Stable organic carbon isotope stratigraphy across Oceanic Anoxic Event 2 of Demerara Rise, western tropical Atlantic

[ 1] Ocean Drilling Program (ODP) Leg 207 recovered expanded sections of organic-carbon-rich laminated shales on Demerara Rise ( western tropical Atlantic). High-resolution organic carbon isotope and total organic carbon ( TOC) records are presented, which span the Cenomanian-Turonian boundary interval ( CTBI), including the Oceanic Anoxic Event ( OAE) 2, from four sites oriented along a NW striking depth transect. These records represent the first high-resolution carbon isotope records across OAE 2 from the South American margin of the tropical Atlantic. Due to the scarcity of age significant fossils, the main purpose of this study was to develop a detailed carbon isotope stratigraphy in order to correlate the CTBI across the depth transect and to tie this to biostratigraphically well-defined sections in the Western Interior Basin ( Pueblo, USA), boreal shelf seas ( Eastbourne, England), and western Tethys ( Oued Mellegue, Tunisia). All four sections studied document a 6% increase of delta(13)C(org) values at the base of the CTBI, which is followed by an interval of elevated delta(13)C(org) values and a subsequent decrease. Our results supply an important stratigraphic base for subsequent paleoceanographic studies on Late Cenomanian to Early Turonian sediments from Demerara Rise and elsewhere. Components: 4631 words, 4 figures.