Implications of Polonium Radiohalos in Nested Plutons of the Tuolumne Intrusive Suite, Yosemite, California by Dr. Andrew Snelling and Dallel Gates April 8, 2009 Abstract The formation of granite plutons has conventionally been thought to be a slow process requiring millions of years from generation to cooling. Even though new mechanisms for rapid emplacement of plutons have now been proposed, radioisotope dating still dominates and dictates long timescales for pluton formation. However, a new challenge to those long timescales has arisen from radiohalos. Polonium radiohalos found in biotite flakes of granites in Yosemite National Park place severe time constraints on...