Albitite-Trondhjemite-A-Type Granite Association in the Prakasam Alkaline Province, Andhra Pradesh

Two dykes of albitite intruding a trondhjemite-A-type granite suite in the Prakasam alkaline province in Andhra Pradesh contain >90% modal plagioclase (albite), and accessory quantities of hornblende, apatite, sphene, anatase and opaque ores. The normative 100·Ab/(Ab + An) is 96 to 100, indicating pure albitic nature of the plagioclase. A two-stage 'branching' differentiation is suggested for this petrological association.