In this example, the authors collected sand samples from the French Broad River (western North Carolina–eastern Tennessee, United States) and six tributaries in the Appalachian Blue Ridge and analyzed them with both zircon and monazite U-Pb dating in order to investigate the geochronologial signature of the source area and its tectonic significance.
Whereas detrital U-Pb zircon ages (by MC-LA-ICPMS) record Grenville (ca. 470–440 Ma) signals, they exhibit a very limited Acadian (ca.
(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.
Whereas zircons occur in most magmatic, metamorphic, and sedimentary rocks, other minerals, such as apatite, monazite, and white mica, are less abundant.
Paleozoic–Mesozoic basins in Cordilleran terranes of western North America contain detrital zircon U-Pb age distributions that vary over 10–100 Ma in a systematic and predictable manner.
A minimum of four detrital zircon age distributions, here termed “detrital zircon facies,” are present: (1) Paleoproterozoic and Archean facies, chiefly found in Paleozoic and early Mesozoic accretionary complexes, is defined by late Archean–early Proterozoic (ca. 2.0–1.6 Ga) with variable quantities of Paleozoic and early Mesozoic ages.
420–380 Ma) signal and do not record the Alleghanian (ca. Detrital monazites from the same sediments record the complete Paleozoic collisional history of the Appalachian orogen (including the Alleghanian event) as well as the main events for the Grenville basement.
The authors point out that the younger signals are only partially recorded in rims of detrital zircons, and may be missed without careful imaging and domain sampling in a strictly detrital zircon approach.
(3) Triassic and Jurassic facies, found in Late Jurassic–Early Cretaceous basins, is defined by Late Jurassic ages (peak ca. Detrital zircon U-Pb ages from terranes of western North America record stages of basin formation during phases of the supercontinent cycle and reflect second-order variability in the tectonic setting of an active continental plate margin.