JG vol. 118, no. 1 2010 Tuesday Oct 27 2009 01:03 PM/80097/MILLERD CHECKED Application of Foreland Basin Detrital-Zircon Geochronology to the Reconstruction of the Southern and Central Appalachian Orogen Hyunmee Park, David L. Barbeau Jr., Alan Rickenbaker, Denise Bachmann-Krug, and George Gehrels1 Department of Earth and Ocean Sciences, University of South Carolina, Columbia, South Carolina 29208, U.S.A. (e-mail:
[email protected]) ABSTRACT q1 We report the U-Pb age distribution of detrital zircons collected from central and southern Appalachian foreland basin strata, which record changes of sediment provenance in response to the different phases of the Appalachian orogeny. Taconic clastic wedges have predominantly ∼1080–1180- and ∼1300–1500-Ma zircons, whereas Acadian clastic wedges contain abundant Paleozoic zircons and minor populations of 550–700- and 1900–2200-Ma zircons q2 consistent with a Gondwanan affinity. Alleghanian clastic wedges contain large populations of ∼980–1080-Ma, ∼2700- Ma, and older Archean zircons and fewer Paleozoic zircons than occur in the Acadian clastic wedges. The abundance of Paleozoic detrital zircons in Acadian clastic wedges indicates that the Acadian hinterland consisted of recycled material and possible exposure of Taconic-aged plutons, which provided significant detritus to the Acadian foreland basin. The appearance of Pan-African/Brasiliano- and Eburnean/Trans-Amazonian-aged zircons in Acadian clastic wedges suggests a Devonian accretion of the Carolina terrane. In contrast, the relative decrease in abundance of Paleozoic detrital zircons coupled with an increase of Archean and Grenville zircons in Alleghanian clastic wedges indicates the development of an orogenic hinterland consisting of deformed passive margin strata and Grenville basement.