Pre-nucleation geochemical heterogeneity within glassy anatectic inclusions and the role of water in glass preservation
Glassy melt inclusions are unique geological repositories that preserve evidence of the formation and evolution of mantle and crustal-derived magmas. However, the mechanisms responsible for their preservation in slowly cooled crustal rocks remain contentious, in some part due to their small size (co...
| Main Authors: | , , , , , , , |
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| Format: | Journal Article |
| Language: | English |
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SPRINGER
2021
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| Subjects: | |
| Online Access: | http://purl.org/au-research/grants/arc/DP160104637 http://hdl.handle.net/20.500.11937/89403 |
| _version_ | 1848765211081703424 |
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| author | Tacchetto, Tom Reddy, Steven Bartoli, O. Rickard, William Fougerouse, Denis Saxey, David Quadir, Z. Clark, Chris |
| author_facet | Tacchetto, Tom Reddy, Steven Bartoli, O. Rickard, William Fougerouse, Denis Saxey, David Quadir, Z. Clark, Chris |
| author_sort | Tacchetto, Tom |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Glassy melt inclusions are unique geological repositories that preserve evidence of the formation and evolution of mantle and crustal-derived magmas. However, the mechanisms responsible for their preservation in slowly cooled crustal rocks remain contentious, in some part due to their small size (commonly < 10 µm) and the technical difficulty in quantifying composition and microstructures. In this work, time-of-flight secondary ion mass spectrometry, transmission electron microscopy and atom probe tomography are used to characterize glassy melt inclusions found in peritectic garnets of a migmatite from the Spanish Betic Cordillera. The glassy melt inclusions coexist in a close spatial relationship with partially to totally crystallized melt inclusions (nanogranitoids). Analyses of the glassy inclusions show a heterogeneous, patchy distribution of Na and K within the glass and along inclusion walls. Nanoscale spherical domains of Al, Fe, K, Na, Cl and Li are also found systematically distributed at inclusion edges, and are interpreted to represent pre-nucleation clusters. The location and compositional similarity of these clusters with micas and feldspars in nanogranitoids indicate that the glassy inclusions represent former nanogranitoids “captured” at an earlier stage of crystallization, suggesting a likely common origin for both the glassy inclusions and nanogranitoids. A comparison between the composition of melt inclusions with previously published data reveals that preserved glassy inclusions contain significant less H2O (av. 2.72 wt%) than nanogranitoids (average of 6.91 wt%). This suggests the low-H2O content representing a further impediment to crystallization, along with the very small volume of these cavities, favouring the coexistence of glassy inclusions and nanogranitoids. In contrast, crystal nucleation is enhanced in more hydrous melts, where H2O reduces melt viscosity and promotes diffusion. |
| first_indexed | 2025-11-14T11:31:38Z |
| format | Journal Article |
| id | curtin-20.500.11937-89403 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T11:31:38Z |
| publishDate | 2021 |
| publisher | SPRINGER |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-894032022-10-17T05:35:23Z Pre-nucleation geochemical heterogeneity within glassy anatectic inclusions and the role of water in glass preservation Tacchetto, Tom Reddy, Steven Bartoli, O. Rickard, William Fougerouse, Denis Saxey, David Quadir, Z. Clark, Chris Science & Technology Physical Sciences Geochemistry & Geophysics Mineralogy Primary glassy inclusions Nanogranitoids Garnet Pre-nucleation clusters TEM Atom probe tomography MELT INCLUSIONS LOCAL MAGNIFICATION RONDA PERIDOTITES CONTINENTAL-CRUST FLUID INCLUSIONS BETIC CORDILLERA U-PB CRYSTALLIZATION GROWTH H2O Glassy melt inclusions are unique geological repositories that preserve evidence of the formation and evolution of mantle and crustal-derived magmas. However, the mechanisms responsible for their preservation in slowly cooled crustal rocks remain contentious, in some part due to their small size (commonly < 10 µm) and the technical difficulty in quantifying composition and microstructures. In this work, time-of-flight secondary ion mass spectrometry, transmission electron microscopy and atom probe tomography are used to characterize glassy melt inclusions found in peritectic garnets of a migmatite from the Spanish Betic Cordillera. The glassy melt inclusions coexist in a close spatial relationship with partially to totally crystallized melt inclusions (nanogranitoids). Analyses of the glassy inclusions show a heterogeneous, patchy distribution of Na and K within the glass and along inclusion walls. Nanoscale spherical domains of Al, Fe, K, Na, Cl and Li are also found systematically distributed at inclusion edges, and are interpreted to represent pre-nucleation clusters. The location and compositional similarity of these clusters with micas and feldspars in nanogranitoids indicate that the glassy inclusions represent former nanogranitoids “captured” at an earlier stage of crystallization, suggesting a likely common origin for both the glassy inclusions and nanogranitoids. A comparison between the composition of melt inclusions with previously published data reveals that preserved glassy inclusions contain significant less H2O (av. 2.72 wt%) than nanogranitoids (average of 6.91 wt%). This suggests the low-H2O content representing a further impediment to crystallization, along with the very small volume of these cavities, favouring the coexistence of glassy inclusions and nanogranitoids. In contrast, crystal nucleation is enhanced in more hydrous melts, where H2O reduces melt viscosity and promotes diffusion. 2021 Journal Article http://hdl.handle.net/20.500.11937/89403 10.1007/s00410-021-01826-0 English http://purl.org/au-research/grants/arc/DP160104637 SPRINGER restricted |
| spellingShingle | Science & Technology Physical Sciences Geochemistry & Geophysics Mineralogy Primary glassy inclusions Nanogranitoids Garnet Pre-nucleation clusters TEM Atom probe tomography MELT INCLUSIONS LOCAL MAGNIFICATION RONDA PERIDOTITES CONTINENTAL-CRUST FLUID INCLUSIONS BETIC CORDILLERA U-PB CRYSTALLIZATION GROWTH H2O Tacchetto, Tom Reddy, Steven Bartoli, O. Rickard, William Fougerouse, Denis Saxey, David Quadir, Z. Clark, Chris Pre-nucleation geochemical heterogeneity within glassy anatectic inclusions and the role of water in glass preservation |
| title | Pre-nucleation geochemical heterogeneity within glassy anatectic inclusions and the role of water in glass preservation |
| title_full | Pre-nucleation geochemical heterogeneity within glassy anatectic inclusions and the role of water in glass preservation |
| title_fullStr | Pre-nucleation geochemical heterogeneity within glassy anatectic inclusions and the role of water in glass preservation |
| title_full_unstemmed | Pre-nucleation geochemical heterogeneity within glassy anatectic inclusions and the role of water in glass preservation |
| title_short | Pre-nucleation geochemical heterogeneity within glassy anatectic inclusions and the role of water in glass preservation |
| title_sort | pre-nucleation geochemical heterogeneity within glassy anatectic inclusions and the role of water in glass preservation |
| topic | Science & Technology Physical Sciences Geochemistry & Geophysics Mineralogy Primary glassy inclusions Nanogranitoids Garnet Pre-nucleation clusters TEM Atom probe tomography MELT INCLUSIONS LOCAL MAGNIFICATION RONDA PERIDOTITES CONTINENTAL-CRUST FLUID INCLUSIONS BETIC CORDILLERA U-PB CRYSTALLIZATION GROWTH H2O |
| url | http://purl.org/au-research/grants/arc/DP160104637 http://hdl.handle.net/20.500.11937/89403 |