L. Corriveau et D. Leblanc, SEQUENTIAL NESTING OF MAGMAS IN MARBLE, SOUTHWESTERN GRENVILLE PROVINCE, QUEBEC - FROM FRACTURE PROPAGATION TO DIAPIRISM, Tectonophysics, 246(1-3), 1995, pp. 183-200
In the southwestern Grenville Province (Quebec), 1090-1070 My old K-ri
ch alkaline equidimensional plutons, such as the Kensington pluton, oc
cur in marble-rich country rock, but coeval dykes bearing lower-crusta
l xenoliths are found only in a quartzofeldspathic gneiss complex. The
sequential nesting of magmas, the various episodes of skam formation
and the progressively more mafic character of the intruding magmas of
the Kensington pluton are interpreted in terms of magma ascent through
a series of propagating fractures, cessation of upward fracturing and
pooling of magma in marble-rich ductile crust, diapirism, radial shor
tening of wall rock, and in-situ pluton expansion. This suite provides
evidence that at deep crustal levels, the country-rock theology influ
ences the mode of magma ascent and emplacement and that diapirism is a
possible mechanism of magma transport through rocks behaving theologi
cally by a power-law model.