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Majumder, Tapan
- Stratigraphy and Structure of the Precambrian Banded Iron Formation and Chromite-Bearing Ultramafic Rocks of Sukinda Valley, Orissa
Authors
1 Department of Geological Sciences, Jadavpur University, Calcutta 700032, IN
2 Department of Applied Geology, Indian School of Mines, Dhanbad 826004, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 21, No 8 (1980), Pagination: 398-404Abstract
The Sukinda Valley of Orissa is underlain by the banded iron formation (BlF) and chromite-bearing ultramafic rocks of Precambrian age. Besides these, local exposure of a quartz-arenite bed with basal conglomerate is correlated with the Kolhans. A basal quartzite horizon is conformably overlain by the BIF. lhe quartz-arenite (Kolhans?) with a conglomerate at the base lies with a local disconformity over the BIF. Chromitebearing ultramafites are pre-kinematic intrusives into the iron formation and have been co-folded with the older sediments. Orthopyroxenite and granitic rocks are intrusive into the chromiferous ultramafites. Occasional intrusive dolerite dykes in the valley may be correlated with the Newer Dolerites of Singhbhum.
The regional structure of the Precambrian rocks of the Sukinda Valley, as established by the present authors, is a cross-folded doubly plunging syncline with the culminated fold axis striking ENE-WSW which is parallel to the main fold axis of the Eastern Ghats Orogenic belt. The plunge of the main fold axis is towards NE and wsw. The cross-folded axis, lying between Tungaisuni and Champajhar villages, trends NNW-SSE and is subparallel to the cross-folded axes of the Eastern Ghat Orogenic belt.
- Geological Aspects of the Banded Iron-Formation of Bihar and Orissa
Authors
1 Department of Geological Sciences, Jadavpur University, Calcutta 32, IN
2 Department of Applied Geology, Indian School of Mines, Dhanbad, Bihar, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 28, No 2&3 (1986), Pagination: 109-133Abstract
The metamorphic age (2.55-3.07 Ga) of BIF of Tomka-Daiteri belt has been established from Sm/Nd data which seemingly indicates that the sedimentation age of BIF is older than Singhbhum granite (3.12±0.OI Ga). Intrusive evidences of Singhbhum granite into BIF have been documented. An older age of the GorumahisaniBadampahar- Tomka·Daiteri-Malayagiri BIF with respect to that of Jamda-Koira Valley is supported.
The BIF, consisting predominantly of magnetite-chert, magnetite-jasper (BMJ) hematite-jasper (BHJ) or martite-quartz (BMtQ}form part of a sedimentary succession, underlain by quartz-arenite or lithic wacke and interlayered with altered volcanic tuff (shale ?). Magnetite, hematite and chert were primary precipitates in the BIF. No primary carbonate, silicate or sulphide have been noticed to occur in these rocks excepting sporadic occurrence of carbonate pseudomorphs in the underlying quartz-arenite.
Primary sedimentary structures like current ripples, syneresis cracks, penecontemporaneous deformation structures (e.g. folds, faults, micro-brecciation, pods, etc.) and diagenetic recrystallization features are described.
Similar to other world deposits of Precambrian and Archaean age, the BIF of Bihar and Orissa are also deficient in major, trace (TE) and rare earth elements (REE). Mineralogical composition and geochemistry suggest that they belong to the oxide facies iron-formation, Low concentration of Al203, CaO, MgO. MnO and of Zr, Cr, Ti, V, Ni and Cu in the BIF with respect to their abundance in. the interlayered pyroclastics presumably suggests a non-volcanogenic source of iron and silica. Eu/Sm ratio (0.541.01) indicates an Archaean age for the BJF. A shallow water marine environment is predicted for the deposition of BIF.
- Structures and Textures of Vanadium-Bearing Titaniferous Magnetite Ores and their Interpretation
Authors
1 Department of Geological Sciences, Jadavpur University, Calcutta 32, IN
2 Department of Applied Geology, Indian School of Mines, Dhanbad, Bihar, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 31, No 3 (1988), Pagination: 305-313Abstract
Various types of exsolution and replacement structures and textures uf the vanadium-bearing titano-magnetite ores have been described from the titano-magnetite deposits occurring in the gabbro-anorthosite complexes of Orissa, India. Attempt has been made to correlate different textures to various oxidation stages. The ores were formed within the temperature range of 600°-800°C and average fO2 = 18.4.- Zoned Sedimentary Magnetites from Precambrian Banded Iron Formation of Eastern India
Authors
1 Department of Applied Geology, Indian School of Mines, Dhanbad 826 004, IN
2 Department of Geological Sciences, Jadavpur University, Calcutta 700 032, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 32, No 1 (1988), Pagination: 61-64Abstract
Electron microprobe study of low temperature zoned magnetite grains of primary sedimentary origin from the Precambrian banded iron formation (BIF) of Eastern India revealed alternate micro-bands rich in silica and iron, while minor concentration of magnesium is also found in silica-rich bands. X-ray data indicate a normal type of magnetite structure and trace element values support its primary sedimentary origin. Origin of the zoning in magnetite is attributed to enrichment of Si and Fe in alternate bands on a microscale simulating the alternate silica and iron rich bands of the host-rock-banded iron formation.Full Text
