The Albian to Turonian record of IODP Site U1407 (SE Newfoundland Ridge)

Abstract

At IODP Site U1407 (SE Newfoundland Ridge, IODP Expedition 342) a 270-m-thick sedimentary succession of Cretaceous and Paleogene age has been recovered. The two holes U1407A and B contain the transition from the reef basement to fine grained (hemi-)pelagic marls at ~270 mCCSF. The basal, incomplete short-cores of these two holes revealed a number of shallow-water fossils such as gastropods, corals, rudists and larger foraminifera (orbitulinids; Norris et al., 2014) from the top of the reef. In addition, a well-developed Cenomanian-Turonian Boundary (CTB) with its typical black shale expression of the Oceanic Anoxic Event 2 is represented in the cores. Here, we present a high-resolution carbon isotope record of the 40-m-thick succession from the top of the reef to the bathyal CTB black shales. Beside the typical δ13C anomalies associated with the CTB we identified the decline of δ13C values related to the top of the Albian-Cenomanian boundary interval and the Mid-Cenomanian Event. We further present new biostratigraphic results based on calcareous nannofossils as well as 87Sr/86Sr isotope ages for the top of the reef analyzed on Orbitulina. These new data in combination with the identified, stratigraphically well-calibrated events allow for a detailed comparison with other mid-Cretaceous records around the world and provide new insights into the subsidence history of the western Atlantic margin off Newfoundland.Reference:Norris, R.D., et al. 2014. Site U1407. Proceedings of the Integrated Ocean Drilling Program, Volume 342, doi:10.2204/iodp.proc.342.108.2014.