Tectonically driven changes in the Indian Ocean circulation over the last 25 Ma: Neodymium isotope evidence

Indian Ocean circulation and productivity during the last glacial cycle

“…Thirdly, it is not likely that local changes in seawater Nd isotopic composition affected (Stoll et al, 2007), and the acid-leachable component of bulk sediments (Gourlan et al, 2008) from the Bengal fan, both interpreted as near-surface water compositions, show Holocene and glacial Nd isotopic compositions which are very similar to those we have measured in the leached Fe−Mn oxides from SK129−CR2. If the records of (Gourlan et al, 2008;Stoll et al, 2007) are being correctly interpreted as recording surface water, this may suggest that surface and deep waters in the equatorial Indian Ocean have no Nd isotope gradient and that surface and deep waters changed in a similar way at these locations on glacial−interglacial timescales.…”

“…If the records of (Gourlan et al, 2008;Stoll et al, 2007) are being correctly interpreted as recording surface water, this may suggest that surface and deep waters in the equatorial Indian Ocean have no Nd isotope gradient and that surface and deep waters changed in a similar way at these locations on glacial−interglacial timescales. Although nearby seawater Nd isotopic compositions are yet to be measured, it seems highly unlikely that local Ganges−Brahmaputra river outflow and global deep-ocean circulation changed in unison to give the same Nd isotopic composition.…”

Late Cenozoic history of deep water circulation in the western North Pacific: Evidence from Nd isotopes of ferromanganese crusts

“…Finally, Nd isotopes extracted from the carbonate fraction of site 807 (3°4′N, 156°4′E, 2815 m) [55], which located directly east of the Indonesian islands, displayed a similar evolution pattern as that of crust MDD53 (Figure 4(b)), i.e. an abrupt increase in  Nd during the Pliocene and a small overall shift in Nd isotopes from ~15 to 5 Ma.…”

“…We therefore suggest that the low  Nd values of MKD13 in the early Miocene indicated the presence of direct supply of less radiogenic Nd isotopic southern component surface and middle water [55] via the Indonesian gateway. Such scenario was also proposed by Meynadier et al [62].…”

“…(a) Shallower crust MKD13 and D11-1 (Nd isotope data for D11-1 is from Ling et al [6], and the age data is based on 10 Be dating and minorly revised according to Tl isotope stratigraphy [53]). (b) Deeper cust MDD53 and carbonate fraction of the western equatorial sediment core Site 807 [55].…”