Secular Variation of Iron Isotopes in North Atlantic Deep Water

Abstract

A high-precision iron isotope time series for a ferromanganese crust demonstrates that the iron isotope composition in North Atlantic Deep Water has changed substantially over the past 6 million years and that iron isotope variations in the crust are closely correlated to those of lead isotopes. The close correlation between the two isotope series indicates that the observed iron isotope variations predominantly reflect those of iron input from terrigenous sources and provides no evidence for biologically induced mass fractionation within North Atlantic Deep Water.

Evidence for hydrothermal venting in Fe isotope compositions of the deep Pacific Ocean through time

“…1), which shows close correlations between Fe and Pb isotope compositions, particularly over the past 1 Ma. However, Levasseur et al [12] have recently re-analysed the 3 top-most layers from the same crust and failed to find any δ 56 Fe values > − 0.4‰, contrary to the prior analysis by Zhu et al [11], although the Pb isotope compositions in both studies agreed. The origin of this discrepancy remains unknown, and further studies of temporal Fe isotope variations in the North Atlantic Ocean are needed.…”

“…9 Be concentrations were obtained from the same aliquots by ICP-MS (PlasmaQuad 2+, VG Elemental) at the National Oceanography Centre, Southampton (NOCS). For sample D105-5AB, 10 Be (1) two ODP TMAR records at site 803 [64] and site 871 [65] and (2) FeMn crust from the North Atlantic Ocean (BM1969.05) that Zhu et al [11] have previously studied for temporal Fe isotope variations. Modern dust source regions and wind trajectories [14] are labelled in grey shaded areas and solid arrows.…”

“…To date, only one marine Fe isotope time-series is available from the NW Atlantic Ocean [11] (Fig. 1), which shows close correlations between Fe and Pb isotope compositions, particularly over the past 1 Ma.…”

Cu isotopic compositions in Elsholtzia splendens: Influence of soil condition and growth period on Cu isotopic fractionation in plant tissue

“…The Cu isotopic ratio ( 65 Cu/ 63 Cu) of purified samples was determined by ICP-MS (Nu Plasma HR MC-ICP-MS, Nu Instruments, UK), and mass bias was corrected through standard-sample-standard bracketing Zhu et al, 2000). …”

Fe Isotopic Compositions of Modern Seafloor Hydrothermal Systems and Their Influence Factors

“…The range of Fe isotope compositions of seawater is from −0.64‰ to 0.80‰, with an average 56 ; the black rectangle shows the average value of 56 Fe. All data from the literatures: river [3,4,11,12]; ocean water [13][14][15][16]; oceanic sediment [6,7,12,17]; hydrothermal sulfide [6,[18][19][20]; hydrothermal fluid [6,7,[19][20][21]; Fe-Mn noddle and crust [8,[22][23][24]; deposit [25][26][27][28][29][30][31]; banded Fe formations [32][33][34][35][36][37][38][39][40][41][42]; carbonate rock [36,43,44]; loess/dust [6,…”