Vertical deformation partitioning across a collapsing large and hot orogen

Featuring 3 000- km-   long large and hot orogen, the Mantiqueira Province provides a rare opportunity to study the process of gravitational collapse at mid to deep crustal levels.  Distinct  but  contemporary  (~500 Ma) post-collisional intrusions show struc-tures and anisotropy of magnetic susceptibility (AMS) fabrics related to their em-placements,  recording  different  flow  patterns.  In  southern  deep-seated  intrusions,  ellipsoidal-shaped  roots  with  gabbroic-to-  hybrid  cores  surrounded  by  granitic  rocks  show concentric patterns of AMS fabrics that cut across the NE-trending regional foli-ation. In contrast, northern intrusions, exposed as the upper sections of batholith-size bodies of coarse- grained granite emplaced at the shallow to mid-crust, show general NS-   trending magnetic fabrics roughly parallel to strike of the orogen and the regional foliation of host rocks. These contrasting magnetic patterns from shallow to deeper crust suggest vertical magma migration from the overthickened orogenic core to be emplaced across its thinner stretched flanks during the gravitational collapse of the orogenic edifice.