Journal of Sedimentary Research, 2013, v. 83, 786–802 Research Article DOI: 10.2110/jsr.2013.63 TRACING CLASTIC DELIVERY TO THE PERMIAN DELAWARE BASIN, U.S.A.: IMPLICATIONS FOR PALEOGEOGRAPHY AND CIRCULATION IN WESTERNMOST EQUATORIAL PANGEA GERILYN S. SOREGHAN AND MICHAEL J. SOREGHAN School of Geology and Geophysics, University of Oklahoma, Norman, Oklahoma 73019, U.S.A. ABSTRACT: The Guadalupe Mountains of the southwestern U.S. (New Mexico–West Texas) expose the shelf edge of the Permian Delaware Basin, which formed near the western edge of the Central Pangean suture in equatorial Pangea. Voluminous siliciclastic strata filled this basin in mid-Permian time, and compose the Delaware Mountain Group (Brushy Canyon, Cherry Canyon, and Bell Canyon formations). These units have long been recognized to record ultimate deepwater deposition of siliciclastic sediments that were pre-sorted via eolian transport as they progressed toward the shelf edge of the Delaware Basin in Permian time. The generally arkosic mineralogy led most previous researchers to identify crystalline basement uplifts of the Ancestral Rocky Mountains (ARM) of the western U.S. as the primary source for the large volumes of Permian siliciclastic material that fill this basin. New provenance data combining modal mineralogy with detrital-zircon geochronology, however, refute this interpretation. Rather than an ARM basement source, indicated by Paleoproterozoic ages, the predominant age populations, comprising 70–80% of the grains, reflect contributions from Paleozoic, Neoproterozoic, and Mesoproterozoic (Grenvillian) age basement. The combined (arkosic–subarkosic) mineralogy and provenance spectra of the siliciclastic strata from the Delaware Mountain Group, together with comparisons with coeval strata and available paleocurrent data indicate sources in the Ouachita system, including recycled Appalachian detritus, and terranes accreted and uplifted south of the Ouachita suture, now in Mexico and Central America. Dispersal pathways likely involved a component of fluvial transport draining the piedmont region of the Ouachita orogenic belt, and ultimate eolian deflation of these fluvial systems within an easterly to southeasterly and seasonal westerly to northwesterly atmospheric circulation. Monsoonal transport, especially northern excursions of the ITCZ during northern hemisphere summers, would have facilitated transport from terranes south of the Ouachita–Marathon suture in present-day Mexico and Central America. Source locations predominantly south-southeast of the study region potentially obviate the need to call upon transcontinental fluvial transport directly from the Appalachian orogen to the southwestern edge of Pangea, at least for this time period. Furthermore, these results place new constrains on the final docking, major uplift, and consequent erosion of the Yucatan–Maya terrane south of the Ouachita orogenic belt, which provided significant siliciclastic detritus to depocenters in the western U.S. during middle Permian time. In contrast, the uplifts of the ARM were either covered, or greatly diminished as sources by this time. INTRODUCTION The Delaware Basin (Figs. 1, 2) formed one of the southwesternmost sedimentary basins of Permian equatorial Pangea. An exhumed, virtually undisturbed shelf-basin transect reveals world-renowned exposures of evaporite–carbonate–clastic depositional systems, which have been inten- sively studied to assess sedimentary processes, sequence stratigraphy, and paleoecology in lithologically diverse environments. Siliciclastic strata form most of the thick basin fill, and they have undergone substantial study from the standpoint of depositional interpretations, but provenance of the voluminous siliciclastic material remains inconclusive. Sources that have been suggested nearly span the compass, from northwest clockwise to southwest, suggesting various dispersal pathways. Most authors have posited a generally northern source emanating from the remnant uplifts of the crystalline-basement-cored Ancestral Rocky Mountains (Fig. 1; references below), implying continual erosion of these uplifts through Permian time, and paleocurrents emanating from the north. Detrital-zircon geochronology (U-Pb) can help define potential ultimate bedrock source regions and thus shed new light on provenance relations (e.g., Rainbird et. al 1992; Riggs et al. 1996), especially when combined with other methods such as modal mineralogy and paleocur- rents. Detrital-zircon provenance data from Mesozoic sandstone units of the western U.S. have refined continental-scale paleogeographic recon- structions (Dickinson and Gehrels 2008, 2009a, 2009b; Dickinson et al. 2010). Fewer data (e.g., Dickinson and Gehrels 2003) exist on Paleozoic sandstone strata, but Gehrels et al. (2011) recently presented data from Paleozoic strata of the Grand Canyon and demonstrated several provenance shifts, including one beginning in the Early to middle Permian. Permian siliciclastic strata of the Delaware Basin accumulated predominantly within deep- (basinal) to shallow- (shelf) marine environ- ments. However, these sediments are thought to have reached the shoreline not by fluvial systems but via eolian transport (e.g., Fischer and Sarnthein 1988, and references below). The purpose of this paper is to ascertain the source(s) of these siliciclastic strata to provide insights into paleodispersal patterns and paleogeography—including major highland regions—in western equatorial Pangea at a time (from the middle Permian to Late Permian) and a place (southwesternmost Laurentia) that represents a data gap in provenance relations. These new data resolve Published Online: August 2013 Copyright E 2013, SEPM (Society for Sedimentary Geology) 1527-1404/13/083-786/$03.00