Major and trace element data with partition coefficients for lava flows from the San Francisco volcanic field

Major and trace element data from San Francisco Mountain (a stratovolcano), as well as major element data from representative flows of the surrounding volcanic field (figure 1), are presented in this report. Also included are conventional and normalized partition coefficients for trace elements in each of the coexisting mineral phases and mesostasis from San Francisco Mountain lavas.

The San Francisco Mountain lavas are from the upper portion of the southeast slope of Humphreys Peak which is composed of three petrographically distinct types: (1) a lower series of hornblende pyroxene andesites, (2) a middle group of hypersthene dacites, and (3) an upper series of olivine andesites. The sequence of volcanic flows was measured and analyzed for the major elements and fifteen trace elements Sc, V, Cr, Cq Ni, Cu, Zn, Ga, Sr, Y, Zr, Ba, La, Ce, and Yb) in each of the coexisting mineral phases, groundmass and bulk rock. The constituent mineral phases (not all are present in every sample) are plagioclase, hypersthene, augite, hornblende, olivine, magnetite, and ilmenite/hematite.