Geochemistry of metavolcanic rocks of the Ross Island and Ingalls Head formations, Grand Manan Island, New Brunswick
Southeastern Grand Manan Island consists of explosive and effusive volcanic rocks of the Ross Island and Ingalls Head formations that include syn-eruptive sediments and hyaloclaslites Lavas are commonly amygdaloidal and/or microporphyritic with phenocrysts of feldspar and. more rarely, pyroxene or q...
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ftuninewbrunojs:oai:ojs.journals.lib.unb.ca:article/2014 2023-05-15T18:07:24+02:00 Geochemistry of metavolcanic rocks of the Ross Island and Ingalls Head formations, Grand Manan Island, New Brunswick Pe-Piper, Georgia Wolde, Begashaw 2000-10-01 application/pdf https://journals.lib.unb.ca/index.php/ag/article/view/2014 eng eng Atlantic Geoscience Society https://journals.lib.unb.ca/index.php/ag/article/view/2014/2378 https://journals.lib.unb.ca/index.php/ag/article/view/2014 Copyright (c) 2015 Atlantic Geology Atlantic Geoscience; Vol. 36 No. 2/3 (2000) 2564-2987 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion research-article 2000 ftuninewbrunojs 2022-07-11T11:41:49Z Southeastern Grand Manan Island consists of explosive and effusive volcanic rocks of the Ross Island and Ingalls Head formations that include syn-eruptive sediments and hyaloclaslites Lavas are commonly amygdaloidal and/or microporphyritic with phenocrysts of feldspar and. more rarely, pyroxene or quartz, set in a glassy to microcrystalline groundmass. They are compositionally similar to orogenic andesites with elevated TiO2 (up to 1.5%). The andesites are divisible in two groups that differ in CaO, Na2O, P2O5, Cr and Sr contents, and in the enrichment of Ba relative to Rb and Th. Among the chemically similar andesite samples, those with higher MgO also contain higher amounts of incompatible elements. Unusually for such rocks, there is no evidence for a significant role of feldspar in the evolution from andesite (6l% SiO2) to dacite (66% Si)2). A sample from a mafic dyke cutting the Ingalls Mead Formation contains high FeO(>l2% vs. ≤9% in the host rocks) and TiO2 (>2%). The incompatible element pattern of the dyke sample exhibits troughs at Nb-Ta and Sr similar to those shown by the andesite and dacite samples, but not at Ti. The geochemical characteristics of andesite and the time-space-compositional relationship of the dyke with the host andesite are considered to reflect the origin of these rocks by partial melting of hydrous mafic crust under moderate to low pressure (<8 kbar). The melts may have formed in equilibrium with olivine + orthopyroxene + clinopyroxene ± amphibolc ± plagioclasc ± apatite ± Fe-Ti oxide. Some of the volcanic rocks resemble late Cambrian to late Ordovician rocks of the New River belt on the northwestern margin of the Avalon composite terrane. RÉSUMÉ Le sud-est de l’ile Grand Manan est constitué de roches volcaniques d'épanehement et d'explosion des formations de Ross Island et d'lngalls Head, qui comprennent des sédiments syn-éruptifs el des hyaloclaslites. Les laves sont communément amygdaloides ... Article in Journal/Newspaper Ross Island University of New Brunswick: Centre for Digital Scholarship Journals Manan ENVELOPE(8.748,8.748,62.793,62.793) Ross Island Atlantic Geology 36 2 |
institution |
Open Polar |
collection |
University of New Brunswick: Centre for Digital Scholarship Journals |
op_collection_id |
ftuninewbrunojs |
language |
English |
description |
Southeastern Grand Manan Island consists of explosive and effusive volcanic rocks of the Ross Island and Ingalls Head formations that include syn-eruptive sediments and hyaloclaslites Lavas are commonly amygdaloidal and/or microporphyritic with phenocrysts of feldspar and. more rarely, pyroxene or quartz, set in a glassy to microcrystalline groundmass. They are compositionally similar to orogenic andesites with elevated TiO2 (up to 1.5%). The andesites are divisible in two groups that differ in CaO, Na2O, P2O5, Cr and Sr contents, and in the enrichment of Ba relative to Rb and Th. Among the chemically similar andesite samples, those with higher MgO also contain higher amounts of incompatible elements. Unusually for such rocks, there is no evidence for a significant role of feldspar in the evolution from andesite (6l% SiO2) to dacite (66% Si)2). A sample from a mafic dyke cutting the Ingalls Mead Formation contains high FeO(>l2% vs. ≤9% in the host rocks) and TiO2 (>2%). The incompatible element pattern of the dyke sample exhibits troughs at Nb-Ta and Sr similar to those shown by the andesite and dacite samples, but not at Ti. The geochemical characteristics of andesite and the time-space-compositional relationship of the dyke with the host andesite are considered to reflect the origin of these rocks by partial melting of hydrous mafic crust under moderate to low pressure (<8 kbar). The melts may have formed in equilibrium with olivine + orthopyroxene + clinopyroxene ± amphibolc ± plagioclasc ± apatite ± Fe-Ti oxide. Some of the volcanic rocks resemble late Cambrian to late Ordovician rocks of the New River belt on the northwestern margin of the Avalon composite terrane. RÉSUMÉ Le sud-est de l’ile Grand Manan est constitué de roches volcaniques d'épanehement et d'explosion des formations de Ross Island et d'lngalls Head, qui comprennent des sédiments syn-éruptifs el des hyaloclaslites. Les laves sont communément amygdaloides ... |
format |
Article in Journal/Newspaper |
author |
Pe-Piper, Georgia Wolde, Begashaw |
spellingShingle |
Pe-Piper, Georgia Wolde, Begashaw Geochemistry of metavolcanic rocks of the Ross Island and Ingalls Head formations, Grand Manan Island, New Brunswick |
author_facet |
Pe-Piper, Georgia Wolde, Begashaw |
author_sort |
Pe-Piper, Georgia |
title |
Geochemistry of metavolcanic rocks of the Ross Island and Ingalls Head formations, Grand Manan Island, New Brunswick |
title_short |
Geochemistry of metavolcanic rocks of the Ross Island and Ingalls Head formations, Grand Manan Island, New Brunswick |
title_full |
Geochemistry of metavolcanic rocks of the Ross Island and Ingalls Head formations, Grand Manan Island, New Brunswick |
title_fullStr |
Geochemistry of metavolcanic rocks of the Ross Island and Ingalls Head formations, Grand Manan Island, New Brunswick |
title_full_unstemmed |
Geochemistry of metavolcanic rocks of the Ross Island and Ingalls Head formations, Grand Manan Island, New Brunswick |
title_sort |
geochemistry of metavolcanic rocks of the ross island and ingalls head formations, grand manan island, new brunswick |
publisher |
Atlantic Geoscience Society |
publishDate |
2000 |
url |
https://journals.lib.unb.ca/index.php/ag/article/view/2014 |
long_lat |
ENVELOPE(8.748,8.748,62.793,62.793) |
geographic |
Manan Ross Island |
geographic_facet |
Manan Ross Island |
genre |
Ross Island |
genre_facet |
Ross Island |
op_source |
Atlantic Geoscience; Vol. 36 No. 2/3 (2000) 2564-2987 |
op_relation |
https://journals.lib.unb.ca/index.php/ag/article/view/2014/2378 https://journals.lib.unb.ca/index.php/ag/article/view/2014 |
op_rights |
Copyright (c) 2015 Atlantic Geology |
container_title |
Atlantic Geology |
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36 |
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2 |
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1766179492094541824 |