Mineralisation of Corundum at Gobbagurti: A Geoscientific Approach.

Semi-precious Corundum, (ruby and abrasive variety) occurs in and around Lakshmipuram and Gobbagurti areas of Khammam District of Andhra Pradesh. . The nature of occurrence of corundum in these areas rep- resents in-situ, float, and placer concentrations.

Corundum occurs along with biotite gneisses, amphi- bolites, and sillimanite-cordierite-diopside- bearing rocks, and magnesium-aluminium rich pelitic granu- lites. Tonalitic gneisses, cordierite- corundum rock and sillimanite schists form small lenticular bodies. The host rocks of corundum are intruded younger pegmatite veins which also have cut through the Pre- cambrian suite of rocks.

A detailed and comprehensive geological studies on the sporadic occurrences of precious and semi-pre- cious corundum over wide areas associated within the zones of metamorphosed supracrustals has been attempted. Although corundum has been reported and excavated at different places in Konijerla Man- dal, no comprehensive model for its genesis has been evolved.

In view of the complexities involved on the nature and controls of mineralisation of corundum, in the mined out areas, as well as in the inaccessible virgin areas, particularly the Gobbagurti Reserve Forest, system- atic investigations comprising remote sensing, petro- mineralogical and geochemical investigations were carried out to explore the geo-genetic relationship so as to identify newer occurrences in a similar geologi- cal set-up.