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Genesis of high-grade iron ores of the Archean Iron Ore Group around Noamundi, India

Nicolas J. Beukes, Joydip Mukhopadhyay and Jens Gutzmer
Genesis of high-grade iron ores of the Archean Iron Ore Group around Noamundi, India
Economic Geology and the Bulletin of the Society of Economic Geologists (April 2008) 103 (2): 365-386

Abstract

High-grade hematite ores of the Iron Ore Group in the Noamundi area, Jharkhand state, India, are hosted by a laterally extensive, 220-m-thick banded iron formation (BIF) in a folded greenstone belt succession of Paleoarchean age. Single orebodies, which are up to 3 km long along strike and several hundred meters wide, depending on dip of the beds, are strata bound and composed of two major ore types--namely, hard hematite ore that is of ancient geologic origin and ores related to recent weathering along a lateritized Cretaceous-Cenozoic land surface. The ancient hard hematite orebodies comprise laminated hematite ores in which microplaty hematite is dominant, and massive ores composed almost entirely of martite. Supergene ores, in contrast, are comprised of goethite-rich duricrust and soft saprolitic hematite ores representing the leached zone of the Cretaceous-Cenozoic laterite profile. Hard hematite-martite ores formed by hydrothermal replacement of BIF protolith, not only through leaching of silica but possibly also through introduction of iron by hydrothermal fluids of meteoric origin. Hematite iron ore pebbles in a conglomerate at the base of the Meso- to Neoproterozoic Kolhan Group near Noamundi attest to the antiquity of the hard hematite orebodies. Soft saprolitic iron ores formed as a product of lateritic weathering processes in Cretaceous-Cenozoic times. Supergene alteration took place under the influence of reducing and acidic meteoric water, which is typical for lateritic soil profiles developed under humid tropical climatic conditions with lush plant cover. Goethitic duricrusts capping the laterite profile suggest alternating wet and dry seasons in this environment.


ISSN: 0361-0128
EISSN: 1554-0774
Coden: ECGLAL
Serial Title: Economic Geology and the Bulletin of the Society of Economic Geologists
Serial Volume: 103
Serial Issue: 2
Title: Genesis of high-grade iron ores of the Archean Iron Ore Group around Noamundi, India
Affiliation: University of Johannesburg, Department of Geology, Paleoproterozoic Mineralization Research Group, Johannesburg, South Africa
Pages: 365-386
Published: 200804
Text Language: English
Publisher: Economic Geology Publishing Company, Lancaster, PA, United States
References: 57
Accession Number: 2008-104090
Categories: Economic geology, geology of ore deposits
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sects., strat. cols., 4 tables, sketch maps
N20°00'00" - N23°00'00", E86°00'00" - E88°00'00"
Secondary Affiliation: Presidency College, ZAF, South Africa
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, Copyright, Society of Economic Geologists. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 200836
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