@article {pienkowski_revised_2022, title = {Revised marine reservoir offset (ΔR) values for molluscs and marine mammals from Arctic North America}, journal = {Boreas}, year = {2022}, note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/bor.12606}, month = {11/2022}, abstract = {Appropriate marine{\textendash}terrestrial reservoir offset (ΔR) values are essential for accurate calibration of marine radiocarbon dates. However, ΔR values are only valid for the specific calibration curve that their calculation is based on. Here, we present revised ΔR values for the Marine20 calibration curve from Arctic North America, based on previously published 14C dates on pre-bomb live-collected marine molluscs (n = 124) and cetaceans (beluga whales; tooth dentine; n = 12), and bowhead whale{\textendash}driftwood age comparisons from the same glacio-isostatically uplifted shorelines (n = 18). Molluscan-based ΔR are: Chukchi/Beaufort sea coasts, 265{\textpm}116 14C years; NW Canadian Arctic Archipelago, 188{\textpm}91 14C years; NE Baffin Island, 81{\textpm}18 14C years; SE Baffin Island, 14{\textpm}58 14C years; Hudson Strait, -73{\textpm}64 14C years; Ungava Bay, 0{\textpm}86 14C years; Foxe Basin, 175{\textpm}89 14C years; Hudson Bay, -21{\textpm}72 14C years; James Bay, 209{\textpm}114 14C years; West Greenland, -93{\textpm}111 14C years. Species-specific marine mammal ΔR terms are 107{\textpm}59 14C years for beluga and 24{\textpm}58 14C years for bowheads. Our revised ΔR values are applicable for as long as the same broad oceanographic conditions (circulation, ventilation) have persisted, i.e. through the Holocene. While molluscan values are applicable to other marine carbonate (e.g. foraminifera), cetacean ΔR are valid only for the species they were calculated for and should not be applied to other marine mammals. Importantly, the ΔR terms calculated here are only valid for Marine20 and should not be used with earlier or later calibration curves.}, doi = {https://doi.org/10.1111/bor.12606}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/bor.12606}, author = {Pie{\'n}kowski, Anna J. and Coulthard, Roy D. and Furze, Mark F. A.} } @article {2574, title = {Deglaciation and ice shelf development at the northeast margin of the Laurentide Ice Sheet during the Younger Dryas chronozone}, journal = {Boreas}, year = {2017}, month = {Nov-06-2018}, abstract = {Core 2011804-0010 from easternmost Lancaster Sound provides important insights into deglacial timing and style at the marine margin of the NE Laurentide Ice Sheet (LIS). Spanning 13.2{\textendash}11.0 cal. ka BP and investigated for ice-rafted debris (IRD), foraminifera, biogenic silica and total organic carbon, the stratigraphy comprises a lithofacies progression from proximal grounding line and sub-ice shelf environments to open glaciomarine deposition; a sequence similar to deposits from Antarctic ice shelves. These results are the first marine evidence of a former ice shelf in the eastern Northwest Passage and are consistent with a preceding phase of ice streaming in eastern Lancaster Sound. Initial glacial float-off and retreat occurred >13.2 cal. ka BP, followed by formation of an extensive deglacial ice shelf during the Younger Dryas, which acted to stabilize the retreating margin of the NE LIS until 12.5 cal. ka BP. IRD analyses of sub-ice shelf facies indicate initial high input from source areas on northern Baffin Island delivered to Lancaster Sound by a tributary ice stream in Admiralty Inlet. After ice shelf break-up, Bylot Island became the dominant source area. Foraminifera are dominated by characteristic ice-proximal glaciomarine benthics (Cassidulina reniforme, Elphidium excavatum f. clavata), complemented by advected Atlantic water (Cassidulina neoteretis, Neogloboquadrina pachyderma) and enhanced current indicators (Lobatula lobatula). The biostratigraphy further supports the ice shelf model, with advection of sparse faunas beneath the ice shelf, followed by increased productivity under open water glaciomarine conditions. The absence of Holocene sediments in the core suggests that the uppermost deposits were removed, most likely due to mass transport resulting from the site{\textquoteright}s proximity to modern tidewater glacier margins. Collectively, this study presents important new constraints on the deglacial behaviour of the NE Laurentide Ice Sheet, with implications for past ice sheet stability, ice-rafted sediment delivery, and ice-ocean interactions in this complex archipelago setting.}, doi = {10.1111/bor.12265}, url = {http://doi.wiley.com/10.1111/bor.12265}, author = {Furze, Mark F. A. and {\'n}kowski, Anna J. and McNeely, Morgan A. and Bennett, Robbie and Cage, Alix G.} } @article {41, title = {The late Quaternary environmental evolution of marine Arctic Canada: Barrow Strait to Lancaster Sound}, journal = {Quaternary Science Reviews}, volume = {91}, year = {2014}, pages = {184-203}, abstract = {A marine sediment core from the east-central Canadian Arctic Archipelago (Core 86027-154; 74{\textdegree} 22.01'N 89{\textdegree} 51.26'W; 329 m water depth), studied by a multiproxy approach [lithostratigraphy, biogeochemistry, micropalaeontology (dinoflagellate cysts, other non-pollen palynomorphs, benthic and planktonic foraminifera, ostracods)], and encompassing 14 AMS 14C dates, provides valuable insights into regional deglacial to Holocene palaeoenvironments. Six palaeoenvironmental zones are recognized, based on prominent changes in the litho- and biostratigraphy. The waterlain diamicton of Zone I records immediate deglaciation, being derived from lift-off and calving of previously grounded glacial ice. Though deglacial timing is complicated by the sparsity of dating materials and the Portlandia Effect, age{\textendash}depth model extrapolation places deglaciation at 11.54 cal ka BP. Zone II (11.5{\textendash}11.0 cal ka BP) represents a distinct progression from initially ice-proximal to increasingly ice-distal conditions, interrupted by an interval of pervasive sea-ice (11.4{\textendash}11.2 cal ka BP). Noteworthy biological activity commences in Zone III (11.0{\textendash}9.7 cal ka BP) with a prominent signal of planktonic foraminifera (Neogloboquadrina pachyderma). This likely signifies penetration of deeper, Atlantic-derived water through the central Canadian Arctic Archipelago upon deglaciation, facilitated by the greater, glacioisostatically-induced water depths (+80 m), and implies separation of Laurentide and Innuitian ice sheets by \~{}11.0 cal ka BP. Zone IV (9.7{\textendash}7.2 cal ka BP) records ameliorated, biologically favourable conditions with reduced seasonal sea-ice accompanied by high microfossil species diversity and the presence of subpolar taxa. Zone V (7.2{\textendash}6.5 cal ka BP) signals the exclusion of Atlantic-derived water, concomitant with increasing sea-ice, simultaneously representing the termination of the dynamic deglacial to early Holocene environments (zones I{\textendash}IV). Conditions similar to modern typified by uniform sediment characteristics, present-day microfossil assemblage structures, and sparse benthic foraminifera were established by 5.6 cal ka BP (Zone VI).}, issn = {0277-3791}, doi = {10.1016/j.quascirev.2013.09.025}, url = {http://www.sciencedirect.com/science/article/pii/S0277379113003752}, author = {Pie{\'n}kowski, Anna J. and England, John H. and Furze, Mark F. A. and MacLean, Brian and Blasco, Steve} } @article {64, title = {New cetacean ΔR values for Arctic North America and their implications for marine-mammal-based palaeoenvironmental reconstructions}, journal = {Quaternary Science Reviews}, volume = {91}, year = {2014}, pages = {218-241}, abstract = {Radiocarbon-dated marine mammal remains from emergent Arctic coastlines have frequently been used to reconstruct Holocene sea-ice histories. The use of such reconstructions has hitherto been complicated by uncertain marine reservoir corrections precluding meaningful intercomparisons with data reported in calibrated or sidereal years. Based on an exhaustive compilation of previously published marine mammal radiocarbon dates (both live-harvested materials and subfossils) from the Canadian Arctic Archipelago (CAA), new, statistically-derived δ13C and ΔR values are provided. Average δ13C values are: -16.1 {\textpm} 1.1{\textperthousand} (bone collagen; n = 193) for bowhead (Balaena mysticetus); -14.4 {\textpm} 0.5{\textperthousand} (n = 44; dentine) for beluga (Delphinapterus leucas); -14.8 {\textpm} 1.9{\textperthousand} (teeth and tusks; n = 18) and -18.0 {\textpm} 4.7{\textperthousand} (n = 9; bone collagen) for walrus (Odobenus rosmarus). ΔR values are 170 {\textpm} 95 14C years for bowhead (n = 23) and 240 {\textpm} 60 14C years for beluga (n = 12). Scarce data preclude calculation of meaningful, statistically robust walrus ΔR. Using the new ΔR values, an expanded and revised database of calibrated bowhead dates (651 dates; many used in previous CAA sea-ice reconstructions) shows pronounced late Quaternary spatio-temporal fluctuations in bone abundance. Though broadly resembling earlier bowhead subfossil frequency data, analysis of the new expanded database suggests early- and mid-Holocene increases in whale abundance to be of longer duration and lower amplitude than previously considered. A more even and persistent spread of infrequent low-abundance remains during {\textquotedblleft}whale free{\textquotedblright} intervals is also seen. The dominance of three eastern regions (Prince Regent Inlet \& Gulf of Boothia; Admiralty Inlet; Berlinguet Inlet/Bernier Bay) in the CAA data, collectively contributing up to 88\% of all subfossil remains in the mid-Holocene, is notable. An analysis of calibrated regional sea-level index points suggests that severance of the Admiralty Inlet-Gulf of Boothia marine channel due to isostatically-driven regression may have played a significant role in enhanced whale mortality during this interval. Comparisons between the newly calibrated bowhead data and other regional sea-ice proxy data further highlight spatial and temporal discrepancies, potentially due to regional asynchronicities and variable sensitivities in proxy response to climate and oceanographic forcing. However, the limited number of deglacial{\textendash}postglacial marine records continues to hamper extensive intercomparisons between marine mammal and other proxy datasets. Nevertheless, an examination of assumptions inherent in linking bowhead subfossil frequencies, population densities, and sea-ice thickness and distribution, shows that such relationships are highly complex. Factors such as broad sea-ice preferences, variable mortality rates and causes, long distance carcass transport, variable coastline and basin/channel geometries, and changing emergence rates all complicate the correlation of whale bone abundance to sea-ice histories.}, issn = {0277-3791}, doi = {10.1016/j.quascirev.2013.08.021}, url = {http://www.sciencedirect.com/science/article/pii/S027737911300334X}, author = {Furze, Mark F. A. and Pie{\'n}kowski, Anna J. and Coulthard, Roy D.} } @article {86, title = {11,000 yrs of environmental change in the Northwest Passage: A multiproxy core record from central Parry Channel, Canadian High Arctic}, journal = {Marine Geology}, volume = {341}, year = {2013}, note = {id: 2343}, pages = {68-85}, abstract = {Piston core 97022-004PC (74{\textdegree} 48.0'N 97{\textdegree}05.9'W; 267 m water depth) represents a rare paleoenvironmental archive from the understudied west-central Canadian Arctic Archipelago. Lithological, biogeochemical, and microfossil (dinoflagellate cysts, non-pollen palynomorphs, benthic and planktonic foraminifera) characteristics, in combination with a chronostratigraphy based on seventeen radiocarbon dates, show seven prominent paleoenvironmental episodes since the end of the last regional glaciation. The basal diamict (Zone I) records decoupling of previously grounded glacial ice, followed by ice-proximal conditions (Zone IIa) commencing at ~ 10.8 cal ka BP (age-depth model extrapolation). After an interval of pervasive sea-ice (Zone IIb), ice-distal conditions are established (Zone IIc). Although sparse microfossils are present in glaciomarine sediments (Zone II), noticeable biological activity with heightened abundances and diversities across all groups begins in the postglacial Zone III (10.3{\textendash}10.0 cal ka BP) when planktonic foraminifera (Neogloboquadrina pachyderma) appear. As planktonics are excluded from the study area today (due to shallow inter-channel sills), this likely signals the inflow of relatively warm and saline Atlantic-derived Arctic Intermediate Water below 250 m, presumably facilitated by glacio-isostatically enhanced deglacial water depths. The subsequent Zone IV (10.0{\textendash}7.0 cal ka BP), characterized by heightened biological productivity in both plankton and benthos and reduced seasonal sea-ice cover, may correspond to a previously proposed Holocene Thermal Maximum. This apparent amelioration ends by the mid Holocene (Zone V; 7.0{\textendash}5.7 cal ka BP) when Arctic Intermediate Water is excluded from the study area and water depths approach modern values. High-Arctic conditions with seasonal sea-ice cover, a circulation dominated by Arctic Ocean Surface Water, and microfossil assemblages similar to modern are found from ~ 5.7 cal ka BP onwards (Zones VI{\textendash}VII). As only minor environmental fluctuations are apparent during the late Holocene, shorter-term climatic episodes (e.g. Little Ice Age) are not recognized in this record.}, issn = {0025-3227}, doi = {10.1016/j.margeo.2013.04.008}, url = {http://www.sciencedirect.com/science/article/pii/S0025322713000522}, author = {Pie{\'n}kowski, A. J. and England, John H. and Furze, Mark F. A. and Blasco, Steve and Mudie, Peta J. and MacLean, Brian} } @article {141, title = {The deglacial to postglacial marine environments of SEBarrow Strait, Canadian Arctic Archipelago}, journal = {Boreas}, volume = {41}, year = {2012}, note = {id: 2342}, pages = {141-179}, abstract = {Core 86027-144 (74{\textdegree}15.56?N, 91{\textdegree}14.21?W) represents a rare, continuous record of Late Pleistocene to Holocene sediments from High Arctic Canada extending from the end of the Last Glaciation. Based on microfossils (dinocysts, non-pollen palynomorphs, benthic and planktonic foraminifera), foraminiferal ?18O and ?13C, and sedimentology, seven palaeoenvironmental zones were identified. Zone I (>10.8?cal.?ka BP) records deglaciation, ice-sheet destabilization, float-off and subsequent break-up. Zone II (c.?10.8?10.4?cal.?ka BP) shows ice-proximal to ice-distal glaciomarine conditions, interrupted by pervasive land-fast sea-ice marked by a hiatus in coarse sediment deposition. Significant biological activity starts in Zone III (10.4?9.9?cal.?ka BP), where planktonic foraminifera (Neogloboquadrina pachyderma) suggest early oceanic throughflow. Surface waters flowed NW?SE; however, the deep-water origin remains unclear (potentially NW Arctic Ocean or Baffin Bay). Postglacial amelioration (open-water season greater than present) in Zone IV (9.9?7.8?cal.?ka BP) perhaps corresponds to the regional ?Holocene Thermal Maximum? previously proposed. A transitional period (Zone V; 7.8?6.7?cal. ka BP) of rapid environmental change fluctuating on a scale not observed today is marked by increasing sea-ice and reduced oceanic influence. This probably signals the exclusion of deeper Atlantic water owing to the glacio-isostatic shallowing of inter-island sills, coupled with generally cooling climate. Conditions analogous to those at present, with increased sea-ice and modern microfossil assemblages, commence at c. 6.7?cal.?ka BP (zones VI?VII). Although climate ultimately forces long-term environmental trends, core 86027-144 data imply that regional dynamics, especially changes in sea-level, exert a significant control on marine conditions throughout the Canadian Arctic Archipelago.}, issn = {1502-3885}, doi = {10.1111/j.1502-3885.2011.00227.x}, url = {http://dx.doi.org/10.1111/j.1502-3885.2011.00227.x}, author = {Pie{\'n}kowski, A. J. and England, John H. and Furze, Mark F. A. and Marret, Fabienne and Eynaud, Fr{\'e}d{\'e}rique and Vilks, Gustav and MacLean, Brian and Blasco, Steve and Scourse, James D.} } @article {191, title = {Late Holocene environmental conditions in Coronation Gulf, southwestern Canadian Arctic Archipelago: evidence from dinoflagellate cysts, other non-pollen palynomorphs, and pollen}, journal = {Journal of Quaternary Science}, volume = {26}, year = {2011}, note = {id: 2344}, pages = {839-853}, abstract = {Boxcore 99LSSL-001 (68.095{\textdegree}?N, 114.186{\textdegree} W; 211?m water depth) from Coronation Gulf represents the first decadal-scale marine palynology and late Holocene sediment record for the southwestern part of the Northwest Passage. The record was studied for organic-walled microfossils (dinoflagellate cysts, non-pollen palynomorphs), pollen, terrestrial spores, and sediment characteristics. 210Pb, 137Cs, and three accelerator mass spectrometry 14C dates constrain the chronology. Three prominent palaeoenvironmental zones were identified. During the interval AD 1470?1680 (Zone I), the climate was warmer and wetter than at present, and environmental conditions were more favourable to biological activity and northward boreal forest migration, with reduced sea-ice and a longer open-water (growing) season. The interval AD 1680?1940 (Zone II) records sea-ice increase, and generally cool, polar conditions during the Little Ice Age. During AD 1940?2000 (Zone III), organic microfossils indicate an extended open-water season and decreased sea-ice, with suggested amelioration surpassing that of Zone I. Although more marine studies are needed to place this record into an appropriate context, the succession from ameliorated (Zone I) to cooler, sea-ice influenced conditions (Zone II) and finally to 20th-century warming (Zone III) corresponds well with several terrestrial climatic records from the neighbouring mainland and Victoria Island, and with lower-resolution marine records to the west. Copyright {\textcopyright} 2011 John Wiley \& Sons, Ltd.}, issn = {1099-1417}, doi = {10.1002/jqs.1503}, url = {http://dx.doi.org/10.1002/jqs.1503}, author = {Pie{\'n}kowski, A. J. and Mudie, Peta J. and England, John H. and Smith, John N. and Furze, Mark F. A.} }