Methane-seep brachiopod fauna within turbidites of the Sinaia Formation, Eastern Carpathian Mountains, Romania

Author(s)

Michael R. Sandy, Iuliana Lazar, Jörn Ludwig Peckmann, Daniel Birgel-Rennebeck, Marius Stoica, Relu Roban

Abstract

This study elucidates the paleoecology and paleobiogeography of the Early Cretaceous brachiopod Peregrinella

known in museum collections from a few localities in Romania, supplemented with new material from a rediscovered

locality firstmentioned in the 1870s.Most Peregrinella fossils are enclosed in mass waste deposits, but at

two sites authigenic limestones with assemblages of brachiopods preserved in life position have been recognized.

Paleontological, petrographic, stable isotopic, and organic geochemical investigations of these

brachiopod-bearing limestones from the Upper Sinaia Formation, Eastern CarpathianMountains, Romania, confirm

Peregrinella as having lived at methane seeps in a siliciclastic-dominated flysch basin. The seeps developed

on the slope of the External Dacides Basin. The new collections of Peregrinella indicate that shells derived from

contemporaneous intrabasin methane seeps and were transported downslope by turbidity currents. Previous

paleoecological models that consider Peregrinella to be solely derived from transport downslope from shelf environments

are questionable especially as Peregrinella has never been recovered from typical shelf faunas; in

the instance documented here fromthe External Dacides Basin methane-seep faunas with Peregrinella are likely

to be the origin of such allochthonous faunas. The Sinaia Formationwas deposited in a deep-water marine basin,

derived from an intracontinental rift that developed during Late Jurassic-Early Cretaceous extension. The fractured

and faulted basin margin provided the backdrop for the development of the methane seepage and the associated

fauna. Foraminifera from background sediments in the sequence with turbidites confirm a late

Hauterivian to early Barremian age for Peregrinella within the Sinaia Formation. This is significant because it indicates

that Peregrinella ranged through into the Barremian, whereas it has typically been considered to range

only as high as the Hauterivian.

Organisation(s)

Department of Geology

External organisation(s)

University of Dayton, University of Bucharest

Journal

Palaeogeography, Palaeoclimatology, Palaeoecology

Pages

42-59

No. of pages

18

ISSN

0031-0182

Publication date

2012

Peer reviewed

Yes

Austrian Fields of Science 2012

105121 Sedimentology, 105105 Geochemistry, 105101 General geology

Sustainable Development Goals

SDG 14 - Life Below Water

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