scholarly journals Tectonic variation and structural evolution of the West Greenland continental margin

AAPG Bulletin ◽  
2015 ◽  
Vol 99 (09) ◽  
pp. 1689-1711 ◽  
Author(s):  
S. Alsulami ◽  
D.A. Paton ◽  
D.G. Cornwell
Keyword(s):  
Continental Margin ◽  
Structural Evolution ◽  
The West ◽  
West Greenland

scholarly journals Tectonostratigraphy and evolution of the West Greenland continental margin

2020 ◽  
Vol 67 ◽  
pp. 1-21 ◽  
Author(s):  
Ulrik Gregersen ◽  
Paul C. Knutz ◽  
Henrik Nøhr-Hansen ◽  
Emma Sheldon ◽  
John R. Hopper
Keyword(s):  
Oceanic Crust ◽  
Continental Margin ◽  
Volcanic Rocks ◽  
Sedimentary Basins ◽  
Magnetic Data ◽  
The West ◽  
Seismic Reflection Data ◽  
Baffin Bay ◽  
West Greenland ◽  
North East

Large structural highs and sedimentary basins are identified from mapping of the West Greenland continental margin from the Labrador Sea to the Baffin Bay. We present a new tectonic elements map and a map of thickness from the seabed to the basement of the entire West Greenland margin. In addition, a new stratigraphic scheme of the main lithologies and tectonostratigraphy based on ties to all offshore exploration wells is presented together with seven interpreted seismic sections. The work is based on interpretation of more than 135 000 km of 2D seismic reflection data supported by other geophysical data, including gravity- and magnetic data and selected 3D seismic data, and is constrained by correlation to wells and seabed samples. Eight seismic mega-units (A–H) from the seabed to the basement, related to distinct tectonostratigraphic phases, were mapped. The oldest units include pre-rift basins that contain Proterozoic and Palaeozoic successions. Cretaceous syn-rift phases are characterised by development of large extensional fault blocks and basins with wedge-shaped units. The basin strata include Cretaceous and Palaeogene claystones, sandstones and conglomerates. During the latest Cretaceous, Paleocene and Eocene, crustal extension followed by oceanic crust formation took place, causing separation of the continental margins of Greenland and Canada with north-east to northward movement of Greenland. From Paleocene to Eocene, volcanic rocks dominated the central West Greenland continental margin and covered the Cretaceous basins. Development of the oceanic crust is associated with compressional tectonics and the development of strike-slip and thrust faults, pull-apart basins and inversion structures, most pronounced in the Davis Strait and Baffin Bay regions. During the late Cenozoic, tectonism diminished, though some intra-plate vertical adjustments occurred. The latest basin development was characterised by formation of thick Neogene to Quaternary marine successions including contourite drifts and glacial related shelf progradation towards the west and south-west.

scholarly journals Genetic mixed-stock analysis disentangles spatial and temporal variation in composition of the West Greenland Atlantic Salmon fishery

2016 ◽  
Vol 73 (9) ◽  
pp. 2311-2321 ◽  
Author(s):  
Ian R. Bradbury ◽  
Lorraine C. Hamilton ◽  
Timothy F. Sheehan ◽  
Gerald Chaput ◽  
Martha J. Robertson ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
North American ◽  
Temporal Stability ◽  
Spatial And Temporal Variation ◽  
Published Data ◽  
The West ◽  
West Greenland ◽  
Archived Samples ◽  
Mixed Stock ◽  
Salmon Fishery

Abstract The West Greenland Atlantic Salmon (Salmo salar) fishery represents the largest remaining mixed-stock fishery for Atlantic Salmon in the Northwest Atlantic and targets multi-sea-winter (MSW) salmon from throughout North America and Europe. We evaluated stock composition of salmon harvested in the waters off West Greenland (n = 5684 individuals) using genetic mixture analysis and individual assignment to inform conservation of North American populations, many of which are failing to meet management targets. Regional contributions to this fishery were estimated using 2169 individuals sampled throughout the fishery between 2011 and 2014. Of these, 22% were identified as European in origin. Major North American contributions were detected from Labrador (∼20%), the Southern Gulf/Cape Breton (29%), and the Gaspe Peninsula (29%). Minor contributions (∼5%) were detected from Newfoundland, Ungava, and Quebec regions. Region-specific catches were extrapolated using estimates of composition and fishery catch logs and harvests ranged from 300 to 600 and 2000 to 3000 individuals for minor and major constituents, respectively. To evaluate the temporal stability of the observed fishery composition, we extended the temporal coverage through the inclusion of previously published data (1995–2006, n = 3095) and data from archived scales (1968–1998, n = 420). Examination of the complete time-series (47 years) suggests relative stability in stock proportions since the late 1980s. Genetic estimates of stock composition were significantly associated with model-based estimates of returning MSW salmon (individual years r = 0.69, and overall mean r = 0.96). This work demonstrates that the analysis of both contemporary and archived samples in a mixed-stock context can disentangle levels of regional exploitation and directly inform assessment and conservation of Atlantic Salmon in the West Greenland interceptory Atlantic Salmon fishery.

scholarly journals Topographic and Glaciological Controls on Holocene Ice-Sheet Margin Dynamics. Central West Greenland

1990 ◽  
Vol 14 ◽  
pp. 307-310 ◽  
Author(s):  
C.R. Warren ◽  
N.R.J. Hulton
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Glacial Maximum ◽  
Warm Climate ◽  
Short Term ◽  
The West ◽  
West Greenland ◽  
The Past

The retreat of the West Greenland ice sheet from its Sisimiut (Wisconsinan) glacial maximum, was punctuated by a series of Stillstands or small readvances that formed numerous moraines. These landforms have been interpreted in the past as the result of short-term, regional falls in ablation-season temperatures. However, mapping of the geomorphological evidence south of Ilulissat (Jakobshavn) suggests that retreat behaviour was not primarily governed by climate, and therefore that the former ice margins are not palaeoclimatically significant. During warm climate ice-sheet wastage, the successive quasi-stable positions adopted by the ice margin were largely governed by topography. The retreat of the inherently unstable calving glaciers was arrested only at topographically-determined locations where stability could be achieved.

Anorogenic magmatism and the Grenvillian Orogeny

1989 ◽  
Vol 26 (3) ◽  
pp. 479-489 ◽  
Author(s):  
Brian F. Windley
Keyword(s):  
United States ◽  
South America ◽  
Continental Margin ◽  
South Atlantic ◽  
Island Arc ◽  
The South ◽  
The West ◽  
Continental Block ◽  
Grenvillian Orogeny ◽  
Alkaline Complexes

The Grenvillian Orogeny was preceded by extensive anorogenic volcanism and plutonism in the period 1500–1300 Ma in the form of rhyolites, epizonal granites, anorthosites, gabbros, alkaline complexes, and basic dykes. An analogue for the mid-Proterozoic anorogenic complexes is provided by the 2000 km by 200 km belt of anorogenic complexes in the Hoggar, Niger, and Nigeria, which contain anorthosites, gabbros, and peralkaline granites and were generated in a Cambrian to Jurassic rift that farther south led to the formation of the South Atlantic. An analogue for the 1 × 106 km2 area of 1500–1350 Ma rhyolites (and associated epizonal granites) that underlie the mid-continental United States is provided by the 1.7 × 106 km2 area of Jurassic Tobifera rhyolites in Argentina, which were extruded on the stretched continental margin of South America immediately preceding the opening of the South Atlantic. The mid-Proterozoic complexes were intruded close to the continental margin of the Grenvillian ocean and were commonly superimposed by the craton-directed thrusts that characterized the final stages of the Grenvillian Orogeny. The bulk of the Keweenawan rift and associated anorogenic magmatism formed about 1100 Ma at the same time as the Ottawan Orogeny in Ontario, which probably resulted from the collision of the island arc of the Central Metasedimentary Belt attached to the continental block in the east with the continental block to the west. The most appropriate modern equivalent would be the Rhine Graben, which formed at the same time as the main Alpine compression.

scholarly journals Quaternary deposits between the Sukkertoppen ice cap and Nordre Strømfjord

1970 ◽  
Vol 28 ◽  
pp. 23-25
Author(s):  
A Weidick ◽  
N.W Ten Brink
Keyword(s):  
Land Area ◽  
The West ◽  
Quaternary Deposits ◽  
Sea Levels ◽  
West Greenland ◽  
Marine Deposits ◽  
Ice Cap

The area investigated during 1969 is located approximate1y between 66° 10' and 67° 30' N, and 50° and 52° W, the eastem half of the West Greenland ice-free land area transected by Søndre Strømfjord. The principal objectives of the work were to map and describe the glacial and emerged marine deposits for a Quatemary map at 1:500 000 scale, and to collect material for establishing a radiometric chronology of former ice-margin positions and sea levels. In order to study as large an area as possible, the investigations north of Søndre Strømfjord and Sondrestrom Airbase were conducted by A. Weidick, the area south of this by N. W. Ten Brink.

scholarly journals A pilot seismo-stratigraphic study on the West Greenland continental shelf

1989 ◽  
Vol 142 ◽  
pp. 1-16
Author(s):  
J.A Chalmers
Keyword(s):  
Petroleum Industry ◽  
Source Rocks ◽  
Tectonic Activity ◽  
The West ◽  
West Greenland ◽  
Main Site ◽  
Half Graben ◽  
Greenland Basin ◽  
Seismic Sections ◽  
Structural Closure

Seismo-stratigraphic interpretation of seismic sections dating from the mid-1970s has disclosed the existence of four megasequences of sediments, the oldest of which has not previously been reported from West Greenland. The basins containing these sediments developed as a series of coalescing half graben, in which the main site of tectonic activity changed with time. A structural closure of sufficient size to contain interesting quantities of hydrocarbons, given suitable source rocks, reservoir and seal, is identified. The study has shown that the evaluation of the West Greenland Basin during the 1970s was inadequate, and that abandonment of exploration by the petroleum industry may have been premature.

scholarly journals Application of seismo-stratigraphic interpretation techniques to offshore West Greenland

1988 ◽  
Vol 140 ◽  
pp. 64-66
Author(s):  
J.A Chalmers
Keyword(s):  
Pilot Study ◽  
Seismic Data ◽  
Seismic Interpretation ◽  
Shelf Break ◽  
The West ◽  
Regional Geology ◽  
West Greenland ◽  
Oil Companies ◽  
Greenland Basin ◽  
Basement Ridge

A pilot study is being conducted to determine if the use of seismo-stratigraphic interpretation techniques can increase the understanding af the geology of offshore West Greenland in order to reassess the prospectivity of the area. During the period 1975 to 1979, a number of concessions offshore West Greenland were licensed to various consortia of oil companies to search for petroleum. Some 40 000 km of seismic data were acquired, all of which is now released. Five wells were drilled, all of them dry, and all concessions were relinquished by the industry by 1979. The regional geology of offshore West Greenland has been summarised by Manderscheid (1980) and Henderson et al. (1981). They show the West Greenland Basin to consist of fairly uniformly westward dipping sediments bordered near the shelf break by a basement ridge. These authors used what may be termed 'conventional' techniques of seismic interpretation. However, since that time the techniques of seismo-stratigraphy (Vail et al., 1977; Hubbard et al., 1985) have become established. They are now being applied to study seismic data acquired during the mid-1970s.

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