Browsing by Author "England, John H."
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- Item11,000 yrs of environmental change in the Northwest Passage; a multiproxy core record from central Parry Channel, Canadian High Arctic(2013) Pieńkowski, Anna J.; England, John H.; Furze, Mark F.A.; Blasco, Steve; Mudie, Peta J.; MacLean, Briana 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 (10.3–10.0 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 (10.0–7.0 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; 7.0–5.7 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–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.
- ItemAtlantic water inflow in the early Holocene Northwest Passage marked by planktonic foraminifera (Neogloboquadrina pachyderma)(2015) Pieńkowski, Anna J.; Cage, Alix; Furze, Mark F.A.; Figueiredo Martins, Ana Sílvia de; England, John H.; McLean, Brian; Blasco, SteveFour marine piston cores from the central Canadian Arctic Archipelago (CAA), investigated for sedimentology, micropalaeontology, and biogeochemistry (52 AMS radiocarbon dates), uniformly show the prominent early Holocene (˜10 cal ka BP) appearance of planktonic foraminifera immediately following deglaciation.
- ItemComment on "Multi-proxy record of postglacial environmental change, south-central Melville Island, Northwest Territories, Canada" by Peros et al., 2010, Quaternary Research 73, 247-258(2010) Furze, Mark F.A.; England, John H.The new multi-proxy paleoenvironmental record recently reported from Lake BC01, on south-central Melville Island, western Canadian Arctic Archipelago (CAA), constitutes an important contribution to the regional literature (Peros et al., 2010). This continuous record, spanning the last ~12,000 cal yr BP, provides an important link between the late glacial and postglacial vegetation history, and related paleoclimatic conditions deciphered from them. Although we welcome these new perspectives, the summary of the late Quaternary glacial geology that the paper also addresses contains problematic interpretations of recently published regional revisions (England et al., 2006, 2009) that warrant clarification.
- ItemComment: Holocene palaeoceanographic changes in Barrow Strait, Canadian Arctic: foraminiferal evidence(2010) Furze, Mark F.A.; Pieńkowski, Anna J.; England, John H.; Gregory, Thomas R.; Smart, Christopher W.; Hart, Malcolm B.; Masse, Guillaume; Vare, Lindsay L.; Belt, Simon T.Comment on the article Holocene palaeoceanographic changes in Barrow Strait, Canadian Arctic: foraminiferal evidence.
- ItemCorrigendum to “Revision of the NW Laurentide Ice Sheet: implications for paleoclimatic, the northeast extremity of Beringia, and Arctic Ocean sedimentation” [Quat. Sci. Rev. 28 (2009) 1573–1596](2010) England, John H.; Furze, Mark F.A.; Doupe, Jonathan P.For the past half-century, reconstructions of North American ice cover during the Last Glacial Maximum have shown ice-free land distal to the Laurentide Ice Sheet, primarily on Melville and Banks islands in the western Canadian Arctic Archipelago. Both islands reputedly preserve at the surface multiple Laurentide till sheets, together with associated marine and lacustrine deposits, recording as many as three pre-Late Wisconsinan glaciations. The northwest corner of Banks Island was purportedly never glaciated and is trimmed by the oldest and most extensive glaciation (Banks Glaciation) considered to be of Matuyama age (>780 ka BP). Inside the limit of Banks Glaciation, younger till sheets are ascribed to the Thomsen Glaciation (pre-Sangamonian) and the Amundsen Glaciation (Early Wisconsinan Stade). The view that the western Canadian Arctic Archipelago remained largely ice-free during the Late Wisconsinan is reinforced by a recent report of two woolly mammoth fragments collected on Banks and Melville islands, both dated to w22 ka BP. These dates imply that these islands constitute the northeast extremity of Beringia. A fundamental revision of this model is now warranted based on widespread fieldwork across the adjacent coastlines of Banks and Melville islands, including new dating of glacial and marine landforms and sediments. On Dundas Peninsula, southern Melville Island, AMS 14C dates on ice-transported marine molluscs within the most extensive Laurentide till yield ages of 25–49 ka BP. These dates require that Late Wisconsinan ice advanced northwestward from Visount Melville Sound, excavating fauna spanning Marine Isotope Stage 3. Laurentide ice that crossed Dundas Peninsula (300 m asl) coalesced with Melville Island ice occupying Liddon Gulf. Coalescent Laurentide and Melville ice continued to advance westward through M’Clure Strait depositing granite erratics at 235 m asl that require grounded ice in M’Clure Strait, as do streamlined bedforms on the channel floor. Deglaciation is recorded by widespread meltwater channels that show both the initial separation of Laurentide and Melvile ice, and the successive retreat of Laurentide ice southward across Dundas Peninsula into Viscount Melville Sound. Sedimentation from these channels deposited deltas marking deglacial marine limit. Forty dates on shells collected from associated glaciomarine rhythmites record nearsynchronous ice retreat from M’Clure Strait and Dundas Peninsula to north-central Victoria Island w11.5 ka BP. Along the adjacent coast of Banks Island, deglacial shorelines also record the retreat of Laurentide ice both eastward through M’Clure Strait and southward into the island’s interior. The elevation and age (w11.5 ka BP) of deglacial marine limit there is fully compatible with the record of ice retreat on Melville Island. The last retreat of ice from Mercy Bay (northern Banks Island), previously assigned to northward retreat into M’Clure Strait during the Early Wisconsinan, is contradicted by geomorphic evidence for southward retreat into the island’s interior during the Late Wisconsinan. This revision of the pattern and age of ice retreat across northern Banks Island results in a significant simplification of the previous Quaternary model. Our observations support the amalgamation of multiple till sheets – previously assigned to at least three pre-Late Wisconsinan glaciations – into the Late Wisconsinan. This revision also removes their formally named marine transgressions and proglacial lakes for which evidence is lacking. Erratics were also widely observed armouring meltwater channels originating on the previously proposed never-glaciated landscape. An extensive Late Wisconsinan Laurentide Ice Sheet across the western Canadian Arctic is compatible with similar evidence for extensive Laurentide ice entering the Richardson Mountains (Yukon) farther south and with the Innuitian Ice Sheet to the north. Widespread Late Wisconsinan ice, in a region previously thought to be too arid to sustain it, has important implications for paleoclimate, ice sheet modelling, Arctic Ocean ice and sediment delivery, and clarifying the northeast limit of Beringia. Unfortunately, when this paper was originally published there were missing data in Table 2, i.e. eight Reservoir-corrected dates were not included. The correct Table 2 is printed on the following pages.
- ItemIceshelf instability and the collapsing NW margin of the Laurentide Ice Sheet: core evidence from Viscount Melville Sound, Arctic Canada(2013) Furze, Mark F.A.; Pieńkowski, Anna J.; England, John H.; Esteves, Mariana da Silveira Ramos; Bennett, Robbie; Krywko, Jack; Glembiski, Danna; McLean, Brian; Blasco, SteveRecent work in the western Canadian Arctic Archipelago has seen a dramatic re-evaluation of the timing and extent of Late Wisconsinan glaciation by a primarily cold-based Laurentide Ice sheet. This has included the occupation by ice of formerly-considered ice free terrain and the extension of grounded ice from the main channels of the Northwest Passage, westwards onto the Beaufort Sea continental shelf. Nonetheless, while the pattern of ice extent and initial retreat is now well constrained, significant questions remain regarding the main phase of ice retreat southeastwards onto mainland Canada and the stability of the retreating margin in response to ameliorating climate and sea-level change.
- ItemLate Holocene environmental conditions in Coronation Gulf, southwestern Canadian Arctic Archipelago; evidence from dinoflagellate cysts, other non-pollen palynomorphs, and pollen(2011) Pieńkowski, Anna J.; Mudie, Peta J.; England, John H.; Smith, John N.; Furze, Mark F.A.Boxcore 99LSSL-001 (68.095°?N, 114.186° 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.
- ItemLate Quaternary marine records from High Arctic Canada: problems, solutions, and multiproxy perspectives(2013) Pieńkowski, Anna J.; Furze, Mark F.A.; England, John H.; MacLean, Brian; Von Prause, Markus; Blasco, SteveThe Canadian Arctic Archipelago (= CAA) constitutes a significant geographic region within the Arctic Ocean Basin, influencing its oceanography, biology, ecology, and climate. Yet comparatively little is known about the long-term (post-Late Wisconsinan) environmental history of the marine channels of this region (the “Northwest Passage” = NWP). New marine data emerging from the central CAA extending back to regional deglaciation highlight the potential of multiproxy approaches in high-latitude settings.
- ItemMost northerly observation of a grizzly bear (ursus arctos) in Canada: photographic and DNA evidence from Melville Island, Northwest Territories(2007) Doupe, Jonathan P.; England, John H.; Furze, Mark F.A.; Paetkau, D.During geological studies in 2003 and 2004 on Melville Island, Northwest Territories, Canada, field parties photographed and gathered genetic information on one or more grizzly bears (Ursus arctos). To our knowledge, these data constitute the most northerly observations made of this species in North America. The DNA of a hair sample collected on Melville Island in 2004 is genetically indistinguishable from DNA collected from a population of grizzly bears around Paulatuk, Northwest Territories, along the northern mainland coast. It is also distinct from the DNA of the Viscount Melville polar bear (Ursus maritimus) population. Our evidence and review suggest that, at a minimum, transient grizzly bears are now regular visitors to the Canadian Arctic Archipelago. More research will be required to understand the significance of these observations, but a small viable population of grizzly bears may now be using areas in or around Melville Island.
- ItemNew evidence from the western Canadian Arctic Archipelago for the resubmergence of Bering Strait(2008) England, John H.; Furze, Mark F.A.Widespread molluscan samples were collected from raised marine sediments to date the last retreat of the NW Laurentide Ice Sheet from the western Canadian Arctic Archipelago. At the head of Mercy Bay, northern Banks Island, deglacial mud at the modern coast contains Hiatella arctica and Portlandia arctica bivalves, as well as Cyrtodaria kurriana, previously unreported for this area. Multiple H. arctica and C. kurriana valves from this site yield a mean age of 11.5 14C ka BP (with 740 yr marine reservoir correction). The occurrence of C. kurriana, a low Arctic taxon, raises questions concerning its origin, because evidence is currently lacking for a molluscan refugium in the Arctic Ocean during the last glacial maximum. Elsewhere, the oldest late glacial age available on C. kurriana comes from the Laptev Sea where it is < 10.3 14C ka BP and attributed to a North Atlantic source. This is 2000 cal yr younger than the Mercy Bay samples reported here, making the Laptev Sea, ~ 3000 km to the west, an unlikely source. An alternate route from the North Atlantic into the Canadian Arctic Archipelago was precluded by coalescent Laurentide, Innuitian and Greenland ice east of Banks Island until ~ 10 14C ka BP. We conclude that the presence of C. kurriana on northern Banks Island records migration from the North Pacific. This requires the resubmergence of Bering Strait by 11.5 14C ka BP, extending previous age determinations on the reconnection of the Pacific and Arctic oceans by up to 1000 yr. This renewed ingress of Pacific water likely played an important role in re-establishing Arctic Ocean surface currents, including the evacuation of thick multi-year sea ice into the North Atlantic prior to the Younger Dryas geochron.
- ItemNew marine ΔR values for Arctic Canada(2010) Coulthard, Roy D.; Furze, Mark F.A.; Pieńkowski, Anna J.; Nixon, F. Chantel; England, John H.For more than four decades, the reporting of 14C dates on marine molluscs from Arctic Canada has been notable for the lack of consistently applied marine reservoir corrections. We propose that the common approach of reporting Canadian Arctic marine 14C dates using presumed time-invariant reservoir corrections be abandoned in favour of calibration of 14C dates, using the current standard protocol. This approach best facilitates inter- and intra-regional correlation, and correlation with other geochronometers. In order to enable the consistent calibration of marine 14C dates from Arctic Canada, we analysed a 14C database of 108 marine mollusc samples collected live between 1894 and 1956, and determined regional reservoir offset values (ΔR) for eight oceanographically distinct regions. The following new ΔR values should be used for 14C calibration: NW Canadian Arctic Archipelago, 335 ± 85 yrs; Foxe Basin, 310 ± 90 yrs; NE Baffin Island, 220 ± 20 yrs; SE Baffin Island, 150 ± 60 yrs; Hudson Strait, 65 ± 60 yrs; Ungava Bay, 145 ± 95 yrs; Hudson Bay, 110 ± 65 yrs; and James Bay, 365 ± 115 yrs.
- ItemRevising the limit of the NW Laurentide Ice Sheet: extensive glaciation in NE Beringia(2010) Furze, Mark F.A.; England, John H.; Doupe, Jonathan P.For the past half-century, reconstructions of North American ice cover during the Last Glacial Maximum have shown ice-free land distal to the Laurentide Ice Sheet, primarily on Melville and Banks islands in the western Canadian Arctic Archipelago. Both islands reputedly preserve at the surface multiple Laurentide till sheets, together with associated marine and lacustrine deposits, recording as many as three pre-Late Wisconsinan glaciations. The northwest corner of Banks Island was purportedly never glaciated and is trimmed by the oldest and most extensive glaciation (Banks Glaciation) considered to be of Matuyama age (>780 ka BP). The view that the western Canadian Arctic Archipelago remained largely ice-free during the Late Wisconsinan, serving as the NE extremity of Beringia, is reinforced by a recent report of two woolly mammoth fragments collected on Banks and Melville islands, both dated to ∼22 ka BP. Well developed periglacial features present, in particular on Banks Island, have also been considered to record a long interval of ice-free conditions throughout the LGM.
- ItemRevision of the NW Laurentide Ice Sheet: implications for paleoclimatic, the northeast extremity of Beringia, and Arctic Ocean sedimentation(2010) England, John H.; Furze, Mark F.A.; Doupe, Jonathan P.For the past half-century, reconstructions of North American ice cover during the Last Glacial Maximum have shown ice-free land distal to the Laurentide Ice Sheet, primarily on Melville and Banks islands in the western Canadian Arctic Archipelago. Both islands reputedly preserve at the surface multiple Laurentide till sheets, together with associated marine and lacustrine deposits, recording as many as three pre-Late Wisconsinan glaciations. The northwest corner of Banks Island was purportedly never glaciated and is trimmed by the oldest and most extensive glaciation (Banks Glaciation) considered to be of Matuyama age (>780 ka BP). Inside the limit of Banks Glaciation, younger till sheets are ascribed to the Thomsen Glaciation (pre-Sangamonian) and the Amundsen Glaciation (Early Wisconsinan Stade). The view that the western Canadian Arctic Archipelago remained largely ice-free during the Late Wisconsinan is reinforced by a recent report of two woolly mammoth fragments collected on Banks and Melville islands, both dated to ∼22 ka BP. These dates imply that these islands constitute the northeast extremity of Beringia.
- ItemThe deglacial to postglacial marine environments of SE Barrow Strait, Canadian Arctic Archipelago(2012) Pieńkowski, Anna J.; England, John H.; Furze, Mark F.A.; Marret, Fabienne; Eynaud, Frederique; Vilks, Gustav; MacLean, Brian; Blasco, Steve; Scourse, James D.Core 86027-144 (74°15.56′N, 91°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 δ18O and δ13C, 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.
- ItemThe late Quaternary environmental evolution of marine Arctic Canada; Barrow Strait to Lancaster Sound(2014) Pieńkowski, Anna J.; England, John H.; Furze, Mark F.A.; MacLean, Brian; Blasco, SteveA marine sediment core from the east-central Canadian Arctic Archipelago (Core 86027-154; 74° 22.01′N 89° 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–depth model extrapolation places deglaciation at 11.54 cal ka BP. Zone II (11.5–11.0 cal ka BP) represents a distinct progression from initially ice-proximal to increasingly ice-distal conditions, interrupted by an interval of pervasive sea-ice (11.4–11.2 cal ka BP). Noteworthy biological activity commences in Zone III (11.0–9.7 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 (9.7–7.2 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 (7.2–6.5 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–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).