U-Pb ages of detrital zircons in Jurassic eolian and associated sandstones of the Colorado Plateau: Evidence for transcontinental dispersal and intraregional recycling of sediment

Abstract

U-Pb ages for 1655 individual detrital zircon grains in 18 samples of eolian and associated marine and fl uvial sandstones of the Glen Canyon and San Rafael Groups from the Colorado Plateau and contiguous areas shed light on patterns of Jurassic sediment dispersal within Laurentia. Most detrital zircon grains in Jurassic eolianites were derived ultimately from basement provinces older than 285 Ma in eastern and central Laurentia, rather than from rock assemblages of the nearby Cordilleran margin. The most prominent peaks of constituent age populations at 420 Ma, 615 Ma, 1055 Ma, and 1160 Ma refl ect derivation from Paleozoic, Neoproterozoic, and Grenvillian sources within the Appalachian orogen or its sedimentary cover. Sediment was transported to a position upwind to the north of the Colorado Plateau by a transcontinental paleoriver system with headwaters in the central to southern Appalachian region, but subordinate non-Appalachian detritus was contributed by both northern and southern tributaries during sediment transit across the continent. Subordinate detrital zircons younger than 285 Ma in selected Middle to Upper Jurassic eolianites were derived from the Permian-Triassic East Mexico and the MesozoicCordilleran magmatic arcs. Lower Jurassic fl uvial sandstones typically contain a mixture of detrital zircons redistributed from eolian sand and derived from the East Mexico arc, which lay up-current to the southeast. Zircons in marine Curtis sandstone were largely reworked from underlying Entrada eolianite, with minor contributions from the Jurassic backarc igneous assemblage of the Great Basin. Once mature quartzose detritus was dispersed widely across southwest Laurentia by a transcontinental paleoriver system and paleowinds, which deposited extensive Jurassic ergs, durable zircon grains were recycled by multiple intraregional depositional systems. Lower Jurassic fl uvial sand is locally composed, however, of detritus derived from the nearby Cordilleran magmatic arc assemblage and its Precambrian basement.

A Late Jurassic to Early Cretaceous record of orogenic wedge evolution in the Western Interior basin, USA and Canada

“…Neoproterozoic detrital zircon grains (850-550 Ma) are derived from peri-Gondwanan terranes that collided with North America during the Appalachian Orogen (Eriksson et al, 2004;Becker et al, 2005;Park et al, 2010). Plutons associated with the Appalachian Orogen and precursor rift assemblages span the Neoproterozoic to the Paleozoic and supply a portion of the 760-285 Ma grains (Dickinson and Gehrels, 2009b;Park et al, 2010).…”

“…Neoproterozoic to Paleozoic (670-370 Ma) zircon ages also occur in composite signature of the Mesozoic eolianites of the southwestern United States and in populations of Group 1 (Fig. 4) (Dickinson and Gehrels, 2009b). The upper sandstone of the Flood Member could record either the recycling of Jurassic-Lower Cretaceous foreland basin strata or the reincorporation of pre-foreland sedimentary strata into the drainage system.…”

The Paleogene California River: Evidence of Mojave-Uinta paleodrainage from U-Pb ages of detrital zircons

“…More surprising, when the two Colton samples are combined into a single population and compared with the McCoy Mountains sample, the resulting P value is 0.23. Thus, the samples are statistically indistinguishable for the purpose of assessing provenance relations (Dickinson and Gehrels, 2009).…”

Understanding a critical basinal link in Cretaceous Cordilleran paleogeography: Detailed provenance of the Hornbrook Formation, Oregon and California

“…Detrital zircon rarely occurs in samples lacking detrital quartz (Gehrels et al, 2006), and most detrital zircon is derived from felsic to intermediate igneous rocks and recycled clastic sedimentary or metasedimentary successions (Gehrels, 2000;Dickinson and Gehrels, 2009b;LaMaskin et al, 2011).…”