Stable carbon and oxygen isotope ratios of foraminifera from Cretaceous and Paleocene sediments

• Main Authors: Boersma, Anne, Shackleton, Nicholas J, Hall, Michael A, Given, Quentin
• Format: Dataset
• Language: English
• Published: PANGAEA 1979
• Subjects: 10-86; 10-94; 10-95; 14-144A; 3-20C; 3-21; 39-356; 39-357; 43-384; 63-472; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Glomar Challenger; Gulf of Mexico/BENCH; Gulf of Mexico/SCARP; Leg10; Leg14; Leg3; Leg39; Leg43; Leg63; North Atlantic/CONT RISE; North Atlantic/RIDGE; North Pacific/PLATEAU; South Atlantic/CONT RISE; South Atlantic/PLATEAU; South Atlantic/VALLEY; Pacific; North Atlantic; Planktonic foraminifera
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.726830; https://doi.org/10.1594/PANGAEA.726830

Detailed analysis of over 200 samples of uppermost Cretaceous and Paleocene sediments from Atlantic Ocean DSDP Sites 384, 86, 95, 152, 144, 20C, 21, 356, 357, and 329 provides new information on the temperature stratification of Paleocene planktonic foraminifera, the temperature and carbon isotopic changes across the Cretaceous/Tertiary boundary, and the fluctuating temperature and carbon isotopic records through the Paleocene ~64.5-54 m.y.). There was a significant temperature rise across the Cretaceous/Tertiary boundary both at the surface and in deep waters of the Atlantic Ocean. This temperature rise occurred before the basal Tertiary 'Globigerina' eugubina Zone, so that in the oldest Paleocene sample yet analyzed from the deep sea (Site 356) temperatures are already three degrees higher at the bottom and at the surface than in the Cretaceous. The temperature rise across the boundaryis more pronounced on the bottom and in samples from higher latitudes. Accompanying the temperature rise across the boundary there is a significant shift in the carbon isotope profile. In the basal Paleocene the foraminifera of the surface zone demonstrate very negative carbon isotope values (unlike in the Cretaceous of today's ocean), while deeper dwelling species have more positive values which then decrease to the bottom. The unusual carbon isotope gradients persist through the first three million years of the Paleocene until towards the top of planktonic foraminiferal Zone P.1 (G. trinidadensis Zone) the foraminifera record a profile more positive at the surface and decreasing towards the bottom (as in today's ocean). During the Paleocene there are two noteworthy rises in surface water temperature; the first around 62-61 m.y. (G. trinidadensis Zone), and the second near the base of the Globorotalia angulata Zone, 60-59 m.y. At this time surface temperatures at low to mid latitudes reached values near 25°C, while at mid-latitude Site 384 temperature highs near 22°C were registered. At a sample spacing of around one per million ...