INTRODUCTION

A greatly expanded sedimentary sequence of virtually continuous Cretaceous black shales characterized by moderately enriched total organic carbon (TOC) contents (mostly 2 wt%) was cored at Ocean Drilling Program Leg 210 Site 1276. The sequence extends from the lowermost Albian, or possibly uppermost Aptian, to the Cenomanian/Turonian boundary and is considered to be equivalent to the Hatteras Formation (Jansa et al., 1979). Based on preliminary geochemical analyses and palynological data, much of the organic matter preserved in these hemipelagic and turbiditic sediments is likely of terrigenous origin and was deposited under dysoxic/anoxic conditions (Shipboard Scientific Party, 2004).

The mid-Cretaceous (~124–90 Ma) was characterized by warm global climate and rising sea level (e.g., Wilson and Norris, 2001). Periodically, organic carbon–rich black shales were deposited in response to the development of dysoxic and anoxic conditions in oxygen-minimum zones along the continental margins of the tropical Tethys Sea, in restricted epicontinental seas, and in basins of the widening North and South Atlantic.

The Cretaceous sequence recovered during Leg 210 includes six sedimentary intervals with high TOC contents, in several instances of probable marine origin, which may record oceanic anoxic events (OAEs). These include the Cenomanian–Turonian OAE 2 ("Bonarelli" event); the "mid-Cenomanian" event; and OAE 1b ("Paquier" event), 1c, and 1d in the Albian (Leckie et al., 2002, and references therein). In addition, another interval with OAE-like geochemical characteristics and located between OAEs 1c and 1b was recognized in the Albian, although it does not correspond to any of the known OAEs.

The recovery of sediments geochemically comparable to OAE-related black shales in the Newfoundland Basin is especially important in that it allows the investigation of paleoceanographic links between this part of the expanding Cretaceous North Atlantic and the rest of the world ocean. Here we report the results of shorebased analyses of the carbon and nitrogen stable isotope compositions of organic matter, rock-eval pyrolysis of bulk organic matter, and major and trace metal compositions of whole-sediment samples.