Metamorphism of the Arseno Lake area, N.W.T., Canada: an Abukuma facies series of Aphebian age
Progressive mineralogical and mineral–chemical changes are described for metapelitic rocks from an Abukuma-type metamorphic series ranging from greenschist to upper amphibolite – granulite facies in the Bear Structural Province, Northwest Territories, Canada.The first appearance of the following min...
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crcansciencepubl:10.1139/e86-066 2023-12-17T10:47:42+01:00 Metamorphism of the Arseno Lake area, N.W.T., Canada: an Abukuma facies series of Aphebian age Nielsen, Peter A. 1986 http://dx.doi.org/10.1139/e86-066 http://www.nrcresearchpress.com/doi/pdf/10.1139/e86-066 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 23, issue 5, page 646-669 ISSN 0008-4077 1480-3313 General Earth and Planetary Sciences journal-article 1986 crcansciencepubl https://doi.org/10.1139/e86-066 2023-11-19T13:38:26Z Progressive mineralogical and mineral–chemical changes are described for metapelitic rocks from an Abukuma-type metamorphic series ranging from greenschist to upper amphibolite – granulite facies in the Bear Structural Province, Northwest Territories, Canada.The first appearance of the following minerals defines six isograds: biotite; andalusite; cordierite (muscovite + chlorite out); sillimanite (andalusite out); sillimanite + K-feldspar (muscovite + quartz out); and almandine + K-feldspar ± cordierite (biotite + sillimanite + quartz out).Electron microprobe analyses of the Fe–Mg silicates, biotite, cordierite, and garnet, display two distinct trends of mineral chemistry with increasing metamorphic grade. In the almandine + K-feldspar ± cordierite zone, where garnet is present, Fe/(Fe + Mg) decreases in all of the Fe–Mg silicates observed. However, in the cordierite zone and in the higher grade rocks where garnet is absent, Fe/(Fe + Mg) increases in both biotite and cordierite. Ilmenite and rutile are involved in all continuous reactions and lead to increasing Fe/Mg with grade unless garnet is a product of reaction. There is also a displacement towards lower Fe content at the sillimanite + K-feldspar isograd.The scale of equilibration decreases to 1–2 mm in the almandine + K-feldspar ± cordierite zone, which is most probably a function of the decrease of [Formula: see text] and therefore [Formula: see text]in the metamorphic fluid with increasing metamorphic grade.The physical conditions of metamorphism in the Arseno Lake area range from [Formula: see text] at 2–2.5 kbar with[Formula: see text] in the chlorite zone to ≥650 °C at 3.5–4.0 kbar where [Formula: see text] in the almandine + K-feldspar ± cordierite zone. Article in Journal/Newspaper Northwest Territories Canadian Science Publishing (via Crossref) Northwest Territories Canada Arseno Lake ENVELOPE(-115.651,-115.651,64.567,64.567) Canadian Journal of Earth Sciences 23 5 646 669 |
institution |
Open Polar |
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Canadian Science Publishing (via Crossref) |
op_collection_id |
crcansciencepubl |
language |
English |
topic |
General Earth and Planetary Sciences |
spellingShingle |
General Earth and Planetary Sciences Nielsen, Peter A. Metamorphism of the Arseno Lake area, N.W.T., Canada: an Abukuma facies series of Aphebian age |
topic_facet |
General Earth and Planetary Sciences |
description |
Progressive mineralogical and mineral–chemical changes are described for metapelitic rocks from an Abukuma-type metamorphic series ranging from greenschist to upper amphibolite – granulite facies in the Bear Structural Province, Northwest Territories, Canada.The first appearance of the following minerals defines six isograds: biotite; andalusite; cordierite (muscovite + chlorite out); sillimanite (andalusite out); sillimanite + K-feldspar (muscovite + quartz out); and almandine + K-feldspar ± cordierite (biotite + sillimanite + quartz out).Electron microprobe analyses of the Fe–Mg silicates, biotite, cordierite, and garnet, display two distinct trends of mineral chemistry with increasing metamorphic grade. In the almandine + K-feldspar ± cordierite zone, where garnet is present, Fe/(Fe + Mg) decreases in all of the Fe–Mg silicates observed. However, in the cordierite zone and in the higher grade rocks where garnet is absent, Fe/(Fe + Mg) increases in both biotite and cordierite. Ilmenite and rutile are involved in all continuous reactions and lead to increasing Fe/Mg with grade unless garnet is a product of reaction. There is also a displacement towards lower Fe content at the sillimanite + K-feldspar isograd.The scale of equilibration decreases to 1–2 mm in the almandine + K-feldspar ± cordierite zone, which is most probably a function of the decrease of [Formula: see text] and therefore [Formula: see text]in the metamorphic fluid with increasing metamorphic grade.The physical conditions of metamorphism in the Arseno Lake area range from [Formula: see text] at 2–2.5 kbar with[Formula: see text] in the chlorite zone to ≥650 °C at 3.5–4.0 kbar where [Formula: see text] in the almandine + K-feldspar ± cordierite zone. |
format |
Article in Journal/Newspaper |
author |
Nielsen, Peter A. |
author_facet |
Nielsen, Peter A. |
author_sort |
Nielsen, Peter A. |
title |
Metamorphism of the Arseno Lake area, N.W.T., Canada: an Abukuma facies series of Aphebian age |
title_short |
Metamorphism of the Arseno Lake area, N.W.T., Canada: an Abukuma facies series of Aphebian age |
title_full |
Metamorphism of the Arseno Lake area, N.W.T., Canada: an Abukuma facies series of Aphebian age |
title_fullStr |
Metamorphism of the Arseno Lake area, N.W.T., Canada: an Abukuma facies series of Aphebian age |
title_full_unstemmed |
Metamorphism of the Arseno Lake area, N.W.T., Canada: an Abukuma facies series of Aphebian age |
title_sort |
metamorphism of the arseno lake area, n.w.t., canada: an abukuma facies series of aphebian age |
publisher |
Canadian Science Publishing |
publishDate |
1986 |
url |
http://dx.doi.org/10.1139/e86-066 http://www.nrcresearchpress.com/doi/pdf/10.1139/e86-066 |
long_lat |
ENVELOPE(-115.651,-115.651,64.567,64.567) |
geographic |
Northwest Territories Canada Arseno Lake |
geographic_facet |
Northwest Territories Canada Arseno Lake |
genre |
Northwest Territories |
genre_facet |
Northwest Territories |
op_source |
Canadian Journal of Earth Sciences volume 23, issue 5, page 646-669 ISSN 0008-4077 1480-3313 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/e86-066 |
container_title |
Canadian Journal of Earth Sciences |
container_volume |
23 |
container_issue |
5 |
container_start_page |
646 |
op_container_end_page |
669 |
_version_ |
1785571642543439872 |