scholarly journals Biostratigraphy, Age, and Paleoenvironment of the Pliocene Beaufort Formation on Meighen Island, Canadian Arctic Archipelago

2021 ◽  
Author(s):  
R.W. Barendregt ◽  
J.V. Matthews ◽  
V. Behan-Pelletier ◽  
J. Brigham-Grette ◽  
J.G. Fyles ◽  
...  
Keyword(s):  
Sea Level ◽  
Marine Sediments ◽  
Canadian Arctic ◽  
The Arctic ◽  
Canadian Arctic Archipelago ◽  
Organic Debris ◽  
Late Neogene ◽  
Key Factor ◽  
Stratigraphic Succession ◽  
Sequence Unit

ABSTRACT Meighen Island, in the Canadian Arctic Archipelago, is one of the most important localities for study of the late Neogene Beaufort Formation because of the presence of marine sediments interbedded with terrestrial fossiliferous sands. The stratigraphic succession, fossils from the marine beds, correlation with reconstructions of sea level, and paleomagnetic data from the Bjaere Bay region of the island suggest that the Beaufort Formation on Meighen Island was likely deposited either at 3.2–2.9 Ma or during two intervals at ca. 4.5 Ma and 3.4 Ma. The exposed Beaufort Formation on Meighen Island probably encompasses at least one warm interval and eustatic sea-level highstand of the Pliocene. Fossils of plants and arthropods are abundant in the alluvial sands exposed in the Bjaere Bay region. The lower part of the sequence (Unit A), beneath the muddy marine sequence (Unit B), contains plant taxa that have not been seen above the marine beds. Sediments below the marine beds are dominated more by fossils of trees, whereas the organic debris from above marine beds contains many fossils of plants, insects, and mites characteristic of open treeless sites. Regional tree line probably occurred on Meighen Island during deposition of the upper sediments, which implies a mean July climate at least 9 °C warmer than at present. When the marine sediments were deposited, nearshore water temperatures probably did not fall below 0 °C; hence, the Arctic Ocean probably lacked perennial ice cover. This confirms recent modeling experiments exploring the causes of Arctic amplification of temperature that have found the removal of sea ice to be a key factor in resolving previous proxy-model mismatches.

Geomorphic diversity and complexity of the inner shelf, Canadian Arctic Archipelago, based on LiDAR and multibeam sonar surveys

2020 ◽  
Vol 57 (1) ◽  
pp. 123-132
Author(s):  
John Shaw ◽  
D. Patrick Potter ◽  
Yongsheng Wu
Keyword(s):  
Sea Level ◽  
Gas Hydrate ◽  
Canadian Arctic ◽  
Slight Modification ◽  
The Arctic ◽  
Canadian Arctic Archipelago ◽  
Beach Ridge ◽  
Terrestrial Lidar ◽  
Sea Levels ◽  
Glacial Landforms

Data from two surveys by multi-beam sonar and two by marine/terrestrial LiDAR are used to evaluate the geomorphology of the seafloor in littoral areas of the Canadian Arctic Channels, near King William Island, Nunavut. Submarine terrains show well-preserved glacial landforms (drumlins, mega-scale glacial lineations, iceberg-turbated terrain, recessional moraines, and glaciofluvial landforms) with only slight modification by modern processes (wave action and sea-ice activity). At Gjoa Haven the seafloor is imprinted by fields of pits 2 m wide and 0.15 m deep. They may result from gas hydrate dissolution triggered by falling relative sea levels. The Arctic Archipelago displays what might be termed inverted terrains: marine terrains, chiefly beach ridge complexes, exist above modern sea level and well-preserved glacial terrains are present below modern sea level. This is the inverse of the submerging regimes of Atlantic Canada, where glacial terrains exist on land, but below sea level they have been effaced and modified by marine processes down to the lowstand depth.

Biostratigraphy, Age, and Paleoenvironment of the Pliocene Beaufort Formation on Meighen Island, Canadian Arctic Archipelago

2021 ◽  
Keyword(s):  
Sea Level ◽  
Marine Sediments ◽  
Canadian Arctic ◽  
Atmospheric Co2 ◽  
Paleomagnetic Data ◽  
Canadian Arctic Archipelago ◽  
Warm Climate ◽  
Western Side ◽  
Continuous Deposition

The Beaufort Formation records extraordinary details of Arctic environments and amplified temperatures at approximately modern levels of atmospheric CO2. It was deposited during the Neogene on the western side of what is now the Canadian Arctic Archipelago. Meighen Island is a key locality for studying this formation because marine sediments there are interbedded with terrestrial fossiliferous sands. The biostratigraphic succession, fossils from the marine beds, and paleomagnetic data from the Bjaere Bay region of the island suggest two potential ages for the studied exposures: either continuous deposition at ca. 3.0 Ma, or a sequence of deposits at ca. 4.5 Ma and 3.4 Ma. The sediments appear to encompass at least two eustatic highstands of sea level and a particularly warm climate interval of the Pliocene Arctic.

scholarly journals Regional variability of acidification in the Arctic: a sea of contrasts

2014 ◽  
Vol 11 (2) ◽  
pp. 293-308 ◽  
Author(s):  
E. E. Popova ◽  
A. Yool ◽  
Y. Aksenov ◽  
A. C. Coward ◽  
T. R. Anderson
Keyword(s):  
Climate Change ◽  
Primary Production ◽  
Arctic Ocean ◽  
Canadian Arctic ◽  
Atmospheric Co2 ◽  
The Arctic ◽  
Canadian Arctic Archipelago ◽  
Regional Variability ◽  
The Arctic Ocean ◽  
The Impact

Abstract. The Arctic Ocean is a region that is particularly vulnerable to the impact of ocean acidification driven by rising atmospheric CO2, with potentially negative consequences for calcifying organisms such as coccolithophorids and foraminiferans. In this study, we use an ocean-only general circulation model, with embedded biogeochemistry and a comprehensive description of the ocean carbon cycle, to study the response of pH and saturation states of calcite and aragonite to rising atmospheric pCO2 and changing climate in the Arctic Ocean. Particular attention is paid to the strong regional variability within the Arctic, and, for comparison, simulation results are contrasted with those for the global ocean. Simulations were run to year 2099 using the RCP8.5 (an Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) scenario with the highest concentrations of atmospheric CO2). The separate impacts of the direct increase in atmospheric CO2 and indirect effects via impact of climate change (changing temperature, stratification, primary production and freshwater fluxes) were examined by undertaking two simulations, one with the full system and the other in which atmospheric CO2 was prevented from increasing beyond its preindustrial level (year 1860). Results indicate that the impact of climate change, and spatial heterogeneity thereof, plays a strong role in the declines in pH and carbonate saturation (Ω) seen in the Arctic. The central Arctic, Canadian Arctic Archipelago and Baffin Bay show greatest rates of acidification and Ω decline as a result of melting sea ice. In contrast, areas affected by Atlantic inflow including the Greenland Sea and outer shelves of the Barents, Kara and Laptev seas, had minimal decreases in pH and Ω because diminishing ice cover led to greater vertical mixing and primary production. As a consequence, the projected onset of undersaturation in respect to aragonite is highly variable regionally within the Arctic, occurring during the decade of 2000–2010 in the Siberian shelves and Canadian Arctic Archipelago, but as late as the 2080s in the Barents and Norwegian seas. We conclude that, for future projections of acidification and carbonate saturation state in the Arctic, regional variability is significant and needs to be adequately resolved, with particular emphasis on reliable projections of the rates of retreat of the sea ice, which are a major source of uncertainty.

ADDITIONAL HEAT FLOW DETERMINATIONS IN THE AREA OF MOULD BAY, ARCTIC CANADA

1966 ◽  
Vol 3 (2) ◽  
pp. 237-246 ◽  
Author(s):  
W. S. B. Paterson ◽  
L. K. Law
Keyword(s):  
Heat Flow ◽  
Canadian Arctic ◽  
The Arctic ◽  
Canadian Arctic Archipelago ◽  
General Area ◽  
Geothermal Heat ◽  
Field Methods ◽  
The Mean ◽  
Water Depths ◽  
Made In

Seven determinations of geothermal heat flow were made in the general area of southern Prince Patrick Island in the Canadian Arctic Archipelago. Measurements were made from sea ice in water depths of between 200 and 600 m. The mean heat flow for the two stations on the continental shelf in the Arctic Ocean was 0.46 ± 0.08 μcal cm−2 s−1. The mean heat flow for the five stations in the channels to the east of Mould Bay was 1.46 ± 0.16 μcal cm−2 s−1. The instrument and field methods are described. Errors due to the instrument and to the environment are discussed.

scholarly journals Arctic marine secondary organic aerosol contributes significantly to summertime particle size distributions in the Canadian Arctic Archipelago

2019 ◽  
Vol 19 (5) ◽  
pp. 2787-2812 ◽  
Author(s):  
Betty Croft ◽  
Randall V. Martin ◽  
W. Richard Leaitch ◽  
Julia Burkart ◽  
Rachel Y.-W. Chang ◽  
...  
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Secondary Organic Aerosol ◽  
Canadian Arctic ◽  
Particle Growth ◽  
Organic Aerosol ◽  
The Arctic ◽  
Canadian Arctic Archipelago ◽  
Size Distributions ◽  
Fractional Error

Abstract. Summertime Arctic aerosol size distributions are strongly controlled by natural regional emissions. Within this context, we use a chemical transport model with size-resolved aerosol microphysics (GEOS-Chem-TOMAS) to interpret measurements of aerosol size distributions from the Canadian Arctic Archipelago during the summer of 2016, as part of the “NETwork on Climate and Aerosols: Addressing key uncertainties in Remote Canadian Environments” (NETCARE) project. Our simulations suggest that condensation of secondary organic aerosol (SOA) from precursor vapors emitted in the Arctic and near Arctic marine (ice-free seawater) regions plays a key role in particle growth events that shape the aerosol size distributions observed at Alert (82.5∘ N, 62.3∘ W), Eureka (80.1∘ N, 86.4∘ W), and along a NETCARE ship track within the Archipelago. We refer to this SOA as Arctic marine SOA (AMSOA) to reflect the Arctic marine-based and likely biogenic sources for the precursors of the condensing organic vapors. AMSOA from a simulated flux (500 µgm-2day-1, north of 50∘ N) of precursor vapors (with an assumed yield of unity) reduces the summertime particle size distribution model–observation mean fractional error 2- to 4-fold, relative to a simulation without this AMSOA. Particle growth due to the condensable organic vapor flux contributes strongly (30 %–50 %) to the simulated summertime-mean number of particles with diameters larger than 20 nm in the study region. This growth couples with ternary particle nucleation (sulfuric acid, ammonia, and water vapor) and biogenic sulfate condensation to account for more than 90 % of this simulated particle number, which represents a strong biogenic influence. The simulated fit to summertime size-distribution observations is further improved at Eureka and for the ship track by scaling up the nucleation rate by a factor of 100 to account for other particle precursors such as gas-phase iodine and/or amines and/or fragmenting primary particles that could be missing from our simulations. Additionally, the fits to the observed size distributions and total aerosol number concentrations for particles larger than 4 nm improve with the assumption that the AMSOA contains semi-volatile species: the model–observation mean fractional error is reduced 2- to 3-fold for the Alert and ship track size distributions. AMSOA accounts for about half of the simulated particle surface area and volume distributions in the summertime Canadian Arctic Archipelago, with climate-relevant simulated summertime pan-Arctic-mean top-of-the-atmosphere aerosol direct (−0.04 W m−2) and cloud-albedo indirect (−0.4 W m−2) radiative effects, which due to uncertainties are viewed as an order of magnitude estimate. Future work should focus on further understanding summertime Arctic sources of AMSOA.

Recent changes in the exchange of sea ice between the Arctic Ocean and the Canadian Arctic Archipelago

2013 ◽  
Vol 118 (7) ◽  
pp. 3595-3607 ◽  
Author(s):  
Stephen E. L. Howell ◽  
Trudy Wohlleben ◽  
Mohammed Dabboor ◽  
Chris Derksen ◽  
Alexander Komarov ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Canadian Arctic ◽  
The Arctic ◽  
Canadian Arctic Archipelago ◽  
The Arctic Ocean

scholarly journals Using <sup>226</sup>Ra and <sup>228</sup>Ra isotopes to distinguish water mass distribution in the Canadian Arctic Archipelago

2020 ◽  
Author(s):  
Chantal Mears ◽  
Helmuth Thomas ◽  
Paul B. Henderson ◽  
Matthew A. Charette ◽  
Hugh MacIntyre ◽  
...  
Keyword(s):  
Water Exchange ◽  
Water Mass ◽  
Dissolved Inorganic Carbon ◽  
Canadian Arctic ◽  
Atlantic Water ◽  
Radioactive Isotopes ◽  
Total Alkalinity ◽  
The Arctic ◽  
Canadian Arctic Archipelago ◽  
Wide Range

Abstract. As a shelf dominated basin, the Arctic Ocean and its biogeochemistry are heavily influenced by continental and riverine sources. Radium isotopes (226Ra, 228Ra, 224Ra, 223Ra), are transferred from the sediments to seawater, making them ideal tracers of sediment-water exchange processes and ocean mixing. 226Ra and 228Ra are the two longer-lived isotopes of the Radium Quartet (226Ra, t1/2 = 1600 y and 228Ra, t1/2 = 5.8 y). Because of their long half-lives they can provide insight into the water mass compositions, distribution patterns, as well as mixing processes and the associated timescales throughout the Canadian Arctic Archipelago (CAA). The wide range of 226Ra, 228Ra, and of the 228Ra / 226Ra ratio, measured in water samples collected during the 2015 GEOTRACES cruise, complemented by additional chemical tracers (dissolved inorganic carbon (DIC), total alkalinity (AT), barium (Ba), and the stable oxygen isotope composition of water (δ18O)) highlight the dominant biogeochemical, hydrographic and bathymetric features of the CAA. Bathymetric features, such as the continental shelf and shallow coastal sills, are critical in modulating circulation patterns within the CAA, including the bulk flow of Pacific waters and the inhibited eastward flow of denser Atlantic waters through the CAA. Using a Principal Component Analysis, we unravel the dominant mechanisms and the apparent water mass end-members that shape the tracer distributions. We identify two distinct water masses located above and below the upper halocline layer throughout the CAA, as well as distinctly differentiate surface waters in the eastern and western CAA. Furthermore, we identify water exchange across 80° W, inferring a draw of Atlantic water, originating from Baffin Bay, into the CAA. In other words, this implies the presence of an Atlantic water U-turn located at Barrow Strait, where the same water mass is seen along the northernmost edge at 80° W as well as along south-easternmost confines of Lancaster Sound. Overall, this study provides a stepping stone for future research initiatives within the Canadian Arctic Archipelago, revealing how quantifying disparities in radioactive isotopes can provide valuable information on the potential effects of climate change within vulnerable areas such as the CAA.

scholarly journals Palaeoenvironmental Interpretation of Late Quaternary Marine Molluscan Assemblages, Canadian Arctic Archipelago

2002 ◽  
Vol 54 (3) ◽  
pp. 301-315 ◽  
Author(s):  
Sandra Gordillo ◽  
Alec E. Aitken
Keyword(s):  
Environmental Factors ◽  
Species Composition ◽  
Continental Shelf ◽  
Marine Sediments ◽  
High Latitude ◽  
Late Quaternary ◽  
Canadian Arctic ◽  
High Arctic ◽  
Canadian Arctic Archipelago ◽  
Preservation Potential

Abstract This study examines neonto- logical and palaeontological data pertaining to arctic marine molluscs with the goal of reconstructing the palaeoecology of Late Quaternary ca. 12-1 ka BP glaciomarine environments in the Canadian Arctic Archipelago. A total of 26 taxa that represent 15 bivalves and 11 gastropods were recorded in shell collections recovered from Prince of Wales, Somerset, Devon, Axel Heiberg and Ellesmere islands. In spite of taphonomic bias, the observed fossil faunas bear strong similarities to modern benthic molluscan faunas inhabiting high latitude continental shelf environments, reflecting the high preservation potential of molluscan taxa in Quaternary marine sediments. The dominance of an arctic-boreal fauna represented by Hiatella arctica, Mya truncata and Astarte borealis is the product of natural ecological conditions in high arctic glaciomarine environments. Environmental factors controlling the distribution and species composition of the Late Quaternary molluscan assemblages from this region are discussed.

Beach observations of plastic and marine litter along the Northwest Passage

2020 ◽  
Author(s):  
Peter Gijsbers ◽  
Hester Jiskoot
Keyword(s):  
Marine Pollution ◽  
Chukchi Sea ◽  
Canadian Arctic ◽  
The Arctic ◽  
Canadian Arctic Archipelago ◽  
Bering Strait ◽  
Marine Litter ◽  
Northwest Passage ◽  
Distant Early Warning ◽  
Dew Line

&lt;p&gt;Marine litter and microplastics are everywhere. Even the Arctic Ocean, Svalbard and Jan Mayen Island are contaminated as various publications confirm. Little, however, is reported about marine waters and shores of the Canadian Arctic Archipelago. This poster presents the results of a privately funded citizen science observation to scan remote beaches along the Northwest Passage for marine litter pollution.&lt;/p&gt;&lt;p&gt;The observations were conducted while enjoying the 2019 Northwest Passage sailing expedition of the Tecla, a 1915 gaff-ketch herring drifter. The expedition started in Ilulissat, Greenland, on 1 August and ended in Nome, Alaska, on 18 September. After crossing Baffin Bay, the ship continued along Pond Inlet, Navy Board Inlet, Lancaster Sound, Barrow Strait, Peel Sound, Franklin Strait, Rea Strait, Simpson Strait, Queen Maud Gulf, Coronation Gulf, Amundsen Gulf, Beaufort Sea, Chukchi Sea and Bering Strait. The vessel anchored in the settlement harbours of Pond Inlet, Taloyoak, Gjoa Haven, Cambridge Bay and Herschel Island. In addition, Tecla&amp;#8217;s crew made landings at remote beaches on Disko Island (Fortune Bay, Disko Fjord), Beechey Island (Union Bay), Somerset Island (Four Rivers Bay), Boothia Peninsula (Weld Harbour), King William Island (M&amp;#8217;Clintock Bay), Jenny Lind Island, and at Kugluktuk and Tuktoyaktuk Peninsula.&lt;/p&gt;&lt;p&gt;Following the categorization of the OSPAR Guideline for Monitoring Marine Litter on Beaches, litter observations were conducted without penetrating the beach surfaces. Beach stretches scanned varied in length from 100-400 m. No observations were conducted at inhabited settlements or at the abandoned settlements visited on Disko Island (Nipisat) and Beechey Island (Northumberland House).&lt;/p&gt;&lt;p&gt;Observations on the most remote beaches found 2-5 strongly bleached or decayed items in places such as Union Bay, Four Rivers Bay, Weld Harbour, Jenny Lind Island (Queen Maud Gulf side). Landings within 15 km of local settlements (Fortune Bay, Disko Fjord, Kugluktuk, Tuktoyaktuk) or near military activity (Jenny Lind Island, bay side) showed traces of local camping, hunting or fishing activities, resulting in item counts between 7 and 29. At the lee shore spit of M&amp;#8217;Clintock Bay, significant pollution (&gt; 100 items: including outboard engine parts, broken ceramic, glass, clothing, decayed batteries, a crampon and a vinyl record) was found, in contrast to a near-pristine beach on the Simpson Strait side. The litter type and concentration, as well as the remains of a building and shipwrecked fishing vessel indicate that this is an abandoned settlement, possibly related to the construction of the nearby Distant Early Warning Line radar site CAM-2 of Gladman Point. DEW Line sites have long been associated with environmental disturbances.&lt;/p&gt;&lt;p&gt;Given the 197 beach items recorded, it can be concluded that the beaches of the Canadian Arctic Archipelago, which are blocked by sea ice during most of the year, are not pristine. Truly remote places have received marine pollution for decades to centuries. Where (abandoned) settlements are at close range pollution from local activities can be discovered, while ocean currents, wind patterns, ice rafting, distance to river mouths, and flotsam, jetsam and derelict also determine the type and amount of marine litter along the Northwest Passage.&lt;/p&gt;

scholarly journals Arctic marine secondary organic aerosol contributes significantly to summertime particle size distributions in the Canadian Arctic Archipelago

2018 ◽  
Author(s):  
Betty Croft ◽  
Randall V. Martin ◽  
W. Richard Leaitch ◽  
Julia Burkart ◽  
Rachel Y.-W. Chang ◽  
...  
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Secondary Organic Aerosol ◽  
Canadian Arctic ◽  
Particle Growth ◽  
Organic Aerosol ◽  
The Arctic ◽  
Canadian Arctic Archipelago ◽  
Size Distributions ◽  
Fractional Error

Abstract. Summertime Arctic aerosol size distributions are strongly controlled by natural regional emissions. Within this context, we use a chemical transport model with size-resolved aerosol microphysics (GEOS-Chem-TOMAS) to interpret measurements of aerosol size distributions from the Canadian Arctic Archipelago during the summer of 2016, as part of the NETwork on Climate and Aerosols: addressing key uncertainties in Remote Canadian Environments (NETCARE). Our simulations suggest that condensation of secondary organic aerosol (SOA) from precursor vapors emitted in the Arctic and near Arctic marine (open ocean and coastal) regions plays a key role in particle growth events that shape the aerosol size distributions observed at Alert (82.5° N, 62.3° W), Eureka (80.1° N, 86.4° W), and along a NETCARE ship track within the Archipelago. We refer to this SOA as Arctic marine SOA (Arctic MSOA) to reflect the Arctic marine-based and likely biogenic sources for the precursors of the condensing organic vapors. Arctic MSOA from a simulated flux (500 μg m−2 d−1, north of 50° N) of precursor vapors (assumed yield of unity) reduces the summertime particle size distribution model-observation mean fractional error by 2- to 4-fold, relative to a simulation without this Arctic MSOA. Particle growth due to the condensable organic vapor flux contributes strongly (30–50 %) to the simulated summertime-mean number of particles with diameters larger than 20 nm in the study region, and couples with ternary particle nucleation (sulfuric acid, ammonia, and water vapor) and biogenic sulfate condensation to account for more than 90 % of this simulated particle number, a strong biogenic influence. The simulated fit to summertime size-distribution observations is further improved at Eureka and for the ship track by scaling up the nucleation rate by a factor of 100 to account for other particle precursors such as gas-phase iodine and/or amines and/or fragmenting primary particles that could be missing from our simulations. Additionally, the fits to observed size distributions and total aerosol number concentrations for particles larger than 4 nm improve with the assumption that the Arctic MSOA contains semi-volatile species; reducing model-observation mean fractional error by 2- to 3-fold for the Alert and ship track size distributions. Arctic MSOA accounts for more than half of the simulated total particulate organic matter mass concentrations in the summertime Canadian Arctic Archipelago, and this Arctic MSOA has strong simulated summertime pan-Arctic-mean top-of-the-atmosphere aerosol direct (−0.04 W m−2) and cloud-albedo indirect (−0.4 W m−2) radiative effects. Future work should focus on further understanding summertime Arctic sources of Arctic MSOA.

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