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The timing of mantle and crustal events in South Namibia, as defined by SHRIMP-dating of zircon domains from a garnet peridotite xenolith of the Gibeon Kimberlite Province

Liati, Anthi; Franz, Leander; Gebauer, Dieter; Fanning, Christopher

Description

The Gibeon Kimberlite Province, southern Namibia, comprises numerous, 70-80 Ma old kimberlite pipes and dykes commonly containing abundant mantle and crustal xenoliths. We dated by SHRIMP II zircons from a garnet peridotite xenolith (Pipe Hanaus 1). The xenolith consists of garnet, orthopyroxene, clinopyroxene and, almost completely serpentinised, olivine. Crystallisation P-T conditions range between ca. 3.3 GPa, 910 °C (core composition of minerals) and ca. 3.5 GPa, 1000 °C (rim composition)....[Show more]

dc.contributor.authorLiati, Anthi
dc.contributor.authorFranz, Leander
dc.contributor.authorGebauer, Dieter
dc.contributor.authorFanning, Christopher
dc.date.accessioned2015-12-13T22:49:04Z
dc.date.available2015-12-13T22:49:04Z
dc.identifier.issn0899-5362
dc.identifier.urihttp://hdl.handle.net/1885/80362
dc.description.abstractThe Gibeon Kimberlite Province, southern Namibia, comprises numerous, 70-80 Ma old kimberlite pipes and dykes commonly containing abundant mantle and crustal xenoliths. We dated by SHRIMP II zircons from a garnet peridotite xenolith (Pipe Hanaus 1). The xenolith consists of garnet, orthopyroxene, clinopyroxene and, almost completely serpentinised, olivine. Crystallisation P-T conditions range between ca. 3.3 GPa, 910 °C (core composition of minerals) and ca. 3.5 GPa, 1000 °C (rim composition). Fifteen ca. 150-40 μm long and 70-10 μm wide zircon crystals show more or less pronounced oscillatory zoning indicating precipitation in a melt or fluid. The SHRIMP results define three age groups: 1013 ± 22 Ma, 751 ± 28 Ma and 627 ± 24 Ma. These ages are clearly correlated with large-scale crustal events in the broad area of Namibia, namely with the granulite-facies metamorphism during the Namaqua collisional event and post-collisional magmatism (ca. 1000-1100 Ma), with the intense magmatic activity and initial rifting stages in the Damara belt (ca. 730-770 Ma) and with the Early Pan-African orogeny, responsible for the formation of the Damara orogen (ca. 650 Ma), respectively. Formation of zircon in the xenoliths is related to the generation and migration of fluids/melts in the mantle via e.g. asthenospheric mantle upwelling or dehydration of subducting lithosphere, associated with crustal large-scale events.
dc.publisherPergamon-Elsevier Ltd
dc.sourceJournal of African Earth Sciences
dc.titleThe timing of mantle and crustal events in South Namibia, as defined by SHRIMP-dating of zircon domains from a garnet peridotite xenolith of the Gibeon Kimberlite Province
dc.typeJournal article
local.description.notesImported from ARIES
local.description.refereedYes
local.identifier.citationvolume39
dc.date.issued2004
local.identifier.absfor040203 - Isotope Geochemistry
local.identifier.ariespublicationMigratedxPub8630
local.type.statusPublished Version
local.contributor.affiliationLiati, Anthi, ETH Zurich
local.contributor.affiliationFranz, Leander, Bergakademie Freiberg
local.contributor.affiliationGebauer, Dieter, ETH Zurich
local.contributor.affiliationFanning, Christopher, College of Physical and Mathematical Sciences, ANU
local.bibliographicCitation.startpage147
local.bibliographicCitation.lastpage157
local.identifier.doi10.1016/j.jafrearsci.2004.07.054
dc.date.updated2015-12-11T10:32:29Z
local.identifier.scopusID2-s2.0-8644271646
CollectionsANU Research Publications

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