| Popis: |
Intervals of faunal turnover in the fossil record are often preserved at unconformities, suggesting that their apparent abruptness is an artifact of geologic discontinuities. A detailed investigation of the Middle Devonian Kacak Bioevents of the Appalachian Basin focused on stratigraphically complete sections of eastern New York State to further elucidate the nature and timing of faunal turnover where not cloaked by an unconformity. The Lower Kacak Bioevent is fairly well constrained to the lower portion of the East Berne Member of the Mount Marion Formation. The Upper Kacak Bioevent is less well constrained to within the middle to upper East Berne Member, however. A thorough dissection of the East Berne Member has yielded the more precise timing of the initial Hamilton Fauna incursion, occurring at the level of the thin, fossiliferous, Dave Elliot Bed (DEB). The occurrence of the goniatite Tornoceras aff. mesopleuron below the DEB constrains the Hamilton incursion to the earliest Givetian age. T... |
