Tectonic stratigraphy and structural continuity of the northernmost Moine Thrust Zone and Moine Nappe, Scottish Caledonides
Published:January 01, 2007
R. E. Holdsworth, G. I. Alsop, R. A. Strachan, 2007. "Tectonic stratigraphy and structural continuity of the northernmost Moine Thrust Zone and Moine Nappe, Scottish Caledonides", Deformation of the Continental Crust: The Legacy of Mike Coward, A. C. Ries, R. W. H. Butler, R. H. Graham
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The Moine Thrust Zone and overlying Moine Nappe represent classic ground in Scottish geology in which Neoproterozoic Moine metasedimentary rocks were translated towards the WNW over the Laurentian foreland comprising Lewisian basement gneisses and a Cambrian cover succession during Caledonian orogenesis at c. 430 Ma. Systematic mapping of both the Moine Nappe and underlying Moine Thrust Zone in the Loch Hope to Whiten Head region of Sutherland extends the tectonic stratigraphy developed in other parts of the thrust zone to the little-studied north coast section. An apparent continuum of deformation is recognized from the Moine Nappe down into the underlying thrust zone with a consistent gently ESE-dipping foliation associated with down-dip mineral and extension lineations. The polyphase fold history present within the Moine Nappe and the thrust zone results from progressive deformation during thrusting. Thrust-related fold axes and bedding-cleavage intersections are typically subparallel to the transport direction in high-strain zones, whereas gently north- or south-plunging attitudes are common in lower strain portions of the thrust zone. Thrusts are commonly deformed by folds developed within their footwalls, consistent with a foreland-propagating sequence of deformation. The newly defined Lochan Riabhach Thrust is interpreted as an ‘out-of-sequence’ structure that sliced at low angles across the thrust zone and toward the WNW after initial thrust stacking. Comparison with the downfaulted segment of the Moine Nappe and thrust zone exposed on the foreland at Faraid Head demonstrates cross-strike continuity of the thrust sheet template and structural history for at least 15 km to the NW.
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Deformation of the Continental Crust: The Legacy of Mike Coward
This Special Publication, in memory and celebration of the work of Professor Mike Coward, is about the deformation of the continental lithosphere. The collected papers discuss geometry, structural principles, processes and problems in a wide range of tectonic settings and thereby reflect the breadth of Coward's interests. They encompass the evolution of Precambrian basement gneiss terrains, the geometry and evolution of thrust systems, basement involvement and structural inheritance in basins, syn-orogenic extension, salt tectonics, the implication of structural evolution on hydrocarbon prospectivity and structural controls on mineralization. Examples are drawn from the Lewisian and Moine Thrust Belt of NW Scotland, the Italian Apennines, NW Himalayas, the Cyclades, Oman, Zagros Mountains, Colombian Cordillera, Carpathians, North Sea, offshore Brazil, regional studies of the Irumide Belt (central Africa), Taurus Mountains (Turkey), greater South America, and from the Witwatersrand Basin of South Africa and the Antler Orogeny of SW USA.