usually granites mostly igneous fractionated contain accessories more and recycled that is the crustal remelts may not contain.. The final granite composition depends mostly on the source rock unless there is extensive tectonic activity near the reservoir'

Dear Dr. Latha,

rocks of the granitic suite are mainly investigated based upon their mineralogical composition, being made up of feldspar enriched in Na and K and poor in Ca, quartz and mica. There exists a wide range of origin from migmatitic mobilizates poor or devoid of accessory minerals and rare elements to highly-differentiated granites with a variegated spectrum of minerals abundant in F, B, Nb/Ta, Li, Be, Cs, P, U  etc. You have to consider the granites first and foremost as a geological body which is embedded into its host rocks revealing a clearcut relationship in time (pre-, syn-, postorogenic) and space (in-situ to intrusive). If you got a full blown picture of the geology, mineralogy and chemistry of the granitic rock and last-but-not least its geodynamic setting it is easy to predict and account for why some contain accessory minerals and others do not do so. It would go far beyond this Q&R process to assess in a porfound way the emplacement and evolution of rocks of the granite clan (also including more basic predecessors or relic rocks (e.g. melanosome) as well as the courser-grained pegmatites and finer-grained aplitic rocks.

The attached study may give you and overview of pegmatites and aplites but may also be applied to the granitoids.

I wish you much success

H.G.Dill

It is difficult to compare one granite to the other . I worked for long starting from the closepet granite ,an archaean-proterozoic transition crustal remelting granite (Ph.D thesis) the Donargrh granite,Zinghee granite(tectonic affected),bundelkhand of  similar age ,the early to late archaean peninsular gneissic complex along with the greenstone belts, younger granites from Himalayan chain Joshimath,Badrinath granites Bageswar Almora Pithoragah etc including the granites (or so called leptynites) from the Eastern Ghat granulte terrain ,the Central Indian granites and procured voluminous ,mineralogicak,petroligical,geochemical,including REE data published .The final conclusion is only one ,EACH GRANITE IS UNIQUE and needs special attention.

very useful literature:

www.minersoc.org/pages/Archive-MM/Volume_35/35-272-628.pdf

Thank you all for your valuable information.

It really enriched my understanding.

I find it hard to accept that there would be no mineral other than feldspars and quartz in a granite. May be the accessory minerals, such as apatite, zircon, sphene, even opaque oxide, etc., are in very fine grains and not readily detectable under polarizing microscope.

Dr Asoori Latha, next time when you have such a granite, please analyse it chemically for minor and trace elements. Not all of the elements would be accommodated in the  two-feldspars or quartz stoichiometrically. 

Prof Divakara Rao, it is good to see your comments. Long time, isn't it?

Qasim Jan

Sometimes very fractionated granites not contain accessory minerals but you should analyzed carefully. Please clarify what type of granite you study, in which tectonic setting, and geochemistry. 

It depends on the degree of fractionation of your granite. It is rare, but can happen. The granites that I am studying right now contain basically zircon and apatite as accessory phases.

I also find it hard to believe there are absoluetly no accessory phases present. Granites are by definition coarse grained rocks, so I suppose it would be possible to cut a single thin section and not see any accessory phases. How many sections have been examined? Phases such as apatite can be very difficult to spot using standard light microscopy, so it might be worth putting a few sections under an SEM and looking at them in backscatter mode....you might be surprised what jumps out at you!