The 3.5 Ga Siurua trondhjemite gneiss in the Archaean Pudas-
In the Archaean Pudasjärvi Complex the pyroxene-bearing rocks are considered to form a belt, the Pudasjärvi Granulite Belt (PGB). The major rock types of the PGB are meta-igneous mafi c and felsic granulites, and trondhjemite gneisses. Red alaskites, white leu-cogranites and trondhjemitic pegmatoids...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.597.9918 2023-05-15T16:13:03+02:00 The 3.5 Ga Siurua trondhjemite gneiss in the Archaean Pudas- Järvi Granulite Belt Northern Finl Tapani Mutanen Hannu Huhma The Pennsylvania State University CiteSeerX Archives application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.597.9918 http://www.geologinenseura.fi/bulletin/Volume75/MutanenHuhma.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.597.9918 http://www.geologinenseura.fi/bulletin/Volume75/MutanenHuhma.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://www.geologinenseura.fi/bulletin/Volume75/MutanenHuhma.pdf Corresponding author text ftciteseerx 2016-01-08T13:49:34Z In the Archaean Pudasjärvi Complex the pyroxene-bearing rocks are considered to form a belt, the Pudasjärvi Granulite Belt (PGB). The major rock types of the PGB are meta-igneous mafi c and felsic granulites, and trondhjemite gneisses. Red alaskites, white leu-cogranites and trondhjemitic pegmatoids are locally abundant. Ion microprobe U-Pb anal-yses on zircons suggest a magmatic age of ca. 3.5 Ga for the trondhjemite gneiss in Siu-rua, considered the oldest rock so far identifi ed in the Fennoscandian Shield. The old age is supported by the Sm-Nd depleted mantle model age of 3.5 Ga, and by convention-al U-Pb zircon data, which have provided a minimum age of 3.32 Ga. The U-Pb sims-da-ta on the Siurua gneiss are, however, heterogeneous and suggest several stages of zircon growth, mostly at 3.5–3.4 Ga. An inherited core in one crystal provided an age of 3.73 Ga, whereas the youngest two analyses yield ages of 3.1 and 3.3 Ga. Metamorphic mon-azite formed in the Siurua gneiss ca. 2.66 Ga ago, roughly contemporaneously with the high-grade metamorphism recorded by zircon in a mafi c granulite. Magmatic zircons from a felsic high-grade rock provide ages of ca. 2.96 Ga, but no zircons coeval with the 2.65 Ga metamorphism were detected by ion-microprobe. As a whole the PGB seems to be a tectonic block-mosaic containing rocks with Sm-Nd crustal formation ages ranging from 3.5 to 2.8 Ga. Text Fennoscandian Unknown Rua ENVELOPE(14.750,14.750,64.583,64.583) |
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Corresponding author Järvi Granulite Belt Northern Finl Tapani Mutanen Hannu Huhma The 3.5 Ga Siurua trondhjemite gneiss in the Archaean Pudas- |
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Corresponding author |
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In the Archaean Pudasjärvi Complex the pyroxene-bearing rocks are considered to form a belt, the Pudasjärvi Granulite Belt (PGB). The major rock types of the PGB are meta-igneous mafi c and felsic granulites, and trondhjemite gneisses. Red alaskites, white leu-cogranites and trondhjemitic pegmatoids are locally abundant. Ion microprobe U-Pb anal-yses on zircons suggest a magmatic age of ca. 3.5 Ga for the trondhjemite gneiss in Siu-rua, considered the oldest rock so far identifi ed in the Fennoscandian Shield. The old age is supported by the Sm-Nd depleted mantle model age of 3.5 Ga, and by convention-al U-Pb zircon data, which have provided a minimum age of 3.32 Ga. The U-Pb sims-da-ta on the Siurua gneiss are, however, heterogeneous and suggest several stages of zircon growth, mostly at 3.5–3.4 Ga. An inherited core in one crystal provided an age of 3.73 Ga, whereas the youngest two analyses yield ages of 3.1 and 3.3 Ga. Metamorphic mon-azite formed in the Siurua gneiss ca. 2.66 Ga ago, roughly contemporaneously with the high-grade metamorphism recorded by zircon in a mafi c granulite. Magmatic zircons from a felsic high-grade rock provide ages of ca. 2.96 Ga, but no zircons coeval with the 2.65 Ga metamorphism were detected by ion-microprobe. As a whole the PGB seems to be a tectonic block-mosaic containing rocks with Sm-Nd crustal formation ages ranging from 3.5 to 2.8 Ga. |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Järvi Granulite Belt Northern Finl Tapani Mutanen Hannu Huhma |
author_facet |
Järvi Granulite Belt Northern Finl Tapani Mutanen Hannu Huhma |
author_sort |
Järvi Granulite Belt |
title |
The 3.5 Ga Siurua trondhjemite gneiss in the Archaean Pudas- |
title_short |
The 3.5 Ga Siurua trondhjemite gneiss in the Archaean Pudas- |
title_full |
The 3.5 Ga Siurua trondhjemite gneiss in the Archaean Pudas- |
title_fullStr |
The 3.5 Ga Siurua trondhjemite gneiss in the Archaean Pudas- |
title_full_unstemmed |
The 3.5 Ga Siurua trondhjemite gneiss in the Archaean Pudas- |
title_sort |
3.5 ga siurua trondhjemite gneiss in the archaean pudas- |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.597.9918 http://www.geologinenseura.fi/bulletin/Volume75/MutanenHuhma.pdf |
long_lat |
ENVELOPE(14.750,14.750,64.583,64.583) |
geographic |
Rua |
geographic_facet |
Rua |
genre |
Fennoscandian |
genre_facet |
Fennoscandian |
op_source |
http://www.geologinenseura.fi/bulletin/Volume75/MutanenHuhma.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.597.9918 http://www.geologinenseura.fi/bulletin/Volume75/MutanenHuhma.pdf |
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Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
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1765998656596475904 |