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Fig. 15. Thick Bandelier Tuff deposits form the mesas of the Pajarito Plateau. Upper photograph, looking across Pueblo Canyon toward the northwest, shows, in ascending order, the Otowi Member (Qbo), the Cerro Toledo interval (Qct), and the Tshirege Member (Qbt 1 g to Qbt 3, see text). Subunits of the Tshirege Member are defined by changes in welding and crystallization properties within this compound cooling unit. Middle photograph, in upper Pueblo Canyon, shows well-stratified, tuffaceous sandstones of the Cerro Toledo interval (Qct) between light-colored, slope-forming, nonwelded, vitric ash-flow tuffs of the Otowi Member (Qbo, below) and the cliff of nonwelded, vitric ash-flow tuffs of subunit Qbt 1 g of the Tshirege Member (above). Bottom photograph, east of the confluence of Pueblo and Los Alamos Canyons, shows stratified pumice-fall deposits of the Guaje Pumice Bed (Qbog) overlain by Otowi Member ash-flow tuffs (Qbo, massive light-colored deposits in slope). The Guaje Pumice Bed overlies Cerros del Rio basalt (Tb4).
