Numerous iron ore deposits are hosted within the Meso to Neo-Archean banded iron formations (BIFs) extending across the Singhbhum-Orissa Craton, eastern India. Despite the widespread distribution of BIFs, which forms part of the iron ore group (IOG), heterogeneity in their grade and mineral composition is occasionally observed even within a single ore deposit. Kiriburu-Meghahatuburu iron ore deposit (KMIOD), west Singhbhum district, Jharkhand, eastern India is characterized by a dominant hematite (often martitized) occurrence with a total resource of >150 million tonnes (MT) at 62.85 wt % Fe. Very high-grade blue dust ore (friable and powdery hematitewith~67% Fe), high-grade massive, hard laminated hematitic ores (~66% Fe) and medium to low grade goethitic/lateritic ores (50%–60% Fe) are the common iron-ore lithologies in KMIOD. These ores can be distinguished in the field from their physical appearance, meso-scale texture and spatial occurrences with the host rocks along with the variation in chemical composition. The high-grade ores are characterized by high Fe (>62 wt %), low Al₂O₃ (1.5–2.5 wt %), low SiO₂ (2.0–4.5 wt %) and low P (<0.06 wt %). Detailed field studies and laboratory investigations on the ore mineral assemblages suggest that the mineralization of high-grade iron ores at KMIOD is controlled by three major parameters, i.e., lithological, paleoclimatic and structural controls. High-grade iron ores such as blue dust seem to be formed during leaching processes through inter-bedded ferruginous shale and banded hematite jasper (BHJ) occurring within BIFs. Structural elements such as folds, joint network, fracture arrays, local faults and steeply dipping bedding planes are surmised as strong controls for the evolution of different iron ore types from the BHJ. Most of the high-grade ores are concentrated at the hinge portions of second generation folds (F₂) owing to the easy access for circulation of meteoric solution along the fractures developed due to release of stresses at the hinge portions aided by supergene ore enrichment processes. The BHJ and interbedded ferruginous shale seem to have been given a significant contribution for the formation of different grades of iron ores over the area. Lithologically, the BIFs are governed by rheological features providing channel ways in the ore enrichment process. The variation in the iron ore mineralogy is caused by the variation in depositional and paleoclimatic environment, structural setting and lithological attributes. Hence, these parameters could be used for future exploration and grade recovery of iron ore resources in the region and in the adjoining areas.

The core of detrital zircons from the southern Meiganga gold-bearing placers were analyzed by Laser Ablation Split Stream analytical techniques to determine their trace element abundances and U-Pb ages. The obtained data were used to characterize each grain, determine its formation condition, and try to trace the provenance. The Hf (5980 to 12,010 ppm), Y (27–1650 ppm), U (25–954 ppm), Th (8–674 ppm), Ti (2–256 ppm), Ta, Nb, and Sr (mainly <5 ppm), Th/U (0.06–2.35), Ti zircon temperature (617–1180 °C), ∑REE (total rare earth element) (98–1030 ppm), and Eu/Eu* (0.03 to <1.35) are predominant values for igneous crustal-derived zircons, with very few from mantle sources and of metamorphic origin. Crustal igneous zircons are mainly inherited grains crystallized in granitic magmas (with some charnockitic and tonalitic affinities) and a few from syenitic melts. Mantle zircons were crystallized in trace element depleted mantle source magmatic intrusion during crustal opening. Metamorphic zircons grown in sub-solidus solution in equilibrium with garnet “syn-metamorphic zircons” and in equilibrium with anatectic melts “anatectic zircons” during crustal tectono-metamorphic events. The U-Pb (3671 ± 23–612 ± 11 Ma) ages distinguish: Eoarchean to Neoproterozoic igneous zircons; Neoarchean to Mid Paleoproterozoic anatectic zircons; and Late Neoproterozoic syn-metamorphic grains. The Mesoarchean to Middle Paleoproterozoic igneous zircons are probably inherited from pyroxene-amphibole-bearing gneiss (TTGs composition) and amphibole-biotite gneiss, whose features are similar to those of the granites, granodiorites, TTG, and charnockites found in the Congo Craton, south Cameroon. The youngest igneous zircons could be grains eroded from Pan-African intrusion(s) found locally. Anatectic and syn-metamorphic zircons could have originated from amphibole-biotite gneiss underlying the zircon-gold bearing placers and from locally found migmatized rocks that are from the Cameroon mobile belt, which could be used as proxies for tracking gold.

Trace element concentrations and U–Pb ages were obtained using Laser Ablation Split Stream Method from the core of 115 zircon grains from the western Meiganga gold placer deposit. The data was used to characterize zircon, to understand the history of crystallization and to locate source rocks within the local and regional geological settings. Zircon trace element geochemistry was used to distinguish between magmatic and metamorphic affinity. The magmatic zircons have characteristics compatible with their probable origin from granitoid, syenite, tonalite, charnockite and mafic to ultramafic rocks. The metamorphic zircons composition is compatible with growth from anatectic melts and by sub-solidus crystallization in equilibrium with garnet. The zircon ages reveal Archean, Paleoproterozoic, Mesoproterozic, and Neoproterozoic events with the principal source could mainly belong to Paleoproterozoic magmatic lineage. Some of the Paleoproterozoic magmatic zircons were probably sourced from two mica granite found within the local geology, whereas the remaining zircons have features indicating source rocks within the Congo Craton. We suggest that the geologic history of these zircons is related to crustal-scale magmatic and/or tectono-metamorphic events, possibly linked to Eburnean and Pan-African orogeny.