Spatial distribution and structural characteristics of Imorona-Itsindro suite in Ambatofinandrahana district, Madagascar

Abstract

The principal aim of this study is to map the lithology of the Imorona-Itsindro suite and to constrain the tectonic framework of the Ambatofinandrahana district in the Itremo group using the combination of maximum likelihood classification, petrographic analysis, and structural data. Supervised classification successfully delineated distinct magmatic formations within the Imorona-Itsindro suite, revealing their spatial distribution and compositional heterogeneity. Petrographic observations from thin sections corroborated these units by revealing distinctive mineralogical features. Structural analyses further demonstrated a transpressional tectonic regime, characterized by ENE-WSW shortening and WNW-ESE trending strike-slip faults and associated shear zones. These structures accommodated strain through a combination of horizontal shortening and lateral movement, suggesting syn-magmatic deformation influenced by regional tectonics during the final stage of the amalgamation of Gondwana.