Metamorphism and cooling of the NE Dalradian

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doi: 10.1144/gsjgs.152.2.0383
Authors:Dempster, T. J.; Hudson, N. F. C.; Rogers, G.
Author Affiliations:Primary:
University of Glasgow, Department of Geology and Applied Geology, Glasgow, United Kingdom
University of Derby, United Kingdom
Scottish Universities Research and Reactor Centre, United Kingdom
Volume Title:Journal of the Geological Society of London
Source:Journal of the Geological Society of London, Vol.152(Part 2), p.383-390. Publisher: Geological Society of London, London, United Kingdom. ISSN: 0016-7649
Publication Date:1995
Note:In English. 67 refs.; illus., incl. sect., 1 table, geol. sketch map
Summary:The Buchan area of Dalradian rocks represents a distinct tectonothermal domain in the Scottish Highlands, the Portsoy-Duchray Hill lineament on the W margin of this block being one of the best examples of a long-lived domain boundary. Rb-Sr mica cooling ages indicate a prolonged Ordovician cooling history. Delayed, but then rapid, cooling to the W of the Portsoy-Duchray Hill lineaments is recognized, whereas to the E the age data point to a high heat flow regime lasting >> 50 m.y. The isotopic ages suggest that ∼ 460 m.y. was a time of active tectonism, resulting in final cooling of the low-grade rocks and differential uplift and rapid cooling of deeper structural levels to the W. The overprinting of andalusite-bearing assemblages by kyanite to the W of the Portsoy-Duchray Hill lineament is linked to P increases associated with the intrusion of the Newer Gabbros and represents a magmatic loading related to the same tectono-thermal event that generated low-P metamorphism, rather than a separate tectonic episode. [R.A.H.]
Subjects:Absolute age; Alkali metals; Alkaline earth metals; Cooling; Dalradian; Dates; Intrusions; Lineaments; Metals; Metamorphism; Rb/Sr; Rubidium; Strontium; Whole rock; Europe; Great Britain; Scotland; Scottish Highlands; United Kingdom; Western Europe
Abstract Numbers:95M/3684
Record ID:1995029731
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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