Zircon (U-Th)/He thermochronology reveals pre-Great Unconformity paleotopography in the Grand Canyon region, USA

The Biogeographic Significance of a Large, Deep Canyon: Grand Canyon of the Colorado River, Southwestern USA

Mercury and selenium accumulation in the Colorado River food web, Grand Canyon, USA.

Mercury (Hg) and selenium (Se) biomagnify in aquatic food webs and are toxic to fish and wildlife. The authors measured Hg and Se in organic matter, invertebrates, and fishes in the Colorado River food web at sites spanning 387 river km downstream of Glen Canyon Dam (AZ, USA). Concentrations were relatively high among sites compared with other large rivers (mean wet wt for 6 fishes was 0.17-1.5...

The pre-Flood/Flood Boundary: As Defined in Grand Canyon, Arizona and eastern Mojave Desert, California

The singular events which occurred at the initiation of the Flood should have produced a geologic signature with at least five characteristics: (a) a mechanical-erosional discontinuity (ED) identified by regional structural analysis—probably the most significant unconformity in any given area; (b) a time or age discontinuity (AD) identified by coarse sediments above the erosional unconformity c...

The mystery of the pre–Grand Canyon Colorado River— Results from the Muddy Creek Formation

The Colorado River’s integration off the Colorado Plateau remains a classic mystery in geology, despite its pivotal role in the cutting of Grand Canyon and the region’s landscape evolution. The upper paleodrainage apparently reached the southern plateau in the Miocene, and recent work supports the longstanding idea that the river was superimposed over the Kaibab uplift by this time. Once off th...

Cluster-Analysis Classification of Wintertime Wind Patterns in the Grand Canyon Region

Twelve typical wintertime wind patterns for the Grand Canyon region were derived from a two-stage cluster analysis wind-field classification scheme. The wind measurements were collected by a surface network of 15 stations deployed for a period of approximately three months. The wind patterns are strongly influenced by the complex terrain of the region. The analyses relate the wind patterns to m...