Dynamics of Early Neoproterozoic accretion, west-central India: I. Geochronology and Geochemistry

The Godhra-Chhota Udepur (GC) sector (west-central India) is the zone of convergence between two crustal-scale accretion zones, i.e. N/NNE-striking Aravalli Delhi Fold Belt (ADFB) against E-striking Central Indian Tectonic Zone (CITZ). In this study, we demonstrate orogens welded during Early Neoproterozoic. GC sector, recumbently folded basement gneisses, shallow-dipping granitoid mylonites and a suite allochthonous supracrustal rocks experienced top-to-the south thrusting nappe formation (D2 deformation). crustal domain was modified by superposition network WNW/W-striking transpressional shear zones related folds (D3 D2-D3 deformations occurred due to oblique marked emplacement pre-D2, post-D2 syn-D3 granitoids. post-D2, granite-granodiorites are weakly peraluminous, calc-alkalic, having ferroan magnesian affinity, characterised LREE-enriched moderately fractionated REE patterns with variable negative Eu anomalies. Trace element geochemistry whole rock Sr-Nd systematics suggest granitoids were derived from dominantly meta-greywacke precursors. South-GC, U-Pb zircons in gneisses yield upper intercept/Concordia dates at 1.65–1.60 Ga for high-grade metamorphism. lower coincide 0.95–0.93 age post-D2/syn-D3 throughout GC. However, pre-D2 South-GC older, ~1.03 Ga. By contrast, North-GC Late Neoarchean (2.5 Ga) Concordia/upper intercept ages, identical Archean granites ADFB; 2.5 did not experience metamorphism, but both lithodemic units shared deformation-metamorphism juxtaposition ~2.5 attributed 1.03–0.93 ADFB-CITZ that involved contemporaneous syn-collisional S-type granitoids..