Petrology and mineral chemistry of shallow intrusive carbonatites : examples from the Kola Peninsula and Cape Verde
Analysis of hypabyssal carbonatite and associated silicate rocks from three locations was undertaken to establish the processes leading to their textural and chemical diversity. Carbonatite dykes from Vuorijarvi (Kola Peninsula) show good evidence of magmatic processes and were least affected by fen...
Main Author: | |
---|---|
Format: | Thesis |
Language: | English |
Published: |
2022
|
Subjects: | |
Online Access: | https://eprints.bbk.ac.uk/id/eprint/49511/ https://eprints.bbk.ac.uk/id/eprint/49511/1/Barbara%20Smith%20revised%20PhD%20thesis.pdf |
id |
ftbirkbeckcoll:oai:eprints.bbk.ac.uk.oai2:49511 |
---|---|
record_format |
openpolar |
spelling |
ftbirkbeckcoll:oai:eprints.bbk.ac.uk.oai2:49511 2023-05-15T17:04:56+02:00 Petrology and mineral chemistry of shallow intrusive carbonatites : examples from the Kola Peninsula and Cape Verde Smith, Barbara 2022-10 text https://eprints.bbk.ac.uk/id/eprint/49511/ https://eprints.bbk.ac.uk/id/eprint/49511/1/Barbara%20Smith%20revised%20PhD%20thesis.pdf en eng https://eprints.bbk.ac.uk/id/eprint/49511/1/Barbara%20Smith%20revised%20PhD%20thesis.pdf Smith, Barbara (2022) Petrology and mineral chemistry of shallow intrusive carbonatites : examples from the Kola Peninsula and Cape Verde. [Thesis] (Unpublished) Earth and Planetary Sciences Thesis NonPeerReviewed 2022 ftbirkbeckcoll 2022-10-20T22:22:46Z Analysis of hypabyssal carbonatite and associated silicate rocks from three locations was undertaken to establish the processes leading to their textural and chemical diversity. Carbonatite dykes from Vuorijarvi (Kola Peninsula) show good evidence of magmatic processes and were least affected by fenitization. Globular calcite and apatite inclusions in silicate phases indicate precipitation from a silicate melt; subsolidus recrystallisation of olivine to monticellite implies an early stage of carbonatite formation; complex substitution in perovskite formed Zr-garnet. Occurrences of xenocrysts suggest extensive wall-rock interaction. Primary tabular calcite was replaced by secondary mosaic calcite, and amphibole was formed by early fenitisation. Calcite and apatite host LREE; Zr-garnet and perovskite show strong compatibility for Zr, Nb and all REE. Hypabyssal carbonatites of Fogo, Cape Verde, contain glimmerite sheets which formed hydrothermal pathways in which accessory minerals crystallised. Shearing also formed pathways for oxidised low-temperature REE-rich hydrothermal fluids which caused veined and pervasive K- and Na-fenitization that modified the texture and chemistry of primary phases. Hf-bearing phlogopite is associated with Hf-poor titanite, zirconolite, zircon and pyrochlore; Nb-Th-U-rich pyrochlore formed via hydrothermal dissolution of Zr-rich precursors; post-magmatic changes progressively altered magnetite to titanomagnetite, ilmenite, garnet and titanite. Calcite and apatite are the main trace-element-bearing phases; post-magmatic garnet and titanite are enriched in REEs and U, Th and Nb. Carbonatites and syenites from Brava, Cape Verde, show extensive fenitisation. Sövites contain primary (Sr-calcite, Ca-strontianite, carbocernaite), metasomatic (parisite) and hydrothermal (burbankite, barite) phases. Apatite and calcite show several orders of REE enrichment. Clinopyroxene evolved from diopside towards aegirine enriched in Zr, Th, U and LREEs; amphibole is both primary and secondary; phlogopite ... Thesis kola peninsula BIROn - Birkbeck Institutional Research Online (Birkbeck University of London) Fogo ENVELOPE(-54.281,-54.281,49.717,49.717) Kola Peninsula |
institution |
Open Polar |
collection |
BIROn - Birkbeck Institutional Research Online (Birkbeck University of London) |
op_collection_id |
ftbirkbeckcoll |
language |
English |
topic |
Earth and Planetary Sciences |
spellingShingle |
Earth and Planetary Sciences Smith, Barbara Petrology and mineral chemistry of shallow intrusive carbonatites : examples from the Kola Peninsula and Cape Verde |
topic_facet |
Earth and Planetary Sciences |
description |
Analysis of hypabyssal carbonatite and associated silicate rocks from three locations was undertaken to establish the processes leading to their textural and chemical diversity. Carbonatite dykes from Vuorijarvi (Kola Peninsula) show good evidence of magmatic processes and were least affected by fenitization. Globular calcite and apatite inclusions in silicate phases indicate precipitation from a silicate melt; subsolidus recrystallisation of olivine to monticellite implies an early stage of carbonatite formation; complex substitution in perovskite formed Zr-garnet. Occurrences of xenocrysts suggest extensive wall-rock interaction. Primary tabular calcite was replaced by secondary mosaic calcite, and amphibole was formed by early fenitisation. Calcite and apatite host LREE; Zr-garnet and perovskite show strong compatibility for Zr, Nb and all REE. Hypabyssal carbonatites of Fogo, Cape Verde, contain glimmerite sheets which formed hydrothermal pathways in which accessory minerals crystallised. Shearing also formed pathways for oxidised low-temperature REE-rich hydrothermal fluids which caused veined and pervasive K- and Na-fenitization that modified the texture and chemistry of primary phases. Hf-bearing phlogopite is associated with Hf-poor titanite, zirconolite, zircon and pyrochlore; Nb-Th-U-rich pyrochlore formed via hydrothermal dissolution of Zr-rich precursors; post-magmatic changes progressively altered magnetite to titanomagnetite, ilmenite, garnet and titanite. Calcite and apatite are the main trace-element-bearing phases; post-magmatic garnet and titanite are enriched in REEs and U, Th and Nb. Carbonatites and syenites from Brava, Cape Verde, show extensive fenitisation. Sövites contain primary (Sr-calcite, Ca-strontianite, carbocernaite), metasomatic (parisite) and hydrothermal (burbankite, barite) phases. Apatite and calcite show several orders of REE enrichment. Clinopyroxene evolved from diopside towards aegirine enriched in Zr, Th, U and LREEs; amphibole is both primary and secondary; phlogopite ... |
format |
Thesis |
author |
Smith, Barbara |
author_facet |
Smith, Barbara |
author_sort |
Smith, Barbara |
title |
Petrology and mineral chemistry of shallow intrusive carbonatites : examples from the Kola Peninsula and Cape Verde |
title_short |
Petrology and mineral chemistry of shallow intrusive carbonatites : examples from the Kola Peninsula and Cape Verde |
title_full |
Petrology and mineral chemistry of shallow intrusive carbonatites : examples from the Kola Peninsula and Cape Verde |
title_fullStr |
Petrology and mineral chemistry of shallow intrusive carbonatites : examples from the Kola Peninsula and Cape Verde |
title_full_unstemmed |
Petrology and mineral chemistry of shallow intrusive carbonatites : examples from the Kola Peninsula and Cape Verde |
title_sort |
petrology and mineral chemistry of shallow intrusive carbonatites : examples from the kola peninsula and cape verde |
publishDate |
2022 |
url |
https://eprints.bbk.ac.uk/id/eprint/49511/ https://eprints.bbk.ac.uk/id/eprint/49511/1/Barbara%20Smith%20revised%20PhD%20thesis.pdf |
long_lat |
ENVELOPE(-54.281,-54.281,49.717,49.717) |
geographic |
Fogo Kola Peninsula |
geographic_facet |
Fogo Kola Peninsula |
genre |
kola peninsula |
genre_facet |
kola peninsula |
op_relation |
https://eprints.bbk.ac.uk/id/eprint/49511/1/Barbara%20Smith%20revised%20PhD%20thesis.pdf Smith, Barbara (2022) Petrology and mineral chemistry of shallow intrusive carbonatites : examples from the Kola Peninsula and Cape Verde. [Thesis] (Unpublished) |
_version_ |
1766059292420472832 |