Permian felsic magmatism in the Neoproterozoic Nagar Parkar Igneous Complex of the Malani Igneous Suite: Evidence from zircon U–Pb age

We report Permian (ca. 272 Ma ±5.4 Ma) felsic dykes that intrude into the Neoproterozoic (ca. 750 Ma) magmatic suite of the Nagar Parkar Igneous Complex (NPIC), the western extension of the Malani Igneous Suite (MIS). The NPIC consists of Neoproterozoic basement amphibolites and granites (riebeckite–aegirine gray granites and the biotite–hornblende pink granites), all of which are intruded by several generations of mafic and felsic dykes. Granitic magmatism occurred in the Late Neoproterozoic (ca. 750 Ma) due to the subduction‐, followed by the rift‐related tectonic regime during the breakup of the Rodinia supercontinent. U–Th–Pb zircon and monazite CHIME age data of 700–800 Ma from the earlier generation porphyritic felsic dykes suggest the dyke intrusion was coeval or soon after the emplacement of the host granites. Our findings of Permian age orthophyric felsic dykes provide new insights for the prevalence of active tectonics in the MIS during late Paleozoic. Textural features and geochemistry also make the orthophyric dykes distinct from the early‐formed porphyritic dykes and the host granites. Our newly obtained age data combined with geochemistry, suggest the existence of magmatism along the western margin of India (peri‐Gondwana margin) during Permian. Like elsewhere in the region, the Permian magmatism in the NPIC could be associated with the rifting of the Cimmerian micro‐continents from the Gondwana. We report 272 Ma felsic dykes that intrude into the 750 Ma granites of the Nagar Parkar Igneous Complex of the Malani Igneous Suite (MIS). The granites and some of the felsic dykes formed during the breakup of Rodinia supercontinent. A younger dyke swarm, petrologically ad geochemically distinct from granites and the older dykes, indicate active tectonics along the western margin of India during Permian, associated with the rifting of the Cimmerian micro‐continents from the Gondwana. インドMalani Igneous Suite(MIS)の西方延長にあたるパキスタンNagar Parkar Igneous Complex(NPIC)の新原生代(約750Ma)火成岩類から，ペルム紀(272 ± 5.4 Ma)の正長斑岩状岩脈を見いだした. NPICはロディニア大陸を構成する角閃岩類・花崗岩類と苦鉄質・珪長質の岩脈からなる. 珪長質斑岩状岩脈の年代は700〜800Maを示し，一連の火成活動の産物と考えられる. 発見した正長斑岩状岩脈岩の岩石学的・地球化学的・年代学的特徴は，早期に生成した斑岩状岩脈や被貫入花崗岩類と異なり，ペルム紀のインド西端(ゴンドワナ大陸縁辺域)沿いの火成活動を示唆する. 今後同様の発見例が増えることで，後期古生代のMISにおけるテクトニクスやゴンドワナ大陸からCimmerian micro‐continentのリフティングに関わった一連の火成活動がより明確になる. ジルコンU‐Th年代，Nagar Parkar Igneous Complex，Malani Igneous Suite，インド楯状地，新原生代花崗岩類，ペルム紀珪長質岩脈，Cimmerian micro‐continent，ゴンドワナ.