The Lewisian complex: a typical Precambrian high-grade terrain?

Park, R. G.; Tarney, J.

doi:10.1144/gsl.sp.1987.027.01.03

Cited by 66 publications

(65 citation statements)

References 52 publications

(44 reference statements)

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“…Northwest of the leading edge of the Moine Thrust, rocks of the Laurentian foreland crop out both on the Scottish mainland and in the Outer Hebrides. The Lewisian gneisses of this foreland have Archaean protoliths that have been affected by several, subsequent, high-grade metamorphic and deformation events (Lyon and Bowes, 1977;Kinny and Friend, 1997;Park and Tarney, 1987;Cliff and Rex, 1989;Friend and Kinny, 1995;Friend and Kinny, 2001;Kinny and Friend, 2005). The occurrence of 1.08 Ga eclogites at Glenelg implies that the Caledonian in the northwest experienced crustal thickening by imbrication (Sanders et al, 1984).…”

Section: Potential Magma Sources In the Crust And Mantlementioning

confidence: 98%

Sources of post-orogenic calcalkaline magmas: The Arrochar and Garabal Hill–Glen Fyne complexes, Scotland

Clemens

Darbyshire

Flinders

2009

Lithos

106

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The 425 Ma Arrochar and Garabal Hill-Glen Fyne complexes of highland Scotland are examples of post-orogenic magmatism accompanying extensional collapse of an orogen, in this case the Caledonian. The rocks are dominantly high-K series, but range from medium-K to shoshonitic. Mantle upwelling, melting and the intrusion of large volumes of mafic magma into the crust are inferred to have accompanied lithospheric thinning, and to have provided the heat source for melting of young arc crust accreted during the preceding subduction epoch.Fluids evolved from the subducting slab are inferred to have caused high degrees of enrichment in the overlying mantle wedge. Deep in the crust, the mantle-derived, K-rich mafic to intermediate magmas mixed with felsic crustal melts to form the spectrum of magmas intruded in the two complexes. Microgranular enclaves in the granitic rocks represent mafic magmas derived from the enriched mantle and hybridised by reaction, diffusion and mechanical mixing with their host felsic magmas, but they do not form part of the evolutionary series that produced the host magmas. Rather than inheriting its LILEenriched character directly from crustal melts, or from crustal assimilation by mafic magmas, the high-K series may commonly owe at least part of its potassic character to the involvement of mantle (highly metasomatised by slab-derived fluids) as a major magma source. Enclave suites, though prominent in some granitic rocks should not be assumed to represent magmas that played a significant role in the production of the chemical variations in their host magmas.

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Section: Potential Magma Sources In the Crust And Mantlementioning

confidence: 98%

Sources of post-orogenic calcalkaline magmas: The Arrochar and Garabal Hill–Glen Fyne complexes, Scotland

Clemens

Darbyshire

Flinders

2009

Lithos

106

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“…Beach et al (1974) studied the structural 184 evolution of the Loch Laxford area, and recognised three significant deformation 185 phases in the Laxford area, one pre-Scourie Dyke intrusion and two post-dyke. They 186 mapped and described pre-Scourie Dyke folds but did not directly correlate their 187 structures with the Inverian event, as defined near Lochinver by Evans (1965) tectonically accreted to the continental margin (Park and Tarney, 1987). 207 Coward and Park (1987) and Coward (1990) re-investigated the structures of the 208 Laxford area.…”

Section: Noted That the Area Around Loch 168mentioning

confidence: 99%

The Laxford Shear Zone: an end-Archaean terrane boundary?

Goodenough

Park²,

Krabbendam

et al. 2010

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22The Lewisian Gneiss Complex of north-western Scotland consists of Archaean 23 gneisses, variably reworked during the Proterozoic. It can be divided into three 24 districts -a central granulite-facies district between districts of amphibolite-facies 25 gneiss to the north and south. Recent work has interpreted these districts in terms of 26 separate terranes, initiating a controversy that has implications for how Precambrian 27 rocks are understood worldwide. The northern district of the Lewisian Gneiss 28Complex (

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“…The Scourie dykes intruded during at least two different events at 2418 Ma and 1992 Ma [72,75,108,109]. The youngest of these dykes intruded into hot gneissic and migmatitic rocks syn-kinematically with a late stage of shear zone deformation [79,107], of the same kind as that shown in Figure 14d.…”

Section: A Chronology Of Eventsmentioning

confidence: 77%

“…These dykes display many different geometries and attitudes, mostly steeply dipping, and they cut all Neoarchaean folds and planar fabrics ( Figure 15). The composition of the dykes varies from mafic to ultramafic [105], and their trace element geochemistry indicate formation in a marginal continental setting, as island arcs or from a mixtures of crustal and oceanic material [106,107]. The Scourie dykes intruded during at least two different events at 2418 Ma and 1992 Ma [72,75,108,109].…”

Section: A Chronology Of Eventsmentioning

confidence: 99%