Geochemistry and Geochronology of Naweoba Ophiolitic Mélange in Western Pakistan: Constraints on the Tectonics of Neo‐Tethys Ocean

ABSTRACT The tectonic evolution of the Neo‐Tethys Ocean in northwestern Pakistan remains a subject of ongoing debate. The Naweoba ophiolitic mélange, situated at the suture zone between the Indian and Eurasian plates, preserves critical geological records for deciphering the Neo‐Tethyan Oceanic history. However, its origin and tectonic significance remain poorly understood. This study integrates field observations, petrography, zircon U–Pb geochronology and whole‐rock geochemistry to examine the Naweoba ophiolitic mélange. Our results reveal that the mélange comprises two distinct igneous units: (1) ophiolitic components dominated by gabbro, plagiogranite and pillow andesite and (2) basalt with oceanic island basalt (OIB) affinity. The gabbro exhibits normal mid‐oceanic ridge basalt (N‐MORB) geochemical signatures, defined by depleted to flat large‐ion lithophile elements (LILE), flat to depleted high‐field‐strength elements (HFSE) and insignificant niobium‐tantalum (Nb‐Ta) anomalies, indicating derivation from a depleted mantle source in a mid‐ocean ridge basalt (MORB) setting. The plagiogranites display negative europium anomalies (Eu/Eu* = 0.43–0.75), depleted to flat LILE, differentiated HFSE without significant Nb‐Ta anomaly and low Sr concentrations (60.53–106.58 ppm), consistent with plagioclase‐dominated fractional crystallisation of MORB magma. Associated pillow andesites show low total REE, flat to enriched LREE patterns and no significant depleted trace element signatures (Nb, Ta, Ti) similar to MORB tectonic setting. In contrast, the basalts are enriched in incompatible element concentrations, have higher ΣREE contents with negative Ba and Sr anomalies, enriched LILE and OIB‐type geochemical affinities, indicating derivation from plume‐related mantle melting. Zircon grains from gabbro and plagiogranite show the Late Cretaceous U–Pb crystallisation ages of 92.2 ± 1.3 Ma and 92.3 ± 1.1 Ma, respectively. These contrasting magmatic signatures, now tectonically juxtaposed within the mélange, reflect a complex geodynamic evolution involving Late Cretaceous seafloor spreading, mantle plume magmatism and subsequent convergence and accretion along the Indian Plate margin. The Naweoba ophiolitic mélange preserves evidence of Neo‐Tethyan oceanic crust formed through seafloor spreading and plume‐ridge interactions and provides new constraints on the tectonic architecture of the western Indian Plate.