scholarly journals Crustal domains in the Western Barents Sea

2020 ◽  
Vol 221 (3) ◽  
pp. 2155-2169
Author(s):  
Alexey Shulgin ◽  
Jan Inge Faleide ◽  
Rolf Mjelde ◽  
Asbjørn Breivik ◽  
Ritske Huismans
Keyword(s):  
Seismic Reflection ◽  
Barents Sea ◽  
The Body ◽  
Gravity Modelling ◽  
Southern Boundary ◽  
Mafic Intrusions ◽  
Crustal Block ◽  
The Barents Sea ◽  
Crystalline Crust ◽  
Regional Gravity

SUMMARY The crustal architecture of the Barents Sea is still enigmatic due to complex evolution during the Timanian and Caledonian orogeny events, further complicated by several rifting episodes. In this study we present the new results on the crustal structure of the Caledonian–Timanian transition zone in the western Barents. We extend the work of Aarseth et al. (2017), by utilizing the seismic tomography approach to model Vp, Vs and Vp/Vs ratio, combined with the reprocessed seismic reflection line, and further complemented with gravity modelling. Based on our models we document in 3-D the position of the Caledonian nappes in the western Barents Sea. We find that the Caledonian domain is characterized by high crustal reflectivity, caused by strong deformation and/or emplacement of mafic intrusions within the crystalline crust. The Timanian domain shows semi-transparent crust with little internal reflectivity, suggesting less deformation. We find, that the eastern branch of the earlier proposed Caledonian suture, cannot be associated with the Caledonian event, but can rather be a relict from the Timanian terrane assemblance, marking one of the crustal microblocks. This crustal block may have an E–W striking southern boundary, along which the Caledonian nappes were offset. A high-velocity/density crustal body, adjacent to the Caledonian–Timanian contact zone, is interpreted as a zone of metamorphosed rocks based on the comparison with global compilations. The orientation of this body correlates with regional gravity maxima zone. Two scenarios for the origin of the body are proposed: mafic emplacement during the Timanian assembly, or massive mafic intrusions associated with the Devonian extension.

scholarly journals Extensive Sills in the Continental Basement from Deep Seismic Reflection Profiling

Geosciences ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 449
Author(s):  
Larry D. Brown ◽  
Doyeon Kim
Keyword(s):  
Seismic Reflection ◽  
Country Rock ◽  
High Amplitude ◽  
Tectonic Activity ◽  
Seismic Profiles ◽  
Mafic Intrusions ◽  
Bright Spots ◽  
Crystalline Crust ◽  
Seismic Reflection Profiling ◽  
Fluid Magma

Crustal seismic reflection profiling has revealed the presence of extensive, coherent reflections with anomalously high amplitudes in the crystalline crust at a number of locations around the world. In areas of active tectonic activity, these seismic “bright spots” have often been interpreted as fluid magma at depth. The focus in this report is high-amplitude reflections that have been identified or inferred to mark interfaces between solid mafic intrusions and felsic to intermediate country rock. These “frozen sills” most commonly appear as thin, subhorizontal sheets at middle to upper crustal depths, several of which can be traced for tens to hundreds of kilometers. Their frequency among seismic profiles suggest that they may be more common than widely realized. These intrusions constrain crustal rheology at the time of their emplacement, represent a significant mode of transfer of mantle material and heat into the crust, and some may constitute fingerprints of distant mantle plumes. These sills may have played important roles in overlying basin evolution and ore deposition.

scholarly journals A lithosphere-scale structural model of the Barents Sea and Kara Sea region

Solid Earth ◽  
2015 ◽  
Vol 6 (1) ◽  
pp. 153-172 ◽  
Author(s):  
P. Klitzke ◽  
J. I. Faleide ◽  
M. Scheck-Wenderoth ◽  
J. Sippel
Keyword(s):  
Upper Mantle ◽  
Lithospheric Mantle ◽  
Structural Model ◽  
Barents Sea ◽  
Seismic Velocity ◽  
Kara Sea ◽  
Late Cenozoic ◽  
Low Velocity ◽  
The Barents Sea ◽  
Crystalline Crust

Abstract. We introduce a regional 3-D structural model of the Barents Sea and Kara Sea region which is the first to combine information on the sediments and the crystalline crust as well as the configuration of the lithospheric mantle. Therefore, we have integrated all available geological and geophysical data, including interpreted seismic refraction and reflection data, seismological data, geological maps and previously published 3-D models into one consistent model. This model resolves four major megasequence boundaries (earliest Eocene, mid-Cretaceous, mid-Jurassic and mid-Permian) the top crystalline crust, the Moho and a newly calculated lithosphere–asthenosphere boundary (LAB). The thickness distributions of the corresponding main megasequences delineate five major subdomains (the northern Kara Sea, the southern Kara Sea, the eastern Barents Sea, the western Barents Sea and the oceanic domain comprising the Norwegian–Greenland Sea and the Eurasia Basin). Relating the subsidence histories of these subdomains to the structure of the deeper crust and lithosphere sheds new light on possible causative basin forming mechanisms that we discuss. The depth configuration of the newly calculated LAB and the seismic velocity configuration of the upper mantle correlate with the younger history of this region. The western Barents Sea is underlain by a thinned lithosphere (80 km) resulting from multiple Phanerozoic rifting phases and/or the opening of the NE Atlantic from Paleocene/Eocene times on. Notably, the northwestern Barents Sea and Svalbard are underlain by thinnest continental lithosphere (60 km) and a low-velocity/hot upper mantle that correlates spatially with a region where late Cenozoic uplift was strongest. As opposed to this, the eastern Barents Sea is underlain by a thicker lithosphere (~ 110–150 km) and a high-velocity/density anomaly in the lithospheric mantle. This anomaly, in turn, correlates with an area where only little late Cenozoic uplift/erosion was observed.

The identity of the larval nematodes found in the body muscles of the cod (Gadus callarias L.)

Parasitology ◽  
1959 ◽  
Vol 49 (1-2) ◽  
pp. 121-131 ◽  
Author(s):  
J. N. R. Grainger
Keyword(s):  
Barents Sea ◽  
The Body ◽  
Culture Period ◽  
Culture Temperature ◽  
High Culture ◽  
The Barents Sea ◽  
State 1

Larval nematodes occurring in cysts in the body musculature of Icelandic cod have been identified as belonging to Porrocaecum Raillet & Henry, 1912 (subgenus Terranova Leiper & Atkinson, 1914), probably P. decipiens Krabbe and Anisakis Dujardin, 1845. Identification was made possible by rearing them in vitro to the pre-adult condition. The experiments show that the following conditions are necessary for the moult to the pre-adult state; (1) a fairly high culture temperature (37° C.); (2) the presence of pieces of fish for 24 hr. towards the beginning of the culture period. 1 % pepsin, while it assists the hatching from the cysts, is not essential for the moult to the pre-adult condition. Experiments indicate that the moult takes place 3–5 days after fish has been supplied.The larvae and pre-adults of both genera are described. Samples of larvae from cod from Greenland and the Barents Sea probably consist only of Porrocaecum and Anisakis, but a sample from West Scotland contained only Porrocaecum. The significance of the moult to the pre-adult state is discussed.

Gravity modelling along a Lithoprobe seismic traverse, northern Grenville Province, western Quebec

1997 ◽  
Vol 34 (2) ◽  
pp. 127-134 ◽  
Author(s):  
Hamid Telmat ◽  
Caroline N. Antonuk ◽  
Jean-Claude Mareschal
Keyword(s):  
Lower Crust ◽  
Seismic Reflection ◽  
Gravity Data ◽  
Regional Scale ◽  
Gravity Anomalies ◽  
Gravity Modelling ◽  
Grenville Province ◽  
Seismic Reflection Data ◽  
Mafic Intrusions ◽  
Reflection Data

High-precision gravity data were collected along Lithoprobe seismic reflection lines in the northern part of the Grenville Province, in western Quebec. An interpretation is presented for line 52, which starts some 60 km southeast of the Grenville Front, traverses the parautochthonous Reservoir Dozois Terrane including the allochthonous slice of the Réservoir Cabonga Terrane, and ends near the town of Mont-Laurier, in the allochthonous Mont-Laurier Terrane. On the regional scale, the Bouguer gravity anomaly is consistent with the interpretation of the seismic reflection data. It supports crustal thinning southward of the Grenville Front, under the Cabonga allochthon. This thinning may be related to postorogenic extension. The gravity modelling shows dramatic thinning of the lower crust and suggests that extension was accommodated by extrusion of the lower crust. The gravity modelling also requires a steep boundary between the Réservoir Cabonga and the Réservoir Dozois terranes extending to ~ 15 km. The geometry of the Baskatong ramp derived from gravity data is also consistent with the seismic interpretation. This supports the suggestion that the Baskatong ramp is a major discontinuity along which Proterozoic terranes were accreted. In the Réservoir Cabonga Terrane in the northern part of the profile, the residual gravity anomalies (short wavelength variations) are related to outcropping mafic intrusions. Modelling of these anomalies complements the seismic reflection data, which did not image the base of the intrusions. The interpretation calls for three small distinct gabbroic bodies that extend no deeper than 3 km. The total volume of the intrusions is ~ 3000 km3.

scholarly journals Some information on biology of three-spined stickleback Gasterosteus aculeatus Linnaeus, 1758 in the Barents Sea coastal region (East Murman)

Vestnik MGTU ◽  
2020 ◽  
Vol 23 (2) ◽  
pp. 115-121
Author(s):  
M. V. Garmash ◽  
N. G. Zhuravleva
Keyword(s):  
Body Length ◽  
Gasterosteus Aculeatus ◽  
Barents Sea ◽  
Coastal Region ◽  
The Body ◽  
Published Data ◽  
Weight Changes ◽  
The Barents Sea ◽  
Catchment Areas ◽  
Murmansk Region

Three-spined stickleback is one of the widespread fish species of East Murman. It is found in 13 catchment areas of the Barents Sea coast in the eastern part of the Murmansk region, including major rivers, shallow river basins and inter-basin spaces. Stickleback is found in such lakes as Enozero, Pervoe Titovskoe, Opasovskoe, Dolgoe, etc, and in the rivers Yokanga, Varzina, Kharlovka, Voronia, Teriberka, etc. There is no detailed biological description of stickleback in this area, and the information available only mentions its presence in water bodies and occurrence in the stomachs of predators. The present paper provides data on three-spined stickleback caught in the coastal region of the Barents Sea at a depth of 120-123 m. The marine form of stickleback spends entire life cycle in the sea. In the Barents Sea, stickleback has a pelagic way of life, going quite far from the shore. According to the published data, its habitat depth in the Barents Sea is 50-450 m, with an average of 270 m, where temperature varies from 0 to 4 °C, with salinity 33-35 ‰. It has been found out that stickleback is represented by two morphotypes - trachurus with a keel (98 %) and semiarmatus (2 %) with a keel. The study has revealed different number of lateral plates and the nature of their distribution on the body of stickleback. In the study area, individuals of different size groups could be found. On average their body length ranges from 51 to 60 mm with a maximum length of 81 mm; the weight changes from 0.79 to 1.39 g. The authors have observed positive allometry of the dependence of mass on body length. Proportion of empty stomachs is almost 100 % with the fat content 1-2 points. The gonads of males and females caught in August 2015 were in after spawning condition. Females comprise the majority of the population (65 %). Infestation of stickleback with helminths is insignificant. Larvae of Anisakis simplex nematode have been observed most frequently during the examination of internal organs and body cavity.

Method application of optimal multi-parameter analysis to assess the distribution of water masses as an example of CTD data of the Barents Sea in summer 2017

2019 ◽  
pp. 38-51
Author(s):  
Valeriy G. Yakubenko ◽  
Anna L. Chultsova
Keyword(s):  
Barents Sea ◽  
Field Measurements ◽  
Structural Similarity ◽  
Water Masses ◽  
Parameter Analysis ◽  
Water Dynamics ◽  
Phosphorus Concentration ◽  
Nitrogen And Phosphorus ◽  
The Barents Sea ◽  
Expert Assessments

Identification of water masses in areas with complex water dynamics is a complex task, which is usually solved by the method of expert assessments. In this paper, it is proposed to use a formal procedure based on the application of the method of optimal multiparametric analysis (OMP analysis). The data of field measurements obtained in the 68th cruise of the R/V “Academician Mstislav Keldysh” in the summer of 2017 in the Barents Sea on the distribution of temperature, salinity, oxygen, silicates, nitrogen, and phosphorus concentration are used as a data for research. A comparison of the results with data on the distribution of water masses in literature based on expert assessments (Oziel et al., 2017), allows us to conclude about their close structural similarity. Some differences are related to spatial and temporal shifts of measurements. This indicates the feasibility of using the OMP analysis technique in oceanological studies to obtain quantitative data on the spatial distribution of different water masses.

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