Halos And Unknown Natural Radioactivity
R.V. Gentry is well known for his studies of giant halos in minerals, particularly micas from Madagascar. Recently, intense debate seems to have determined that these Madagascar giant halos are not due to naturally occurring superheavy elements. But what did cause them? In this article, Gentry, et al present data for giant halos in Swedish biotite. No conclusion is given as to their possible origin, but it is noted that some of these giant halos have bleached circles around their centers. These circles seem related to the enigmatic dwarf halos known and unexplained for more than 50 years.
(Gentry, R.V., et al; "Implications on Unknown Radioactivity of Giant and Dwarf Haloes in Scandanavian Rocks," Nature, 274:457, 1978.)
Comment. The "halo" problem is not as trivial as it may seem because anomalous radioactivity, presumably with a very short half-life, should not be present in billion-year-old rocks such as the Madagascar micas. One implication: geological dating is all wrong!