Geochemistry of a continental tholeiite suite: late Palaeozoic quartz dolerite dykes of Scotland
Abstract The late Carboniferous quartz dolerite suite of Scotland consists mainly of quartz tholeiites, with subordinate olivine tholeiites and tholeiitic andesites. The low pressure evolution of the magmas was controlled by fractionation of olivine–plagioclase–pyroxene–oxides assemblages from more...
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1981
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crcambridgeupr:10.1017/s0263593300003230 2024-09-15T18:14:12+00:00 Geochemistry of a continental tholeiite suite: late Palaeozoic quartz dolerite dykes of Scotland Macdonald, R. Gottfried, D. Farrington, M. J. Brown, F. W. Skinner, N. G. 1981 http://dx.doi.org/10.1017/s0263593300003230 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0263593300003230 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Transactions of the Royal Society of Edinburgh: Earth Sciences volume 72, issue 1, page 57-74 ISSN 0263-5933 1473-7116 journal-article 1981 crcambridgeupr https://doi.org/10.1017/s0263593300003230 2024-07-31T04:01:29Z Abstract The late Carboniferous quartz dolerite suite of Scotland consists mainly of quartz tholeiites, with subordinate olivine tholeiites and tholeiitic andesites. The low pressure evolution of the magmas was controlled by fractionation of olivine–plagioclase–pyroxene–oxides assemblages from more magnesian compositions and plagioclase–pyroxene–oxides–apatite removal from intermediate compositions. A higher pressure stage dominated by olivine fractionation is suggested by the presence of olivine nodules in a magnesian basalt dyke from Fife. The suite is of high-Fe-Ti type, closely comparable to certain basalts erupted in areas of active lithospheric spreading or “hot spots”, such as Iceland and Hawaii. The ppO 2 can be inferred to have been rather higher in the Scottish rocks than in comparative suites, promoting earlier separation of Fe-Ti oxides, with the consequent effects on trace element distribution. Apart from varying degrees of fractionation, chemical variations in the dykes are of three types: rather minor variations along individual dykes, variations across certain thicker dykes, and minor and trace element variations reflecting chemical heterogeneities in the mantle sources. The dykes and sills are inferred to have been fed from a plexus of small, partly independent, magma reservoirs. New trace element data on tholeiitic lavas from the Oslo Rift confirm recently revived suggestions that the Scottish and northern English quartz dolerites are part of a larger province extending into Scandinavia. Article in Journal/Newspaper Iceland Cambridge University Press Transactions of the Royal Society of Edinburgh: Earth Sciences 72 1 57 74 |
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English |
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Abstract The late Carboniferous quartz dolerite suite of Scotland consists mainly of quartz tholeiites, with subordinate olivine tholeiites and tholeiitic andesites. The low pressure evolution of the magmas was controlled by fractionation of olivine–plagioclase–pyroxene–oxides assemblages from more magnesian compositions and plagioclase–pyroxene–oxides–apatite removal from intermediate compositions. A higher pressure stage dominated by olivine fractionation is suggested by the presence of olivine nodules in a magnesian basalt dyke from Fife. The suite is of high-Fe-Ti type, closely comparable to certain basalts erupted in areas of active lithospheric spreading or “hot spots”, such as Iceland and Hawaii. The ppO 2 can be inferred to have been rather higher in the Scottish rocks than in comparative suites, promoting earlier separation of Fe-Ti oxides, with the consequent effects on trace element distribution. Apart from varying degrees of fractionation, chemical variations in the dykes are of three types: rather minor variations along individual dykes, variations across certain thicker dykes, and minor and trace element variations reflecting chemical heterogeneities in the mantle sources. The dykes and sills are inferred to have been fed from a plexus of small, partly independent, magma reservoirs. New trace element data on tholeiitic lavas from the Oslo Rift confirm recently revived suggestions that the Scottish and northern English quartz dolerites are part of a larger province extending into Scandinavia. |
format |
Article in Journal/Newspaper |
author |
Macdonald, R. Gottfried, D. Farrington, M. J. Brown, F. W. Skinner, N. G. |
spellingShingle |
Macdonald, R. Gottfried, D. Farrington, M. J. Brown, F. W. Skinner, N. G. Geochemistry of a continental tholeiite suite: late Palaeozoic quartz dolerite dykes of Scotland |
author_facet |
Macdonald, R. Gottfried, D. Farrington, M. J. Brown, F. W. Skinner, N. G. |
author_sort |
Macdonald, R. |
title |
Geochemistry of a continental tholeiite suite: late Palaeozoic quartz dolerite dykes of Scotland |
title_short |
Geochemistry of a continental tholeiite suite: late Palaeozoic quartz dolerite dykes of Scotland |
title_full |
Geochemistry of a continental tholeiite suite: late Palaeozoic quartz dolerite dykes of Scotland |
title_fullStr |
Geochemistry of a continental tholeiite suite: late Palaeozoic quartz dolerite dykes of Scotland |
title_full_unstemmed |
Geochemistry of a continental tholeiite suite: late Palaeozoic quartz dolerite dykes of Scotland |
title_sort |
geochemistry of a continental tholeiite suite: late palaeozoic quartz dolerite dykes of scotland |
publisher |
Cambridge University Press (CUP) |
publishDate |
1981 |
url |
http://dx.doi.org/10.1017/s0263593300003230 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0263593300003230 |
genre |
Iceland |
genre_facet |
Iceland |
op_source |
Transactions of the Royal Society of Edinburgh: Earth Sciences volume 72, issue 1, page 57-74 ISSN 0263-5933 1473-7116 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/s0263593300003230 |
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Transactions of the Royal Society of Edinburgh: Earth Sciences |
container_volume |
72 |
container_issue |
1 |
container_start_page |
57 |
op_container_end_page |
74 |
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1810451980069371904 |