Initial Flood Deposits of the Western North American Cordillera: California, Utah and Idaho

Discontinuous but widespread coherent packages (unbroken by major unconformities) of Neoproterozoic sedimentary strata, recognized by basal diamictite deposits (debris flows), outcrop throughout the western North American Cordillera. These phenomenal clastic packages, which represent high-energy sedimentary environments, overlie older sedimentary, metamorphic and igneous rocks, and underlie younger regionally widespread fossiliferous sandstone, carbonate and shale. The basal, high-energy debris flow deposits sporadically occur throughout the length of the western North American Cordillera and locally contain submarine volcanic extrusive and igneous intrusive rocks. Geological activity during the start of the Flood when, "all the fountains of the great deep burst forth" necessitates a record of geologic signatures or discontinuities on a grand scale. Explanation for these high-energy geologic events needs to proceed from a Biblical worldview supported by the empirical data contained within the rocks. High-energy catastrophic processes recorded: mechanical-erosional, timeage, tectonic, sedimentary, and paleontologic discontinuities in the western North American Cordillera. Clastic sedimentary rocks underlying the western Cordillera thicken remarkably while the same sediments thin towards the east and truncate with regional fossiliferous sandstones. Igneous activity and contemporaneous deposition across fault-bounded basins record tectonic discontinuities. The coarse to fine megasuccession found in the North American Cordillera characterize initial and early Flood deposits. Three rock units are considered: the Kingston Peak Formation in the Death Valley region of California, the Dutch Peak Formation in the Sheeprock Mountains in central Utah, and the Pocatello Formation in the vicinity of Pocatello, Idaho. These formations display abrupt thickening of sediments towards presumed fault-bounded basins, overlie older sedimentary, igneous or metamorphic rocks, and underlie thick successions of clastic rock with increasing megafossil content upwards. Additionally, some of the debris flows contain evidence of contemporaneous submarine volcanic activity. The high-energy debris flow deposits found in the Kingston Peak, Dutch Peak and Pocatello Formations mark the catastrophic events occurring at the initial stages of the Flood. INTRODUCTION The North American Cordillera "mountain chain," extends from northern Mexico, traverses the western United States then crosses up through Canada and into Alaska. Neoproterozoic and Cambrian sedimentary rocks (Sauk Sequence), composed predominantly of clastic material with carbonate, outcrop in various mountain ranges within the Cordillera. These sedimentary successions record continuous deposition of deep-water facies in the west and a shallow-water facies in the east of the Cordillera. In addition, sediments thicken remarkably in the west and thin out in the east forming a clastic wedge. At the base of these sedimentary successions, unique deposits of diamictites, conglomerates and volcanic rocks outcrop. Figure 1 shows the geographical extent and thickness of the sedimentary wedge and the outcrop occurrences of basal diamictite and volcanic rocks in the western Cordillera.