Caledonian plutonism and major lineaments in the SW Scottish Highlands

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doi: 10.1144/gsjgs.151.6.0955
Authors:Jacques, J. M.; Reavy, R. J.
Author Affiliations:Primary:
University of Durham, Department of Geological Sciences, Durham, United Kingdom
Other:
University of Oxford, United Kingdom
Volume Title:Journal of the Geological Society of London
Source:Journal of the Geological Society of London, Vol.151 (Part 6), p.955-969. Publisher: Geological Society of London, London, United Kingdom. ISSN: 0016-7649
Publication Date:1994
Note:In English. 53 refs.; illus., incl. block diags., 2 tables, geol. sketch maps
Summary:Several NE-SW-trending shear zones and faults related to the Caledonian transpressional collision are recognized in the SW Grampian Highlands as being distinct from an intersecting set of pre-Caledonian crustal lineaments with the same trend which were reactivated during Caledonian orogenesis. Geochemical and isotopic characteristics of the 425-400 m.y. granitic rocks of this region show that they were derived by anatexis of the lower crust associated with a mantle component which provided mantle heat and/or metasomatic fluids; their spatial distribution suggests a genetic relationship with Caledonian shear zones. Making the distinction between ascent (transport) and emplacement (arrival) configurations for granitic magmas, new data for these plutons show that: 1) a common modal sequence of intrusive phases can be recognized, 2) these phases are all sited at shear zones or lineament intersections where transtensional zones allowed and facilitated ascent, and 3) emplacement was often by a process of localized in situ ballooning. The existence of such lineaments in these orientations in this area may indicate that the structure of the lower crust can be regarded as a series of blocks bounded by intersecting ductile zones of high strain. Such a pattern of structural interactions within the lower crust could provide a mechanistic framework within which the location of anatectic zones, siting and ascent pathways and any subsequent emplacement phenomena can be explained in orogenic belts. [R.A.H.]
Subjects:Caledonian Orogeny; Emplacement; Faults; Granites; Igneous rocks; Intrusions; Lineaments; Paleozoic; Plutonic rocks; Plutons; Shear zones; Strike-slip faults; Tectonics; Europe; Grampian Highlands; Great Britain; Scotland; Scottish Highlands; United Kingdom; Western Europe
Abstract Numbers:95M/2085
Record ID:1997005347
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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