Abstract

U–Pb ages of individual detrital zircon grains from deltaic and turbidite sandstones of the lower to middle Pennsylvanian Haymond Formation (Marathon basin, west Texas) range from 320 Ma to 3 Ga, indicating a mixed provenance broadly similar to that of Ouachita Carboniferous turbidites and related fluvio-deltaic facies of Arkansas–Oklahoma. Differences with the Ouachita assemblage are attributed to the unique depositional setting of the Haymond Formation, which records final closure of a Hercynian-age remnant ocean basin at the western termination of the Ouachita–Marathon suture zone. Tectonic and sedimentary recycling along subduction zones separating Gondwanan (upper plate) and Laurentian (lower plate) blocks likely contributed to the Laurentia-dominated distribution of age provinces observed in the zircon population. Detrital-zircon age spectra are nearly identical for both facies of the Haymond Formation, reinforcing the hypothesis that subaerial fan or braid delta sandstones, and foredelta submarine-ramp turbidites, were part of an integrated depositional system fed by the same sources.