Petrogenesis and U–Pb zircon dating of the Chaitma Alkaline Complex from the southern margin of the Central Indian Tectonic Zone: geodynamic implications

In this study, we constrain the petrogenesis and U–Pb zircon age of a newly discovered alkaline complex, christened the Chaitma Alkaline Complex at the southern margin of the Central Indian Tectonic Zone in central India. The Chaitma Alkaline Complex comprises syenites and gabbros, emplaced coevally, and show features consistent with magma mixing. Geochemically, syenites are potassic–ultrapotassic (K2O/Na2O: 0.79–3.42), and contain high Ba (c. 800–2700 ppm) and Sr (c. 1400–3200 ppm). They show enrichment of the light rare earth elements (LREEs) relative to the heavy rare earth elements (HREEs) (La/Yb: 32–103) and do not display any Eu anomaly. Based on their geochemical signatures, such as low MgO (