The geological study of the kinds of rocks selected for use as tools, using petrographic, geochemical, or other methods can be used to understand ancient patterns of mobility and exchange. I have applied these techniques to a number of Holocene assemblages from the northeastern US and eastern Africa.
Frahm, E.; Tryon, C.A. (2018) Later Stone Age toolstone acquisition in the Central Rift Valley of Kenya: Portable XRF of Eburran obsidian artifacts from Leakey’s excavations at Gamble’s Cave II. Journal of Archaeological Science: Reports 18:475-486.pdf
Frahm, E.; Goldstein, S.T.; Tryon, C.A. (2017) Forager-fisher and pastoralist interactions along the Lake Victoria shores, Kenya: Perspectives from portable XRF of obsidian artifacts from Kansyore rock shelters. Journal of Archaeological Science Reports 11: 717-742..pdf
Tryon, C.A. & Philpotts, A.R. (1997) Possible sources of mylonite and hornfels debitage from the Cooper Site, Lyme, Connecticut. Bulletin of the Archaeological Society of Connecticut 60:3-12..pdf