Provenance of the Paleocene-Eocene Wilcox Group, western Gulf of Mexico basin: Evidence for integrated drainage of the southern Laramide Rocky Mountains and Cordilleran arc

Abstract

Laramide basement blocks of the U.S. Rocky Mountain Province have long been considered the sediment source of the Paleocene-Eocene Wilcox Group, implying that large-scale progradation driven by Laramide uplift induced a transition from carbonate to clastic deposition in the Gulf of Mexico. Detrital zircon U-Pb age spectra from 10 samples collected from the Wilcox Group in south Texas reveal a complex grain assemblage with major age populations at ca. 1800-1300 Ma and 350-50 Ma and minor populations at 1300-950 Ma, 3250-1850 Ma, and 900-400 Ma. Modal data for Wilcox Group sand grain populations from the same region suggest a diverse provenance, including sources from the Cordilleran magmatic arc and subordinate reworked sedimentary rocks. Sediment was primarily derived from a mix of crystalline basement blocks in the U.S. southern Rocky Mountains and northern Mexico, the Cordilleran arc of western Mexico and the southwestern United States, and Mesozoic-Paleogene magmatic rocks of northern Mexico. Secondary sources include recycled strata from Sevier-Laramide basins in the southwestern United States and northern Mexico. Comparisons of detrital zircon U-Pb age spectra show that the Lower Wilcox subunit contains signifi cant magmatic arc-derived sediment, whereas the Upper Wilcox subunit is more enriched in basement and recycled sedimentary detritus. Therefore, the relatively quartzose composition of the bulk detrital assemblages throughout the Wilcox Group of south Texas is not an accurate refl ection of the range of volcanic and basement sources indicated by the associated U-Pb ages, suggesting signifi cant attrition of unstable grains during long-distance (>500-1000 km) transport.

Validation of empirical source-to-sink scaling relationships in a continental-scale system: The Gulf of Mexico basin Cenozoic record

“…General paleoclimate data were derived from the website http:// www .scotese .com /climate .htm. Recent provenance analysis using detrital zircons, which to a great degree is also a test of method, has largely supported the catchment interpretations for the Paleocene-Eocene Wilcox, Oligocene, and Lower Miocene intervals (Mackey et al, 2012;Craddock and Kylander-Clark, 2013;Blum and Pecha, 2014;Xu et al, 2016;Bush et al, 2016). Channel-belt scaling, an empirical approach to drainage basin estimation, also confirms the Lower Miocene catchment reconstructions (Xu et al, 2017).…”

“…Catchment reconstructions are based on those of Galloway et al (2011) and have been since refined (Xu et al, 2016;this study). This paleogeographic mapping has been fine-tuned by recent detrital-zircon analyses (e.g., Mackey et al, 2012;Blum and Pecha, 2014;Craddock and Kylander-Clark, 2013;Wahl et al, 2016;Xu et al, 2016;Sharman et al, 2017;Blum et al, 2017). Our goals are to test and validate the source-to-sink approach in a large, well-documented system where the answers can be determined independently, so as to facilitate global application to ancient deepwater depositional systems in less well-constrained basins, and expand the use of this important approach to the deep-time sedimentary archive.…”

Diachronous episodes of Cenozoic erosion in southwestern North America and their relationship to surface uplift, paleoclimate, paleodrainage, and paleoaltimetry

“…Paleogene rivers draining the east fl ank of the Laramide orogen and the southeastern Colorado Plateau fl owed southeastward across the Great Plains region to depocenters in the Gulf of Mexico (Galloway et al, 2011). Laramide depocenters in the northwest Gulf of Mexico basin received sediments from sources as distant as the Cordilleran arc terranes of northern Mexico and southeastern California (Mackey et al, 2012). The Colorado Mineral Belt formed a subregional drainage divide within the Laramide foreland because of high topog raphy associated with constructional volcanism, but perhaps also as a result of mantle buoyancy related to magmatism (see following discussions of mantle-buoyancy effects associated with magmatism in the Jemez lineament and the Sierra Madre Occidental).…”

A Late Triassic tectonothermal event in the eastern Acatlán Complex, southern Mexico, synchronous with a magmatic arc hiatus: The result of flat-slab subduction?

“…238 and 220 Ma in Coahuila (Jones et al, 1995;McKee et al, 1999;González-León et al, 2009) suggest that magmatic arc activity here extended well into the Triassic. This conclusion is supported by the detrital zircon record from arc-derived sedimentary sequences in Arizona, Nevada, New Mexico, and Texas (Manuszak et al, 2000;Fox et al, 2005Fox et al, , 2006Dickinson and Gehrels, 2008;Mackey et al, 2012;Riggs et al, 2012), Sonora (Gehrels and Stewart, 1998;González-León et al, 2005Riggs et al, 2009;Mauel et al, 2011;Peryam et al, 2011), and Baja California (Alsleben et al, 2012). These data (Fig.…”