Magma emplacement and mafic–felsic magma hybridization: structural evidence from the Pan-African Negash pluton, Northern Ethiopia

摘要: Abstract The Negash pluton (50 km 2 ) consists of late Pan-African, high-K, calc-alkaline granitoids intruded into low-grade metavolcanics–metasediments. This almost circular massif monzogranites, granodiorites, diorites–gabbrodiorites, and hybrid diorites. anisotropy magnetic susceptibility (AMS) method was used to determine internal structures the pluton. foliation trajectories are concentric inward dipping. lineation pattern displays an external zone characterised by horizontal concentrically oriented lineations with NW–SE lineations. These petro-structural data clearly locate feeder at north-western tip indicate subsequent expansion magmas towards SE. is a result in-situ assembly four magma batches, which were forcefully injected pre-existing foliated country rocks in relation transpressional tectonic regime. Two types mafic–felsic interactions recognised: homogeneous heterogeneous diorites part, mingled interfaces diorite–granodiorite contact zones mainly visible eastern south-eastern parts. mingling along contacts achieved level emplacement during injection dioritic felsic while assumed from two-way conduit mixing simultaneous rising mafic magmas.