Dausmann, Veit; Frank, Martin; Gutjahr, Marcus; Rickli, Jörg Dominik (2017): (Table S1) Results of Nd measurements on uncleaned, mixed-planktonic foraminiera, bulk sediment leachates and detrital material. PANGAEA, https://doi.org/10.1594/PANGAEA.871943, Supplement to: Dausmann, V et al. (2017): Glacial reduction of AMOC strength and long term transition in weathering inputs into the Southern Ocean since the Mid Miocene: Evidence from radiogenic Nd and Hf isotopes. Paleoceanography, 32(3), 265-283, https://doi.org/10.1002/2016PA003056
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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.
Latitude: -41.136060 * Longitude: 13.562830
Date/Time Start: 1997-12-17T09:45:00 * Date/Time End: 1997-12-17T23:15:00
Minimum DEPTH, sediment/rock: 0.1450 m * Maximum DEPTH, sediment/rock: 222.0500 m
177-1088B * Latitude: -41.136060 * Longitude: 13.562830 * Date/Time Start: 1997-12-17T09:45:00 * Date/Time End: 1997-12-17T23:15:00 * Elevation: -2081.2 m * Penetration: 129 m * Recovery: 125.55 m * Location: South Atlantic Ocean * Campaign: Leg177 * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 14 cores; 129 m cored; 0 m drilled; 97.3 % recovery
|#||Name||Short Name||Unit||Principal Investigator||Method/Device||Comment|
|1||Sample code/label||Sample label||Dausmann, Veit||ODP sample designation|
|2||Method comment||Method comm||Dausmann, Veit|
|3||DEPTH, sediment/rock||Depth||m||Dausmann, Veit||Geocode|
|4||AGE||Age||ka BP||Dausmann, Veit||Geocode|
|5||Neodymium 143/Neodymium 144||143Nd/144Nd||Dausmann, Veit|
|6||Neodymium 143/Neodymium 144, standard deviation||143Nd/144Nd std dev||±||Dausmann, Veit|
|8||ε-Neodymium, standard deviation||ε-Nd std dev||±||Dausmann, Veit|
|9||Hafnium 176/Hafnium 177||176Hf/177Hf||Dausmann, Veit|
|10||Hafnium 176/Hafnium 177, standard deviation||176Hf/177Hf std dev||±||Dausmann, Veit|
|12||ε-Hafnium, standard deviation||ε-Hf std dev||±||Dausmann, Veit|
|13||Northern Component Water||NCW||%||Dausmann, Veit||NASW = North Atlantic Sourced Water.|
1456 data points