Sm-Nd and Lu-Hf isotope and trace-element systematics of Mesoarchaean amphibolites, inner Ameralik fjord, southern West Greenland
Fragmented supracrustal rocks are typical components of Archaean high-grade gneiss terranes, such as those in the North Atlantic Craton. Here we present the first major, trace element and Nd-Hf isotope data for amphibolites collected in the yet poorly studied southern inner Ameralik fjord region of...
| Main Authors: | , , , , , , |
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| Format: | Journal Article |
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Mineralogical Society
2015
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| Online Access: | http://hdl.handle.net/20.500.11937/53087 |
| _version_ | 1848759062724870144 |
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| author | Szilas, K. Hoffmann, J. Hansmeier, C. Hollis, Julie Münker, C. Viehmann, S. Kasper, H. |
| author_facet | Szilas, K. Hoffmann, J. Hansmeier, C. Hollis, Julie Münker, C. Viehmann, S. Kasper, H. |
| author_sort | Szilas, K. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Fragmented supracrustal rocks are typical components of Archaean high-grade gneiss terranes, such as those in the North Atlantic Craton. Here we present the first major, trace element and Nd-Hf isotope data for amphibolites collected in the yet poorly studied southern inner Ameralik fjord region of southern West Greenland. In addition, new U-Pb zircon ages were obtained from the surrounding TTG gneisses. Based on their trace-element patterns, two different groups of amphibolites can be distinguished. Following screening for post-magmatic alteration and outlying ε values, a reduced sample set defines a 147Sm/143Nd regression age of 3038 Ma ±310 Ma (MSWD = 9.2) and a 176Lu/176Hf regression age of 2867 ±160 Ma (MSWD = 5.5). Initial εNd2970Ma values of the least-altered amphibolites range from 0.0 to +5.7 and initial εHf2970Ma range from +0.7 to +10.4, indicating significant isotopic heterogeneity of their mantle sources with involvement of depleted domains as well as crustal sources. Surprisingly, the amphibolites which are apparently most evolved and incompatible element-rich have the most depleted Hf-isotope compositions. This apparent paradox may be explained by the sampling of a local mantle source region with ancient previous melt depletion, which was re-enriched by a fluid component during subduction zone volcanism or alternatively by preferential melting of an ancient pyroxenite component in the mantle source of the enriched rocks. |
| first_indexed | 2025-11-14T09:53:55Z |
| format | Journal Article |
| id | curtin-20.500.11937-53087 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T09:53:55Z |
| publishDate | 2015 |
| publisher | Mineralogical Society |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-530872017-10-13T07:10:56Z Sm-Nd and Lu-Hf isotope and trace-element systematics of Mesoarchaean amphibolites, inner Ameralik fjord, southern West Greenland Szilas, K. Hoffmann, J. Hansmeier, C. Hollis, Julie Münker, C. Viehmann, S. Kasper, H. Fragmented supracrustal rocks are typical components of Archaean high-grade gneiss terranes, such as those in the North Atlantic Craton. Here we present the first major, trace element and Nd-Hf isotope data for amphibolites collected in the yet poorly studied southern inner Ameralik fjord region of southern West Greenland. In addition, new U-Pb zircon ages were obtained from the surrounding TTG gneisses. Based on their trace-element patterns, two different groups of amphibolites can be distinguished. Following screening for post-magmatic alteration and outlying ε values, a reduced sample set defines a 147Sm/143Nd regression age of 3038 Ma ±310 Ma (MSWD = 9.2) and a 176Lu/176Hf regression age of 2867 ±160 Ma (MSWD = 5.5). Initial εNd2970Ma values of the least-altered amphibolites range from 0.0 to +5.7 and initial εHf2970Ma range from +0.7 to +10.4, indicating significant isotopic heterogeneity of their mantle sources with involvement of depleted domains as well as crustal sources. Surprisingly, the amphibolites which are apparently most evolved and incompatible element-rich have the most depleted Hf-isotope compositions. This apparent paradox may be explained by the sampling of a local mantle source region with ancient previous melt depletion, which was re-enriched by a fluid component during subduction zone volcanism or alternatively by preferential melting of an ancient pyroxenite component in the mantle source of the enriched rocks. 2015 Journal Article http://hdl.handle.net/20.500.11937/53087 10.1180/minmag.2015.079.4.02 Mineralogical Society restricted |
| spellingShingle | Szilas, K. Hoffmann, J. Hansmeier, C. Hollis, Julie Münker, C. Viehmann, S. Kasper, H. Sm-Nd and Lu-Hf isotope and trace-element systematics of Mesoarchaean amphibolites, inner Ameralik fjord, southern West Greenland |
| title | Sm-Nd and Lu-Hf isotope and trace-element systematics of Mesoarchaean amphibolites, inner Ameralik fjord, southern West Greenland |
| title_full | Sm-Nd and Lu-Hf isotope and trace-element systematics of Mesoarchaean amphibolites, inner Ameralik fjord, southern West Greenland |
| title_fullStr | Sm-Nd and Lu-Hf isotope and trace-element systematics of Mesoarchaean amphibolites, inner Ameralik fjord, southern West Greenland |
| title_full_unstemmed | Sm-Nd and Lu-Hf isotope and trace-element systematics of Mesoarchaean amphibolites, inner Ameralik fjord, southern West Greenland |
| title_short | Sm-Nd and Lu-Hf isotope and trace-element systematics of Mesoarchaean amphibolites, inner Ameralik fjord, southern West Greenland |
| title_sort | sm-nd and lu-hf isotope and trace-element systematics of mesoarchaean amphibolites, inner ameralik fjord, southern west greenland |
| url | http://hdl.handle.net/20.500.11937/53087 |