Little is known about the acquisition and transport of rare or “exotic” raw materials in the Initial Upper Paleolithic (IUP). A recently discovered perforated muscovite (mica) flakelet at the Kharganyn Gol 5 site in the middle Selenga Basin of Mongolia raises the question of how far ancient humans ranged to access this material. Here, we present the initial results of an ongoing study, including dating by 40Ar/39Ar and identification of the muscovite source. The age of the Mongolian muscovite correlates with the Oktyabr'skaya outcrop in the Russian Transbaikal region, >500 km from the site. The Buteeliin Nuruu Mountains, near the Kharganyn Gol 5 site, are geologically similar and potentially contain as-yet unknown muscovite outcrops. This evidence suggests that Initial Upper Paleolithic populations had developed social networks or moved over long distances, using the Upper Paleolithic Selenga Corridor in both cases. Alternatively, the area's Pleistocene occupants may have known the geological resources of their home range better than we do now.