Magmatic records of Gondwana assembly and break-up in the eastern Himalayan syntaxis, northeast India

•Two episodes of pre-collisonal magmatism are discovered from Abor magmatic rocks of Siang Window, Eastern Himalaya syntaxis, northeast India.•Initial impact of magmatism at Siang window occurred at ∼500–473 Ma as passive margin extensional environment coeval with Gondwana assembly.•Second phase of magmatism impacted the Eastern Himalaya at ∼145–132 Ma due to Kerguelen mantle plume upwelling and the Gondwana break-up.