Detrital zircon dating

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As such, they are here designated “detrital zircon facies.” The age ranges present in a given detrital zircon facies (i.e., their recognition criteria) relate directly to known regional source areas of both primary Figure 4 Chronostratigraphic distribution of detrital zircon facies in western North American terranes, as well as referenced samples from the western U. The provenance of PPA facies is either (1) crystalline sources in northwestern Laurentia (Gehrels et al., 1995, 2000), (2) rifted and translated crustal fragments of the Precambrian–Paleozoic northwestern Laurentian miogeocline (Nelson and Gehrels, 2007; cf.

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155 Ma) with a subordinate proportion of Triassic ages (peak ca. (4) Jurassic and Early Cretaceous facies is found in late Early–early Late Cretaceous marginal basins and is defined by Jurassic and Early Cretaceous ages (ca. At this temporal and spatial scale, the integrated evolution of orogenic, erosion, and sediment-transport systems controls sediment provenance.Lindsley-Griffin et al., 2006), and was subsequently recycled along the margin (Fig.4) (e.g., Scherer et al., 2010; La Maskin et al., 2011). Dickinson and Gehrels, 2003, 2009; Rahl et al., 2003).Noteworthy, non-PPA age distributions in Paleozoic accretionary-subduction complexes of the Klamath Mountains and Sierra Nevada may represent exotic crust, structurally intercalated with PPA-bearing rocks, or may suggest other explanations (e.g., Harding et al., 2000; Wright and Wyld, 2007; Grove et al., 2008). The presence of a transcontinental signature in each of these Early–Late Jurassic basins (Fig. Izsak et al., 2007; Dickinson and Gehrels, 2008a, 2009; La Maskin et al., 2011) suggests proximity to North America and the modern southwestern U. in early Mesozoic time, and that active orogenic structures and the plate-margin arc itself were not barriers to sediment transfer from the craton to the arc.The age distribution in MPP facies represents transcontinental sand shed from the greater Ouachita-Appalachian orogeny and enriched by southwestern Laurentian sources, as well as early Mesozoic, plate-margin magmatism in the western U. Existing data suggest that these transcontinental sediments were not incorporated into western North American peripheral-arc systems until Early Jurassic time (Fig. 190–185 Ma, Klamath Mountains, North Fork terrane) (Scherer and Ernst, 2008).

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