Stable isotope and Mg/Ca ratio of sediment core GeoB12610-2, supplement to: Rippert, Nadine; Baumann, Karl-Heinz; Pätzold, Jürgen (2015): Thermocline fluctuations in the western tropical Indian Ocean during the past 35 ka. Journal of Quaternary Science, 30(3), 201-210


To reconstruct the still poorly understood thermocline fluctuations in the western tropical Indian Ocean, a sediment core located off Tanzania (GeoB12610-2; 04°49.00'S, 39°25.42'E, 399 m water depth) covering the last 35 ka was analysed. Mg/Ca-derived temperatures from the planktonic foraminifera Globigerinoides ruber (white) and Neogloboquadrina dutertrei indicate that the last glacial was ~2.5 °C colder in the surface waters and ~3.5 °C colder in the thermocline compared with the present day. The depth of the thermocline and thus the stratification of the water column were shallower during glacial periods and deepened during the deglaciation and Holocene. The increased inflow of Southern Ocean Intermediate Waters via 'ocean tunnels' appears to cool the thermocline from below, leading to a similarity between the thermocline record of GeoB12610-2 with the Antarctic EDML temperature curve during the glacial. With rising sea level and the corresponding greater inflow of Red Sea Waters and Indonesian Intermediate Waters, the proportion of Southern Ocean Intermediate Water within the South Equatorial Current is reduced and, by Holocene time, the correlation to Antarctica is barely traceable. Comparison with the eastern Indian Ocean reveals that the thermocline depth reverses from the last glacial to present.

Related Identifier
Metadata Access
Creator Rippert, Nadine; Baumann, Karl-Heinz; Pätzold, Jürgen
Publisher PANGAEA - Data Publisher for Earth & Environmental Science
Publication Year 2015
Rights Creative Commons Attribution 3.0 Unported
OpenAccess true
Language English
Resource Type Supplementary Dataset
Format text/tab-separated-values
Size 1258 data points
Discipline Earth System Research
Spatial Coverage (39.424 LON, -4.817 LAT); Pemba Channel