A Discussion on global tectonics in Proterozoic times - Proterozoic magnetostratigraphy and the tectonic evolution of Laurentia*

There have been two major orogenic cycles in the Proterozoic of Laurentia which culminated at about -1850 (Hudsonian) and -1000 Ma (Grenvillian). A third event, the so-called Elsonian ‘Orogeny’ ( —1400Ma) was dominantly a phase of igneous intrusion. The palaeomagnetic poles from Laurentia are review...

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Published in:Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences
Format: Article in Journal/Newspaper
Language:English
Published: The Royal Society 1976
Subjects:
Online Access:http://dx.doi.org/10.1098/rsta.1976.0006
https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.1976.0006
id crroyalsociety:10.1098/rsta.1976.0006
record_format openpolar
spelling crroyalsociety:10.1098/rsta.1976.0006 2024-09-09T19:58:04+00:00 A Discussion on global tectonics in Proterozoic times - Proterozoic magnetostratigraphy and the tectonic evolution of Laurentia* 1976 http://dx.doi.org/10.1098/rsta.1976.0006 https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.1976.0006 en eng The Royal Society https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences volume 280, issue 1298, page 433-468 ISSN 0080-4614 2054-0272 journal-article 1976 crroyalsociety https://doi.org/10.1098/rsta.1976.0006 2024-07-29T04:23:13Z There have been two major orogenic cycles in the Proterozoic of Laurentia which culminated at about -1850 (Hudsonian) and -1000 Ma (Grenvillian). A third event, the so-called Elsonian ‘Orogeny’ ( —1400Ma) was dominantly a phase of igneous intrusion. The palaeomagnetic poles from Laurentia are reviewed, and an attempt is made to order them into a path of apparent polar wander (a.p.w.). We have constructed this path so as to minimize its length without violating the palaeomagnetic or geological observations. This a.p.w. path defines a magnetic stratigraphy for the Proterozoic of Laurentia which bears on the nature of the above orogenic events and the tectonic evolution that they may signify. If the results from the Grenville Structural Province are excluded, a single polar path for the interval —2200 to -1300 Ma can be constructed, indicating that Laurentia has not been dismembered and that the Hudsonian Orogeny occurred by internal deformation. The geological evidence is consistent with this view, and also indicates that deformation occurred marginally in the Coronation Geosyncline at about 1800 Ma. Poles from the Grenville Province available at present are displaced from the poles from the rest of Laurentia, and may indicate that the southern part of the Grenville Province was displaced 5000 km at about -1150 Ma. The geological evidence is insufficient to determine whether or not such a reconstruction is correct, but it is notable that the Grenville orogenic cycle is preceded by, and is in part contemporaneous with, extensive rift systems, which developed following the Elsonian ‘Orogeny’. The Grenville Province may then be a product of marginal tectonics and the first instance of the opening and closing of an ocean basin whose descendant is the present day North Atlantic. It is concluded that during the interval —2200 to —1400 Ma both marginal and internal tectonics occurred in Laurentia, whereas in the later Proterozoic marginal tectonics dominated. The Elsonian ‘Orogeny’ was apparently the time of changeover ... Article in Journal/Newspaper North Atlantic The Royal Society Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences 280 1298 433 468
institution Open Polar
collection The Royal Society
op_collection_id crroyalsociety
language English
description There have been two major orogenic cycles in the Proterozoic of Laurentia which culminated at about -1850 (Hudsonian) and -1000 Ma (Grenvillian). A third event, the so-called Elsonian ‘Orogeny’ ( —1400Ma) was dominantly a phase of igneous intrusion. The palaeomagnetic poles from Laurentia are reviewed, and an attempt is made to order them into a path of apparent polar wander (a.p.w.). We have constructed this path so as to minimize its length without violating the palaeomagnetic or geological observations. This a.p.w. path defines a magnetic stratigraphy for the Proterozoic of Laurentia which bears on the nature of the above orogenic events and the tectonic evolution that they may signify. If the results from the Grenville Structural Province are excluded, a single polar path for the interval —2200 to -1300 Ma can be constructed, indicating that Laurentia has not been dismembered and that the Hudsonian Orogeny occurred by internal deformation. The geological evidence is consistent with this view, and also indicates that deformation occurred marginally in the Coronation Geosyncline at about 1800 Ma. Poles from the Grenville Province available at present are displaced from the poles from the rest of Laurentia, and may indicate that the southern part of the Grenville Province was displaced 5000 km at about -1150 Ma. The geological evidence is insufficient to determine whether or not such a reconstruction is correct, but it is notable that the Grenville orogenic cycle is preceded by, and is in part contemporaneous with, extensive rift systems, which developed following the Elsonian ‘Orogeny’. The Grenville Province may then be a product of marginal tectonics and the first instance of the opening and closing of an ocean basin whose descendant is the present day North Atlantic. It is concluded that during the interval —2200 to —1400 Ma both marginal and internal tectonics occurred in Laurentia, whereas in the later Proterozoic marginal tectonics dominated. The Elsonian ‘Orogeny’ was apparently the time of changeover ...
format Article in Journal/Newspaper
title A Discussion on global tectonics in Proterozoic times - Proterozoic magnetostratigraphy and the tectonic evolution of Laurentia*
spellingShingle A Discussion on global tectonics in Proterozoic times - Proterozoic magnetostratigraphy and the tectonic evolution of Laurentia*
title_short A Discussion on global tectonics in Proterozoic times - Proterozoic magnetostratigraphy and the tectonic evolution of Laurentia*
title_full A Discussion on global tectonics in Proterozoic times - Proterozoic magnetostratigraphy and the tectonic evolution of Laurentia*
title_fullStr A Discussion on global tectonics in Proterozoic times - Proterozoic magnetostratigraphy and the tectonic evolution of Laurentia*
title_full_unstemmed A Discussion on global tectonics in Proterozoic times - Proterozoic magnetostratigraphy and the tectonic evolution of Laurentia*
title_sort discussion on global tectonics in proterozoic times - proterozoic magnetostratigraphy and the tectonic evolution of laurentia*
publisher The Royal Society
publishDate 1976
url http://dx.doi.org/10.1098/rsta.1976.0006
https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.1976.0006
genre North Atlantic
genre_facet North Atlantic
op_source Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences
volume 280, issue 1298, page 433-468
ISSN 0080-4614 2054-0272
op_rights https://royalsociety.org/journals/ethics-policies/data-sharing-mining/
op_doi https://doi.org/10.1098/rsta.1976.0006
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