heee Ce aR eae Y. LEVY et al. activity ence of ms conradionuroducts. he coral nd subYo such 2st year dionuclng-lived easily lochem‘vations ion by isturbed iods of d trace ity, that ticulate ed speiods of ntity of is coral h also of the of the Jin the 3 asso- d “py to find it year ntly in radiosrmine w they spot” uctive ys in “ith a '. The on of e test virens yn of iod is a powerful tool for revealing the exact distribution patterns of alpha emitters in the Origins of Radioactive Fall-out Geochim. cosmochim. Acta 18, 42. 217 Particles”, range analyzed. Using the method in con- Ba74_ Banard L. A., Macintyre [.G. and Pierce to different matrices within the coral skeleton and structure, leading to better understanding of the factors which lead to the concentration of not only alpha emitters but trace elements as Well in corals. cisco, CA. Do74 Dodge R. E. and Thomson J., 1974, “The Natural Radiochemical and Growth Records in junction with thin section petrography shows that it is possible to assign the alpha activity Acknowledgements —Several intriguing and dynamic conversations concerning thin section petrography and interpretations were held with J. Carew, F. Ricart,W.Goter and P. Bretsky, which were most helpful. The thin sections of coral provided by F. Ricart were of outstanding help. David Van Voorhis is thanked for his great patience in counting of tracks. Critical review of the manuscript by R. L. Fleischer, S. Katz, and H. Clark is appreciated. This research program is supported by the Division of Biomedical and Environmental Research of U.S. Energy Research and Development Administration through Contract No. E(1I- 1)-3462. REFERENCES Ad60 Adams C. E., Farlow N. H. and Scheil W.R., 1960, ‘‘The Composition, Structures and J. W., 1974, ‘Possible Environmental Index in Tropical Reef Corals’, Nature. Lond. 252, 219. Be68 Benton E. V., 1968. “A Study of Charged Particle Tracks in Cellulose Nitrate”. U.S. Naval Radiological Defence Laboratory, San Fran- Contemporary Hermatypic Corals from the Atlantic and Caribbean", Earth Planet. Sci. Lett. 23, 313. F175 Fleischer R. L., Price P.B. and Walker R. M., 1975, Nuclear Tracks in Solids (Berkeley: University of California Press). No70 Northcliffe L. C. and Schilling R. F., 1970, “Range and Stopping Power Tables for Heavy Ions”, Nuclear Data, 7, 233-463 (New York: Academic Press). No75 Noshkin V. E., Wong K. M., Eagle R. J. and Gatrousis C., 1975, ‘“Transuranics and other Radionuclides in Bikini Lagoon: Concentration Data Retrieved from Aged Coral Sections”, Limnol. Oceanogr. 20, 729-742. Ra75 Raghavayya M., Jha G. and Markose P. M., 1975, “Correction for Self Absorption in Alpha Sources’, Health Phys. 29, 782.