scholarly journals Early tertiary larix from the Buchanan Lake formation, Canadian Arctic Archipelago, and a consideration of the phytogeography of the genus

1991 ◽  
Author(s):  
B A Lepage ◽  
J F Basinger
Keyword(s):  
Canadian Arctic ◽  
Canadian Arctic Archipelago ◽  
Early Tertiary ◽  
Lake Formation

Origin of iron-oxide and silicate melt rocks in Paleogene sediments of southern Ellesmere Island, Canadian Arctic Archipelago, Nunavut

2007 ◽  
Vol 44 (7) ◽  
pp. 1005-1013 ◽  
Author(s):  
Karsten Piepjohn ◽  
Solveig Estrada ◽  
Lutz Reinhardt ◽  
Werner von Gosen ◽  
Harald Andruleit
Keyword(s):  
Canadian Arctic ◽  
Ellesmere Island ◽  
Anthropogenic Activity ◽  
Canadian Arctic Archipelago ◽  
X Ray Diffraction ◽  
Coal Seams ◽  
Volcanic Origin ◽  
X Ray ◽  
Early Tertiary ◽  
Unconsolidated Sand

Between Vendom Fiord and Makinson Inlet on southern Ellesmere Island, Canadian Arctic Archipelago, Nunavut, isolated and fault-bounded Early Tertiary basins are exposed. The basin deposits are Paleocene to Eocene in age and overlie unconformably folded Ordovician and Silurian carbonates of the Paleozoic Franklinian Basin that were affected by intense, pre-Paleocene weathering and karstification in places. The Tertiary sediments consist mainly of dark unconsolidated sand and silt and are interbedded with many centimetre- to metre-thick coal seams. In several places, round orange and red "spots" occur within the dark grey Tertiary basin fills and are clustered on top of the dark grey Tertiary occurrences. The "spots" are up to 100 m in diameter and consist of consolidated burnt shards of clay or clinker. In the centre of the reddish "spots," dark, massive, and partly high-magnetic lava- or slag-like rocks are poorly exposed as masses that are a decimetre or less in scale. These rocks were investigated using thin section studies, as well as X-ray diffraction and X-ray flourescence analyses. The melt rocks are composed of glass, cordierite-group minerals, hematite, magnetite, tridymite, mullite, and cristobalite. They represent paralavas resulting from subsurface combustion of the Tertiary coal seams under conditions similar to those in a blast furnace. An origin by anthropogenic activity or a volcanic origin can be ruled out.

Stratigraphy and floristics of Eocene swamp forests from Axel Heiberg Island, Canadian Arctic Archipelago

1993 ◽  
Vol 30 (9) ◽  
pp. 1914-1923 ◽  
Author(s):  
David R. Greenwood ◽  
James F. Basinger
Keyword(s):  
Canadian Arctic ◽  
System Structure ◽  
Forest Community ◽  
Forest Composition ◽  
Small Scale ◽  
Canadian Arctic Archipelago ◽  
Lake Formation ◽  
Axel Heiberg Island ◽  
Density And Biomass

A record of polar Eocene forests is preserved as in situ tree-stump fields and leaf-litter mats in Buchanan Lake Formation sediments on Axel Heiberg Island, in the Canadian Arctic Archipelago. Stratigraphic examination at the centimetre to metre scale of peat–coal lithology and macrofossil floristics in two levels of these fossil forests reflects small-scale changes in forest composition and swamp hydrology horizontally and temporal variation vertically. Root system structure and tree base stratigraphy suggest that exposed tree stumps may not include only coeval individuals of a single forest stand, but rather also individuals representing different phases of the forest through one cycle of the hydrological development of this Eocene polar forest community. Earlier calculations of stand density and biomass, based upon the assumption that all stumps represent coeval trees, may therefore be greatly overestimated. A mosaic of Alnus – fern bog, mixed coniferous community, and taxodiaceous (Metasequoia–Glyptostrobus) swamp appears to have produced both the leaf mats and the in situ stumps, with the taxodiaceous swamp the dominant peat-accumulating phase.

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.

scholarly journals On the Thermal Regime of a High-Arctic Valley Glacier

1976 ◽  
Vol 16 (74) ◽  
pp. 119-133 ◽  
Author(s):  
Fritz Müller
Keyword(s):  
Thermal Regime ◽  
Energy Input ◽  
Canadian Arctic ◽  
High Arctic ◽  
Canadian Arctic Archipelago ◽  
Valley Glacier ◽  
Drilling Technique ◽  
Percolation Zone ◽  
Mean Annual Air Temperature ◽  
Upper Boundary

AbstractThe 10 m temperatures were measured over several years at 16 sites on the White Glacier (lat. 80° N.), Axel Heiberg Island, Canadian Arctic Archipelago. At three sites deep profiles were made using a new drilling technique, reaching a maximum depth of 280 m. Large differences in the 10 m temperatures between locations and from year to year were observed. The deviations of these temperatures from the almost isothermal mean annual air temperature over the glacier are discussed. The heating effect of the melt water in the lower percolation zone was found to be very important. A conceptual model is developed to assess the influence of these irregularities in the energy input at the upper boundary on the thermal regime of the entire glacier. So far a quantitative analysis has been made only for the relatively simple 30 m temperature profile measured on the tongue of the glacier.

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