Melt-filled, conjugate shear zones developed in granitic orthogneisses of the Grenville Province along the shore of the St-Lawrence River (Quebec). The orientation of these shear zones was used to derived the spatial distribution of the principal directions of the strain ellipsoid. The radial distribution of maximal stretching directions around km-scale domes is one of the arguments for the model of diapiric rise of partially molten orthogneisses induced by the sagduction of the heavy Davy synform. The 3-10 km wide domes and the adjacent (NW) ca. 50 X 100 km, north plunging synform are clearly visible on the Google image.
Gervais, F., Nadeau, L., Malo, M., 2004. Migmatitic structures and solid-state diapirism in orthogneiss domes, Eastern Grenville Province, Canada. In Hodges, K., Whitney, D. and Teyssier, C. (eds). Gneiss domes in Orogeny: Geological Society of America Special Paper 380, p. 359-378.
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