Tectonic control on coarse-grained foreland-basin sequences: An example from the Cordilleran foreland basin, Utah

Figure 1. A: Map of Charleston-Nebo salient and northernmost Book Cliffs showing rock units, thrust faults (dashed where buried), key seismic coverage (gray lines), measured stratigraphic sections (1–7; 8 is location of additional Blackhawk sandstone samples), and wells. Rock units: KTs—Cretaceous–Tertiary strata (North Horn and younger formations), Kmv—Cretaceous Mesaverde Group (Blackhawk, Castlegate, and Price River Formations; dot pattern), Km— Cretaceous Mancos Shale, PPoq—Pennsylvanian–Permian Oquirrh Group, M—Mississippian, pC–C—Precambrian–Cambrian. Inset map shows Sevier thrust front, Laramide basement uplifts, and Canyon Range (CRT) and Pavant thrusts (PT). B: Chronostratigraphic chart for Campanian–Maastrichtian deposits across central Utah, modified from Robinson and Slingerland (1998). Vertical ruled pattern denotes nondepositional or erosional hiatus. ABSTRACT Newly released reflection seismic and borehole data, combined with sedimentological, provenance, and biostratigraphic data from Upper Cretaceous–Paleocene strata in the proximal part of the Cordilleran foreland-basin system in Utah, establish the nature of tectonic controls on stratigraphic sequences in the proximal to distal foreland basin. During Campanian time, coarse-grained sand and gravel were derived from the internally shortening CharlestonNebo salient of the Sevier thrust belt. A rapid, regional Campanian progradational event in the distal foreland basin (.200 km from the thrust belt in ,8 m.y.) can be tied directly to active thrustgenerated growth structures and an influx of quartzose detritus derived from the Charleston-Nebo salient. Eustatic sea-level variation exerted a minimal role in sequence progradation.