A two-phase Mammalian Dispersal Event across the Paleocene–Eocene transition
Hooker, J. J.
Newsletters on Stratigraphy Volume 48 Number 2 (2015), p. 201 - 220
published: Apr 1, 2015
ArtNo. ESP026004802006, Price: 29.00 €
Biostratigraphy of 11 geographically isolated Late Paleocene and earliest Eocene mammal faunas in NW Europe, using parsimony analysis of shared taxa, confirms an earlier study that recognized two time successive biozones (PE I and II) across the Paleocene–Eocene transition. Calibration of PE II to onset of the Carbon Isotope Excursion (CIE), plus regional correlation using non-mammal biostratigraphy and other chemostratigraphical evidence, shows that mammals of biozone PE I are latest Paleocene in age. PE I records the Mammalian Dispersal Event (MDE), which brings the first primates, artiodactyls and perissodactyls into the Northern Hemisphere continents and carnivorans and rodents into Europe. The MDE has previously been directly linked to CIE onset in North America and therefore to the Paleocene–Eocene boundary. The new dating of the MDE in NW Europe as latest Paleocene means that the first appearance of orders Primates, Artiodactyla and Perissodactyla is instead latest Paleocene and that the MDE occurred in two phases. Phase 1 brought these new orders to Europe from mid-latitude Asia, plus rodents and extinct groups from high latitude North America and low latitude Africa. Phase 2 brought these new orders into North America from Europe and a few additional taxa to Europe from North America at the beginning of the Eocene. Low sea-levels at the Th-5 sequence boundary in the latest Paleocene allowed phase 1 dispersal into Europe, but it was not until the beginning of the Eocene that warming at the Paleocene–Eocene Thermal Maximum allowed phase 2 high latitude dispersal of lower latitude-originating faunas.