Jumbo Dome, Interior Alaska: Whole-rock, major- and trace-element analyses

Jumbo Dome is a hornblende andesite dome of Pleistocene age located in the Healy Quadrangle of central Alaska, about 19 km northeast of Healy, Alaska. Jumbo Dome is approximately 1.6 km long, 1.3 km wide, and 500 m high and intrudes the Devonian Keevy Peak Formation basement (slate, quartz-sericite schist, graphitic schist, calcareous schist, quartz-feldspar metawacke, and conglomerate) and overlying Tertiary Suntrana Formation (sandstone, clay, and coal). Jumbo Dome is not well studied and these samples plus the three analyses from Albanese (1980) represent the known total of published whole-rock geochemical analyses for this volcanic feature. Jumbo Dome lava has the diagnostic arc signature of low ratios of concentrations of high-field-strength elements to large-ion-lithophile elements (for example, Nb/La, Nb/Rb).