A BIMODAL distribution of zircons consisting of rounded, variably radiation damaged grains and clear, euhedral grains is present in the sandstones of the Scotland Formation, part of an accretionary prism exposed in northeastern Barbados. Fission track dating of detrital zircons indicates the presence of a component with ages ranging from 20 to 100 Ma with a strong grouping between 20 to 50Ma. Results indictate that the Scotland Fm., previously dated by paleontologic methods as Eocene, may actually be as young as late Oligocene. These ages better constrain the time of deposition for these sediments and support the proposal that the late middle Eocene-early Oligocene Oceanic Fm. has overthrust the Scotland Fro. The rounded zircons yield a mixture of ages with strong groupings between 200-350 Ma and greater than 500 Ma. The circum-Maracaibo region, which has been proposed as a source area for these sediments, is discounted because zircon fission-track ages reported from this area yield ages between 85 and 100 Ma. Zircon ages from the Caribbean Mt. system cluster around approx. 20 Ma, while accessory minerals from rocks of the Orinoco river basin give fission track ages greater than 500 Ma. This contrast is in part to be expected, as the Maracaibo and Caribbean Mt. ages reflect material derived from uplifted areas of northern South America whereas the Orinoco ages reflect material derived from the South American craton. 4Β°Ar/39Ar age spectrum analysis of detrital feldspars from the Scotland formation provides additional evidence of a cratonic source for these sediments. Results from this study, together with paleogeographic constraints, suggest that the source area for these sediments was an area of the Guyana Shield which was drained by the proto-Orinoco river and deposited in a submarine fan north of the Unare depression.