The statement "no age information is expected" is not a scientific hypothesis.
Hence, Snelling's article is by no means a 'research' paper, but rather a lab report that contains his educated opinion.
In other words, geologists can use independent lines of evidence to study the history of these rocks: one isotopic system (U-Pb) to date the rocks and several others (Sr-Rb, Sm-Nd, Lu-Hf, etc.) to distinguish the origin and ascent of the magma.
As an aside, the oldest zircons to date were found in the Jack Hills of western Australia and date as old as 4,404±4 million years (see the PDF of the original article by Wilde et al., 2001).
This is much like trying to weigh a few grains of sand on the vegetable scale at the grocery store and then complaining that their scales are broken! Snelling can effectively discuss 'age data' in these rocks if he refuses to apply any of the commonly used, modern methods in his study. Before diving into a mash of petrological details, Snelling summarizes a couple of well-known geochemistry textbooks with respect to the general use of radiogenic isotopic analyses in volcanic island arcs.
He writes: "...radioisotopes in [historic/recent] lavas reflect the isotopic compositions of the mantle sources of these lavas, and of any crustal contamination the magmas may have incorporated during ascent and extrusion." (emphasis mine) This should sound familiar to you by now.
Unfortunately, he reports this research through 'technical' articles that are unintelligible to much of his audience, and therein he hides the fact that the results actually contradict his professed beliefs. Snelling depends on the ignorance of his readers regarding geology—specifically geochronology, which entails various methods of dating rocks.
These crystals are quite small and rare, but are incredibly resistant to chemical alteration.Conversely, Young-Earth models do not predict the isotopic data at volcanic island arcs, primarily because they offer no model by which the mantle and crust evolved to drastically different isotopic values.Ratios of radiogenic isotopes can be combined with geochronological data (radiometric dates) to elucidate tectonic processes over time.Why not offer a means by which to test the young-earth model with the new isotope data?Unfortunately for Snelling, no such test exists, but with a handful of tables and verbose petrological descriptions, he is successful in misdirecting his audience.Snelling was the whole-rock K-Ar method, which yielded model ages between zero and 3.5±0.2 Ma (see original article here).