A statistical approach to evolving guides for mica search in Nellore mica belt around Gudur, Andhra Pradesh

Search for mica deposits presents peculiar problems owing to great complexi ties associated with pegmatite bodies. All pegmatites do not develop mica a rid not all mica-bearing pegmatites carry commercially workable quantity of mica. Prospecting for mica has therefore been a highly speculative and ris ky venture. It is in this context that the use of characteristic analysis, a multivariate statistical technique, has been made for the development of a composite geological model of the most typical indices of pegmatites of N ellore mica belt around Gudur in Andhra Pradesh, in order to evolve prospec ting guides for mica search. Data pertaining to geological variables gathered through surface mapping, f ield observation and geological studies of pegmatite bodies of Gudur mica r egion have been statistically treated for characteristic analysis. The appr oach elucidates most typical characteristics of pegmatites favourable for h osting commercially workable mica deposits. The geological variables associ ated with mica mineralization have been selected through an extensive surve y and analogy. The model is governed by choosing sample locations and geolo gical variables that best reflect mica mineralization. Presence of albite, undeformed pegmatite and kaolinization have been determined to be the most characteristic indices for mica search in the pegmatites of Nellore mica be lt around Gudur.