(Table S1) Results of Nd measurements on uncleaned, mixed-planktonic foraminiera, bulk sediment leachates and detrital material

• Main Authors: Dausmann, Veit, Frank, Martin, Gutjahr, Marcus, Rickli, Jörg Dominik
• Format: Dataset
• Language: English
• Published: PANGAEA 2017
• Subjects: 177-1088B; AGE; DEPTH; sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Hafnium-176/Hafnium-177; standard deviation; Joides Resolution; Leg177; Method comment; Neodymium-143/Neodymium-144 ratio; Northern Component Water; Ocean Drilling Program; ODP; Sample code/label; South Atlantic Ocean; ε-Hafnium; ε-Neodymium; Antarc*; Antarctic; NADW; North Atlantic Deep Water; North Atlantic; Southern Ocean
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.871943; https://doi.org/10.1594/PANGAEA.871943

Combined seawater radiogenic hafnium (Hf) and neodymium (Nd) isotope compositions were extracted from bulk sediment leachates and foraminifera of Site 1088, ODP Leg 177, 2082 m water depth on the Agulhas Ridge. The new data provide a continuous reconstruction of long and short-term changes in ocean circulation and continental weathering inputs since the Mid-Miocene. Due to its intermediate water depth the sediments of this core sensitively recorded changes in admixture of North Atlantic Deep Water (NADW) to the Antarctic Circumpolar Current (ACC) as a function of the strength of the Atlantic Meridional Overturning Circulation (AMOC). Nd isotope compositions (epsilon-Nd) range from -7 to -11 with glacial values generally 1 to 3 units more radiogenic than during the interglacials of the Quaternary. The data reveal episodes of significantly increased AMOC strength during late Miocene and Pliocene warm periods whereas peak radiogenic epsilon-Nd values mark a strongly diminished AMOC during the major intensification of Northern Hemisphere Glaciation near 2.8 Ma and in the Pleistocene after 1.5 Ma. In contrast, the Hf isotope compositions (epsilon-Hf) show an essentially continuous evolution from highly radiogenic values of up to +11 during the Miocene to less radiogenic present day values (+2 to +4) during the late Quaternary. The data document a long-term transition in dominant weathering inputs, where inputs from the South America are replaced by those from Southern Africa. Moreover, radiogenic peaks provide evidence for the supply of radiogenic Hf originating from Patagonian rocks to the Atlantic sector of the Southern Ocean via dust inputs.