Stable carbon isotope record of Bahama Bank sediments

The carbon-isotopic composition (d13C) of bulk carbonates, obtained from a transect of sites drilled through platform and periplatform sediments of Holocene to Early Miocene age, has been compared to ascertain whether changes in the d13C can be correlated between sediments of equivalent ages and whether such changes can be related to global changes in the d13C of the dissolved inorganic carbon in the oceans over this time period.

Five of the sites were drilled during Leg 166 of the Ocean Drilling Project (1003–1007) in a transect ranging from five km to 25 km away from the platform margin and penetrating sediments of Holocene to Oligocene age that are contained in 17 depositional sequences (A–Q). Two shallow-water sites, Clino and Unda were situated on a extension of the same transect on Great Bahama Bank in a water depth of 10–15 m. With the exception of Unda and Clino, the d13C of the carbonates ranges from +5 per mil in the younger sequences to +1 per mil in the Early Miocene.