Detrital zirconU-Pb ageLaurentia-Gondwana collisionZircon morphologyHf isotopeU-PB AGESANCESTRAL ROCKY-MOUNTAINSDETRITAL ZIRCON GEOCHRONOLOGYPERI-GONDWANAN TERRANESSANTA-ROSA FORMATIONDELAWARE BASINWEST TEXASLU-HFISOTOPIC COMPOSITIONSDEPOSITIONAL SYSTEMS