scholarly journals Freshwater Export in the East Greenland Current Freshens the North Atlantic

2018 ◽  
Vol 45 (24) ◽  
Author(s):  
L. Steur ◽  
C. Peralta‐Ferriz ◽  
O. Pavlova
Keyword(s):  
North Atlantic ◽  
East Greenland ◽  
The North ◽  
East Greenland Current ◽  
The North Atlantic ◽  
Freshwater Export

scholarly journals C14 content of recent molluscs from Scoresby Sund, central East Greenland

1975 ◽  
Vol 75 ◽  
pp. 95-99
Author(s):  
H Tauber ◽  
S Funder
Keyword(s):  
North Atlantic ◽  
East Coast ◽  
Marine Organisms ◽  
Water Masses ◽  
Lower Activity ◽  
Terrestrial Plants ◽  
East Greenland ◽  
The North ◽  
The North Atlantic ◽  
Turn Over

C14 dating of subfossil marine shelIs presupposes a knowledge of the original C14 activity of the organisms while living. Due to the slow turn over of water masses, the C14 activity of marine bicarbonate and marine organisms is not the same in all parts of the oceans, but may show marked deficiencies in certain oceanic areas, especially at southern latitudes. In large areas of the North Atlantic the C14 activity seems to be fairly uniform and equal to or only slightly lower than that of 'pre-industrial' terrestrial plants (Broecker et al., 1960; Mangerud, 1972; Krog & Tauber, 1974). In certain areas, however, a somewhat lower activity seems to occur; trus has been noted for areas along the east coast of Greenland (Fonselius & Ostlund, 1959; Hjort, 1973).

Dating of late Paleozoic rifting events in the North Atlantic: New biostratigraphic data from the uppermost Devonian and Carboniferous of East Greenland

Geology ◽  
1991 ◽  
Vol 19 (3) ◽  
pp. 218 ◽  
Author(s):  
Lars Stemmerik ◽  
Jorunn Os Vigran ◽  
Stefan Piasecki
Keyword(s):  
North Atlantic ◽  
Late Paleozoic ◽  
East Greenland ◽  
The North ◽  
The North Atlantic

scholarly journals Nd and Sr isotope compositions from the Gardiner Complex, East Greenland Tertiary igneous province

1993 ◽  
Vol 40 ◽  
pp. 280-287
Author(s):  
Troels F. D. Nielsen ◽  
Paul M. Holm
Keyword(s):  
Isotopic Composition ◽  
North Atlantic ◽  
Alkaline Magmatism ◽  
Sr Isotope ◽  
East Greenland ◽  
The North ◽  
Early Tertiary ◽  
Igneous Province ◽  
The North Atlantic

The Gardiner Complex formed during the early Tertiary opening of the North Atlantic. The complex is strongly alkaline and referred to a zone of alkaline flank magmatism 100 km west of the melting anomaly in the initial rift of the North Atlantic. Earlier investigations have documented that most rocks of the complex can be referred to three suites which are all suggested to have been formed from a single parental melanephelinitic liquid. The Nd and Sr isotope compositions presented here support this conclusion. Minor deviations are believed to be due to interaction with Archaean basement. The isotopic characteristics suggest that the alkaline magmatism originated in a source similar to that of the contemporaneous picritic and basaltic tholeiites. The isotopic composition of the source is Jess depleted than pervalent mantle (PREMA) and sets an upper enrichment limit to the composition of the Icelandic plume component 50 Ma ago.

scholarly journals Geology and petrology of the Lower Tertiary plateau basalts of the Scoresby Sund region, East Greenland

1989 ◽  
Vol 157 ◽  
pp. 1-164
Author(s):  
L.M Larsen ◽  
W.S Watt ◽  
M Watt
Keyword(s):  
North Atlantic ◽  
Mantle Source ◽  
Atlantic Coast ◽  
Crustal Contamination ◽  
Basalt Magma ◽  
Magma Chambers ◽  
East Greenland ◽  
The Third ◽  
The North ◽  
The North Atlantic

The early Tertiary plateau basalts in East Greenland are situated on a continental margin and were erupted during continental break-up and initiation of sea-floor spreading in the North Atlantic. In the region stretching from Scoresby Sund southward to 69°N 40 000 km2of basalts with an average thickness of 1.5 km have been investigated by measuring and flow-to-flow sampling of 130 profiles, followed by major element geochemical analysis and microprobe analysis, trace element analysis and some Sr isotope data. The basalts rest on Mesozoic sediments in the east and on Precambrian gneiss in the west. Six basalt formations are defined: the Magga Dan, Milne Land and Geikie Plateau Formations form a lower regional sequence erupted in one volcanic episode from sites in the NW part of the region; the Rømer Fjord and Skrænterne Formations form an upper regional sequence erupted in a subsequent volcanic episode in which eruption sites moved SE to centres east of the present Atlantic coast; the Igtertivâ Formation and a coast-parallel dyke swarm formed in a third volcanic episode only recorded at the Atlantic coast. The lavas are essentially flat-lying; a narrow strip along the Atlantic coast is extensively block faulted. Single lava flows are extensive (max. 11 000 km2) and voluminous (max. 300 km3). They are well preserved, with metamorphism of the low zeolite facies. All the lavas and most of the dykes are fractionated tholeiitic basalts with Mg/(Mg+Fe2+) ratios of 0.66-0.39 and TiO2 = 1.2-4.5%. The major part (the 'main basalts', 96% by volume) have Mg ratios of 0.56-0.39, while only 4 vol.% are Mg-rich basalts with Mg ratios of 0.66-0.57. A nephelinitic tuff layer occurs at the base of the second sequence. A few dykes are alkaline. The Mg-rich basalts have microphenocrysts of olivine (FO90-70) and chromite, while the main basalts comprise both aphyric and porphyritic sequences. Phenocrysts of plagioclase (An88-37) are abundant, of olivine (FO80-57) are sparse but ubiquitous, and of augite (FS9-20) sparse and often absent. Groundmass phases are olivine (to FO3737), plagioclase (to An13, augite (to FS62), pigeonite (Fs26-50), titanomagnetite and ilmenite. All rocks contain several per cent fine-grained mesostasis. The phenocrysts frequently show disequilibrium textures and a wide range of compositions within one sample. Extrusion temperatures are calculated to 1280-1110°C, and densities to 2.68-2.78 g/cm3, increasing with fractionation. The volcanic episodes are demonstrated in systematic compositional variations with height in the basalt sequence. Each of the two major episodes started with a variety of lava compositions including Mg-rich basalts, followed by a thick sequence of 'main basalts' showing a systematic decrease of TiO2 and other incompatible elements with height, and ending with a reversal to higher TiO2 values. The third episode is not cyclic, and its products have changed incompatible element ratios. The Mg-rich basalts comprise depleted MORB type basalts, relatively enriched olivine tholeiites, and very enriched tholeiites (Mikis type basalt). Sr isotopes show 87Sr/86Sr ratios of 0.7034 in most basalts and 0.7045 in the Mikis type basalt, while some Si-rich basalts have ratios up to 0.7079. The East Greenland basalts are 'initial rifting' basalts very similar to those in Deccan. The magmas have equilibrated at low pressures in crustal magma chambers. The main basalts have fractionated ol + pl + cpx no matter whether they are aphyric or porphyritic. Simple crystal fractionation can account for sub-trends but not for the complete compositional variation of the main basalts. This is considered as resulting from fractionation in open magma chambers which were repeatedly filled, mixed and tapped. The decrease in TiO2 with height in each volcanic episode indicates increasing magma input rate and shorter residence time in the chamber, while the final reversal indicates the decline and cessation of activity. There is evidence for widespread crustal contamination (1-4%) in the magma chambers of the two lowest formations. Crustal contamination of magmas on the way to the surface occurred sporadically throughout both sequences. One case of magma mixing occurred when a Mg-rich basalt magma invaded the regional main basalt magma chamber. The Mg-rich basalts cannot be directly related to each other or to the main basalts. A petrogenetic scheme is suggested where the Mikis type basalt originated in, or contains an addition from, an undepleted or enriched mantle source. All the other magma types originated in a depleted mantle source by varying degrees and possibly depths of melting. Increasing degrees of melting are indicated for the types nephelinite - enriched olivine tholeiite – main basalt parent – MORB type basalt. The MORB type basalt may also be produced by melting of a residuum. The basalts of the third volcanic episode include another component of mantle or basaltic crust. The three recorded volcanic episodes are related to rifting events during the break-up of the North Atlantic continent, viewed as repeated attempts to straighten out a bend in the original line of opening. The two first rifting events failed while the third for a short while produced oceanic crust. Compared to other regions of the North Atlantic volcanic province the Scoresby Sund basalts are similar to basalts from Kangerdlugssuaq, northern East Greenland, West Greenland, the Faeroes, the Vøring Plateau and some basalts on lceland. The main magma source for the North Atlantic province was similar to that of the lceland hotspot, but enriched subcontinental lithosphere may also have participated in the stage of initial rifting. A correlation for the volcanic episodes throughout East Greenland and the Faeroes is proposed.

Pre-basaltic sediments (Aptian–Paleocene) of the Kangerlussuaq Basin, southern East Greenland

2001 ◽  
pp. 99-106 ◽  
Author(s):  
Michael Larsen ◽  
Morten Bjerager ◽  
Tor Nedkvitne ◽  
Snorre Olaussen ◽  
Thomas Preuss
Keyword(s):  
North Atlantic ◽  
Deep Water ◽  
Sediment Supply ◽  
Basin Evolution ◽  
East Greenland ◽  
Sea Floor ◽  
North West ◽  
The North ◽  
The North Atlantic ◽  
Sea Floor Spreading

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Larsen, M., Bjerager, M., Nedkvitne, T., Olaussen, S., & Preuss, T. (2001). Pre-basaltic sediments (Aptian–Paleocene) of the Kangerlussuaq Basin, southern East Greenland. Geology of Greenland Survey Bulletin, 189, 99-106. https://doi.org/10.34194/ggub.v189.5163 _______________ The recent licensing round in the deep-water areas south-east of the Faeroe Islands has emphasised the continued interest of the oil industry in the frontier areas of the North Atlantic volcanic margins. The search for hydrocarbons is at present focused on the Cretaceous– Paleocene succession with the Paleocene deepwater play as the most promising (Lamers & Carmichael 1999). The exploration and evaluation of possible plays are almost solely based on seismic interpretation and limited log and core data from wells in the area west of the Shetlands. The Kangerlussuaq Basin in southern East Greenland (Fig. 1) provides, however, important information on basin evolution prior to and during continental break-up that finally led to active sea-floor spreading in the northern North Atlantic. In addition, palaeogeographic reconstructions locate the southern East Greenland margin only 50–100 km north-west of the present-day Faeroe Islands (Skogseid et al. 2000), suggesting the possibility of sediment supply to the offshore basins before the onset of rifting and sea-floor spreading. In this region the Lower Cretaceous – Palaeogene sedimentary succession reaches almost 1 km in thickness and comprises sediments of the Kangerdlugssuaq Group and the siliciclastic lower part of the otherwise basaltic Blosseville Group (Fig. 2). Note that the Kangerdlugssuaq Group was defined when the fjord Kangerlussuaq was known as ‘Kangerdlugssuaq’. Based on field work by the Geological Survey of Denmark and Greenland (GEUS) during summer 1995 (Larsen et al. 1996), the sedimentology, sequence stratigraphy and basin evolution of the Kangerlussuaq Basin were interpreted and compared with the deep-water offshore areas of the North Atlantic (Larsen et al. 1999a, b).

Large-scale evolution of the central-east Greenland margin: New insights to the North Atlantic glaciation history

2018 ◽  
Vol 163 ◽  
pp. 141-157 ◽  
Author(s):  
Lara F. Pérez ◽  
Tove Nielsen ◽  
Paul C. Knutz ◽  
Antoon Kuijpers ◽  
Volkmar Damm
Keyword(s):  
North Atlantic ◽  
Large Scale ◽  
East Greenland ◽  
The North ◽  
The North Atlantic ◽  
Greenland Margin ◽  
Scale Evolution

scholarly journals The East Greenland rifted volcanic margin

2011 ◽  
Vol 24 ◽  
pp. 1-96 ◽  
Author(s):  
C. Kent Brooks
Keyword(s):  
North Atlantic ◽  
Wide Spectrum ◽  
Radiometric Dating ◽  
Dyke Swarm ◽  
Time Interval ◽  
Short Time Interval ◽  
East Greenland ◽  
The North ◽  
The North Atlantic ◽  
Dyke Swarms

The Palaeogene North Atlantic Igneous Province is among the largest igneous provinces in the world and this review of the East Greenland sector includes large amounts of information amassed since previous reviews around 1990. The main area of igneous rocks extends from Kangerlussuaq (c. 67°N) to Scoresby Sund (c. 70°N), where basalts extend over c. 65 000 km2 , with a second area from Hold with Hope (c. 73°N) to Shannon (c. 75°N). In addition, the Ocean Drilling Project penetrated basalt at five sites off South-East Greenland. Up to 7 km thickness of basaltic lavas have been stratigraphically and chemically described and their ages determined. A wide spectrum of intrusions are clustered around Kangerlussuaq, Kialeeq (c. 66°N) and Mesters Vig (c. 72°N). Layered gabbros are numerous (e.g. the Skaergaard and Kap Edvard Holm intrusions), as are under- and oversaturated syenites, besides small amounts of nephelinite-derived products, such as the Gardiner complex (c. 69°N) with carbonatites and silicate rocks rich in melilite, perovskite etc. Felsic extrusive rocks are sparse. A single, sanidine-bearing tuff found over an extensive area of the North Atlantic is thought to be sourced from the Gardiner complex. The province is famous for its coast-parallel dyke swarm, analogous to the sheeted dyke swarm of ophiolites, its associated coastal flexure, and many other dyke swarms, commonly related to central intrusive complexes as in Iceland. The dyke swarms provide time markers, tracers of magmatic evolution and evidence of extensional events. A set of dykes with harzburgite nodules gives unique insight into the Archaean subcontinental lithosphere. Radiometric dating indicates extrusion of huge volumes of basalt over a short time interval, but the overall life of the province was prolonged, beginning with basaltic magmas at c . 60 Ma and continuing to the quartz porphyry stock at Malmbjerg (c. 72°N) at c. 26 Ma. Indeed, activity was renewed in the Miocene with the emplacement of small volumes of basalts of the Vindtoppen Formation to the south of Scoresby Sund. Although the basalts were extruded close to sea level, this part of East Greenland is a plateau raised to c. 2 km, but the timing of uplift is controversial. Superimposed on the plateau is a major dome at Kangerlussuaq. East Greenland presents a rich interplay between magmatic and tectonic events reflecting the birth of the North Atlantic Ocean. It was active over a much longer period (36 Ma) than other parts of the province (5 Ma in the Hebrides, Northern Ireland and the Faroe Islands) and contains a wider range of products, including carbonatites, and felsic rocks tend to be granitic rather than syenitic. As expected, there are many similarities with Iceland, the present-day expression of activity in the province. Differences are readily explained by higher production rates and the thicker lithospheric lid during the early stages of development in East Greenland. The igneous and related activity clearly results from plate-tectonic factors, but the relationship is not understood in detail. In particular, the nature of the underlying mantle processes, primarily the presence or absence of a plume, is still not resolved.

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