization age of 561 ± 4 Ma for albite granite. However, 40Ar/39Ar data revealed plateau age of 553 ± 4 Ma for phlogopite hornfels, interpreted as the closure time for the metasomatic event responsible for the nucleation and growth of emerald crystals. The short interval of time between U-Pb and Ar-Ar data indicates an intense, but not protracted, metasomatic history, probably due to low volume of intrusive magma.
dc.identifier.doi10.1590/2317-4889201920190081
dc.identifier.issn2317-4889
dc.identifier.otherS2317-48892019000400303-scl
dc.identifier.urihttps://repositorio-aptaregional.agricultura.sp.gov.br/handle/123456789/1877
dc.relation.ispartofBrazilian Journal of Geology
dc.subjectFazenda Bonfim emerald deposit
dc.subjectSeridó Belt
dc.subjectgeology
dc.subjectgeochemistry
dc.subjectU-Pb and Ar-Ar geochronology
dc.titleEdiacaran emerald mineralization in Northeastern Brazil: the case of the Fazenda Bonfim Deposit
dc.typeArtigos
oaire.citation.issue4
oaire.citation.volume49

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