The Laurentia – West Greenland connection at 1.9 Ga: New insights from the Rinkian fold belt

2017 ◽  
Vol 51 ◽  
pp. 289-309 ◽  
Author(s):  
Mary Sanborn-Barrie ◽  
Kristine Thrane ◽  
Natasha Wodicka ◽  
Nicole Rayner
Keyword(s):  
Fold Belt ◽  
West Greenland

scholarly journals New hornblende and muscovite 40Ar/39Ar cooling ages in the central Rinkian fold belt, West Greenland

2006 ◽  
Vol 11 ◽  
pp. 115-124 ◽  
Author(s):  
Ann-Sofie Sidgren ◽  
Laurence Page ◽  
Adam A. Garde
Keyword(s):  
Metamorphic Grade ◽  
Fold Belt ◽  
The South ◽  
Igneous Complex ◽  
West Greenland ◽  
Structural History

The Palaeoproterozoic Rinkian fold belt in West Greenland consists of reworked Archaean basement, mainly orthogneiss, and the unconformably overlying Palaeoproterozoic Karrat Group. Both parts were intensely deformed and metamorphosed at around 1.87 Ga, at which time the crustal anatectic Prøven igneous complex was emplaced into the northern part of the belt. Seven new hornblende and muscovite 40Ar/39Ar cooling ages are presented from the central–northern parts of the Rinkian fold belt. Four 40Ar/39Ar hornblende ages ranging from 1795 ± 3 to 1782 ± 3 Ma were obtained from amphibolite and hornblendite enclaves in the Archaean orthogneiss, and two from relict dyke fragments in the latter that may be of Palaeoproterozoic age. Three 40Ar/39Ar muscovite ages of 1681 ± 6 Ma, 1686 ± 3 Ma and 1676 ± 3 Ma were obtained from samples of Karrat Group metagreywacke, andalusite schist and metasiltstone. The new 40Ar/39Ar ages, from hornblende and muscovite respectively, are very uniform and probably unrelated to local metamorphic grade and structural history, and are interpreted as regional late orogenic cooling ages. The new hornblende ages are significantly older than those previously obtained from the central and northern parts of the adjacent Nagssugtoqidian orogen to the south, and point to different uplift histories, which may suggest that the orogeny was not synchronous in the two regions.

scholarly journals Fossils of Precambrian age from South-West Greenland

1968 ◽  
Vol 15 ◽  
pp. 51-53
Author(s):  
K.R Pedersen
Keyword(s):  
Fold Belt ◽  
West Greenland ◽  
South West

In the Ketilidian fold belt of South-West Greenland some areas are only little metamorphosed and have been shown to contain macroscopic and microscopic fossil structures the age of which must be 1700 - 2000 m. y. (Raunsgaard Pedersen, 1966 and 1967; Bondesen, Raunsgaard Pedersen and Jørgensen, 1967).

Potassium-argon age studies in West Greenland

1968 ◽  
Vol 5 (3) ◽  
pp. 683-691 ◽  
Author(s):  
Ole Larsen ◽  
Jørgen Møller
Keyword(s):  
Central Region ◽  
Shear Zones ◽  
Fold Belt ◽  
West Greenland ◽  
Basement Rocks ◽  
Igneous Activity ◽  
Basement Gneiss ◽  
Age Studies ◽  
North And South ◽  
Age Determinations

Geochronological units have been established in West Greenland partly on the basis of 34 new K–Ar age determinations, of which 32 were made on biotites.The central part of West Greenland belongs to a single basement gneiss unit more than 2700 m.y. old. Blocks of basement rocks are traversed by rectilinear shear zones tens of kilometers long and several kilometers wide. In these tectonic belts relic slices of supracrustal rocks occur within reworked basement gneisses. The latter give K–Ar ages of 2500–2700 m.y. Ages close to 1800 m.y. are found locally. North and south of the central region of old basement younger orogenic rocks are found: the Nagssutôqidian fold belt in northern West Greenland dated at approximately 1700 to 1750 m.y. and the Ketilidian fold belt in South Greenland of which the late- to post-kinematic granites are about 1500 to 1600 m.y. old. The Gardar non-orogenic igneous activity, 1000 to 1300 m.y., is found only in South Greenland.

A coastal survey in the southern part of the Palaeoproterozoic Rinkian fold belt, central West Greenland

2002 ◽  
pp. 33-38 ◽  
Author(s):  
Adam A. Garde ◽  
James N. Connelly ◽  
Adam W. Krawiec ◽  
Sandra Piazolo ◽  
Kristine Thrane
Keyword(s):  
Fold Belt ◽  
The South ◽  
Original Series ◽  
West Greenland ◽  
Field Investigations ◽  
Logistic Support

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article. Garde, A. A., Connelly, J. N., Krawiec, A. W., Piazolo, S., & Thrane, K. (1). A coastal survey in the southern part of the Palaeoproterozoic Rinkian fold belt, central West Greenland. Geology of Greenland Survey Bulletin, 191, 33-38. https://doi.org/10.34194/ggub.v191.5109 A brief but potentially important part of the 2001 field investigations in the Precambrian of West Greenland (van Gool et al. 2002, this volume) was devoted to the southernmost part of the Palaeoproterozoic Rinkian fold belt east of Disko Bugt (Fig. 1). From 9–17 August the five authors carried out a reappraisal of critical Archaean and Proterozoic relationships and collected samples for precise geochronological studies. The principal aims are to date the main Rinkian tectonic and metamorphic events in this region as precisely as possible and compare them with the evolution of the Nagssugtoqidian orogen to the south (see van Gool et al. 2002, this volume, fig. 1). The vessel M/S Søkongen provided logistic support; a helicopter provided transport to Nunatarsuaq.

scholarly journals Precambrian organic compounds from the Ketilidian of South-West Greenland. Part IV

1972 ◽  
Vol 101 ◽  
pp. 1-43
Author(s):  
J Lam ◽  
K.R Pedersen
Keyword(s):  
Organic Compounds ◽  
Organic Material ◽  
Published Data ◽  
Low Grade ◽  
Fold Belt ◽  
Graphite Sample ◽  
Normal Alkanes ◽  
West Greenland ◽  
Three Samples ◽  
Different Types

Organic compounds have been extracted from Ketilidian sedimentary rocks (nearly 2000 m.y. old). The results are compared with the previously published data obtained on material from the Ketilidian low metamorphic (greenschist facies) supracrustals and with results from graphite from the Nagssugtoqidian fold belt of West Greenland. Organic compounds have been extracted from two dolomitic samples and a graphite sample of respectively about 15 kg, 7 kg, and 8.5 kg. A grey dolomitic shale is the only dolomitic sample in which monoterpenoid compounds were found, and it is different from the others in the Jack of normal alkanes, or at least they are present only in trace amounts. A dark dolomitic sample is shown to contain normal alkanes of the range C11 to C20 and a graphite from a high-grade metamorphic gneiss (amphibolite facies) has a content of normal alkanes (C14 to C18), normal fatty acids from C12 to C18 and monounsaturated acids from C15 to C19 besides branched C13-, C14-, and C15-acids. The three samples contain branched-cyclic, aliphatic compounds and various aromatic substances, especially the homologous benzene, naphthalene, and phenanthrene compounds. The organic compounds extracted from the Ketilidian supracrustals are from graphitic and dolomitic rocks of different types deposited under rather different conditions. By comparison it is seen that low-grade metamorphosed samples yield the highest amounts of organic material per kilogram, and that monoterpenoids are present preferentially in coal-graphite samples while only one dolomitic sample contains detectable amounts of monoterpenoid compounds. The variation in the accumulation of organic material was perhaps dependent on the rate of production of organic material and/or on the deposition conditions. There was possibly also a difference in the biological activity, perhaps with different types of organisms, depending on other conditions in the area.

Seasonal diving and foraging behaviour of Eastern Canada-West Greenland bowhead whales

2020 ◽  
Vol 643 ◽  
pp. 197-217 ◽  
Author(s):  
SME Fortune ◽  
SH Ferguson ◽  
AW Trites ◽  
B LeBlanc ◽  
V LeMay ◽  
...  
Keyword(s):  
Climate Change ◽  
Late Summer ◽  
Calanoid Copepods ◽  
Eastern Canada ◽  
West Greenland ◽  
Bowhead Whales ◽  
Seasonal Movement ◽  
Dive Behaviour ◽  
Calanus Glacialis ◽  
Canada West

Climate change may affect the foraging success of bowhead whales Balaena mysticetus by altering the diversity and abundance of zooplankton species available as food. However, assessing climate-induced impacts first requires documenting feeding conditions under current environmental conditions. We collected seasonal movement and dive-behaviour data from 25 Eastern Canada-West Greenland bowheads instrumented with time-depth telemetry tags and used state-space models to examine whale movements and dive behaviours. Zooplankton samples were also collected in Cumberland Sound (CS) to determine species composition and biomass. We found that CS was used seasonally by 14 of the 25 tagged whales. Area-restricted movement was the dominant behaviour in CS, suggesting that the tagged whales allocated considerable time to feeding. Prey sampling data suggested that bowheads were exploiting energy-rich Arctic copepods such as Calanus glacialis and C. hyperboreus during summer. Dive behaviour changed seasonally in CS. Most notably, probable feeding dives were substantially shallower during spring and summer compared to fall and winter. These seasonal changes in dive depths likely reflect changes in the vertical distribution of calanoid copepods, which are known to suspend development and overwinter at depth during fall and winter when availability of their phytoplankton prey is presumed to be lower. Overall, CS appears to be an important year-round foraging habitat for bowheads, but is particularly important during the late summer and fall. Whether CS will remain a reliable feeding area for bowhead whales under climate change is not yet known.

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