scholarly journals Magnetic Survey for Iron-Oxide-Copper-Gold (IOCG) and Alkali Calcic Alteration Signatures in Gadarwara, M.P, India: Implications on Copper Metallogeny

Minerals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 671
Author(s):  
P.V. Sunder Raju ◽  
K. Satish Kumar
Keyword(s):  
Iron Oxide ◽  
Magnetic Anomaly ◽  
Central India ◽  
Iron Formation ◽  
Magnetic Survey ◽  
Banded Iron Formation ◽  
Model Studies ◽  
Copper Mineralization ◽  
Copper Gold ◽  
Magnetic Signatures

A government airborne geophysical survey flown in the late 1970s detected a large Magnetic anomaly at Gadarwara, Madhya Pradesh, in north-central India. Deep drilling indicates that the oval-shaped Magnetic anomaly is caused by underlying Magnetite-bearing banded iron formation belonging to the Mahakoshal Formation of Archean to Early Proterozoic age. The anomaly is hosted in a tectonic rift zone (Narmada-Son Lineament). After drilling alluvium up to 312 m thick, rocks intersected to depths of 612 m provided core samples for research. Broadly speaking, the samples contain banded hematite jaspilite (BHJ) and banded Magnetite (BM) iron formation with pervasive carbonate alterations. Three vertical diamond drill holes were drilled along a 1.4 km long N-S transect across the center of the geophysical anomaly. DDH-1, near the northern edge of the anomaly, went through 309 m of alluvium before intersecting bedrock and then cored 303 m of bedrock for a total depth of 612 m. Copper mineralization with appreciable amounts of cobalt, zinc, molybdenum, silver, rare earth elements, uranium and other elements was intersected. The litho-units are highly oxidised and intensely brecciated with hydrothermal overprinting of Na-K metasomatism alteration mineralogy. The second borehole, DDH-2 failed as the core drilling bit stuck in the alluvium and further drilling was abandoned, whereas the third borehole DDH-3 didnot intersect a Magnetite-hematite association and cored only siltstone. Two-dimensional model studies suggest that the signature of high Magnetic anomaly is at a depth of 0.4 km from the surface, with a width of 3.5 km, dipping at 45∘ in a northerly direction. The causative body has a Magnetic susceptibility of 0.0052 C.G.S. units, suggestive of a hematite with quartz veinlets lithology. Based on predictive Magnetic exploration models for Iron-Oxide-Copper-Gold (IOCG), such deposits can be inferred from geological observations combined with petrophysical data and forward modelling of the observed Magnetic signatures. This paper reports a prospective IOCG-like mineralization style hosted in a rift (Narmada-Son) type of tectonic environment.

Mineral chemistry, P-T pseudosection and in-situ U-Th-Pbtotal monazite geochronology of Banded Iron Formation from Bundelkhand craton North-Central India, and its geodynamic significance

2021 ◽  
Author(s):  
Mohd Baqar Raza ◽  
Pritam Nasipuri ◽  
Hifzurrahman
Keyword(s):  
Central India ◽  
Mineral Chemistry ◽  
Iron Formation ◽  
Age Group ◽  
Banded Iron Formation ◽  
Tectonic Zone ◽  
Third Age ◽  
The Third ◽  
Hydrothermal Activities

<p>The Banded Iron Formation (BIF) in Bundelkhand craton (BuC) occurred as supracrustals associated with TTG’s, amphibolites, calcsilicate rocks, and quartzite within the east-west trending Bundelkhand tectonic zone (BTZ). The BIFs near Mauranipur do not show any prominent iron-rich and silica-rich layer band and are composed of garnet, amphibole, quartz, and magnetite. The volumetrically dominant monoclinic-amphiboles are grunerite in composition. X<sub>Mg</sub> of grunerite varies between 0.39-0.37. The garnets are Mn-rich, the X<sub>Spss</sub> of garnet ranges from 0.26-0.20, X<sub>Pyp</sub> and X<sub>Grs </sub>vary between 0.10-0.06 and 0.07-0.05, respectively. P-T pseudosection analysis indicates that by destabilizing iron-silicate hydroxide phases through a series of dehydration and decarbonation reactions, amphibole and garnet stabilized in BIF at temperature 400-450°C and pressure 0.1-0.2 GPa.</p><p>Massive type BIFs have monazite grains that vary from 10 to 50 µm in size, yield three distinct U-Th-Pb<sub>total</sub> age clusters. 10-20 µm sized monazite grains yield the oldest age, 3098±95 Ma. 2478±37 Ma average age is obtained from the second group, which is relatively larger and volumetrically predominant. The third age group of Monaiztes gives an age of 2088±110 Ma. ~3100 Ma monazite suggests the older supracrustal rocks of Bundelkhand craton, similar to those obtained from Singhbhum and the Dharwar craton. The 2478±37 Ma age is constrained as the timing of metamorphism and stabilization of BuC. The third age group, 2088±110 Ma probably associated with renewed hydrothermal activities, leading to rifting and emplacement of mafic dykes in BuC.</p>

scholarly journals Petrography and Geochemistry of the Banded Iron Formation of the Gangfelum Area, Northeastern Nigeria

2017 ◽  
Vol 7 (1) ◽  
pp. 25
Author(s):  
Anthony Temidayo Bolarinwa
Keyword(s):  
Iron Oxide ◽  
Inductively Coupled Plasma ◽  
Optical Emission ◽  
Iron Formation ◽  
Icp Oes ◽  
Banded Iron Formation ◽  
Basement Complex ◽  
Inductively Coupled ◽  
Iron Precipitation ◽  
Icp Ms

The Gangfelum Banded Iron Formation (BIF) is located within the basement complex of northeastern Nigeria. It is characterized by alternate bands of iron oxide and quartz. Petrographic studies show that the BIF consist mainly of hematite, goethite subordinate magnetite and accessory minerals including rutile, apatite, tourmaline and zircon. Chemical data from inductively coupled plasma optical emission spectrometer (ICP-OES) and inductively coupled plasma mass spectrometer (ICP-MS) show that average Fe2O3(t) is 53.91 wt.%. The average values of Al2O3 and CaO are 1.41 and 0.05 wt.% respectively, TiO2 and MnO are less than 0.5 wt. % each. The data suggested that the BIF is the oxide facies type. Trace element concentrations of Ba (67-332 ppm), Ni (28-35 ppm), Sr (13-55 ppm) and Zr (16-25 ppm) in the Gangfelum BIF are low and similar to the Maru and Muro BIF in northern Nigeria and also the Algoma iron formation from North America, the Orissa iron oxide facies of India and the Itabirite from Minas Gerais in Brazil. The evolution of the Gangfelum BIF involved metamorphism of chemically precipitated or rhythmically deposited iron-rich sediments into hematite-quartz rocks. The banding of the BIF suggested a break in iron precipitation probably due to iron oxide deficiency. 

scholarly journals Origin of iron oxide spherules in the banded iron formation of the Bababudan Group, Dharwar Craton, Southern India

2012 ◽  
Vol 52 ◽  
pp. 31-42 ◽  
Author(s):  
Beate Orberger ◽  
Christiane Wagner ◽  
Richard Wirth ◽  
Eric Quirico ◽  
Jean Paul Gallien ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Dharwar Craton ◽  
Southern India ◽  
Iron Formation ◽  
Banded Iron Formation

Geophysical inversions applied to 3D geology characterization of an iron oxide copper-gold deposit in Brazil

Geophysics ◽  
2017 ◽  
Vol 82 (5) ◽  
pp. K1-K13 ◽  
Author(s):  
Aline Tavares Melo ◽  
Jiajia Sun ◽  
Yaoguo Li
Keyword(s):  
Iron Oxide ◽  
Physical Properties ◽  
Gold Deposit ◽  
Mineral Exploration ◽  
Iron Formation ◽  
Copper Ore ◽  
Rock Types ◽  
Objective Interpretation ◽  
Copper Gold ◽  
Host Rocks

Mineral exploration dynamics often requires an efficient and objective means of evaluating a prospect in early exploration stages, when few holes have been drilled. In the case of deep prospects or prospects under cover, this evaluation will mostly be based on geophysical data. To develop an objective interpretation method capable of combining all the information available, we have developed an integrated interpretation scheme of geophysical models and sparse geologic data. Our method is based on the relationship between recovered physical properties obtained from 2D and 3D inversions, aiming to find patterns associated with geologic units, such as iron formation, copper ore, and host rock. The interpretation is guided by theoretical relations of the minerals of interest (chalcopyrite and magnetite) and the sparse geologic information available. It is suitable for prospects in the initial stages of exploration when only limited mineralogical information is available from, say, one drillhole. We have demonstrated the success of the method using magnetic and DC resistivity data from the Cristalino iron oxide copper-gold deposit, located in northern Brazil, which is covered by a thick soil overburden. The theoretical behavior of the physical properties of chalcopyrite and magnetite was first combined with the rock types identified in the drill cores to find groups or classes associated with different amounts of these minerals. Then, these relative relations between units were applied to define four classes in the scatterplot of recovered susceptibility and conductivity values from 2D inversions. These four classes are associated with iron formation, copper ore, and two types of host rocks. After the validation with the known geology, the same interpretation scheme was applied to the scatterplot of recovered susceptibility and conductivity values from 3D inversions. The final interpreted volume allows the explorationist to have an approximate estimate of the copper body extent.

scholarly journals Neoarchean crustal shear zones and implications of shear indicators in tectonic evolution of Bundelkhand craton, central India

2019 ◽  
Vol 4 (2-2) ◽  
pp. 11
Author(s):  
S C Bhatt ◽  
Vinod K. Singh
Keyword(s):  
Central India ◽  
Shear Zones ◽  
Iron Formation ◽  
Banded Iron Formation ◽  
Quartz Veins ◽  
Mylonitic Foliation ◽  
Ductile Shearing ◽  
Crustal Shear Zones ◽  
Characteristic Features ◽  
The Relationship

The gneisses and granitoids emplaced along E-W sub-vertical crustal shear zones are represented as important tectonic units in Bundelkhand craton of central India. The tonalite-trondhjemite-granodiorite (TTG) gneisses (3.5-3.2 Ga; oldest unit), and streaky to mafic gneisses structurally deformed in D 1 deformation. The metabasic, felsic, banded iron formation and metasedimentaries of greenstone complex exposed in central part, have characteristics of three sets of folding (F 1 -F 3 ). These gneisses associated with migmatite, amphibolite, quartzite, and schist were evolved in D 2 compressive phase, which are not occurring in northern part of craton. The K-rich Neoarchean granitoids (2.6-2.49 Ga) were intruded as granitic complex (D 3 magmatic phase) and the E-W strike-slip Raksa-Garhmau shear zone reported as important tectonic unit, were evolved in asyn-to post-tectonic D 3 phase. The dolerite dykes (ca. 2.0 Ga) were emplaced along NW-SE fractures in extension setting during D 4 magmatic event. The NE-SW riedel shears occupied by giant quartz veins (reefs) evolved in Paleoproterozoic during D 5 endogenic activity. The relationship between macro and microstructural fabrics has been documented within mylonitic foliation, stretching lineation, S-C planes and rotated fabrics, reflect mesoscopic shear indicators, as noted in three types of mylonitic rocks. i) The rotated porphyroclasts of quartz, feldspars and asymmetric pressure shadows showing strong undulose extinction, deformation lamellae, and dynamic recrystallization are characteristic features of protomylonite where altered orthoclase and kinked plagioclase are noticed. ii) Mylonite, a distinct mylonitic foliation represented by parallel orientation of elongated quartz and feldspar with flakes of mica. iii) The ground matrix of recrystallized quartz with few protoliths of quartz and feldspar are observed, important features of ultramylonite. The asymmetric microstructures viz. σa and σb mantled porphyroclasts, othermicrostructures show progressively deformed by crystal plastic (non-coaxial) strain softening under low to moderate temperature conditions. The sinistral top- to- SW sense of shear movement was dominant. The microfractures/ microfaults, kinking and pull apart structures observed in K- feldspars and are indicative of overprinting of brittle deformation on ductile shearing.

Earth’s Middle Ages: What Came after the GOE

2017 ◽  
Author(s):  
Donald Eugene Canfield
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Middle Ages ◽  
Atmospheric Oxygen ◽  
Iron Formation ◽  
Banded Iron Formation ◽  
Dissolved Iron ◽  
Great Oxidation Event ◽  
Low Levels ◽  
Substantial Rise

This chapter considers the aftermath of the great oxidation event (GOE). It suggests that there was a substantial rise in oxygen defining the GOE, which may, in turn have led to the Lomagundi isotope excursion, which was associated with high rates of organic matter burial and perhaps even higher concentrations of oxygen. This excursion was soon followed by a crash in oxygen to very low levels and a return to banded iron formation deposition. When the massive amounts of organic carbon buried during the excursion were brought into the weathering environment, they would have represented a huge oxygen sink, drawing down levels of atmospheric oxygen. There appeared to be a veritable seesaw in oxygen concentrations, apparently triggered initially by the GOE. The GOE did not produce enough oxygen to oxygenate the oceans. Dissolved iron was removed from the oceans not by reaction with oxygen but rather by reaction with sulfide. Thus, the deep oceans remained anoxic and became rich in sulfide, instead of becoming well oxygenated.

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