The Sabine and Wiggins Arch Arc Terranes: Age, Origin, and Impact on the Late Paleozoic Tectono-Stratigraphic Evolution of Southern Laurentia

New and published geochronologic, geochemical, and isotopic data indicate that the Sabine terrane of the northern US Gulf Coast originated as a Proterozoic peri-Gondwanan continental crustal fragment, exotic to Laurentia. A continental margin arc developed on Sabine during the Early Mississippian-Middle Pennsylvanian northwestward convergence between Gondwana and Laurentia. Reappraisal of U-Pb zircon geochronology from Carboniferous Stanley Group (Gp) tuffs, along with new trace element data, links the tuffs to the Pennsylvanian Sabine arc and not the Yucatán/Maya (Chicxulub) Mississippian arc. U-Pb zircon data indicate that crystallization ages of porphyritic granite intrusives, previously reported as Middle Pennsylvanian or older porphyritic rhyolite flows, post-date the Stanley tuffs. Bimodal zircon populations in these and nearby granites yielded Middle Carnian and Early Permian age peaks. Triassic ages reflect hydrothermal alteration of older zircons, plus the addition of new zircons during Mesozoic rifting; Permian ages reflect anatexis within Sabine terrane crust. Sabine Nd isotopic data are unlike data from proximal Laurentian and southern Appalachian sources. However, Nd isotopic data from the Wiggins arch are similar to data from the Uchee/Milledgeville/Savannah River terranes; these combined terranes are interpreted as a Neoproterozoic–Cambrian forearc/arc/back-arc complex, genetically related to the Suwannee–Charleston superterrane. Pennsylvanian siliciclastic sediments and Upper Pennsylvanian tuff from the Pottsville Formation, Black Warrior foreland basin, record northwestward translation of the Sabine arc terrane and Yucatán/Maya block along the southern Laurentian continental margin. The nearby Texarkana retro-arc basin was formed by regional slab rollback and subduction of Laurentian crust by the Sabine terrane and infilled by Pennsylvanian–Permian Morehouse Fm carbonates and siliciclastics derived from the Sabine arc terrane.