A mafic intrusion of “arc affinity” in a post-orogenic extensional setting: A case study from Ganluogou gabbro in the northern Yidun Arc Belt, eastern Tibetan Plateau

•The Ganluogou gabbro (152.1±1.7Ma) was generated long time after subduction event (>∼206Ma).•There are two types of plagioclase and amphibole.•The parental magma is interpreted as a tholeiitic arc-affinity magma.•Ganluogou gabbro formed under a post-orogenic extensional setting.