Diapirism, bulk homogeneous shortening and transcurrent shearing in the Archaean Dharwar craton: the Holenarsipur area, southern India

摘要: Abstract Qualitative strain data are spatially integrated in order to define Archaean foliation trajectories, and variations intensity ellipsoid type, the Holenarsipur area, Dharwar craton, southern India. The study provides constraints on bulk geometry, progressive deformation kinematic history of this region continental crust. Two major structural events have shaped area: (i) a regional diapiric event contemporaneous with magmatic event, (ii) later sinistral transcurrent ductile shear which has locally reoriented both foliations stretching lineations. entire supracrustal belt underwent common tectono-metamorphic that included two metamorphic events. Each corresponds temporally distinct field. first, amphibolite facies was main tectonic probably intrusion Halekote trondhjemites. second occurred under greenschist-facies conditions restricted late zone at eastern boundary greenstone belt. pattern prior shearing cannot be explained by thrusting unless all trace had been erased diapirism. We interpret structures older than direct result vertical movements linked body forces, augmented minor horizontal crustal shortening.