Clinopyroxene and amphibole crystal populations in a lamprophyre sill from the Catalonian Coastal Ranges (NE Spain): a record of magma history and a window to mineral-melt partitioning

Ubide, Teresa, Gale, Carlos, Arranz, Enrique, Lago, Marceliano and Larrea, Patricia (2014) Clinopyroxene and amphibole crystal populations in a lamprophyre sill from the Catalonian Coastal Ranges (NE Spain): a record of magma history and a window to mineral-melt partitioning. Lithos, 184-187 225-242. doi:10.1016/j.lithos.2013.10.029


Author Ubide, Teresa
Gale, Carlos
Arranz, Enrique
Lago, Marceliano
Larrea, Patricia
Title Clinopyroxene and amphibole crystal populations in a lamprophyre sill from the Catalonian Coastal Ranges (NE Spain): a record of magma history and a window to mineral-melt partitioning
Journal name Lithos   Check publisher's open access policy
ISSN 0024-4937
1872-6143
Publication date 2014-01-01
Year available 2013
Sub-type Article (original research)
DOI 10.1016/j.lithos.2013.10.029
Open Access Status Not yet assessed
Volume 184-187
Start page 225
End page 242
Total pages 18
Place of publication Amsterdam, Netherlands
Publisher Elsevier BV
Language eng
Abstract A Cretaceous sill of alkaline lamprophyre (camptonite) cropping out in the northern Catalonian Coastal Ranges includes macrocrysts and microcrysts of clinopyroxene and amphibole with complex zoning patterns. The in-depth petrographic, compositional and barometric study of the different crystal populations, including statistical evaluation of the compositional dataset by principal component analysis, provides insights into the magmatic plumbing system. Macrocryst cores are inherited antecrysts crystallised in a deep (500-800. MPa) magma chamber or conduit. Their reverse zoning patterns reveal repeated injection and mixing of batches of a more primitive and water-rich magma with the resident magma in the magma chamber. Macrocryst rims and microcrysts, in contrast, crystallised during the ascent and shallow emplacement of the magma below 50. MPa pressure. They define normal zoning patterns that can be related to progressive fractionation of the magma. This study shows that an apparently simple porphyritic rock can actually contain a significant amount of recycled crystals, reflecting an open-system magmatic behaviour. Only the groundmass of the sill represents a closed-system, where microphenocryst cores are in chemical equilibrium with the bulk composition of the groundmass. Using trace element compositions obtained by LA-ICP-MS and geochemical modelling, a complete and consistent partition coefficient dataset is obtained for the first time for clinopyroxene and amphibole in camptonite melts. Both minerals show a similar partitioning behaviour for most trace elements. Clinopyroxene-melt and amphibole-melt partition coefficients are overall consistent with data from basic rocks, although clinopyroxene partition coefficients are generally higher than data from basalt and basanite melts. The results from this research support the use of naturally occurring mineral-melt equilibrium pairs for partitioning studies but emphasise the need for a detailed study of the phases used to define the partition relationships.
Keyword Alkaline lamprophyre
Antecryst
Camptonite
Cretaceous
Partition coefficient
Plumbing system
Q-Index Code C1
Q-Index Status Provisional Code
Grant ID BFI06.189
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Earth Sciences Publications
 
Versions
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 15 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 15 times in Scopus Article | Citations
Google Scholar Search Google Scholar
Created: Thu, 10 Nov 2016, 03:15:53 EST by System User on behalf of Learning and Research Services (UQ Library)