The Billefjorden Fault Zone north of Spitsbergen: a major terrane boundary?

The Billefjorden Fault Zone is a major terrane boundary in the Norwegian Arctic. The fault separates basement rocks of Svalbard’s north-eastern and north-western terranes that recorded discrete Precambrian tectonothermal histories and were accreted, intensely deformed and metamorphosed during the Caledonian Orogeny. Although the fault represents a major, crustal-scale tectonic boundary, its north-ward extent is not well constrained. The present short contribution addresses this issue and presents new seismic mapping of structures and rock units north of Wijdefjorden, where the Billefjorden Fault Zone may continue. This study shows that there is no evidence for major faulting of the top-basement reflection, and therefore, that the Billefjorden Fault Zone may die out within Wijdefjorden–Austfjorden, step ≥ 20 km laterally, or be invisible on the presented seismic data. Seismic data also suggest that Caledonian basement rocks in Ny-Friesland (north-eastern terrane) are not significantly different from basement rocks below the Devonian Graben in Andrée Land (north-western terrane). Potential implica-tions include the absence of a major terrane boundary in northern Spitsbergen

Geomorphology and surficial geology of the Femmilsjøen area, northern Spitsbergen

Climate change is amplified in the Arctic, and establishing baseline data for its current character is important. Here we present a map of the geomorphology of the Femmilsjøen area, Spitsbergen, northern Svalbard. The regional physiography is characterised by a low-relief, high elevation mountain plateau, its high-relief steep slopes, and low-relief coastal lowlands. The results indicate that glaciers were most likely warm-based and erosive in the low terrain, whereas there are signatures of colder, less erosive ice on the plateaus during the Late Weichselian. Our study highlights the ongoing glacial and periglacial morphological processes in an area of hard and weathering-resistant bedrock, situated in northern Svalbard

Holocene glacial history of Svalbard: Status, perspectives and challenges

© 2020 The Author(s) We synthesize the current understanding of glacier activity on Svalbard from the end of the Late Pleistocene (12,000 yrs. before present) to the end of the Little Ice Age (c. 1920 AD). Our glacier history is derived from the SVALHOLA database, the first compilation of Holocene geochronology for Svalbard and the surrounding waters, including over 1,800 radiocarbon, terrestrial cosmogenic nuclide and optically stimulated luminescence ages. Data have been categorized by geological setting, uniformly (re-)calibrated, quality assessed and ultimately used to constrain glacier fluctuations (deglaciation, ice free conditions, glacier re-advances and ice marginal positions). We advance existing knowledge by mapping the extent and distribution of ice-cover during the Holocene glacial maximum and the glacial minimum, as well as present retreat rates (and percentages) within Early Holocene fjord-systems. Throughout the Holocene, Svalbard glaciers have responded to a varying combination of climatic, environmental and dynamic driving factors which influence both the extent and behavior of ice margins. We discuss the complexities of glacier systems and their dynamics in response to changes in climate. This review provides a holistic state of the art of Holocene glaciers on Svalbard, suitable for orienting future works which address gaps in our current knowledge

Identificação, dinâmica da produção e potencial de uso do feromônio de agregação de Pseudopiazurus obesus (Boheman, 1838) (Coleoptera : Curculionidae)

Orientador : Paulo H.G. ZarbinDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Biológicas, Programa de Pós-Graduação em Ciências Biológicas (Entomologia). Defesa: Curitiba, 2005Inclui bibliografiaÁrea de concentraçao: EntomologiaResumo: A pesquisa objetivou identificar, determinar a dinâmica da produção e avaliar o potencial de uso do feromônio de agregação de Pseudopiazurus obesus (Boheman, 1838), (Coleoptera: Curculionidae), visando à possibilidade do uso desta alternativa no monitoramento e controle desta praga. O estudo consistiu em três fases, sendo a primeira envolvendo a criação dos insetos; a segunda a obtenção dos voláteis dos insetos e avaliação destes no comportamento dos co-específicos e a terceira abrangendo isolamento, identificação e avaliação da atividade biológica do feromônio sintético em laboratório. Ações complementares de pesquisa ainda foram desenvolvidas como a determinação da dinâmica da produção do feromônio e avaliação da captura dos espécimes em armadilhas a campo. Os principais resultados foram: machos e fêmeas são mais atraídos para voláteis de insetos machos adicionado a partes da planta hospedeira (caule fresco do mamoeiro), sugerindo ação sinergística e potencializando a atratividade de co-específicos; a liberação do feromônio inicia a partir do 18o DAE (dias após a emergência) e ocorre durante a escotofase, sendo observado o pico de produção 4 - 6 h após o seu início; machos virgens e acasalados são semelhantes quanto à produção de feromônio e esta é dependente da planta hospedeira; a duração da produção ocorre até aos 105 DAE; o feromônio é do tipo agregação; grandisal, grandisol e papaianol (composto majoritário, intermediário e minoritário, respectivamente), constituem as substâncias feromonais da espécie; as misturas ternárias e grandisal mostraram ser biologicamente ativos na atratividade de co-específicos; armadilhas colocadas a 1,50 m de altura capturaram mais espécimes em condições de campo.Abstract: The aim of this study was to isolate and identify the aggregation pheromone the papaya weevil, Pseudopiazurus obesus (Boheman, 1838), (Coleoptera: Curculionidae), in order to develop new monitoring and control methods against this pest. The study is based in three stages. The first stage was the rearing of papaya weevil; in the second stage, volatiles were obtained from males and females adults to be evaluated biological activity its in behavioral of the weevils; the third stage experiments were carried out isolation and identification of the aggregation pheromone and to evaluate the biological activity this compounds in behavioral of weevils. The main results was: male and female adults were attracted to volatiles obtained from male adults plus trunk pieces of the host plant. These results demonstrate that host plant volatiles, promote a sinergistic effect when added to male extracts; the male adults are the main responsible for the pheromone release, which starts from the 18th day after emerging; pheromone emission occurs at the scotophase, with a higher emission from 4h to 6h after the onset of the scotophase; there is no difference between pheromone emission from virgim or mated males, but there is difference among volatiles collected from males with or without food; pheromone release is affected by the food quality and decrease within time; occurring until the 105 day of life; three male-specific compounds: grandisal (main pheromone component), grandisol and papaianol are the pheromonals compounds; the ternary mixtures and grandisal show biological activity in both sexes of the papaya weevil; traps localized in 1,50 meter higher show best performance in the captures of weevils in field conditions

Glacial history of the Åsgardfonna Ice Cap, NE Spitsbergen, since the last glaciation

The response of glaciers and ice caps to past climate change provides important insight into how they will react to ongoing and future global warming. In Svalbard, the Holocene glacial history has been studied for many cirque and valley glaciers. However, little is known about how the larger ice caps in Svalbard responded to Late Glacial and Holocene climate changes. Here we use lake sediment cores and geophysical data from Femmilsjøen, one of Svalbard’s largest lakes, to reconstruct the glacial history of the Åsgardfonna Ice Cap since the last deglaciation. We find that Femmilsjøen potentially deglaciated prior to 16.1 ± 0.3 cal ka BP and became isolated from the marine environment between 11.7 ± 0.3 to 11.3 ± 0.2 cal ka BP. Glacial meltwater runoff was absent between 10.1 ± 0.4 and 3.2 ± 0.2 cal ka BP, indicating that Åsgardfonna was greatly reduced or disappeared in the Early and Middle Holocene. Deposition of glacial-meltwater sediments re-commenced in Femmilsjøen at c. 3.2 ± 0.2 cal ka BP, indicating glacier re-growth in the Femmilsjøen catchment and the onset of the Neoglacial. The glacier(s) in the Femmilsjøen catchment area reached sizes no smaller than their modern extents already at c. 2.1 ± 0.7 cal ka BP. Our results suggest that larger Svalbard ice caps such as Åsgardfonna are very sensitive to climate changes and probably melted completely during the Holocene Thermal Maximum. Such information can be used as important constraints in future ice-cap simulations

Postglacial relative sea level change and glacier activity in the early and late Holocene:Wahlenbergfjorden, Nordaustlandet, Svalbard

Publisher's version (útgefin grein).Sediment cores from Kløverbladvatna, a threshold lake in Wahlenbergfjorden, Nordaustlandet, Svalbard were used to reconstruct Holocene glacier fluctuations. Meltwater from Etonbreen spills over a threshold to the lake, only when the glacier is significantly larger than at present. Lithological logging, loss-on-ignition, ITRAX scanning and radiocarbon dating of the cores show that Kløverbladvatna became isolated from Wahlenbergfjorden c. 5.4 cal. kyr BP due to glacioisostatic rebound. During the Late Holocene, laminated clayey gyttja from lacustrine organic production and surface runoff from the catchment accumulated in the lake. The lacustrine sedimentary record suggests that meltwater only spilled over the threshold at the peak of the surge of Etonbreen in AD 1938. Hence, we suggest that this was the largest extent of Etonbreen in the (mid-late) Holocene. In Palanderbukta, a tributary fjord to Wahlenbergfjorden, raised beaches were surveyed and organic material collected to determine the age of the beaches and reconstruct postglacial relative sea level change. The age of the postglacial raised beaches ranges from 10.7 cal. kyr BP at 50 m a.s.l. to 3.13 cal. kyr BP at 2 m a.s.l. The reconstructed postglacial relative sea level curve adds valuable spatial and chronological data to the relative sea level record of Nordaustlandet.Sveinn Brynjólfsson and Sara Mollie Cohen are thanked for field assistance. Fieldwork and radiocarbon dates were funded by the Carlsberg Foundation (CF14-0756 to Schomacker) and Department of Arctic Geology, The University Centre in Svalbard (UNIS), respectively. Geospatial support was provided by the Polar Geospatial Center, and DEM(s) were created from DigitalGlobe, Inc., imagery and funded under National Science Foundation awards 1043681, 1559691, and 1542736. We thank Ole Bennike, Svend Funder, Antony Ruter, and Peter Ilsøe for macrofossil identification and lab assistance. The manuscript benefited from constructive review comments from Andy Emery. The publication charges for this article have been funded by a grant from the publication fund of UiT The Arctic University of Norway.Peer Reviewe

Graduaçăo em comunicaçăo social e tecnologia da informaçăo e comunicaçăo (TIC) : refletindo sobre o currículo /

Orientadora: Gláucia da Silva BritoDissertaçăo (mestrado) - Universidade Federal do Paraná, Setor de Educaçăo, Programa de Pós-Graduaçăo em Educaçăo. Defesa: Curitiba, 2008Inclui bibliografiaÁrea de concentraçăo: Cultura, escola e ensin

Combining terrestrial and marine glacial archives: A geomorphological map of the Nordenskiöldbreen forefield, Svalbard

Recent research suggests that Svalbard glaciers have retreated and thinned since the Little Ice Age. The analysis of glacial landforms and sediment deposits in the terrestrial and marine environments permits the reconstruction of the temporal and spatial variability of recent deglaciations. This study is founded on the analysis and interpretation of a geomorphological map (1:10000) of the foreland of Nordenskiöldbreen (inner Billefjorden, Svalbard). The map covers an area of ca. 43 km2 and is constructed from a combination of field observations and remotely sensed imagery from both the terrestrial and marine environments. Landforms are classified into six genetic categories: (1) subglacial, (2) ice-marginal, (3) supraglacial, (4) proglacial, (5) periglacial and (6) coastal. Glacier front positions from 1896 to present are reconstructed using historical data, oblique and vertical aerial imagery and LANDSAT and ASTER imagery. The preservation of the landform record differs between the terrestrial and marine archive. Previous studies of this region have focused on either marine or terrestrial archives and have failed to capture the complexities of the Nordenskiöldbreen forefield. As a result, pre-existing landsystem models are not applicable to Nordenskiöldbreen. The results of this investigation suggest Nordenskiöldbreen has been a dynamic glacier with components of all Svalbard type glaciers. The retreat pattern reconstructed in this thesis indicates that water depth and bedrock pinning points (sills) played an important role in the antecedent stability of Nordenskiöldbreen. Additionally, existing landsystem models fail to capture the complexity of glaciers with a combined terrestrial and marine terminus such as Nordenskiöldbreen. The application of these models should therefore be carefully considered when investigating glaciers with a mixed terminus. This study contributes to an improved understanding of Svalbard glaciers and their response to recent climate fluctuations

Devonian–Carboniferous extension and Eurekan inversion along an inherited WNW–ESE-striking fault system in Billefjorden, Svalbard [version 2; peer review: 2 approved, 1 not approved]

Background The Billefjorden area in central Spitsbergen hosts thick Lower–lowermost Upper Devonian, late–post-Caledonian collapse deposits presumably deformed during the Late Devonian Svalbardian Orogeny. These rocks are juxtaposed against Proterozoic basement rocks along the Billefjorden Fault Zone and are overlain by uppermost Devonian–early Permian deposits of the Billefjorden Trough, a N–S-trending Carboniferous rift basin bounded by the Billefjorden Fault Zone. Methods We interpreted seismic reflection (also depth-converted), bathymetric, and exploration well data. Results The data show abundant Early Devonian, WNW–ESE-striking (oblique-slip) normal faults segmenting the Billefjorden Trough, and a gradual decrease in tectonic activity from the Early Devonian (collapse phase) to early Permian (post-rift phase). Early Devonian–Middle Pennsylvanian WNW–ESE-striking faults were mildly reactivated and overprinted and accommodated strain partitioning and decoupling in the early Cenozoic. This resulted in intense deformation of Lower Devonian sedimentary rocks and in the formation of bedding-parallel décollements, e.g., between the Lower Devonian Wood Bay and the uppermost Pennsylvanian–lowermost Permian Wordiekammen formations. This suggests that intense deformation within Devonian rocks in Dickson Land can be explained by Eurekan deformation alone. Eurekan deformation also resulted in the formation of WNW–ESE- and N–S- to NNE–SSW-trending, kilometer-wide, open folds such as the Petuniabukta Syncline, and in inversion and/or overprinting of Early Devonian to Early Pennsylvanian normal faults by sinistral-reverse Eurekan thrusts. WNW–ESE-striking faults merge at depth with similarly trending and dipping ductile shear zone fabrics in Proterozoic basement rocks, which likely formed during the Timanian Orogeny. Conclusions A NNE-dipping shear zone, which is part of a large system of Timanian thrusts in the Barents Sea, controlled the formation of WNW–ESE-striking Devonian–Mississippian normal faults and syn-tectonic sedimentary rocks in Billefjorden. Eurekan strain partitioning and decoupling suggest that the Svalbardian Orogeny did not occur in Svalbard

Devonian–Carboniferous extension and Eurekan inversion along an inherited WNW–ESE-striking fault system in Billefjorden, Svalbard

<p> Background: The Billefjorden area in central Spitsbergen hosts thick Lower–lowermost Upper Devonian, late–post-Caledonian collapse deposits presumably deformed during the Late Devonian Svalbardian Orogeny. These rocks are juxtaposed against Proterozoic basement rocks along the Billefjorden Fault Zone and are overlain by uppermost Devonian–early Permian deposits of the Billefjorden Trough, a N–S-trending Carboniferous rift basin bounded by the Billefjorden Fault Zone.</p><p> Methods: We interpreted seismic reflection (also depth-converted), bathymetric, and exploration well data.</p><p> Results: The data show abundant Early Devonian, WNW–ESE-striking (oblique-slip) normal faults segmenting the Billefjorden Trough, and a gradual decrease in tectonic activity from the Early Devonian (collapse phase) to early Permian (post-rift phase). Early Devonian–Middle Pennsylvanian WNW–ESE-striking faults were mildly reactivated and overprinted and accommodated strain partitioning and decoupling in the early Cenozoic. This resulted in intense deformation of Lower Devonian sedimentary rocks and in the formation of bedding-parallel décollements, e.g., between the Lower Devonian Wood Bay and the uppermost Pennsylvanian–lowermost Permian Wordiekammen formations. This suggests that intense deformation within Devonian rocks in Dickson Land can be explained by Eurekan deformation alone. Eurekan deformation also resulted in the formation of WNW–ESE- and N–S- to NNE–SSW-trending, kilometer-wide, open folds such as the Petuniabukta Syncline, and in inversion and/or overprinting of Early Devonian to Early Pennsylvanian normal faults by sinistral-reverse Eurekan thrusts. WNW–ESE-striking faults merge at depth with similarly trending and dipping ductile shear zone fabrics in Proterozoic basement rocks, which likely formed during the Timanian Orogeny.</p><p> Conclusions: A NNE-dipping shear zone, which is part of a large system of Timanian thrusts in the Barents Sea, controlled the formation of WNW–ESE-striking Devonian–Mississippian normal faults and syn-tectonic sedimentary rocks in Billefjorden. Eurekan strain partitioning and decoupling suggest that the Svalbardian Orogeny did not occur in Svalbard.</p&gt