40Ar/39Ar Geochronology, Isotope Geochemistry (Sr, Nd, Pb), and petrology of alkaline lavas near Yampa, Colorado: migration of alkaline volcanism and evolution of the northern Rio Grande rift - Cosca, Michael; Thompson, Ren; Lee, John; Turner, Kenzie; Neymark, Leonid; Premo, Wayne (Geology, 2014)