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Major tunnel valleys and sedimentation changes document extensive Early Pleistocene glaciations of the Barents Sea
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-10-02)Sedimentary records of Early Pleistocene (~2.6–0.8 Ma) glaciations are sparse on shelves, yet trough mouth fans on adjacent continental slopes provide a continuous record of ice-sheet and climate development throughout the Quaternary. Here, we interpret high-quality 3D seismic reflection data combined with borehole and chronostratigraphic information from a shelf-slope setting in the southwestern ... -
Pliocene-Pleistocene warm-water incursions and water mass changes on the Ross Sea continental shelf (Antarctica) based on foraminifera from IODP Expedition 374
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-07-11)International Ocean Discovery Program (IODP) Expedition 374 sailed to the Ross Sea in 2018 to reconstruct paleoenvironments, track the history of key water masses, and assess model simulations that show warm-water incursions from the Southern Ocean led to the loss of marine-based Antarctic ice sheets during past interglacials. IODP Site U1523 (water depth 828 m) is located at the continental shelf ... -
Some issues related to the Svalbardian tectonic event (Ellesmerian Orogeny) in Svalbard
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-07-23)Svalbard has long been thought to represent the easternmost realm of the Ellesmerian Orogeny in the late Devonian or early Mississippian (Svalbardian tectonic event). Several authors do not agree and present alternative interpretations of the observed structures in older and more recent articles. This article discusses a number of issues that, in our opinion, are not sufficiently considered in ... -
Metallogenic model of the Lykling ophiolite-hosted lode Au deposit, Scandinavian Caledonides: Insight from fluid inclusions, mineral chemistry and stable isotope geochemistry
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-09-10)The Lykling lode Au deposit represents a unique example of gold mineralization in the Upper Allochthone of the Scandinavian Caledonides. The mineralization is hosted by the Early Ordovician Lykling Ophiolite Complex and the intruding trondhjemite unit and spatially associated with two generations of mafic dykes that crosscut both the ophiolitic complex and trondhjemite. Field observations indicate ... -
Variations in deep-sea methane seepage linked to millennial-scale changes in bottom water temperatures ~ 50–6 ka, NW Svalbard margin
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-09-27)During the last glaciation, the northern hemisphere experienced profound millennial-scale changes (termed Dansgaard-Oeschger (DO) events) in atmospheric and oceanic temperatures. In the North Atlantic, the fluctuations resulted in extremely unstable bottom water conditions with bottom water temperatures (BWT) varying up to > 5 °C. We have studied these changes in a core from 1,300 m water depth ... -
Tulvat ja tulvasuojelu: esimerkkinä pohjalaismaakuntien kevät 2024
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-07-17) -
Glacial erosion and quaternary landscape development of the Eurasian Arctic
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-09-19)Multiple ice age cycles spanning the last three million years have fundamentally transformed the Arctic landscape. The cadence, intensity and pattern of this glacial modification underpin the stability of Arctic geosystems over geologic time scales, including its hydrology, circulation patterns, slope stability, hydrocarbon fluid flow, geochemical/sediment cycling and nutrient supply. The Barents ... -
Mechanical Impact of Heterogeneously Distributed H2O on Quartz Deformation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-07-31)In order to identify relations between mechanical behavior, deformation mechanisms, microstructural properties, and H<sub>2</sub>O distribution, Tana‐quartzite samples with added H<sub>2</sub>O ranging from 0 to 0.5 wt.% were deformed by axial shortening at constant displacement rates, at 900°C and 1 GPa, reaching up to ∼30% bulk strain. Samples with lower quantities of added H<sub>2</sub>O (0.1 ... -
Deep learning models for regional phase detection on seismic stations in Northern Europe and the European Arctic
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-08-23)Seismic phase detection and classification using deep learning is so far poorly investigated for regional events since most studies focus on local events and short time windows as the input to the detection models. To evaluate deep learning on regional seismic records, we create a data set of events in Northern Europe and the European Arctic. This data set consists of about 151 000 three component ... -
Weichselian–Holocene glacial history of the Sjuøyane archipelago, northern Svalbard
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-08-05)The Sjuøyane archipelago is the northernmost land area of Svalbard; thus, it provides a window to study the terrestrial glacial history and dynamics of the Svalbard–Barents Sea Ice Sheet and complement marine geological studies in the region. To reconstruct the glacial history of Sjuøyane, we describe coastal sedimentary sections in Quaternary sediments and constrain their chronology by radiocarbon ... -
Evolutionary model for glacial lake-outburst fans at the ice-sheet front: Development of meltwater outlets and origins of bedforms
(Journal article; Tidsskriftartikkel, 2024-03-08)<p>Large-scale landforms originated from jökulhlaups or glacial lake-outburst floods (GLOFs), and their small-scale components help in recognising the sedimentary environment of the flood. The GLOF fans that developed along the Pleistocene ice-sheet margin have not been investigated in detail, and north-eastern Poland, with its Megaflood Landform System and Bachanowo and Szeszupka fans, seems ideal ... -
Arctic Freshwater Sources and Ocean Mixing Relationships Revealed With Seawater Isotopic Tracing
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-06-29)The Arctic Ocean and adjacent seas are undergoing increased freshwater influx due to enhanced glacial and sea ice melt, precipitation, and runoff. Accurate delineation of these freshwater sources is vital as they critically modulate ocean composition and circulation with widespread and varied impacts. Despite this, the delineation of freshwater sources using physical oceanographic measurements (e.g., ... -
Tidal and seasonal influence on cold seep activity and methanotroph efficiency in the North Sea
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-06-12)The ocean’s methane emission to the atmosphere is dominated by continental shelves where cold seeps are globally common features. Seeps emit methane into the hydrosphere, but temporal variations and controls of seep activity and the efficiency of the microbial methane filter in the water column are scarce. Here we address these knowledge gaps by measuring whole water column methane inventories and ... -
Unravelling controls on multi-source-to-sink systems: A stratigraphic forward model of the early–middle Cenozoic of the SW Barents Sea
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-07-10)Source-to-sink dynamics are subjected to complex interactions between erosion, sediment transfer and deposition, particularly in an evolving tectonic and climatic setting. Here we use stratigraphic forward modelling (SFM) to predict the basin-fill architecture of a multi-source-to-sink system based on a state-of-the-art numerical approach. The modelling processes consider key source-to-sink parameters ... -
Glacial troughs as centres of organic carbon accumulation on the Norwegian continental margin
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-06-15)The role of continental margin sediments in the carbon cycle and the associated management potential for climate mitigation are currently poorly understood. Previous work has indicated that margin sediments store significant amounts of organic carbon, but few studies have quantified the rates at which organic carbon is accumulated. Here, we use machine learning to make spatial predictions of the ... -
Geological and glaciological controls of 21,700 active methane seeps in the northern Norwegian Barents sea
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-07-11)Due to tectonic uplift in the Cenozoic and numerous shelf-wide glaciations during the Quaternary, ∼1–2.5 km of sedimentary overburden has been eroded from the Barents Sea shelf, leading to the exhumation and partial uncapping of hydrocarbon accumulations. Widespread natural gas and oil leakage from the glacially eroded middle-upper Triassic reservoir directly into the water column has been documented ... -
Near-surface characterization using shear-wave resonances: A case study from offshore Svalbard, Norway
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-06-14)Shear-wave (S-wave) resonances are typically observed when the surficial marine sediments over a rock substrate have relatively low S-wave velocities. We observe these phenomena using ocean-bottom fiber-optic distributed acoustic sensing (DAS) in two subsea fiber-optic telecommunication cables in Svalbard, Norway. Strong seismic energy from sufficiently large earthquakes is required to trigger and ... -
Methanotroph activity and connectivity between two seep systems north off Svalbard
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-06-14)Understanding methane flux dynamics in Arctic cold seep systems and the influence of oceanic currents on microbial methane-oxidizing bacteria (MOB) is crucial for assessing their impact on Arctic methane emissions. Here, we investigate methane dynamics and associated microbial communities at two cold seep areas, Norskebanken and Hinlopen Trough, North of Svalbard. Methane concentrations and methane ... -
A distinctive rare earth element signature for pyrite oxidation and glacial weathering
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-05-15)The application of rare earth elements (REE) and neodymium (Nd) isotopes to authigenic Fe-(oxyhydr)oxide phases leached from marine sediments can be used for reconstructing past ocean circulation and chemical weathering patterns on nearby continental landmasses. To explore the behaviour of REE during chemical weathering in glacial environments, we analyzed the authigenic fraction of glacimarine ... -
Contrasting Methane Seepage Dynamics in the Hola Trough Offshore Norway: Insights From Two Different Summers
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-07-09)This study investigates the temporal variations in methane concentration and flare activity in the Hola trough (offshore Norway) during May 2018 and June 2022. Between these time periods, methane seep activity exhibits 3.5 times increase, as evidenced by hydroacoustic measurements. As the seep area in the Hola trough is constantly within the hydrate stability zone, the observed increase cannot be ...
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