@article {2848,
	title = {A new 30,000-year chronology for rapidly deposited sediments on the Lomonosov Ridge using bulk radiocarbon dating and probabilistic stratigraphic alignment},
	journal = {Geochronology},
	volume = {2},
	year = {2020},
	month = {Jan-01-2020},
	pages = {81 - 91},
	abstract = {We present a new marine chronostratigraphy from a high-accumulation rate Arctic Ocean core at the intersection of the Lomonosov Ridge and the Siberian margin, spanning the last \~{} 30 kyr. The chronology was derived using a combination of bulk 14C dating and stratigraphic correlation to Greenland ice-core records. This was achieved by applying an appositely developed Markov chain Monte Carlo algorithm for Bayesian probabilistic alignment of proxy records. The algorithm simulates depositionally realistic alignments that are consistent with the available radiocarbon age estimates and allows deriving uncertainty bands associated with the inferred alignment. Current composite chronologies from this region are reasonably consistent with our age model during the Holocene and the later part of deglaciation. However, prior to \~{} 14 kyr BP they yield too old age estimates with offsets that linearly increase up to \~{} 40 kyr near the onset of Marine Isotope Stage (MIS) 2. Our results challenge the robustness of previous regional chronostratigraphies and provide a new stratotype for correlation of sediment cores from this sector of the Lomonosov Ridge and East Siberian slope. In particular, they call for a re-interpretation of events in recent sea-ice proxy reconstructions (Xiao et al., 2015) inaccurately attributed to MIS 3 and the Last Glacial Maximum.},
	doi = {10.5194/gchron-2-81-2020},
	url = {https://gchron.copernicus.org/articles/2/81/2020/},
	author = {Muschitiello, Francesco and O{\textquoteright}Regan, Matt and Martens, Jannik and West, Gabriel and Gustafsson, {\"O}rjan and Jakobsson, Martin}
}
@article {2861,
	title = {Early Holocene sea level in the Canadian Beaufort Sea constrained by radiocarbon dates from a deep borehole in the Mackenzie Trough, Arctic Canada},
	journal = {Boreas},
	volume = {47},
	year = {2018},
	month = {Jan-10-2018},
	pages = {1102 - 1117},
	abstract = {Deglacial and Holocene relative sea level (RSL) in the Canadian Beaufort Sea was influenced by the timing and extent of glacial ice in the Mackenzie River corridor and adjacent coastal plains. Considerable evidence indicates extensive ice cover in this region of northwestern Canada during the Late Wisconsinan. However, no absolute ages exist to constrain maximum RSL lowering before the late Holocene (4.2{\textendash}0 ka). In 1984, the Geological Survey of Canada drilled an 81.5-m-deep borehole in the western Mackenzie Trough at 45 m water depth (MTW01). The lower 52.5 m of the borehole was interpreted as a deltaic progradational sequence deposited during a period of rising sea level. The upper 29 m was described as foraminifer-bearing marine sediments deposited after transgression of the site, when RSL rose above ~-74 m. Here, we present radiocarbon measurements from MTW01, acquired from benthic foraminifera, mollusc fragments and particulate organic carbon in the >63 μm fraction (POC>63 μm) in an attempt to constrain the chronology of sediments within this borehole and date the timing of transgression. The deepest carbonate macrofossil was acquired from 8 m above the transgressive surface (equivalent to 21 m b.s.l.), where mollusc fragments returned a date of 9400 +180{\textendash}260 cal. a BP (2σ). This provides the oldest constraint on Holocene sea-level lowering in the region, and implies that transgression at this site occurred prior to the early Holocene. Ages obtained from the lower 52.5 m of the borehole are limited to POC>63 μm samples. These indicate that progradational sediments were deposited rapidly after 24 820 +390{\textendash}380 cal. a BP (2σ). Due to the incorporation of older reworked organic matter, the actual age of progradation is likely to be younger, occurring after Late Wisconsinan glacial ice retreated from the coast.},
	doi = {10.1111/bor.12335},
	url = {https://onlinelibrary.wiley.com/doi/10.1111/bor.12335},
	author = {O{\textquoteright}Regan, Matt and Coxall, Helen and Hill, Philip and Hilton, Robert and Muschitiello, Francesco and Sw{\"a}rd, Henrik}
}
@article {2740,
	title = {The 3.6 ka Aniakchak tephra in the Arctic Ocean: a constraint on the Holocene radiocarbon reservoir age in the Chukchi Sea},
	journal = {Climate of the Past},
	volume = {13},
	year = {2017},
	month = {Jan-01-2017},
	pages = {303 - 316},
	abstract = {The caldera-forming eruption of the Aniakchak volcano in the Aleutian Range on the Alaskan Peninsula at 3.6 cal kyr BP was one of the largest Holocene eruptions worldwide. The resulting ash is found as a visible sediment layer in several Alaskan sites and as a cryptotephra on Newfoundland and Greenland. This large geographic distribution, combined with the fact that the eruption is relatively well constrained in time using radiocarbon dating of lake sediments and annual layer counts in ice cores, makes it an excellent stratigraphic marker for dating and correlating mid{\textendash}late Holocene sediment and paleoclimate records. This study presents the outcome of a targeted search for the Aniakchak tephra in a marine sediment core from the Arctic Ocean, namely Core SWERUS-L2-2-PC1 (2PC), raised from 57 m water depth in Herald Canyon, western Chukchi Sea. High concentrations of tephra shards, with a geochemical signature matching that of Aniakchak ash, were observed across a more than 1.5 m long sediment sequence. Since the primary input of volcanic ash is through atmospheric transport, and assuming that bioturbation can account for mixing up to ca. 10 cm of the marine sediment deposited at the coring site, the broad signal is interpreted as sustained reworking at the sediment source input. The isochron is therefore placed at the base of the sudden increase in tephra concentrations rather than at the maximum concentration. This interpretation of major reworking is strengthened by analysis of grain size distribution which points to ice rafting as an important secondary transport mechanism of volcanic ash. Combined with radiocarbon dates on mollusks in the same sediment core, the volcanic marker is used to calculate a marine radiocarbon reservoir age offset ΔR = 477 {\textpm} 60 years. This relatively high value may be explained by the major influence of typically "carbon-old" Pacific waters, and it agrees well with recent estimates of ΔR along the northwest Alaskan coast, possibly indicating stable oceanographic conditions during the second half of the Holocene. Our use of a volcanic absolute age marker to obtain the marine reservoir age offset is the first of its kind in the Arctic Ocean and provides an important framework for improving chronologies and correlating marine sediment archives in this region. Core 2PC has a high sediment accumulation rate averaging 200 cm kyr throughout the last 4000 years, and the chronology presented here provides a solid base for high-resolution reconstructions of late Holocene climate and ocean variability in the Chukchi Sea.},
	doi = {10.5194/cp-13-303-2017},
	url = {https://cp.copernicus.org/articles/13/303/2017/},
	author = {Pearce, Christof and Varhelyi, Aron and Wasteg{\r a}rd, Stefan and Muschitiello, Francesco and Barrientos, Natalia and O{\textquoteright}Regan, Matt and Cronin, Thomas M. and Gemery, Laura and Semiletov, Igor and Backman, Jan and Jakobsson, Martin}
}
@article {2741,
	title = {The De Long Trough: a newly discovered glacial trough on the East Siberian continental margin},
	journal = {Climate of the Past},
	volume = {13},
	year = {2017},
	month = {Jan-01-2017},
	pages = {1269 - 1284},
	abstract = {Ice sheets extending over parts of the East Siberian continental shelf have been proposed for the last glacial period and during the larger Pleistocene glaciations. The sparse data available over this sector of the Arctic Ocean have left the timing, extent and even existence of these ice sheets largely unresolved. Here we present new geophysical mapping and sediment coring data from the East Siberian shelf and slope collected during the 2014 SWERUS-C3 expedition (SWERUS-C3: Swedish {\textendash} Russian {\textendash} US Arctic Ocean Investigation of Climate-Cryosphere-Carbon Interactions). The multibeam bathymetry and chirp sub-bottom profiles reveal a set of glacial landforms that include grounding zone formations along the outer continental shelf, seaward of which lies a  >  65 m thick sequence of glacio-genic debris flows. The glacial landforms are interpreted to lie at the seaward end of a glacial trough {\textendash} the first to be reported on the East Siberian margin, here referred to as the De Long Trough because of its location due north of the De Long Islands. Stratigraphy and dating of sediment cores show that a drape of acoustically laminated sediments covering the glacial deposits is older than \~{} 50 cal kyr BP. This provides direct evidence for extensive glacial activity on the Siberian shelf that predates the Last Glacial Maximum and most likely occurred during the Saalian (Marine Isotope Stage (MIS) 6).},
	doi = {10.5194/cp-13-1269-2017},
	url = {https://cp.copernicus.org/articles/13/1269/2017/},
	author = {O{\textquoteright}Regan, Matt and Backman, Jan and Barrientos, Natalia and Cronin, Thomas M. and Gemery, Laura and Kirchner, Nina and Mayer, Larry A. and Nilsson, Johan and Noormets, Riko and Pearce, Christof and Semiletov, Igor and Stranne, Christian and Jakobsson, Martin}
}
@article {2739,
	title = {Deglacial sea level history of the East Siberian Sea and Chukchi Sea margins},
	journal = {Climate of the Past},
	volume = {13},
	year = {2017},
	month = {Jan-01-2017},
	pages = {1097 - 1110},
	abstract = {Deglacial (12.8{\textendash}10.7 ka) sea level history on the East Siberian continental shelf and upper continental slope was reconstructed using new geophysical records and sediment cores taken during Leg 2 of the 2014 SWERUS-C3 expedition. The focus of this study is two cores from Herald Canyon, piston core SWERUS-L2-4-PC1 (4-PC1) and multicore SWERUS-L2-4-MC1 (4-MC1), and a gravity core from an East Siberian Sea transect, SWERUS-L2-20-GC1 (20-GC1). Cores 4-PC1 and 20-GC were taken at 120 and 115 m of modern water depth, respectively, only a few meters above the global last glacial maximum (LGM;  \~{}  24 kiloannum or ka) minimum sea level of  \~{}  125{\textendash}130 meters below sea level (m b.s.l.). Using calibrated radiocarbon ages mainly on molluscs for chronology and the ecology of benthic foraminifera and ostracode species to estimate paleodepths, the data reveal a dominance of river-proximal species during the early part of the Younger Dryas event (YD, Greenland Stadial GS-1) followed by a rise in river-intermediate species in the late Younger Dryas or the early Holocene (Preboreal) period. A rapid relative sea level rise beginning at roughly 11.4 to 10.8 ka ( \~{}  400 cm of core depth) is indicated by a sharp faunal change and unconformity or condensed zone of sedimentation. Regional sea level at this time was about 108 m b.s.l. at the 4-PC1 site and 102 m b.s.l. at 20-GC1. Regional sea level near the end of the YD was up to 42{\textendash}47 m lower than predicted by geophysical models corrected for glacio-isostatic adjustment. This discrepancy could be explained by delayed isostatic adjustment caused by a greater volume and/or geographical extent of glacial-age land ice and/or ice shelves in the western Arctic Ocean and adjacent Siberian land areas.},
	doi = {10.5194/cp-13-1097-2017},
	url = {https://cp.copernicus.org/articles/13/1097/2017/},
	author = {Cronin, Thomas M. and O{\textquoteright}Regan, Matt and Pearce, Christof and Gemery, Laura and Toomey, Michael and Semiletov, Igor and Jakobsson, Martin}
}
