Detailed stable isotope and carbonate records from the upper Maestrichtian-lower Paleocene section of Hole 516F (Leg 72) including the Cretaceous/ Tertiary boundary.

Abstract

A detailed oxygen and carbon isotope study of the section reveals that large isotopic anomalies are clearly associated with the Cretaceous/Tertiary boundary. Across the boundary, the total carbonate content reaches a maximum exceeding 80% before rapidly decreasing in covariance with the carbon isotope record. This strong covariance between delta13C and percent CaCO3 suggests either a significant reduction in primary productivity or a rapid shoaling of the calcium carbonate compensation depth. Importantly, the delta13C record 2 Ma after the Cretaceous/Tertiary boundary remained depleted in 13C by at least 0.5 per mille compared to the late Maestrichtian.-Authors