Is there a close spatial relationship between faults and plutons?

Using spatial relationships between individual plutons and faults to suppor t genetic correlations between faulting and magmatism is meaningless since even random magmatic or tectonic processes will result in some plutons adja cent to faults. Our initial analyses of populations of faults and Carbonife rous plutons in the Armorican Massif, France and faults and Alleghanian plu tons in the southern Appalachians, USA indicate that plutons have broad dis tributions with respect to faults but with a tendency for plutons to occur away from faults. Maxima of integrated pluton areas occur at 1/4 (Appalachi ans) and 1/2 (Armorican) of the distance between the average fault spacing in these orogens. Although there is a great need for statistical evaluation s of relationships between populations of igneous bodies and structures in a wide variety of settings and crustal depths, our initial studies suggest that faults do not preferentially channel magma during ascent or emplacemen t and that these are relatively unfocused processes within orogenic belts. (C) 1999 Elsevier Science Ltd. All rights reserved.