Exotic Heavily Ionizing Particles can be Constrained by the Geological Abundance of Fullerenes

The C_{60} molecule exhibits a remarkable stability and inertness that leadsto its survival in ancient carbonaceous rocks initially subject to the hightemperatures requisite for its formation. Elementary particles having very highelectronic stopping powers can similarly form C_{60} and higher fullerenes intheir wake. Combined, these two features point at the possibility of using theC_{60} presence (or absence) in selected bulk geological samples as a new typeof solid-state nuclear track detector, with applications in astro-particlephysics.Comment: Final version (few modifications). Phys. Rev. Lett. (in press). 4 pages LaTeX, 1 eps figure embedde