scholarly journals Influence of the Amazon River on the Nd isotope composition of deep water in the western equatorial Atlantic during the Oligocene–Miocene transition

2016 ◽  
Vol 454 ◽  
pp. 132-141 ◽  
Author(s):  
Joseph A. Stewart ◽  
Marcus Gutjahr ◽  
Rachael H. James ◽  
Pallavi Anand ◽  
Paul A. Wilson
Keyword(s):  
Deep Water ◽  
Isotope Composition ◽  
Amazon River ◽  
Equatorial Atlantic ◽  
Nd Isotope ◽  
Nd Isotope Composition

scholarly journals Glacial–interglacial Nd isotope variability of North Atlantic Deep Water modulated by North American ice sheet

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Ning Zhao ◽  
Delia W. Oppo ◽  
Kuo-Fang Huang ◽  
Jacob N. W. Howe ◽  
Jerzy Blusztajn ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
North Atlantic ◽  
Deep Water ◽  
North American ◽  
Isotope Composition ◽  
Ice Sheet ◽  
North Atlantic Deep Water ◽  
Water Masses ◽  
Nd Isotope ◽  
Nd Isotope Composition

AbstractThe Nd isotope composition of seawater has been used to reconstruct past changes in the contribution of different water masses to the deep ocean. In the absence of contrary information, the Nd isotope compositions of endmember water masses are usually assumed constant during the Quaternary. Here we show that the Nd isotope composition of North Atlantic Deep Water (NADW), a major component of the global overturning ocean circulation, was significantly more radiogenic than modern during the Last Glacial Maximum (LGM), and shifted towards modern values during the deglaciation. We propose that weathering contributions of unradiogenic Nd modulated by the North American Ice Sheet dominated the evolution of the NADW Nd isotope endmember. If water mass mixing dominated the distribution of deep glacial Atlantic Nd isotopes, our results would imply a larger fraction of NADW in the deep Atlantic during the LGM and deglaciation than reconstructed with a constant northern endmember.

Nd isotope composition of the Ediacaran and earliest Cambrian phosphorite nodules and Fe sulphide from the East European Platform

2020 ◽  
Vol 157 (12) ◽  
pp. 2081-2088
Author(s):  
Sergey B Felitsyn ◽  
Eugeny S. Bogomolov
Keyword(s):  
East European Platform ◽  
Isotope Composition ◽  
Water Reservoir ◽  
Secular Change ◽  
Early Cambrian ◽  
Iron Sulphide ◽  
Nd Isotope ◽  
East European ◽  
Moscow Syneclise ◽  
Nd Isotope Composition

AbstractAn enhanced concentration of phosphorus has been found at the stratigraphic level of the disappearance of Ediacaran taxa in two areas, the Cis-Dniester region and the Moscow syneclise, on the East European Platform (EEP). The isotope composition of neodymium was determined in Fe sulphide and phosphorite in the same beds. Measured εNd(t) values in diagenetic phosphate nodules are similar to those in iron sulphide from the same layer. During the Ediacaran − Early Cambrian, accumulation of radiogenic Nd in the epeiric basins on the EEP increased progressively from −17.9 and −19.4 in pyrite from the sequence bottom to −7.9 and −8.5 in the Early Cambrian pyrite of the central part of the EEP. The Ediacaran phosphate nodules show εNd(t) ranging from −12.9 to −15.0, while that in the Early Cambrian nodules is typically c. −9.0. These data indicate the secular change in Nd isotope composition of the water reservoir on the EEP from Ediacaran to Cambrian.

Nd isotope composition of seep carbonates: Towards a new approach for constraining subseafloor fluid circulation at hydrocarbon seeps

2019 ◽  
Vol 503 ◽  
pp. 40-51 ◽  
Author(s):  
Michal Jakubowicz ◽  
Jolanta Dopieralska ◽  
Andrzej Kaim ◽  
Petr Skupien ◽  
Steffen Kiel ◽  
...  
Keyword(s):  
Isotope Composition ◽  
Fluid Circulation ◽  
Nd Isotope ◽  
New Approach ◽  
Hydrocarbon Seeps ◽  
Nd Isotope Composition

The 2405 Ma and 2310 Ma Mafic Dyke Swarms in the Karelian Craton: Age, Chemical and Sr-Nd Isotope Composition, and Tectonic Setting

2016 ◽  
Vol 90 (s1) ◽  
pp. 123-123
Author(s):  
A.V. Stepanova ◽  
E.B. Salnikova ◽  
A.V. Samsonov ◽  
Yu.O. Larionova ◽  
S.V. Egorova ◽  
...  
Keyword(s):  
Isotope Composition ◽  
Tectonic Setting ◽  
Mafic Dyke ◽  
Karelian Craton ◽  
Nd Isotope ◽  
Dyke Swarms ◽  
Nd Isotope Composition

Change of Sm-Nd isotope composition during weathering of till

2000 ◽  
Vol 64 (5) ◽  
pp. 813-820 ◽  
Author(s):  
Björn Öhlander ◽  
Johan Ingri ◽  
Magnus Land ◽  
Hans Schöberg
Keyword(s):  
Isotope Composition ◽  
Nd Isotope ◽  
Nd Isotope Composition

The tectonic setting of the eastern margin of the Sino-Korean Block inferred from detrital zircon U–Pb age and Nd isotope composition of the Pyeongan Supergroup (upper Palaeozoic – Lower Triassic), Korea

2017 ◽  
Vol 156 (3) ◽  
pp. 471-484 ◽  
Author(s):  
MUN GI KIM ◽  
YONG IL LEE ◽  
TAEJIN CHOI ◽  
YUJI ORIHASHI
Keyword(s):  
Detrital Zircon ◽  
Isotope Composition ◽  
Tectonic Setting ◽  
Active Continental Margin ◽  
Lower Triassic ◽  
Zircon Age ◽  
Nd Isotope ◽  
Eastern Margin ◽  
Late Palaeozoic ◽  
Nd Isotope Composition

AbstractThe upper Palaeozoic succession (Pyeongan Supergroup) in central eastern Korea is well correlated with the equivalent successions distributed in North China, suggestive of the Korean upper Palaeozoic being part of the Sino-Korean Block. Detrital zircon U–Pb ages and Sm–Nd isotope compositions of the Pyeongan Supergroup in the Samcheok coalfield of the Taebaeksan Basin were analysed. A single predominant zircon age peak at c. 1.9 Ga (> 70%) is marked in all sedimentary units, followed by varying amounts of minor late Palaeozoic grains (up to 30%). The rarity of Meso- to Neoproterozoic- and Silurian-aged zircons confirms that sediment influx from the South China and Qinling blocks was insignificant. The 2.0–1.8 Ga-dominated zircon age pattern and the Nd isotope composition (average εNd(0) = −15.5±4.0) of the Pyeongan Supergroup most closely reflect the signature of the Yeongnam Massif basements, which supports a previous hypothesis that the Pyeongan Supergroup was mostly derived from a palaeo-orogen located to the east–southeast. Relatively higher εNd(0) values (> −10.1) in the lowermost and the upper parts of the succession are closely matched by the increased occurrence of syn-depositional-aged zircons, which indicates considerable mixing of juvenile materials at c. 320 Ma and 260 Ma. Both arc-related magmatic events are interpreted to have been related to oceanic subduction, suggesting that the eastern margin of the Sino-Korean Block was an active continental margin during late Palaeozoic times.

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