SEDIMENT DISPERSAL HEAT MAPS FOR INTERPRETING PROVENANCE: INSIGHTS INTO NORTH AMERICAN SEDIMENTATION AND TECTONISM

Detrital geochronology provenance studies seek to link basinal strata to sediment sources in the geologic past to interpret ancient sediment pathways, trends in tectonism and uplift, magmatism, and climatic shifts. These studies require a firm understanding of the location of zircon sources. We present zircon distribution models of North America to detail the location and extent of zircon sources from which detrital zircon may be sourced. Zircon distribution models are inverse distance weighted interpolations of zircon age concentrations within N=3,059 samples from available data in North America.

To demonstrate the application of these maps, we combine U-Pb and U-Th/He zircon double dates to pinpoint distinct sediment sources for Pleistocene turbidites in the Gulf of Mexico. Zircon U-Th/He ages contain a variety of age populations, but notably include a well-defined ~84 Ma population (n=5) which correlates to the earliest Laramide or mid-Sevier orogenies in the Rocky Mountains. U-Pb ages for the same zircon grains represent 3 age populations: 163, ~1000, and ~1700 Ma. The only location that meets the criteria of (1) containing the observed zircon U-Pb age populations that might (2) contain reset (U-Th)/He ages associated with construction of the Rocky Mountain and (3) falls within the Mississippi-Missouri river drainage is in NW Wyoming, providing a high resolution interpretation for source-to-sink provenance.