The Proceedings of the Eighth International Conference on Creationism (2018)

geochemically the same as Pb it also bonds with S. Furthermore, the mica sheets making up the biotite structure are weakly bonded by K, OH, and F ions, so S and Cl ions can occasionally substitute at point loci within the cleavage planes. It was thus postulated by Snelling (2005) that as the hydrothermal fluids carrying 222 Rn and the Po along the cleavage planes between the biotite sheets, Po atoms were attracted to those point loci where they decayed, only to be replaced by more Po atoms attracted to the same S or Cl point loci. The Po radiocenters were thus formed surrounded by Po radiohalos. Essential to this hydrothermal fluid model for the transport of the Po isotopes from the decay of 238 U in the radiocenters of 238 U radiohalos is the requirement of grossly accelerated 238 U decay (Vardiman et al. 2005). Several lines of evidence suggest that during the Flood when much of the fossil-bearing sedimentary rock record was accumulating, and when biotite-bearing granites were intruded into those sedimentary rocks, the decay rate of 238 U was grossly accelerated. Thus, whereas today’s very slow 238 U decay rate produces only a few Ra, Rn and Po atoms very slowly, that grossly accelerated decay rate would have produced huge numbers of Ra, Rn and Po atoms very rapidly, which were then easily transported the short distances within the host biotite flakes to precipitate in the adjacent Po radiocenters and produce the Po radiohalos. If the 238 U decay rate was accelerated by five orders of magnitude, as Vardiman et al. (2005) postulated, then it could be supposed the Po isotopes’ decay rates were similarly accelerated, which could make their existence so fleeting there wouldn’t be sufficient time for hydrothermal transport to form radiocenters. However, Vardiman et al. (2005) found that the amount of acceleration was related to the present half-lives of the parent radioisotopes, the slower the present decay rate resulting in the most acceleration. Thus, with such fast decay rates today, the Po isotopes’ decay rates would virtually have not been accelerated. Furthermore, the accelerated decay rates would not have resulted in larger radii for 238 U radiohalos, as ring radii are not affected by the decay rates but are related to the energies of the emitted α-particles (Gentry 1973, 1974). In this hydrothermal model, therefore, the Po accumulated in the radiocenters by time integration as Po was progressively deposited from the passing hydrothermal fluids (Snelling and Armitage 2003; Snelling 2005). So, instead of the Po radiohalos forming virtually instantaneously as proposed by Gentry (1988), the Po radiohalos formed over hours and days. This still has drastic time implications for the formation of granites. Whereas Gentry (1988) concluded that granites were created instantaneously by divine fiat, Snelling (2005, 2008a, 2014) postulated that granite magmas crystallized and cooled within days, which is still very radical compared to the uniformitarian timescale. Subsequently, case studieswere undertaken to test this hydrothermal fluid transport model for the formation of Po radiohalos. Most remarkable was the fulfilled prediction of many more Po radiohalos at the staurolite isograd in regionally metamorphosed sandstones in the Great Smoky Mountains, Tennessee-North Carolina, where the metamorphic reaction would have released a lot of water (Snelling 2008b). Then, in the Cooma regional metamorphic complex of southeastern Australia the numbers of Po radiohalos increased where water was released in the high-grade zone and in the central granodiorite, but decreased sharply in the zone of partial melting where water was dissolved into the melt, just as expected in the model (Snelling 2008c). In granites, increased numbers of Po radiohalos were also found where theywere predicted to be based on the release of hydrothermal fluids during granite crystallization and cooling. In the Shap Granite of northern England, prolific Po radiohalos matched the higher volume of hydrothermal fluids associated with that granite’s large K-feldspar phenocrysts (Snelling 2008d). The nested plutons of the Tuolumne Intrusive Suite, Yosemite, California contain increasing numbers of Po radiohalos proportional to the increased volumes of active hydrothermal fluids within the sequentially emplaced intrusions (Snelling and Gates 2009). High numbers of Po radiohalos and active hydrothermal fluids coincide with the large K-feldspar phenocrysts in the second to last pluton and the connection to explosive volcanism of the last pluton. The Bathurst Batholith west of Sydney, Australia, consists of an enormous pluton (the Bathurst Granite) intruded into fossiliferous sedimentary strata and numerous smaller related satellite plutons and dikes, which field and textural data have established were sequentially intruded while still hot (Snelling 2014). The presence of Po radiohalos in all three sequentially-intruded granite phases is evidence that all this intrusive activity, and the cooling of all three granite phases, must have occurred within a week or two so that these Po radiohalos in them formed subsequently within days to weeks. Initial studies had suggested that more Po radiohalos may be present in granites hosting hydrothermal ore veins, for example, the Land’s End Granite, Cornwall, England, which hosts Sn ore veins (Snelling 2005). It was argued that if the proposed model for the formation of Po radiohalos was correct, then the same hydrothermal fluids responsible for transporting the Po within biotite grains within granites to form Po radiohalos may also have transported other metals. Such hydrothermal fluids are released late in the cooling of granite plutons and have concentrated within them metals of economic significance (Sn, W, Mo, Au, Ag, Cu, Pb, Zn, Sb) which do not substitute in the crystal lattices of granite-forming minerals. These metals subsequently end up being deposited by the hydrothermal fluids as economic ore veins in fractures within the granites and the surrounding host rocks. It was thus suggested that appropriate studies needed to be undertaken to confirm the possibility of Po radiohalos being an exploration pathfinder tool for the discovery of hydrothermal ore deposits in new districts, and where such ore deposits are so deeply buried that they may not be detected by other exploration methods. The New England Batholith of eastern Australia was chosen to test this hypothesis. THE NEW ENGLAND BATHOLITH The New England Batholith of eastern Australia is composed of more than one hundred individual granite plutons (Fig. 1) (Shaw and Flood 1981). With an outcrop area of 15,000 km 2 , it is one of the largest batholiths in eastern Australia. Conventionally dated as Upper Carboniferous (Pennsylvanian) to Triassic, the batholith is composed of 80% adamellite (quartz-rich granites with sub- Snelling ◀ Radiohalos as an exploration pathfinder ▶ 2018 ICC 568