Detrital zircon dating second dating advice

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Detrital zircon dating

Figure 2 Detrital zircon U-Pb age data from (A) Paleozoic–Mesozoic subduction-accretionary complexes and (B) Early to Late Jurassic basins in island-arc complexes.

Specific data sources are shown in Table DR1 (see footnote 1).

It is not clear why transcontinental sediment was not delivered to arc-basin systems of the western U. during late Paleozoic time coincident with onset of the Alleghanian orogeny in eastern Laurentia (Hatcher, 2010).

Additional data is needed from rocks of Late Paleozoic–Early Jurassic age to assess the timing of delivery of transcontinental sands to plate-margin basins and the transition from PPA to MPP facies.

(2) Mixed Proterozoic and Phanerozoic facies is found in Early–Late Jurassic basins and is defined by grains spanning ca.

2.0 Ga–160 Ma, derived from eastern-southwestern Laurentian transcontinental sources and enriched by western U. and eastern Mexican early Mesozoic plate-margin magmatism.

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).

The detrital zircon age distributions represent a definable aspect of large bodies of rock, are observation based, and allow for distinction between adjacent units. GVG—Great Valley Group; PPA—Paleoproterozoic and Archean. Specific data sources are shown in Table DR1 (see footnote 1).Here, I compile published and new detrital zircon U-Pb ages from pre-Devonian–early Late Cretaceous, arc-related basins in terranes of western North America.The compilation includes terranes with sufficient available data from west of the = 0.706 line (Armstrong et al., 1977), from the southern California Coast Range to the Yukon-Tanana terrane in the north.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.Bradley et al., 2007; Beranek et al., 2010a), or (3) originally peri-Gondwanan/Avalonian crust that was tectonically emplaced along the southern Laurentian margin in early–mid-Paleozoic time and subsequently translated along the plate margin in mid–late Paleozoic time (Wright and Wyld, 2006; Grove et al., 2008).

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Supporting evidence for this scale of tectonic control on sedimentary provenance in the ancient rock record exists, but is generally sparse and typically does not document transitional stages of paleotectonics (e.g., Rainbird et al., 1992; Riggs et al., 1996; Dickinson and Gehrels, 2003; Tyrrell et al., 2007; Druschke et al., 2011).

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