THE PALEOECOLOGIC, PALEOBIOGEOGRAPHIC, AND BIOSTRATIGRAPHIC SIGNIFICANCE OF THE EARLY CRETACEOUS RHYNCHONELLID BRACHIOPOD PEREGRINELLA FROM THE SOUTHERN CARPATHIAN MOUNTAINS, ROMANIA

The Early Cretaceous rhynchonellid brachiopod Peregrinella has been recorded from disjunct localities in southern Europe (Tethys), Tibet, California, and Alaska. This enigmatic paleobiogeographic distribution has drawn considerable attention over the past five decades. In addition, Peregrinella is one of the largest post-Paleozoic brachiopods (up to 10 cm in maximum width and length) and a brachiopod of innate beauty. The disjunct distribution of Peregrinella in marine, non-shelf settings has been variously accounted for by sporadic shallowing of deep water basins (e.g., Vocontian Trough of southern France) or the preservation of shallow-water limestones as transported blocks (olistoliths) from shallower-water environments. However Peregrinella has never, to our knowledge, been recorded from normal shallow-marine settings that contain “typical” (i.e., multi-species) shallow-water brachiopod faunas. It occurs in monospecific brachiopod occurrences. In the last decade paleontologic, stratigraphic, sedimentologic, and stable isotope geochemistry has pointed to Peregrinella being an associate of chemosynthetic environments (Campbell, Carlson, and Bottjer, 1993; Campbell and Bottjer, 1995; Sandy 1995) including cold-seeps and carbonates developed associated with serpentinintes. The occurrence of the brachiopod Peregrinella in Romania is known from the Neocomian flysch deposits included within the Sinaia Formation. These deposits belong to the sedimentary cover of the Ceahlau Nappe of the External Dacides – Carpathian Orogen. The brachiopod Peregrinella was mentioned in the Romanian geological literature by Herbich, 1878; Jekelius, 1915, 1917, 1938; Selegian, 1927, Patulius, Dimitrescu, and Gherasi, 1968; Gräf, 1975. There appear to be at least two localities that have yielded Peregrinella. The occurrence of Peregrinella has biostratgigraphic importance in the Sinaia Formation indicating an Early Cretaceous age within the flysch. We will also present results of investigations of the carbonate sedimentology and stable isotope geochemistry associated with Peregrinella. The Peregrinella–bearing carbonate represents the first record of a fossiliferous chemosynthetic environment from Romania. MRS acknowledges the American Chemical Society Petroleum Research Fund.