Comparing dust flux records from the Subarctic North Pacific and Greenland: Implications for atmospheric transport to Greenland and for the application of dust as a chronostratigraphic tool

Abstract

We present a new record of eolian dust flux to the western Subarctic North Pacific (SNP) covering the past 27,000 years based on a core from the Detroit Seamount. Comparing the SNP dust record to the North Greenland Ice Core Project (NGRIP) ice core record shows significant differences in the amplitude of dust changes to the two regions during the last deglaciation, while the timing of abrupt changes is synchronous. If dust deposition in the SNP faithfully records its mobilization in East Asian source regions, then the difference in the relative amplitude must reflect climate-related changes in atmospheric dust transport to Greenland. Based on the synchronicity in the timing of dust changes in the SNP and Greenland, we tie abrupt deglacial transitions in the 230 Th-normalized 4 He flux record to corresponding transitions in the well-dated NGRIP dust flux record to provide a new chronostratigraphic technique for marine sediments from the SNP. Results from this technique are complemented by radiocarbon dating, which allows us to independently constrain radiocarbon paleoreservoir ages. We find paleoreservoir ages of 745 ± 140 years at 11,653 year B.P., 680 ± 228 years at 14,630 year B.P., and 790 ± 498 years at 23,290 year B.P. Our reconstructed paleoreservoir ages are consistent with modern surface water reservoir ages in the western SNP. Good temporal synchronicity between eolian dust records from the Subantarctic Atlantic and equatorial Pacific and the ice core record from Antarctica supports the reliability of the proposed dust tuning method to be used more widely in other global ocean regions.

Paleodust variability since the Last Glacial Maximum and implications for iron inputs to the ocean

“…Our simulations capture the trends in observed dust deposition in Greenland (Figure e) and Antarctica (Figure f), but not all the details, because the model was constrained with a larger data set [ Albani et al ., , ]. The simulated LGM/Holocene dust deposition ratio is ~4 for GISP2, compared to ~17 from the observations (average 19–23 ka BP) for the LGM [ Mayewski et al ., ], which may be substantially influenced by changes in atmospheric circulation [ Serno et al ., ] that are not captured by the model. At Dome C, the simulated LGM/Holocene ratio is larger (~10) but still less than the observations (~25) [ Delmonte et al ., ].…”

Centennial to millennial climate variability in the far northwestern Pacific (off Kamchatka) and its linkage to the East Asian monsoon and North Atlantic from the Last Glacial Maximum to the early Holocene

“…The sequence of centennial events of increased productivity seems to have occurred in phase with decreasing PM in both cores (Fig. 3), indicating a weakening of eolian dust transportation by atmospheric circulation in the study area likely due to climate warming, analogous with millennialscale forcing of dust transportation into the NW Pacific (Serno et al, 2015). Within the constructed age model of core 41-2, different productivity proxies and magnetic records, combined with similar data from core 12KL (Max et al, 2012(Max et al, , 2014) reveal a sequence of noticeable centennial events of increased productivity in the NW Pacific which occurred in phase with Chinese sub-interstadials (CsI) associated with stronger EASM or weaker EAWM (Wang et al, 2008) and changes in atmospheric circulation during 21-8 ka (Figs.…”

“…The sediment paramagnetic magnetization (PM) was formed in marine sediments in the open NW Pacific by silicate, paramagnetic iron sulfide (FeS), and fine clay minerals, the main part of which was transported from land as an eolian dust through atmospheric circulation by westerly jets (Serno et al, 2015). Therefore, the sediment PM may serve as a proxy for the land aridity and atmosphere circulation pattern changes.…”

“…By comparing the dust content in the North Greenland Ice Core Project (NGRIP) ice core with that of the dust record in a sediment core from the subarctic N Pacific, Serno et al (2015) demonstrated synchronicity of millennial-scale changes in atmospheric circulation between the N Pacific and the Greenland during the last 27 kyr (Serno et al, 2015). Previous studies also found the occurrence of increased export of productivity during the period of millennial-scale climate and environmental ameliorations, correlated with DO interstadials, in the Okhotsk and Bering seas Kim et al, 2011;Riethdorf et al, 2013;Seki et al, 2004).…”

Paleoproductivity and Stratification Across the Subarctic Pacific Over Glacial‐Interglacial Cycles

“…High dust fluxes during glacial periods (e.g., McGee et al, ; Serno et al, ; Serno et al, ; Winckler et al, ) would have likely increased surface iron concentrations, a boon to iron‐limited waters that would have promoted high productivity, rather than the low productivity that is actually observed. The combination of low glacial productivity (Figure ), high iron availability, and high nutrient utilization (Ren et al, ) indicates reduced nutrient supply to the euphotic zone during glacial periods (Jaccard et al, ), which may have evolved as result of several possible mechanisms.…”