Cotectic proportions of olivine and spinel in olivine-tholeiitic basalt and evaluation of pre-eruptive processes
The volume %, distribution, texture and composition of coexisting olivine, Cr-spinel and glass has been determined in quenched lava samples from Hawaii, Iceland and mid-oceanic ridges. The volume ratio of olivine to spinel varies from 60 to 2800 and samples with>002 % spinel have a volume ratio o...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.584.5706 2023-05-15T16:51:15+02:00 Cotectic proportions of olivine and spinel in olivine-tholeiitic basalt and evaluation of pre-eruptive processes Peter Roeder Emma Gofton Carl Thornber The Pennsylvania State University CiteSeerX Archives 2006 application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.584.5706 http://petrology.oxfordjournals.org/content/early/2006/02/13/petrology.egi099.full.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.584.5706 http://petrology.oxfordjournals.org/content/early/2006/02/13/petrology.egi099.full.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://petrology.oxfordjournals.org/content/early/2006/02/13/petrology.egi099.full.pdf text 2006 ftciteseerx 2016-08-28T00:06:46Z The volume %, distribution, texture and composition of coexisting olivine, Cr-spinel and glass has been determined in quenched lava samples from Hawaii, Iceland and mid-oceanic ridges. The volume ratio of olivine to spinel varies from 60 to 2800 and samples with>002 % spinel have a volume ratio of olivine to spinel of approx-imately 100. A plot of wt % MgO vs ppm Cr for natural and experimental basaltic glasses suggests that the general trend of the glasses can be explained by the crystallization of a cotectic ratio of olivine to spinel of about 100. One group of samples has an olivine to spinel ratio of approximately 100, with skeletal olivine pheno-crysts and small (<50mm) spinel crystals that tend to be spatially associated with the olivine phenocrysts. The large number of spinel crystals included within olivine phenocrysts is thought to be due to skeletal olivine phenocrysts coming into physical contact with spinel by synneusis during the chaotic conditions of ascent and extrusion. A second group of samples tend to have large olivine phenocrysts relatively free of included spinel, a few large (>100mm) spinel crystals that show evidence of two stages of growth, and a volume ratio of olivine to spinel of 100 to well over 1000. The olivine and spinel in this group have crystallized more slowly with little physical interaction, and show evidence that they have accumulated in a magma chamber. KEY WORDS: olivine; spinel; basalt glass; volume %; cotectic Text Iceland Unknown |
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English |
description |
The volume %, distribution, texture and composition of coexisting olivine, Cr-spinel and glass has been determined in quenched lava samples from Hawaii, Iceland and mid-oceanic ridges. The volume ratio of olivine to spinel varies from 60 to 2800 and samples with>002 % spinel have a volume ratio of olivine to spinel of approx-imately 100. A plot of wt % MgO vs ppm Cr for natural and experimental basaltic glasses suggests that the general trend of the glasses can be explained by the crystallization of a cotectic ratio of olivine to spinel of about 100. One group of samples has an olivine to spinel ratio of approximately 100, with skeletal olivine pheno-crysts and small (<50mm) spinel crystals that tend to be spatially associated with the olivine phenocrysts. The large number of spinel crystals included within olivine phenocrysts is thought to be due to skeletal olivine phenocrysts coming into physical contact with spinel by synneusis during the chaotic conditions of ascent and extrusion. A second group of samples tend to have large olivine phenocrysts relatively free of included spinel, a few large (>100mm) spinel crystals that show evidence of two stages of growth, and a volume ratio of olivine to spinel of 100 to well over 1000. The olivine and spinel in this group have crystallized more slowly with little physical interaction, and show evidence that they have accumulated in a magma chamber. KEY WORDS: olivine; spinel; basalt glass; volume %; cotectic |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Peter Roeder Emma Gofton Carl Thornber |
spellingShingle |
Peter Roeder Emma Gofton Carl Thornber Cotectic proportions of olivine and spinel in olivine-tholeiitic basalt and evaluation of pre-eruptive processes |
author_facet |
Peter Roeder Emma Gofton Carl Thornber |
author_sort |
Peter Roeder |
title |
Cotectic proportions of olivine and spinel in olivine-tholeiitic basalt and evaluation of pre-eruptive processes |
title_short |
Cotectic proportions of olivine and spinel in olivine-tholeiitic basalt and evaluation of pre-eruptive processes |
title_full |
Cotectic proportions of olivine and spinel in olivine-tholeiitic basalt and evaluation of pre-eruptive processes |
title_fullStr |
Cotectic proportions of olivine and spinel in olivine-tholeiitic basalt and evaluation of pre-eruptive processes |
title_full_unstemmed |
Cotectic proportions of olivine and spinel in olivine-tholeiitic basalt and evaluation of pre-eruptive processes |
title_sort |
cotectic proportions of olivine and spinel in olivine-tholeiitic basalt and evaluation of pre-eruptive processes |
publishDate |
2006 |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.584.5706 http://petrology.oxfordjournals.org/content/early/2006/02/13/petrology.egi099.full.pdf |
genre |
Iceland |
genre_facet |
Iceland |
op_source |
http://petrology.oxfordjournals.org/content/early/2006/02/13/petrology.egi099.full.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.584.5706 http://petrology.oxfordjournals.org/content/early/2006/02/13/petrology.egi099.full.pdf |
op_rights |
Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
_version_ |
1766041361914527744 |