C Kasipathi, K Arjunudu, K Sanyasi Rao and M Srinivasa Rao
Keywords: India, Andhra Pradesh, High-grade BIF, Cuddapahs, Nallamalais.
Abstract: The central and southern parts of Andhra Pradesh, India are occupied by the Upper Proterozoic Basins (N Lat : 13o 19’ 20” – 17o 56’ 21” and E. Long : 76o 03’ 18’’ – 80o 11’ 52”), comprising Cuddapah, Pakhal and Bhimas (Purana Basins - corresponding to the Algonkian of USA as per the article published in the Imperial Gazetter of India by Sir T.H.Holland 1904, c.f. Krishnan, 1968) within the age group of 1000 to 500 my. Among the Nallamalai, Chitravati and Papaghni Series of Kurnool Group, the Gulcheru, Vempalle, Pulivendla, Tadpatri, Gandikota, Bairenkonda, Cumbum and Srisailam quartzite-shale-phyllite-intrusive formations show varying lithology and they are found hither to be the best exploration targets for rich banded iron formations. The total thickness of the geological formations was estimated by Geological Survey of India to be about 17.5 kms. These basins cover an area of 44,500 km2 in parts of Chittoor, Anantapur, Cuddapah, Kurnool, Mahabubnagar, Nalgonda, Guntur, Krishna and Prakasam districts of Andhra Pradesh. Potential hematitic ore formations are identified through intensive geoscientific exploration programmes (geological and geophysical electrical Resistivity surveys) in these parts and the hematitic ores show Fe content up to 69.74%, in addition to the discontinuous lenses of magnetite and their details of potentiality are presented. This paper records rich Banded Micaceous Hematitic Quartzite formations from parts of Central and Southern Andhra Pradesh for the first time and warrants a detailed geoscientific investigation for iron-ore sources, which can help in the establishment of minimum two major iron and steel plants and a minimum of two minor ports along the coastal stretch of this region for transport and marketing.
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