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No. 5: November 1978

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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!

From Science Frontiers #5, November 1978. 1978-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:


  • "A sourcebook of unexplained phenomena is therefore a valuable addition to a collection of scientific literature. William R. Corliss has provided this in the past with his source books of scientific anomalies in several subjects, and now he has provided it for astronomy. He has done an excellent job of collecting and editing a large amount of material, taken in part from scientific journals and in part from scientific reporting in the popular or semi-scientific press." -- "The Mysterious Universe: A Handbook of Astronomical Anomalies", reviwed by Thomas Gold, Cornell University, in Icarus, vol.41, 1980

  • "An interesting, systematic presentation of unusual weather [..] This book is recommended for a general audience" --"Corliss, William R., Tornados, Dark Days, Anomalous Precipitation, and Related Weather Phenomena, Sourcebook Project, 1983.", revieweed in Choice, September 1983
  • "..the science is necessarily somewhat speculative, but Corliss's symthesis is based on reputable sources." -- "Corliss, William R. (Compiler). Lightning, Auroras, Nocturnal Lights, and Related Luminous Phenomena" reviwed by Joseph M. Moran, Univ. of Wisconsin in Science Books and Films, Sep/Oct 1983

  • "Before opening the book, I set certain standards that a volume which treads into dangerous grounds grounds like this must meet. The author scrupulously met, or even exceeded those standards. Each phenomenon is exhaustively documented, with references to scientific journals [..] and extensive quotations" -- "Book Review: The moon and planets: a catalog of astronomical anomalies", The Sourcebook Project, 1985., Corliss, W. R., Journal of the Royal Astronomical Society of Canada, Vol. 81, no. 1 (1987), p. 24., 02/1987