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Discussion of ‘Metamorphic P–T and retrograde path of high-pressure Barrovian metamorphic zones near Cairn Leuchan, Caledonian orogen, Scotland’

Published online by Cambridge University Press:  04 March 2014

K. Aoki ,
B. F. Windley ,
S. Maruyama  and
S. Omori
K. Aoki
Affiliation:
Department of Earth Science and Astronomy, The University of Tokyo, Tokyo 153-8902, Japan; email: kazumasa@ea.c.u-tokyo.ac.jp
B. F. Windley
Affiliation:
Department of Geology, University of Leicester, Leicester LE1 7RH, UK
S. Maruyama
Affiliation:
Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo 152-8551, Japan
S. Omori
Affiliation:
Department of Liberal Arts, The Open University of Japan, Chiba 261-8586, Japan
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K. Aoki, B. F. Windley, S. Maruyama & S. Omori reply: First, we thank Viete, Oliver & Wilde for their interesting and thought-provoking comments on the timing of the high-pressure granulite facies (HGR) metamorphism recorded in metamorphic rocks at Cairn Leuchan, Scotland, published by Aoki et al. (2013). Based on new metamorphic data of garnetites and garnet-amphibolites at Cairn Leuchan and new zircon U–Pb ages of amphibolitized eclogite at Tomatin, we suggested in our publication that the HGR metamorphism was retrograde after eclogite facies before the c. 470 Ma ‘Barrovian metamorphism’. Viete, Oliver & Wilde however speculate that the HGR metamorphism at Cairn Leuchan may have occurred at c. 1000 Ma, as a result of their new U–Pb zircon age of the Cowhythe Gneiss at Portsoy and from previous studies of the geological structure and geochronology. We are grateful for this opportunity to describe, albeit in a preliminary manner, our new understanding and tectonic model of the Caledonian orogen in Scotland and western Ireland of which the Barrovian metamorphism is a key component. A reply to a comment is not the correct place to propose an entirely new paradigm for such a classic orogen, but we will present our model more fully in a future publication.

Type
Discussion
Information
Geological Magazine , Volume 151 , Issue 4 , July 2014 , pp. 758 - 763
Copyright
Copyright © Cambridge University Press 2014 

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