@ARTICLE{Johnson2015,
  author = {Johnson, T. E. and Kirkland, C. L. and Reddy, S. M. and Fischer, S.},
  title = {Grampian migmatites in the Buchan Block, NE Scotland},
  journal = {Journal of Metamorphic Geology},
  year = {2015},
  volume = {33},
  pages = {695--709},
  number = {7},
  abstract = {Rocks exposed along the Scottish coast between Fraserburgh and Inzie
	Head contain information critical to understanding the evolution
	of the Buchan Block, the type locality for low-P, high-T regional
	metamorphism, and its relationship with the rest of the Grampian
	terrane, one of the major tectonostratigraphic components of the
	Scottish Caledonides. The ~8 km long section traverses a regional
	network of shear zones and, at the highest grades around Inzie Head,
	passes into the core of the Buchan Anticline, a large-scale open
	fold that is commonly regarded as a late structure, post-dating metamorphism.
	The metasedimentary rocks increase in grade from upper amphibolite
	to granulite facies and preserve unequivocal evidence for partial
	melting. The diatexite migmatites around Inzie Head, along with other
	gneissose units within the Buchan Block, have been regarded as allochthonous
	Precambrian basement rocks that were thrust into their current position
	during the Grampian orogenesis. However, field observations show
	that the onset of in situ partial melting in metapelitic rocks, which
	was associated with the formation of garnet-bearing aplites and associated
	pegmatites, occurred around Fraserburgh, where shear fabrics are
	absent. Thus, the rocks preserve a continuous metamorphic field gradient
	that straddles the shear zone network. This observation supports
	an alternative interpretation that anatexis was the result of mid-Ordovician
	(Grampian) metamorphism, rather than an older tectonothermal event,
	and that the Inzie Head gneisses are autochthonous. Using an average
	mid-Dalradian pelite as a plausible representative protolith, phase
	equilibria modelling satisfactorily reproduces the observed appearance
	and disappearance of key minerals providing that peritectic garnet
	produced with the first formed melts (represented by the garnet-bearing
	aplites) depleted the source rocks in Mn. The modelled metamorphic
	field gradient records a temperature increase of at least 150 °C
	(from ~650 °C near Fraserburgh to in excess of 800 °C at Inzie Head)
	but is isobaric at pressures of 2.7–2.8 kbar, suggesting the Buchan
	Anticline developed synchronous with partial melting. The Buchan
	Anticline is likely an expression of crustal thinning and asthenospheric
	upwelling, which produced voluminous gabbroic intrusions that supplied
	the heat for Buchan metamorphism.},
  doi = {10.1111/jmg.12147},
  keywords = {Buchan Block, Dalradian metapelitic migmatite, Grampian metamorphism,
	manganese, phase equilibria modelling},
  url = {http://dx.doi.org/10.1111/jmg.12147}
}