Tracing the evolution of calc-alkaline magmas: In-situ Sm-Nd isotope studies of accessory minerals in the Bergell Igneous Complex, Italy
The common occurrence of Ca- and Nd-rich accessory minerals titanite, epidote, allanite and apatite in calcalkaline plutonic suites makes them ideal targets for in-situ tracing of the temporal, chemical and isotopic evolution of tonalitic and granodioritic melts. The Sm-Nd isotope composition of acc...
| Main Authors: | , , , |
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| Format: | Journal Article |
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Elsevier Science BV
2009
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| Online Access: | http://hdl.handle.net/20.500.11937/29317 |
| _version_ | 1848752770635530240 |
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| author | Gregory, Courtney McFarlane, C. Hermann, J. Rubatto, D. |
| author_facet | Gregory, Courtney McFarlane, C. Hermann, J. Rubatto, D. |
| author_sort | Gregory, Courtney |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | The common occurrence of Ca- and Nd-rich accessory minerals titanite, epidote, allanite and apatite in calcalkaline plutonic suites makes them ideal targets for in-situ tracing of the temporal, chemical and isotopic evolution of tonalitic and granodioritic melts. The Sm-Nd isotope composition of accessory phases from the calc-alkaline Bergell Pluton and the peraluminous Novate leucogranite (central Alps) were investigated using laser ablation MC-ICPMS techniques. Grouping of individual LA-MC-ICPMS analyses produced average eNd values with typical uncertainties of <0.3 (2s) epsilon units. SHRIMP dating of magmatic allanite cores of epidote grains from a Bergell gabbro yielded a Th-Pb age of 32.40.4 Ma, which provides a new timing constraint on the emplacement of juvenile members within the Bergell intrusive sequence. The Bergell bulkrock mantle-crust isotopic mixing curve was reproduced, demonstrating that integration of U-Th-rich accessory mineral Nd isotope compositions with crystallisation age is capable of tracing the geochemical evolution of magmatic systems over time.Crucially, the isotopic composition of the mantle end-member was successfully constrained by measurement of magmatic REE-epidote, highlighting the compositional versatility of accessory phases. The removal or addition of feldspar controls the Eu signature of both the bulk-rock and single minerals and therefore presents a unique trace element indicator of magmatic differentiation and assimilation processes in accessory minerals. Therefore the in-situ determination of age, Sm-Nd isotopes and trace elements in accessory minerals permits efficient and accurate reconstruction of complex magmatic processes in calc-alkaline plutonic suites. Sub-grain isotopic heterogeneity in magmatic monazite from the Novate leucogranite was identifiable by LA-MC-ICPMS analysis and emphasizes the additional value of a micro-analytical approach to understanding geological processes. |
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| format | Journal Article |
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| institution | Curtin University Malaysia |
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| last_indexed | 2025-11-14T08:13:54Z |
| publishDate | 2009 |
| publisher | Elsevier Science BV |
| recordtype | eprints |
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| spelling | curtin-20.500.11937-293172017-09-13T15:53:33Z Tracing the evolution of calc-alkaline magmas: In-situ Sm-Nd isotope studies of accessory minerals in the Bergell Igneous Complex, Italy Gregory, Courtney McFarlane, C. Hermann, J. Rubatto, D. U-Th-Pb dating Neodymium Allanite Titanite LA-MC-ICPMS The common occurrence of Ca- and Nd-rich accessory minerals titanite, epidote, allanite and apatite in calcalkaline plutonic suites makes them ideal targets for in-situ tracing of the temporal, chemical and isotopic evolution of tonalitic and granodioritic melts. The Sm-Nd isotope composition of accessory phases from the calc-alkaline Bergell Pluton and the peraluminous Novate leucogranite (central Alps) were investigated using laser ablation MC-ICPMS techniques. Grouping of individual LA-MC-ICPMS analyses produced average eNd values with typical uncertainties of <0.3 (2s) epsilon units. SHRIMP dating of magmatic allanite cores of epidote grains from a Bergell gabbro yielded a Th-Pb age of 32.40.4 Ma, which provides a new timing constraint on the emplacement of juvenile members within the Bergell intrusive sequence. The Bergell bulkrock mantle-crust isotopic mixing curve was reproduced, demonstrating that integration of U-Th-rich accessory mineral Nd isotope compositions with crystallisation age is capable of tracing the geochemical evolution of magmatic systems over time.Crucially, the isotopic composition of the mantle end-member was successfully constrained by measurement of magmatic REE-epidote, highlighting the compositional versatility of accessory phases. The removal or addition of feldspar controls the Eu signature of both the bulk-rock and single minerals and therefore presents a unique trace element indicator of magmatic differentiation and assimilation processes in accessory minerals. Therefore the in-situ determination of age, Sm-Nd isotopes and trace elements in accessory minerals permits efficient and accurate reconstruction of complex magmatic processes in calc-alkaline plutonic suites. Sub-grain isotopic heterogeneity in magmatic monazite from the Novate leucogranite was identifiable by LA-MC-ICPMS analysis and emphasizes the additional value of a micro-analytical approach to understanding geological processes. 2009 Journal Article http://hdl.handle.net/20.500.11937/29317 10.1016/j.chemgeo.2008.12.003 Elsevier Science BV fulltext |
| spellingShingle | U-Th-Pb dating Neodymium Allanite Titanite LA-MC-ICPMS Gregory, Courtney McFarlane, C. Hermann, J. Rubatto, D. Tracing the evolution of calc-alkaline magmas: In-situ Sm-Nd isotope studies of accessory minerals in the Bergell Igneous Complex, Italy |
| title | Tracing the evolution of calc-alkaline magmas: In-situ Sm-Nd isotope studies of accessory minerals in the Bergell Igneous Complex, Italy |
| title_full | Tracing the evolution of calc-alkaline magmas: In-situ Sm-Nd isotope studies of accessory minerals in the Bergell Igneous Complex, Italy |
| title_fullStr | Tracing the evolution of calc-alkaline magmas: In-situ Sm-Nd isotope studies of accessory minerals in the Bergell Igneous Complex, Italy |
| title_full_unstemmed | Tracing the evolution of calc-alkaline magmas: In-situ Sm-Nd isotope studies of accessory minerals in the Bergell Igneous Complex, Italy |
| title_short | Tracing the evolution of calc-alkaline magmas: In-situ Sm-Nd isotope studies of accessory minerals in the Bergell Igneous Complex, Italy |
| title_sort | tracing the evolution of calc-alkaline magmas: in-situ sm-nd isotope studies of accessory minerals in the bergell igneous complex, italy |
| topic | U-Th-Pb dating Neodymium Allanite Titanite LA-MC-ICPMS |
| url | http://hdl.handle.net/20.500.11937/29317 |