Stratigraphy of the Chinle and Moenkopi Formations, Navajo and Hopi Indian Reservations, Arizona, New Mexico, and Utah

Dikes, sills, and stress-regime evolution during emplacement of the Jagged Rocks Complex, Hopi Buttes Volcanic Field, Navajo Nation, USA

“…2). The Colorado Plateau successions were formed in a slowly subsiding continental margin to foreland basin setting that evolved from marine to fluvial and lacustrine depositional environments Repenning et al, 1969) while accumulating sediment with cratonic to Laramide-orogen sources (Dickinson et al, 1983). Porous sedimentary rock is part of the global groundwater reservoir (Hay and Leslie, 1990), and it can be inferred that both Mesozoic sedimentary rock and overlying Miocene lacustrine sediments in this region were water-saturated at the time of eruption (White, 1990).…”

Regional correlation of the Sonsela Member (Upper Triassic Chinle Formation) and detrital U-Pb zircon data from the Sonsela Sandstone bed near the Sonsela Buttes, northeastern Arizona, USA, support the presence of a distributive fluvial system

“…At its type section a few kilometers east of Canyon DeChelly National Monument, Arizona at the Sonsela Buttes ( Figs. 1 and 2), the Sonsela Sandstone bed was thought to overly the lower part of the Petrified Forest Member (Akers et al, 1958;Repenning et al, 1969;Stewart et al, 1972), but is now understood to overly the silty mudstone of the Bluewater Creek Member (informally the "lower red member"; Martz and Parker, 2010;Irmis et al, 2011) and is composed of three major divisions: a lower light gray sandstone, a middle blue-gray siltstone, and an upper, thicker light gray sandstone. These sandstones, especially the upper ledge-forming unit, are trough cross-bedded; the coarse bedloads contain volcanic clasts and chert cobbles that preserve Permian macrofossils similar to those found in the Kaibab Formation (Fig.…”

High-precision U-Pb zircon geochronology of the Late Triassic Chinle Formation, Petrified Forest National Park (Arizona, USA): Temporal constraints on the early evolution of dinosaurs

“…By contrast, many workers have noted evidence of large-scale incision and infi lling in the Chinle stratigraphy (Repenning et al, 1969;O'Sullivan, 1970;Stewart et al, 1972;Blakey and Gubitosa, 1983;Kraus and Middleton, 1987). The dissected paleotopography, in concert with the well-documented lenticular, repetitive nature of fl uvial facies (Miall, 1983;e.g., Fastovsky, 1987), has been used to challenge the lateral continuity of the members and formations recognized in the region (Dubiel et al, 1999;Therrien et al, 1999).…”