Dempster, T. and Jess, S. A. (2015) Ikaite pseudomorphs in Neoproterozoic Dalradian slates record Earth’s coldest metamorphism. Journal of the Geological Society, 172, pp. 459-464. (doi: 10.1144/jgs2015-018)
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Abstract
Calcite pseudomorphs have replaced euhedral ikaite (CaCO3.6H2O)porphyroblasts in Dalradian calcareous slates and metadolostones of western Scotland, with a volume decrease of at least 47%. Porphyroblast-fabric relationships indicate that the initial growth of ikaite post-dates a penetrative tectonic fabric developed during upright folding. This is the first reported occurrence of metamorphic ikaite porphyroblasts and points towards growth within the slates during an ultra-low temperature metamorphism with an exceptionally low geothermal gradient. This event is associated with the penetration of long-lived and extreme permafrost deep into sub aerially exposed bedrock during Neoproterozoic glaciation. The presence of the well preserved pseudomorphs within the Easdale slates of the Argyll group implies that a Neoproterozoic orogenic unconformity exists above the stratigraphic position of theserocks.
Item Type: | Articles |
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Status: | Published |
Refereed: | Yes |
Glasgow Author(s) Enlighten ID: | Dempster, Dr Tim |
Authors: | Dempster, T., and Jess, S. A. |
College/School: | College of Science and Engineering > School of Geographical and Earth Sciences |
Journal Name: | Journal of the Geological Society |
Publisher: | Geological Society of London |
ISSN: | 0016-7649 |
ISSN (Online): | 2041-479X |
Copyright Holders: | Copyright © 2015 Geological Society |
First Published: | First published in Journal of the Geological Society 2015 |
Publisher Policy: | Reproduced in accordance with the copyright policy of the publisher. |
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