Evolution of the Boothia Uplift, arctic Canada

1986 ◽  
Vol 23 (3) ◽  
pp. 350-358 ◽  
Author(s):  
A. V. Okulitch ◽  
J. J. Packard ◽  
A. I. Zolnai
Keyword(s):  
Vertical Component ◽  
Crystalline Basement ◽  
Ellesmere Island ◽  
The Arctic ◽  
Low Grade ◽  
Early Paleozoic ◽  
Horizontal Movement ◽  
Compressive Stresses ◽  
Caledonian Orogeny ◽  
Late Stages

The Boothia Uplift extends 1000 km northward from the northern Canadian Shield into the Arctic Archipelago. Consisting of a core of Archean(?) to Aphebian gneissic units and a cover of Proterozoic to Devonian strata of the Arctic Platform and Franklinian Miogeocline, it formed during several minor pulses of uplift in the late Proterozoic and early Paleozoic and a major episode of tectonism during the Siluro-Devonian. Although it has long been regarded as a "horst" or vertical block uplift, compilation of new and previous data suggests that the uplift can be interpreted as a major, west-directed, imbricate mass of crystalline basement mantled by faulted and drape-folded cover. Details of the vertical component of movement have been provided by sedimentological and stratrigraphic studies. Uplift increases northward from the craton to a maximum of 5 km. Estimates of horizontal movement, predicated on assumed fault dips, could be as much as 30 km.Major tectonism of the Boothia Uplift was approximately coeval with uplift on southeastern Ellesmere Island and on northern Axel Heiberg Island, folding and low-grade metamorphism on northernmost Ellesmere Island, and west-directed thrusting and folding on Greenland. The plate tectonic interactions responsible for these events remain obscure; a general regime of west-directed compressive stresses associated with late stages of the Caledonian Orogeny may have been present.

Contributions to the tectonic history of the Innuitian Province, Arctic Canada

1979 ◽  
Vol 16 (3) ◽  
pp. 748-769 ◽  
Author(s):  
H. P. Trettin ◽  
H. R. Balkwill
Keyword(s):  
Late Cretaceous ◽  
Ellesmere Island ◽  
North American Plate ◽  
The Arctic ◽  
Mobile Belt ◽  
Lomonosov Ridge ◽  
Early Paleozoic ◽  
Sverdrup Basin ◽  
History Of ◽  
A Site

The Innuitian Tectonic Province contains the record of a Phanerozoic mobile belt in northern Greenland and the Canadian Arctic Archipelago. Two fundamentally different phases in its development were separated by the Devonian–Carboniferous Ellesmerian Orogeny. The first contribution focuses on the early Paleozoic history of a key area, the second summarizes the Carboniferous to Cenozoic history of most of the Canadian part of the province.(1) The early Paleozoic architecture of the mobile belt is apparent only in Ellesmere Island, where exposures extend from the Canadian Shield through Arctic Platform and Franklinian basin into the Pearya orogenic welt. The Franklinian basin comprised the deep but ensulic Hazen Trough and two unstable shelves bordering it on the northwest and southeast. The northwestern shelf was a site of felsic to intermediate volcanism, mainly in the Ordovician Period. Pearya, a site of granitic plutonism in the Devonian Period, supplied much of the clastic basin fill. Its core consisted of a metamorphic complex, about 1.0 Ga old, exposed in basement uplifts in nor thernmost Ellesmere Island. Both basin and welt essentially formed part of the North American Plate, although rifting, evident from mafic and ultramafic intrusions, probably occurred in Early Devonian (or latest Silurian) time. The history of this part of the province is tentatively interpreted as response to the opening and closure of an ocean, connected with lapetus, that separated northern Ellesmere Island and Greenland from the sialic crust of the present Lomonosov Ridge and Barents Shelf. The Lomonosov Ridge still seems to be attached to the shelf off northeasternmost Ellesmere Island.(2) Deep subsidence and filling of Sverdrup Basin dominated the Innuitian region from Early Carboniferous through Late Cretaceous time. Large halokinetic diapirs and mafic dikes and sills intruded axial parts of the basin succession through Mesozoic time. Steep faults along the northwestern margin of the basin are Middle Cretaceous and older. Part of the northwestern rim of Sverdrup Basin sagged in latest Cretaceous time, becomingpart of the Arctic continental terrace. In the Late Cretaceous and early Tertiary a system of large grabens developed through the southern part of the Innuitian region, linking Canada Basin with Baffin Bay; about the same time, uplift formed some large arches in the northeastern part of the region. Middle Eocene and older rocks were laterally compressed by a phase of pre-Miocene folding and faulting. Some uplift took place in Oligocene or Miocene time on Axel Heiberg Island. The distribution of recent earth quakes does not indicate the presence of modern active plate margins.

scholarly journals New constraints on the age, geochemistry, and environmental impact of High Arctic Large Igneous Province magmatism: Tracing the extension of the Alpha Ridge onto Ellesmere Island, Canada

2020 ◽  
Author(s):  
T.V. Naber ◽  
S.E. Grasby ◽  
J.P. Cuthbertson ◽  
N. Rayner ◽  
C. Tegner
Keyword(s):  
Volcanic Rocks ◽  
High Arctic ◽  
Ellesmere Island ◽  
Large Igneous Province ◽  
The Arctic ◽  
Trace Element Geochemistry ◽  
Volcanic Complex ◽  
Northern Coast ◽  
Element Geochemistry ◽  
Igneous Province

The High Arctic Large Igneous Province (HALIP) represents extensive Cretaceous magmatism throughout the circum-Arctic borderlands and within the Arctic Ocean (e.g., the Alpha-Mendeleev Ridge). Recent aeromagnetic data shows anomalies that extend from the Alpha Ridge onto the northern coast of Ellesmere Island, Nunavut, Canada. To test this linkage we present new bulk rock major and trace element geochemistry, and mineral compositions for clinopyroxene, plagioclase, and olivine of basaltic dykes and sheets and rhyolitic lavas for the stratotype section at Hansen Point, which coincides geographically with the magnetic anomaly at northern Ellesmere Island. New U-Pb chronology is also presented. The basaltic and basaltic-andesite dykes and sheets at Hansen Point are all evolved with 5.5−2.5 wt% MgO, 48.3−57.0 wt% SiO2, and have light rare-earth element enriched patterns. They classify as tholeiites and in Th/Yb vs. Nb/Yb space they define a trend extending from the mantle array toward upper continental crust. This trend, also including a rhyolite lava, can be modeled successfully by assimilation and fractional crystallization. The U-Pb data for a dacite sample, that is cut by basaltic dykes at Hansen Point, yields a crystallization age of 95.5 ± 1.0 Ma, and also shows crustal inheritance. The chronology and the geochemistry of the Hansen Point samples are correlative with the basaltic lavas, sills, and dykes of the Strand Fiord Formation on Axel Heiberg Island, Nunavut, Canada. In contrast, a new U-Pb age for an alkaline syenite at Audhild Bay is significantly younger at 79.5 ± 0.5 Ma, and correlative to alkaline basalts and rhyolites from other locations of northern Ellesmere Island (Audhild Bay, Philips Inlet, and Yelverton Bay West; 83−73 Ma). We propose these volcanic occurrences be referred to collectively as the Audhild Bay alkaline suite (ABAS). In this revised nomenclature, the rocks of Hansen Point stratotype and other tholeiitic rocks are ascribed to the Hansen Point tholeiitic suite (HPTS) that was emplaced at 97−93 Ma. We suggest this subdivision into suites replace the collective term Hansen Point volcanic complex. The few dredge samples of alkali basalt available from the top of the Alpha Ridge are akin to ABAS in terms of geochemistry. Our revised dates also suggest that the HPTS and Strand Fiord Formation volcanic rocks may be the hypothesized subaerial large igneous province eruption that drove the Cretaceous Ocean Anoxic Event 2.

Radiogenic Isotope Signatures of Holocene Sediments from Kane Basin: Linkage with the Re-opening and Evolution of Nares Strait

2021 ◽  
Author(s):  
Lina Madaj ◽  
Friedrich Lucassen ◽  
Claude Hillaire-Marcel ◽  
Simone A. Kasemann
Keyword(s):  
Ellesmere Island ◽  
The Arctic ◽  
Baffin Bay ◽  
Low Salinity ◽  
The Core ◽  
The Past ◽  
Nares Strait ◽  
The North ◽  
Sediment Input ◽  
Detrital Sediment

<p>The re-opening of the Arctic Ocean-Baffin Bay gateway through Nares Strait, following the Last Glacial Maximum, has been partly documented, discussed and revised in the past decades. The Nares Strait opening has led to the inception of the modern fast circulation pattern carrying low-salinity Arctic water towards Baffin Bay and further towards the Labrador Sea. This low-salinity water impacts thermohaline conditions in the North Atlantic, thus the Atlantic Meridional Overturning Circulation. Available land-based and marine records set the complete opening between 9 and 7.5 ka BP [1-2], although the precise timing and intensification of the southward flowing currents is still open to debate. A recent study of a marine deglacial sedimentary record from Kane Basin, central Nares Strait, adds information about subsequent paleoceanographic conditions in this widened sector of the strait and proposed the complete opening at ~8.3 ka BP [3].</p><p>We present complementary radiogenic strontium, neodymium and lead isotope data of the siliciclastic detrital sediment fraction of this very record [3] further documenting the timing and pattern of Nares Strait opening from a sediment provenance approach. The data permit to distinguish detrital material from northern Greenland and Ellesmere Island, transported to the core location from both sides of Nares Strait. Throughout the Holocene, the evolution of contributions of these two sources hint to the timing of the ice break-up in Kennedy Channel, north of Kane Basin, which led to the complete opening of Nares Strait [3]. The newly established gateway of material transported to the core location from the north via Kennedy Channel is recorded by increased contribution of northern Ellesmere Island detrital sediment input. This shift from a Greenland (Inglefield Land) dominated sediment input to a northern Ellesmere Island dominated sediment input supports the hypothesis of the newly proposed timing of the complete opening of Nares Strait at 8.3 ka BP [3] and highlights a progressive trend towards modern-like conditions, reached at about 4 ka BP.</p><p>References:</p><p>[1] England (1999) Quaternary Science Reviews, 18(3), 421–456. [2] Jennings et al. (2011) Oceanography, 24(3), 26-41. [3] Georgiadis et al. (2018) Climate of the Past, 14 (12), 1991-2010.</p>

scholarly journals An estimate of ice wedge volume for a High Arctic polar desert environment, Fosheim Peninsula, Ellesmere Island

2018 ◽  
Vol 12 (11) ◽  
pp. 3589-3604 ◽  
Author(s):  
Claire Bernard-Grand'Maison ◽  
Wayne Pollard
Keyword(s):  
Satellite Imagery ◽  
Regional Scale ◽  
High Arctic ◽  
Ellesmere Island ◽  
The Arctic ◽  
Ground Ice ◽  
Polar Desert ◽  
Ice Volume ◽  
Carbon Release ◽  
Wedge Volume

Abstract. Quantifying ground-ice volume on a regional scale is necessary to assess the vulnerability of permafrost landscapes to thaw-induced disturbance like terrain subsidence and to quantify potential carbon release. Ice wedges (IWs) are a ubiquitous ground-ice landform in the Arctic. Their high spatial variability makes generalizing their potential role in landscape change problematic. IWs form polygonal networks that are visible on satellite imagery from surface troughs. This study provides a first approximation of IW ice volume for the Fosheim Peninsula, Ellesmere Island, a continuous permafrost area characterized by polar desert conditions and extensive ground ice. We perform basic GIS analyses on high-resolution satellite imagery to delineate IW troughs and estimate the associated IW ice volume using a 3-D subsurface model. We demonstrate the potential of two semi-automated IW trough delineation methods, one newly developed and one marginally used in previous studies, to increase the time efficiency of this process compared to manual delineation. Our methods yield acceptable IW ice volume estimates, validating the value of GIS to estimate IW volume on much larger scales. We estimate that IWs are potentially present on 50 % of the Fosheim Peninsula (∼3000 km2), where 3.81 % of the top 5.9 m of permafrost could be IW ice.

Salamander tracks (Ambystomichnus?) from the Cathedral Bluffs tongue of the Wasatch Formation (Eocene), northeastern Green River Basin, Wyoming

2001 ◽  
Vol 75 (4) ◽  
pp. 901-904 ◽  
Author(s):  
John R. Foster
Keyword(s):  
United States ◽  
Skeletal Remains ◽  
Ellesmere Island ◽  
Green River Formation ◽  
Western United States ◽  
The Arctic ◽  
Early Eocene ◽  
Green River Basin ◽  
Green River ◽  
Vertebrate Tracks

Vertebrate tracks are comparatively rare in Tertiary deposits of the western United States. Unlike the deposits of the Mesozoic in this region, in which each formation often has several dozen known tracksites, there are only a few known sites in Paleocene units of the region (Lockley and Hunt, 1995), and though the Eocene Green River Formation contains relatively numerous tracks, especially those of birds, there are only a few taxa represented. The occurrence of amphibian tracks in the Eocene Wasatch Formation is therefore of interest, not only in that it adds to the known ichnological record of the Tertiary of the western United States but also in that the tracks indicate the presence of an otherwise under-represented member of the vertebrate paleofauna of the time. Skeletal remains of amphibians are present but not common in many Tertiary formations of the western United States, and remains of large salamanders are rare. Only the large caudate Piceoerpeton is known from the Tiffanian and Clarkforkian of Montana and Wyoming (Naylor and Krause, 1981), and its only Wasatchian occurrence is at Ellesmere Island, north of the Arctic Circle. The tracks described here appear to represent a nearly Piceoerpeton-sized salamander in the lacustrine shoreline deposits of the early Eocene Wasatch Formation of southwestern Wyoming.

NOTES ON SOME ARCTIC COLLEMBOLA

1938 ◽  
Vol 70 (7) ◽  
pp. 151-154 ◽  
Author(s):  
H. G. James
Keyword(s):  
Canadian Arctic ◽  
Ellesmere Island ◽  
The Arctic ◽  
Baffin Island ◽  
Arctic Circle ◽  
Far North ◽  
Southern Shore

The following notes were made from a study of several species of Arctic Coollembola collected by Mr. W. J. Brown, of the Division of Entomology, Ottawa. Mr. Brown accompanied the voyage of the Canadian Arctic Patrol during August and September, 1935. During the trip he was able to collect on the southern shore of Baffin Island, and also well within the Arctic Circle as far north as Ellesmere Island.

Rapid neoglaciation on Ellesmere Island promoted by enhanced summer snowfall in a transient climate model simulation of the middle-late-Holocene

The Holocene ◽  
2020 ◽  
Vol 30 (10) ◽  
pp. 1474-1480
Author(s):  
Stephen J Vavrus ◽  
Feng He ◽  
John E Kutzbach ◽  
William F Ruddiman
Keyword(s):  
Snow Depth ◽  
Late Holocene ◽  
Climate Model ◽  
Model Simulation ◽  
Short Circuit ◽  
Ellesmere Island ◽  
The Arctic ◽  
Holocene Thermal Maximum ◽  
Model Driven ◽  
The Arctic Oscillation

Arctic neoglaciation following the Holocene Thermal Maximum is an important feature of late-Holocene climate. We investigated this phenomenon using a transient 6000-year simulation with the CESM-CAM5 climate model driven by orbital forcing, greenhouse gas concentrations, and a land use reconstruction. During the first three millennia analyzed here (6–3 ka), mean Arctic snow depth increases, despite enhanced greenhouse forcing. Superimposed on this secular trend is a very abrupt increase in snow depth between 5 and 4.9 ka on Ellesmere Island and the Greenland coasts, in rough agreement with the timing of observed neoglaciation in the region. This transition is especially extreme on Ellesmere Island, where end-of-summer snow coverage jumps from nearly 0 to virtually 100% in 1 year, and snow depth increases to the model’s imposed maximum within 15 years. This climatic shift involves more than the Milankovitch-based expectation of cooler summers causing less snow melt. Coincident with the onset of the cold regime are two consecutive summers with heavy snowfall on Ellesmere Island that help to short-circuit the normal seasonal melt cycle. These heavy snow seasons are caused by synoptic-scale, cyclonic circulation anomalies over the Arctic Ocean and Canadian Archipelago, including an extremely positive phase of the Arctic Oscillation. Our study reveals that a climate model can produce sudden climatic transitions in this region prone to glacial inception and exceptional variability, due to a dynamic mechanism (more summer snowfall induced by an extreme circulation anomaly) that augments the traditional Milankovitch thermodynamic explanation of orbitally induced glacier development.

scholarly journals A new aeromagnetic survey of the North Pole and the Arctic Ocean north of Greenland and Ellesmere Island

2010 ◽  
Vol 62 (10) ◽  
pp. 829-832 ◽  
Author(s):  
Jürgen Matzka ◽  
Thorkild M. Rasmussen ◽  
Arne V. Olesen ◽  
Jens Emil Nielsen ◽  
Rene Forsberg ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Ellesmere Island ◽  
North Pole ◽  
The Arctic ◽  
Aeromagnetic Survey ◽  
The North ◽  
The Arctic Ocean

Slope hummock development, Fosheim Peninsula, Ellesmere Island, Nunavut, Canada

2011 ◽  
Vol 75 (2) ◽  
pp. 334-346 ◽  
Author(s):  
Antoni G. Lewkowicz
Keyword(s):  
Time Frame ◽  
Ellesmere Island ◽  
Silty Sand ◽  
Sensitivity Analyses ◽  
The Arctic ◽  
Patterned Ground ◽  
Vegetation Growth ◽  
Long Term Effect ◽  
Organic Horizons ◽  
Precipitation Increase

AbstractSlope hummocks, a type of nonsorted patterned ground, are composed of stratified, organic, silty sand, and develop through the interaction of niveo-eolian deposition, solifluction, slopewash, and vegetation growth. Fields of hummocks show consistent patterns: forms on convex slopes increase in height downslope until the channel is reached, whereas those on convexo-concave slopes increase on the upper convexity but are buried by niveo-eolian deposition downslope of the snowbank remnant. These trends can be reproduced using a simple numerical model based on measured slope and snow depth profiles, sediment concentrations in the snow and solifluction rates. The model indicates that hummocks transit slopes of 20–40 m in about 2–4 ka, a time-frame that is plausible given site emergence, measured rates of solifluction, and published dates for organic horizons within hummocks on northern Ellesmere Island. Sensitivity analyses show that long-term effect of climate warming on hummock heights may differ depending on whether it is accompanied by precipitation increase or decrease. The required combination of two-sided freezing to promote plug-like movement, incomplete vegetation cover and thin snow that enable eolian erosion during winter and spring, and vegetation growth in snow-bed sites to stabilize niveo-eolian deposits may explain why these forms are important regionally but apparently are not present throughout the Arctic.

Sign in / Sign up

Export Citation Format

Share Document