@article {2978,
	title = {Late Holocene Paleomagnetic Secular Variation in the Chukchi Sea, Arctic Ocean},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {23},
	year = {2022},
	month = {05/2022},
	pages = {1-21},
	abstract = {The geomagnetic field behavior in polar regions remains poorly understood and documented. Although a number of Late Holocene paleomagnetic secular variation (PSV) records exist from marginal settings of the Amerasian Basin in the Arctic Ocean, their age control often relies on a handful of radiocarbon dates to constrain ages over the past 4,200 years. Here we present well-dated Late Holocene PSV records from two sediment cores recovered from the Chukchi Sea, Arctic Ocean. The records are dated using 26 14C measurements, with local marine reservoir corrections calibrated using tephra layers from the 3.6 cal ka BP Aniakchak eruption in Northern Alaska. These 14C-based chronologies are extended into the post-bomb era using caesium-137 dating, and mercury isochrons. Paleomagnetic measurements and rock magnetic analyses reveal stable characteristic remanent magnetization directions, and a magnetic mineralogy dominated by low-coercivity minerals. The PSV records conform well to global spherical harmonic field model outputs. Centennial to millennial scale directional features are synchronous between the cores and other Western Arctic records from the area. Due to the robust chronology, these new high-resolution PSV records provide a valuable contribution to the characterization of geomagnetic field behavior in the Arctic over the past few thousand years, and can aid in developing age models for suitable sediments found in this region.},
	doi = {10.1029/2021GC010187},
	url = {https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021GC010187},
	author = {West, Gabriel and Nilsson, Andreas and Geels, Alexis and Jakobsson, Martin and Moros, Matthias and Muschitiello, Francesco and Pearce, Christof and Snowball, Ian and O{\textquoteright}Regan, Matt}
}
@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}
}
