Petrology and Geochemistry of Base Metal Mineralization in Lesser Himalayan Sequence of Jammu and Kashmir

ABSTRACT Phyllites of the Salkhala Formation (Neoproterozoic), intruded by Palaeozoic granites in the Lesser Himalaya of Jammu and Kashmir, were investigated for base metal mineralization using field, petrographic, mineralogical, and geochemical tools. Four sulphide zones (SZ-1 to SZ-4) were delineated, exhibiting limonitization, ferrugenization, and gossanization. EPMA and XRD analyses confirm dominant sulphides and alteration minerals such as jarosite and jamborite. Mineralization occurs as disseminations and lenses of pyrite (Fe: ~44 wt%), chalcopyrite (Cu: ~34.8 wt%), galena, and bornite. Major oxide data show phyllites with SiO2 ranging from 36.1 to 55.5 wt%, and Dedni granites with SiO2 up to 66.2 wt% and peraluminous character. Trace and REE geochemistry reveals distinct sources for pegmatitic veins with LREE/HREE ratios (12.9–18.4) and negative Eu anomalies (Eu/Eu* = 0.56-0.80), while granites show positive Eu anomalies (Eu/Eu* = 1.23-2.26). CIA values (55–70) and AI (30–60) reflect moderate chemical weathering and hydrothermal alteration. Sulphide paragenesis reflects multistage evolution from syn-volcanic pyrite to IOCG or porphyry-like mineralization associated with granitic intrusions.