New age (ca. 2970 Ma), mantle source composition and geodynamic constraints on the Archean Fiskenaesset anorthosite complex, SW Greenland
The Archean Fiskenaesset Complex, SW Greenland, consists of an association of ca. 550-meter-thick layered anorthosite, leucogabbro, gabbro, and ultramafic rocks (peridotite, pyroxenite, dunite, hornblendite). The complex was intruded by tonalite, trondhjemite, and granodiorite (TTG) sheets (now orth...
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ftulundlup:oai:lup.lub.lu.se:d7c76222-3901-4e39-bd1c-1b246a4b4bc0 2023-05-15T16:27:45+02:00 New age (ca. 2970 Ma), mantle source composition and geodynamic constraints on the Archean Fiskenaesset anorthosite complex, SW Greenland Polat, Ali Frei, Robert Scherstén, Anders Appel, Peter W. U. 2010 https://lup.lub.lu.se/record/1726150 https://doi.org/10.1016/j.chemgeo.2010.06.016 eng eng Elsevier https://lup.lub.lu.se/record/1726150 http://dx.doi.org/10.1016/j.chemgeo.2010.06.016 wos:000282861700001 scopus:77956615577 Chemical Geology; 277(1-2), pp 1-20 (2010) ISSN: 0009-2541 Geology Geochronology Isotopes Archean Anorthosite Fiskenaesset Complex SW Greenland contributiontojournal/article info:eu-repo/semantics/article text 2010 ftulundlup https://doi.org/10.1016/j.chemgeo.2010.06.016 2023-02-01T23:29:44Z The Archean Fiskenaesset Complex, SW Greenland, consists of an association of ca. 550-meter-thick layered anorthosite, leucogabbro, gabbro, and ultramafic rocks (peridotite, pyroxenite, dunite, hornblendite). The complex was intruded by tonalite, trondhjemite, and granodiorite (TTG) sheets (now orthogneisses) during thrusting that was followed by several phases of isoclinal folding. The trace element systematics of the Fiskenaesset Complex and associated volcanic rocks are consistent with a supra-subduction zone geodynamic setting. The Fiskenaesset anorthosites, leucogabbros, gabbros and ultramafic rocks collectively yield an Sm-Nd errorchron age of 2973 +/- 28 Ma (MSWD = 33), with an average initial epsilon(Nd) = + 3.3 +/- 0.7, consistent with a long-term depleted mantle source. Regression of Pb isotope data define an age of 2945 36 Ma (MSWD = 44); and the regression line intersects the average growth curve at 3036 Ma. Slightly lower Pb-Pb errorchron age is interpreted as reflecting partial disturbance of the U-Pb system in gabbros, leucogabbros and ultramafic rocks during intrusion of TTGs. Complex internal structures in zircons from orthogneisses reveal several episodes of zircon growth and recrystallization taking place between ca. 3200 and 2650 Ma. Zircon ages peak at about 3200, 3100, 3000, 2950, 2820, and 2750 Ma. The 3200-3000 Ma zircon cores are interpreted as inherited xenocrysts from older reworked crustal rocks. 2950 Ma is considered as an approximate intrusion age of sampled TTGs. The 29402650 Ma ages are attributed to metamorphic overgrowth and recrystallization in response to multiple tectonothermal events that affected the Fiskenaesset region. On the basis of recently published trace element data, and new Nd and Pb isotope and U-Pb zircon age data, a three-stage geodynamic model is proposed to explain the evolution of the Fiskenaesset Complex. Stage 1 represents the formation of depleted shallow mantle source> 3000 Ma (epsilon(Nd) = + 3.3 +/- 0.7) for the complex. Stage 2 corresponds to the ... Article in Journal/Newspaper Greenland Lund University Publications (LUP) Greenland Chemical Geology 277 1-2 1 20 |
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Open Polar |
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Lund University Publications (LUP) |
op_collection_id |
ftulundlup |
language |
English |
topic |
Geology Geochronology Isotopes Archean Anorthosite Fiskenaesset Complex SW Greenland |
spellingShingle |
Geology Geochronology Isotopes Archean Anorthosite Fiskenaesset Complex SW Greenland Polat, Ali Frei, Robert Scherstén, Anders Appel, Peter W. U. New age (ca. 2970 Ma), mantle source composition and geodynamic constraints on the Archean Fiskenaesset anorthosite complex, SW Greenland |
topic_facet |
Geology Geochronology Isotopes Archean Anorthosite Fiskenaesset Complex SW Greenland |
description |
The Archean Fiskenaesset Complex, SW Greenland, consists of an association of ca. 550-meter-thick layered anorthosite, leucogabbro, gabbro, and ultramafic rocks (peridotite, pyroxenite, dunite, hornblendite). The complex was intruded by tonalite, trondhjemite, and granodiorite (TTG) sheets (now orthogneisses) during thrusting that was followed by several phases of isoclinal folding. The trace element systematics of the Fiskenaesset Complex and associated volcanic rocks are consistent with a supra-subduction zone geodynamic setting. The Fiskenaesset anorthosites, leucogabbros, gabbros and ultramafic rocks collectively yield an Sm-Nd errorchron age of 2973 +/- 28 Ma (MSWD = 33), with an average initial epsilon(Nd) = + 3.3 +/- 0.7, consistent with a long-term depleted mantle source. Regression of Pb isotope data define an age of 2945 36 Ma (MSWD = 44); and the regression line intersects the average growth curve at 3036 Ma. Slightly lower Pb-Pb errorchron age is interpreted as reflecting partial disturbance of the U-Pb system in gabbros, leucogabbros and ultramafic rocks during intrusion of TTGs. Complex internal structures in zircons from orthogneisses reveal several episodes of zircon growth and recrystallization taking place between ca. 3200 and 2650 Ma. Zircon ages peak at about 3200, 3100, 3000, 2950, 2820, and 2750 Ma. The 3200-3000 Ma zircon cores are interpreted as inherited xenocrysts from older reworked crustal rocks. 2950 Ma is considered as an approximate intrusion age of sampled TTGs. The 29402650 Ma ages are attributed to metamorphic overgrowth and recrystallization in response to multiple tectonothermal events that affected the Fiskenaesset region. On the basis of recently published trace element data, and new Nd and Pb isotope and U-Pb zircon age data, a three-stage geodynamic model is proposed to explain the evolution of the Fiskenaesset Complex. Stage 1 represents the formation of depleted shallow mantle source> 3000 Ma (epsilon(Nd) = + 3.3 +/- 0.7) for the complex. Stage 2 corresponds to the ... |
format |
Article in Journal/Newspaper |
author |
Polat, Ali Frei, Robert Scherstén, Anders Appel, Peter W. U. |
author_facet |
Polat, Ali Frei, Robert Scherstén, Anders Appel, Peter W. U. |
author_sort |
Polat, Ali |
title |
New age (ca. 2970 Ma), mantle source composition and geodynamic constraints on the Archean Fiskenaesset anorthosite complex, SW Greenland |
title_short |
New age (ca. 2970 Ma), mantle source composition and geodynamic constraints on the Archean Fiskenaesset anorthosite complex, SW Greenland |
title_full |
New age (ca. 2970 Ma), mantle source composition and geodynamic constraints on the Archean Fiskenaesset anorthosite complex, SW Greenland |
title_fullStr |
New age (ca. 2970 Ma), mantle source composition and geodynamic constraints on the Archean Fiskenaesset anorthosite complex, SW Greenland |
title_full_unstemmed |
New age (ca. 2970 Ma), mantle source composition and geodynamic constraints on the Archean Fiskenaesset anorthosite complex, SW Greenland |
title_sort |
new age (ca. 2970 ma), mantle source composition and geodynamic constraints on the archean fiskenaesset anorthosite complex, sw greenland |
publisher |
Elsevier |
publishDate |
2010 |
url |
https://lup.lub.lu.se/record/1726150 https://doi.org/10.1016/j.chemgeo.2010.06.016 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland |
genre_facet |
Greenland |
op_source |
Chemical Geology; 277(1-2), pp 1-20 (2010) ISSN: 0009-2541 |
op_relation |
https://lup.lub.lu.se/record/1726150 http://dx.doi.org/10.1016/j.chemgeo.2010.06.016 wos:000282861700001 scopus:77956615577 |
op_doi |
https://doi.org/10.1016/j.chemgeo.2010.06.016 |
container_title |
Chemical Geology |
container_volume |
277 |
container_issue |
1-2 |
container_start_page |
1 |
op_container_end_page |
20 |
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1766017267064111104 |