In case of the chronology of sedimentary rocks hosting zircon I would express a stark warning to mix up ages simply based upon isotope data which are passed through a statistical treatment. I recommend to have the mineralogy and sedimentology involved. The mineralogy (+microchemistry - see EMPA) allows to categorize the zircon grains according to their internal textures, overgrowth, zonation etc. and the trace element content which is a good tool to constrain the environment of formation during a provenance analysis. With the aid of the X morphology and granulometry you get another tool that enables you to constrain the physical-chemical regime which the various populations have been derived from and get an idea of the recycling of zircon. Zircon is the most stable heavy mineral besides rutile and tourmaline and subjected to strong recycling. It has also a good preservation potential in terms of mechanical attrition and supergene alteration.

You can judge from these statements how manifold the impacts are on such a chronological approach you are going to take.

Stick to the classical chain of operation geology-mineralogy-chemistry - isotope analysis. Then you are going to build your home on solid grounds.

HGD

You can take some help from this paper "Age, provenance and tectonic setting of metasedimentary rocks of the Simlipal Complex, Singhbhum Craton, eastern India."

In addition to the warning on the treatment of data expressed by Dr. Harald G. Dill, the question arises about how you got the concordant ages too. Do those represent measured single spots on zircons using a SHRIMP? Perhaps you may have got some discordant ages if you have chosen to analyze some other spots on the same zircons. However, if you got the concordance based on (present-day obsolete method of) whole-grain analysis based on a wet-chemical method, it is more reliable than a single concordant SHRIMP spot. I have modeled Pb-redistribution in zircons using computer and find that pseudo-concordance is likely whenever Pb is redistributed and that concordance has no relation to any chronologically distinct component present in a composite zircon. One of the main weaknesses that scientists have in the study of detrital zircons is that many of them appear to think that most recycled zircons are concordant to start with and it is for the first time they are brought into the sediment. But in a sediment, one may come across grains that are both concordant and discordant and recycled several times during their geological history.