ABSTRACT We measured stratigraphic sections and collected samples from Oceanic suite outcrops at Gay’s Cove and Bath Cliffs, Barbados, in order to restudy the late Eocene microtektite layer(s) and provide new geological context. We disaggregated and processed samples into separates of microfossils, microtektites, and heavy minerals, and we present up-to-date glass geochemistry, biostratigraphic analysis, and detrital zircon U-Pb analysis. Results from the new Barbadian microtektite glass chemistry analysis (Gay’s Cove) compare well with those from other published microtektite analyses, as well as those from the correlative North American strewn field. Micropaleontology confirms a late Eocene age for the Oceanic microtektite horizon at Gay’s Cove. Using U-Pb, we dated 24 Tertiary zircon grains, probably from volcanic ash-fall events, which at Gay’s Cove yielded a preliminary, poorly defined, and incorrect depositional age for the microtektite layer (≤31.84 ± 0.85 Ma; weighted mean of only three grains). Three additional new U-Pb depositional ages (≤38.52 ± 1.0 Ma, ≤39.23 ± 0.3 Ma, ≤35.25 ± 0.82 Ma) were obtained from bottom to top in the 24 m section at Bath Cliffs. We also dated 46 Paleozoic–Proterozoic zircon grains using U-Pb and discuss whether these “old” grains represent recycled (subducted and extruded) volcanic grains or windblown silt/sand from Africa.

ABSTRACT A seismic stratigraphic and lithostratigraphic study based on seismic reflection and well log data of Paleogene strata from the southern Beaufort Sea margin of Alaska and Canada has identified major unconformities and depositional sequences. A comparison of the age of the unconformities to regional uplift events, dated with fission track analysis, shows that tectonic events were more important than eustatic changes in controlling the occurrence of regional unconformities. Paleogene sediments were deposited in a foreland basin located north of the Brooks Range. This basin trends offshore and forms part of the southern continental margin of the Beaufort Sea. Mid-Mesozoic thrusting established the basic structure of the foreland basin, which was later filled with sediments and deformed by northward-directed thrusting. Regional unconformities occur near the Cretaceous-Tertiary boundary, within the Paleocene, middle Eocene, upper Eocene, and lower Miocene. These unconformities separate depositional units consisting of northward-prograding deltaic, slope, and turbidite facies. Most Paleogene depositional patterns can be explained as follows: thrust loading with widespread shale deposition in distal parts of the basin and coarse elastics near the thrust front (Late Cretaceous and middle Eocene); then subsequent thrust-belt erosion and uplift with sand deposition across the basin (Paleocene and Oligocene). Latest Eocene to Oligocene subsidence of the Mackenzie delta resulted from local thrust and sediment loading.