Detrital zircon U-Pb ages and provenance study of the late Jurassic Bossier sands, east Texas subsurface

The Bossier sands, a natural gas reservoir, are a series of Jurassic stacked sand layers within the Bossier Shale found in the subsurface of East Texas. Detrital zircons were separated from 5 wells. U-Pb or Pb-Pb ages were determined on 393 zircon grains using LA-ICPMS at the University of Arizona. Results revealed two dominant age peaks: 32.5% have Early Neoproterozoic -Middle Mesoproterozoic ages (950-1360 Ma 'Grenville'), and 27% have Pennsylvanian-Ediacaran ages (300-680 Ma 'Ouachita'). Other age peaks include the Jurassic-Permian (150-300 Ma), Early Mesoproterozoic (1360-1500 Ma), Early Mesoproterozoic-Late Paleoproterozoic (1500-1900 Ma), and the Late-Paleoproterozoic or older (>1900 Ma). We conclude that the dominant provenance for the Bossier sands was from local sources in the Ouachita and Grenville orogens. This suggests that flanking crust in Texas, Oklahoma, and Arkansas was high-standing regions during the Jurassic time, shedding detritus into rivers feeding Bossier depocenters.