The Grenville–Sveconorwegian orogen in the high Arctic

2012 ◽  
Vol 149 (5) ◽  
pp. 875-891 ◽  
Author(s):  
HENNING LORENZ ◽  
DAVID G. GEE ◽  
ALEXANDER N. LARIONOV ◽  
JAROSLAW MAJKA

AbstractThroughout the high Arctic, from northern Canada (Pearya) to eastern Greenland, Svalbard, Franz Josef Land, Novaya Zemlya, Taimyr and Severnaya Zemlya and, at lower Arctic latitudes, in the Urals and the Scandinavian Caledonides, there is evidence of the Grenville–Sveconorwegian Orogen. The latest orogenic phase (c. 950 Ma) is well exposed in the Arctic, but only minor Mesoproterozoic fragments of this orogen occur on land. However, detrital zircons in Neoproterozoic and Palaeozoic successions provide unambiguous Mesoproterozoic to earliest Neoproterozoic (c. 950 Ma) signatures. This evidence strongly suggests that the Grenville–Sveconorwegian Orogen continues northwards from type areas in southeastern Canada and southwestern Scandinavia, via the North Atlantic margins to the high Arctic continental shelves. The widespread distribution of late Mesoproterozoic detrital zircons far to the north of the Grenville–Sveconorwegian type areas is usually explained in terms of long-distance transport (thousands of kilometres) of either sediments by river systems from source to sink, or of slices of lithosphere (terranes) moved on major transcurrent faults. Both of these interpretations involve much greater complexity than the hypothesis favoured here, the former involving recycling of the zircons from the strata of initial deposition into those of their final residence and the latter requiring a diversity of microcontinents. Neither explains either the fragmentary evidence for the presence of Grenville–Sveconorwegian terranes in the high Arctic, or the composition of the basement of the continental shelves. The presence of the Grenville–Sveconorwegian Orogen in the Arctic, mainly within the hinterland and margins of the Caledonides and Timanides, has profound implications not only for the reconstructions of the Rodinia supercontinent in early Neoproterozoic time, but also the origin of these Neoproterozoic and Palaeozoic mountain belts.

2010 ◽  
Vol 107 (5) ◽  
pp. 2078-2081 ◽  
Author(s):  
Carsten Egevang ◽  
Iain J. Stenhouse ◽  
Richard A. Phillips ◽  
Aevar Petersen ◽  
James W. Fox ◽  
...  

The study of long-distance migration provides insights into the habits and performance of organisms at the limit of their physical abilities. The Arctic tern Sterna paradisaea is the epitome of such behavior; despite its small size (<125 g), banding recoveries and at-sea surveys suggest that its annual migration from boreal and high Arctic breeding grounds to the Southern Ocean may be the longest seasonal movement of any animal. Our tracking of 11 Arctic terns fitted with miniature (1.4-g) geolocators revealed that these birds do indeed travel huge distances (more than 80,000 km annually for some individuals). As well as confirming the location of the main wintering region, we also identified a previously unknown oceanic stopover area in the North Atlantic used by birds from at least two breeding populations (from Greenland and Iceland). Although birds from the same colony took one of two alternative southbound migration routes following the African or South American coast, all returned on a broadly similar, sigmoidal trajectory, crossing from east to west in the Atlantic in the region of the equatorial Intertropical Convergence Zone. Arctic terns clearly target regions of high marine productivity both as stopover and wintering areas, and exploit prevailing global wind systems to reduce flight costs on long-distance commutes.


2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Antti Piironen ◽  
Antti Paasivaara ◽  
Toni Laaksonen

Abstract Background Knowledge on migration patterns and flyways is a key for understanding the dynamics of migratory populations and evolution of migratory behaviour. Bird migration is usually considered to be movements between breeding and wintering areas, while less attention has been paid to other long-distance movements such as moult migration. Methods We use high-resolution satellite-tracking data from 58 taiga bean geese Anser fabalis fabalis from the years 2019–2020, to study their moult migration during breeding season. We show the moulting sites, estimate the migratory connectivity between the breeding and the moulting sites, and estimate the utilization distributions during moult. We reveal migration routes and compare the length and timing of migration between moult migrants and successful breeders. Results All satellite-tracked non-breeding and unsuccessfully breeding taiga bean geese migrated annually to the island of Novaya Zemlya in the high Arctic for wing moult, meaning that a large part of the population gathers at the moulting sites outside the breeding range annually for approximately three months. Migratory connectivity between breeding and moulting sites was very low (rm =  − 0.001, 95% CI − 0.1562–0.2897), indicating that individuals from different breeding grounds mix with each other on the moulting sites. Moult migrants began fall migration later in autumn than successful breeders, and their overall annual migration distance was over twofold compared to the successful breeders. Conclusions Regular moult migration makes the Arctic an equally relevant habitat for the taiga bean goose population as their boreal breeding and temperate wintering grounds, and links ecological communities in these biomes. Moult migration plays an important role in the movement patterns and spatio-temporal distribution of the population. Low migratory connectivity between breeding and moulting sites can potentially contribute to the gene flow within the population. Moult migration to the high Arctic exposes the population to the rapid impacts of global warming to Arctic ecosystems. Additionally, Novaya Zemlya holds radioactive contaminants from various sources, which might still pose a threat to moult migrants. Generally, these results show that moult migration may essentially contribute to the way we should consider bird migration and migratory flyways.


Antiquity ◽  
1991 ◽  
Vol 65 (246) ◽  
pp. 64-73 ◽  
Author(s):  
R. S. Thorpe ◽  
O. Williams-Thorpe

The megalithic monuments of western Europe have long been a celebrated proof of the engineering achievements possible in an early farming society. With the engineering skills to raise up the stones went the capability to move them to the site, with Stonehenge the best-known example of an apparent long-distance transport, incorporating Welsh bluestones and sarsens that perhaps originate in the Avebury region to the north. Following their recent challenge to the belief that the builders of Stonehenge did carry its bluestones from west Wales, the authors look critically at the larger pattern of megalithic manoeuvring.


Minerals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 36 ◽  
Author(s):  
Victoria B. Ershova ◽  
Andrei V. Prokopiev ◽  
Andrey K. Khudoley ◽  
Tom Andersen ◽  
Kåre Kullerud ◽  
...  

U–Pb and Lu–Hf isotope analyses of detrital zircons collected from metasedimentary rocks from the southern part of Kara Terrane (northern Taimyr and Severnaya Zemlya archipelago) provide vital information about the paleogeographic and tectonic evolution of the Russian High Arctic. The detrital zircon signatures of the seven dated samples are very similar, suggesting a common provenance for the clastic detritus. The majority of the dated grains belong to the late Neoproterozoic to Cambrian ages, which suggests the maximum depositional age of the enclosing sedimentary units to be Cambrian. The εHf(t) values indicate that juvenile magma mixed with evolved continental crust and the zircons crystallized within a continental magmatic arc setting. Our data strongly suggest that the main provenance for the studied clastics was located within the Timanian Orogen. A review of the available detrital zircon ages from late Neoproterozoic to Cambrian strata across the wider Arctic strongly suggests that Kara Terrane, Novaya Zemlya, Seward Peninsula (Arctic Alaska), Alexander Terrane, De Long Islands, and Scandinavian Caledonides all formed a single tectonic domain during the Cambrian age, with clastics predominantly sourced from the Timanian Orogen.


2019 ◽  
Vol 92 (2) ◽  
pp. 381-387
Author(s):  
R. Lee Lyman

AbstractRemains of the North American water vole (Microtus richardsoni) have previously been recovered from late Pleistocene and Holocene deposits in southwestern Alberta, western Montana, and north-central Wyoming. All are within the historically documented modern range of the metapopulation occupying the Rocky Mountains; no ancient remains of this large microtine have previously been reported from the metapopulation occupying the Cascade Range. Four lower first molar specimens from the late Holocene Stemilt Creek Village archaeological site in central Washington here identified as water vole are from the eastern slope of the Cascade Range and are extralimital to the metapopulation found in those mountains. There is no taphonomic evidence indicating long-distance transport of the teeth, and modern trapping records suggest the local absence of water voles from the site area today is not a function of sampling error. The precise age of the Stemilt Creek Village water voles is obscure but climate change producing well-documented late Holocene advances of nearby alpine glaciers could have created habitat conditions conducive to the apparent modest shift in the range of the species represented by the remains.


The Tertiary was a period of dramatic changes of the palaeo-oceanography of the world’s oceans in general and of the North Atlantic in particular. These changes were caused by (1) the bathymetric evolution of ocean basins and intrabasin pathways (opening of the Norwegian-Greenland Seas and of the pathway to the Arctic Ocean, interruption of the circumglobal equatorial seaway); (2) the geographical development of the oceans and adjacent marginal basins in the context of rapid and intensive eustatic sea level fluctuations; and (3) the deterioration of the global climate throughout the Tertiary (change from a non-glacial to a glacial world, causing major changes in circulation of the surface and deep water). A biostratigraphy of Tertiary sediments deposited close to the continental margins has been developed by using remains of planktonic floras and faunas. Their presence in these sediments and their usefulness for long distance correlations of margin sediments, depend upon the circulation pattern and hydrographic gradients of the oceanic surface and deep water masses, the climatic regime over the continental border zones, and the probability of their post-depositional preservation.


Nature ◽  
10.1038/19891 ◽  
1999 ◽  
Vol 399 (6731) ◽  
pp. 29-30 ◽  
Author(s):  
Ian D. Campbell ◽  
Karen McDonald ◽  
Michael D. Flannigan ◽  
Joanni Kringayark

1989 ◽  
Vol 12 ◽  
pp. 152-156 ◽  
Author(s):  
W.M. Sackinger ◽  
M.O. Jeffries ◽  
H. Tippens ◽  
F. Li ◽  
M. Lu

The largest ice island presently known to exist in the Arctic Ocean has a mass of about 700 × 106 tonnes, an area of about 26 km2, and a mean thickness of 42.5 m. Known as Hobson’s Ice Island, this large ice feature has been tracked almost continuously since August 1983 with a succession of Argos buoys. In this paper, two particular ice-island movement episodes near the north-west coast of Axel Heiberg Island are described: 6–16 May 1986 and 14–21 June 1986. Each movement episode is analyzed in terms of the forces acting on the ice island, including wind shear, water drag, water shear, Coriolis force, sea-surface tilt, and pack-ice force. Ice-island movement is generally preceded by an offshore surface wind, and a threshold wind speed of 6 m s°1 appears to be necessary to initiate ice-island motion. An angle of 50° between surface wind and ice-island movement direction is noted during one episode. The pack-ice force, which appears to be the dominant arresting factor of ice-island motion for these two episodes, varies from 100° to 180° to the left of the ice-island velocity direction, depending upon whether the ice island is accelerating or decelerating.


2021 ◽  
Vol 9 ◽  
Author(s):  
Jean-François Lamarre ◽  
Gilles Gauthier ◽  
Richard B. Lanctot ◽  
Sarah T. Saalfeld ◽  
Oliver P. Love ◽  
...  

Long-distance migrants are under strong selection to arrive on their breeding grounds at a time that maximizes fitness. Many arctic birds start nesting shortly after snow recedes from their breeding sites and timing of snowmelt can vary substantially over the breeding range of widespread species. We tested the hypothesis that migration schedules of individuals co-occurring at the same non-breeding areas are adapted to average local environmental conditions encountered at their specific and distant Arctic breeding locations. We predicted that timing of breeding site availability (measured here as the average snow-free date) should explain individual variation in departure time from shared non-breeding areas. We tested our prediction by tracking American Golden-Plovers (Pluvialis dominica) nesting across the North-American Arctic. These plovers use a non-breeding (wintering) area in South America and share a spring stopover area in the nearctic temperate grasslands, located &gt;1,800 km away from their nesting locations. As plovers co-occur at the same non-breeding areas but use breeding sites segregated by latitude and longitude, we could disentangle the potential confounding effects of migration distance and timing of breeding site availability on individual migration schedule. As predicted, departure date of individuals stopping-over in sympatry was positively related to the average snow-free date at their respective breeding location, which was also related to individual onset of incubation. Departure date from the shared stopover area was not explained by the distance between the stopover and the breeding location, nor by the stopover duration of individuals. This strongly suggests that plover migration schedule is adapted to and driven by the timing of breeding site availability per se. The proximate mechanism underlying the variable migration schedule of individuals is unknown and may result from genetic differences or individual learning. Temperatures are currently changing at different speeds across the Arctic and this likely generates substantial heterogeneity in the strength of selection pressure on migratory schedule of arctic birds migrating sympatrically.


Author(s):  
Alexander Sergunin

This chapter examines an emerging regional security system in the Arctic. There was a significant shift in the Arctic powers' threat perceptions and security policies in the High North. In contrast with the Cold War era when the Arctic was a zone for the global confrontation between the USSR and the U.S./NATO, now this region is seen by international players as a platform for international cooperation. The Arctic countries now believe that there are no serious hard security threats to them and that the soft security agenda is much more important. The military power now has new functions, such as ascertaining coastal states' sovereignty over their exclusive economic zones and continental shelves in the region; protecting the Arctic countries' economic interests in the North, and performing some symbolic functions. The Arctic states believe that the regional cooperative agenda could include climate change mitigation, environmental protection, maritime safety, Arctic research, indigenous peoples, cross- and trans-border cooperative projects, culture, etc.


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