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Borreswara Rao, C.
- Preliminary Ore Microscopic Studies on the Sulphide Ore Minerals from Ingladhal Area, Chitaldrug District, Mysore
Authors
1 Geology Department, Andhra University, Waltair, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 11, No 1 (1970), Pagination: 74-77Abstract
No Abstract.Full Text
- Trace Elements in Minerals and Rocks of the Precambrian Group of the Yellandlapad Area, Andhra Pradesh
Authors
1 Department of Geology, Andhra University, Waltair, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 13, No 2 (1972), Pagination: 165-171Abstract
Eight trace elements Co, Cu, Ga, Ge, Li, Ni, Pb and V have been determined semi-quantitatively with the Hilger spectrograph in 14 minerals and 18 rocks belonging to the Singareni series and the Gneissic complex of the early Precambrian and the Pakhals of the late Precambrian. The Pakhal phyllite is higher in Co, Ga, Ge, Li and Ni and Lower in Cu, Pb and V than the average shale. The pelitic schist of the Singareni Series broadly shows the same order of trace element distribution as that of the Pakhal phyllite. Metamorphism (amphibolite facies) of the Pakhals has not affected any redistribution of the trace elements in them. The granite-gneisses which are the granitised derivatives of the Singareni series show a decrease in Co, Ni and V. The trace elements Co, Cu, Li and Ni follow the major elements Fe, Mg and are preferentially fixed in the ferromagnesian minerals forming the essential constituents of the rock.
- Geochemistry of Sphalerite from Ingaldhal Mine Chitradurga District, Mysore State
Authors
1 Department of Geology, Andhra University, Waltair, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 13, No 4 (1972), Pagination: 402-405Abstract
No Abstract.Full Text
- Mineralogical Studies on the Bauxites from Shevaroy Hills, Tamilnadu State
Authors
1 Geology Department, Andhra University, Waltair, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 15, No 1 (1974), Pagination: 58-64Abstract
Bauxites of Shevaroy hills were analysed for their mineralogical composition adopting X-ray and differential thermal analyses, heavy mineral and microscopic studies. Gibbsite and goethite are the ubiquitous and major constituents while boehmite, hematite, lepidocrocite, kaolinite, halloysite and quartz are present in minor amounts in certain samples only. There is a variation in the abundance of these minerals with the grain size of the bauxite. Magnetite, ilmenite, zircon, rutile and garnets are the heavy minerals present.- Decomposition of Primary Minerals and the Process of Bauxitisation in Shevaroy and Kolli Hills, Salem District, Tamil Nadu
Authors
1 Geology Department, Andhra University, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 17, No 4 (1976), Pagination: 530-538Abstract
The bauxite deposits of Shevaroy and Kolli hills have been investigated to understand the processes involved in decomposition of the primary minerals leading to bauxitisation. The charnockitic suite of rocks underlying the bauxite deposits consists of quartz, plagioclase and potash feldspars, ortho- and cline-pyroxenes, garnet and secondary hornblende. During weathering, feldspars directly give rise to gibbsite and sometimes through kaolinite as an intermediate product. Under similar drainage conditions plagioclase feldspars in particular and mafic rocks in general are found to be more favourable for direct bauxitisation than potash feldspars and felsic rocks. The secondary product from pyroxenes (and hornblendes) is usually goethite but rarely clay minerals of nontronite group. Gibbsite in minor amounts is believed to be another secondary mineral in addition to goethite in the case of garnet alteration. Quartz is subject to dissolution and is replaced by gibbsite and goethite towards the final stages of bauxitisation. Order of mineral stability for weathering is, feldspars=pyroxenes < garnet < quartz.
Secondary enrichment bauxite and/or laterite as a result of migration and reprecipitation of aluminium and iron hydroxides has been observed. Hematite and boehmite are believed to have been formed in the advanced stages of weathering under an acidic environment during these secondary processes.