English
norskInstitutt for geovitenskap
Bla i:
Enhetens samlinger
Nye registreringer
-
Geochemical and mineralogical characteristics of fjord sediments in Arctic Svalbard: insights into Holocene glacial activity and weathering variability
(Journal article; Tidsskriftartikkel; Peer reviewed, 2025-03-18)The Svalbard archipelago at the border of the Arctic Ocean experiences substantial glacier retreat due to global warming, resulting in a retreat of glacier termini from the marine to terrestrial settings. However, the impact of these transitions on marine environments remains poorly understood. To improve our understanding of how Arctic Svalbard responds to fluctuations in climate and glaciers, we ... -
Cold Seeps and Coral Reefs in Northern Norway: Carbon Cycling in Marine Ecosystems With Coexisting Features
(Journal article; Tidsskriftartikkel; Peer reviewed, 2025-03-20)Cold seeps and cold-water corals (CWCs) coexist on Northern Norway's continental shelf at the Hola trough between Lofoten and Vesterålen. Here, cold seeps release methane from the seabed, yet none reaches the sea surface. Instead, the methane dissolves and disperses in the ocean where it is ultimately consumed by methane-oxidizing microorganisms. These microorganisms metabolize methane and release ... -
Miocene ice sheet dynamics and sediment deposition in the central Ross Sea, Antarctica
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-10-09)Drill cores from the Antarctic continental shelf are essential for directly constraining changes in past Antarctic Ice Sheet extent. Here, we provide a sedimentary facies analysis of drill cores from International Ocean Discovery Program (IODP) Site U1521 in the Ross Sea, which reveals a unique, detailed snapshot of Antarctic Ice Sheet evolution between ca. 18 Ma and 13 Ma. We identify distinct ... -
Grain-scale feedback between deformation mechanisms and metamorphic reactions: Dissolution-precipitation processes in the lower crust (Kågen gabbros)
(Journal article; Tidsskriftartikkel; Peer reviewed, 2025-03-02)Strain localization within crustal shear zones involves intricate feedback between deformation mechanisms, metamorphic reactions and fluid circulation. Despite evidence that these high-deformation zones proceed at least partly through dissolution-precipitation creep, available creep laws so far only account for dislocation creep and/ or solid-state diffusion processes. Deciphering the role and ... -
Snow Mass Recharge of the Greenland Ice Sheet Fueled by Intense Atmospheric River
(Journal article; Tidsskriftartikkel; Peer reviewed, 2025-03-03)Atmospheric rivers (ARs) have been linked with extreme rainfall and melt events across the Greenland ice sheet (GrIS), accelerating its mass loss. However, the impact of AR-fueled snowfall has received less attention, partly due to limited empirical evidence. Here, we relate new firn core stratigraphy and isotopic analyses with glacio-meteorological data sets from SE Greenland to examine an intense ... -
Deep learning-based characterization of underwater methane bubbles using simple dual camera platform
(Journal article; Tidsskriftartikkel; Peer reviewed, 2025-02-10)Seabed gas and oil emissions appear as bubble plumes ascending through the water column in various environments. Understanding bubble characteristics—size, rise speed—is important for estimating escape rates of fluids like methane, oil, and carbon dioxide. However, measuring underwater gas bubbles is challenging, often requiring expensive specialized equipment. This study presents a novel methodology ... -
Lithology as a factor for the distribution of metals in stream sediments associated with sediment-hosted Cu deposits: a case study from the Alta-Kvænangen tectonic window, northern Norway
(Journal article; Tidsskriftartikkel; Peer reviewed, 2025-03-04)The Kåfjord area in northern Norway hosts numerous Cu deposits that were subjected to mining activities back in the nineteenth century. Relicts of the historical mining activity are still visible at several abandoned mines and associated mine waste disposal sites that may represent an environmental threat. The area was subjected to mining activities during the nineteenth century and abandoned mines ... -
3D seismic investigation of fluid migration and fluid accumulation related to natural seeps in the Sørvestsnaget Basin, SW Barents Sea
(Mastergradsoppgave; Master thesis, 2025-01-27)This master thesis examines the intricacies of fluid migration, gas seep areas, and fault dynamics in the southwestern Barents Sea. Acoustic evidence, such as pockmarks and gas flares, indicates active fluid movement within the below seabed sedimentary structures, such as clinoforms and the Upper Regional Unconformity (URU). Challenging lowermost reaches of gas chimneys, obscured by acoustic masking, ... -
New xenophyophores (Foraminifera, Monothalamea) from the eastern Clarion-Clipperton Zone (equatorial Pacific)
(Journal article; Tidsskriftartikkel, 2024-03-06)Xenophyophores are large, agglutinated foraminifera that dominate the benthic megafauna in some parts of the deep sea. Here, we describe an assemblage of largely fragmentary specimens from the Clarion-Clipperton Zone (CCZ), an area of the eastern abyssal Pacific hosting large, commercially significant deposits of polymetallic nodules. We recognised 18 morphospecies of which eight yielded DNA sequences. ... -
Cultural activity and impact of extreme weather events revealed by ambient seismic noise and perspective on quick clay failure monitoring in Oslo, Norway
(Journal article; Tidsskriftartikkel; Peer reviewed, 2025-02-01)The study of urban seismic noise offers various approaches to monitor cities, from source identification to structural investigations. We demonstrate its potential to monitor cultural activity and quick clay failure in Oslo, Norway using low-cost seismic sensors. We identify train passages, a rock concert, construction blasts, local earthquakes and a meteor. To retrieve seismic velocity variations ... -
Importance of grain boundary processes for plasticity in the quartz-dominated crust: Implications for flow laws
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-06-01)When H<sub>2</sub>O is present along grain boundaries, the deformation processes responsible for plasticity in silicate mineral aggregates can deviate from what may be conventionally expected. Although a necessary component of understanding crustal deformation processes, there is no theoretical framework that incorporates grain boundary processes into polycrystalline quartz rheology. To address this ... -
Shifts in Greenland interannual climate variability lead Dansgaard–Oeschger abrupt warming by hundreds of years
(Journal article; Tidsskriftartikkel; Peer reviewed, 2025-02-24)During the Last Glacial Period (LGP), Greenland experienced approximately 30 abrupt warming phases, known as Dansgaard–Oeschger (D–O) events, followed by cooling back to baseline glacial conditions. Studies of mean climate change across warming transitions reveal indistinguishable phase offsets between shifts in temperature, dust, sea salt, accumulation, and moisture source, thus preventing a ... -
Lower Cretaceous holostratigraphy in Svalbard: the Arctic key piece of the Boreal basin puzzle
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-04-25)Lower Cretaceous stratigraphy of the high palaeo-latitude Arctic-Boreal Realm is generally more poorly understood than its lower-latitude Tethyan counterpart, prohibiting regional correlations and evaluation of global climate dynamics during this important high-pCO2 period. In this paper, a holostratigraphic scheme and lithostratigraphic revision are presented for the Valanginian–lower Barremian, ... -
Hydroclimate intensification likely aided glacier survival on Svalbard in the Early Holocene
(Journal article; Tidsskriftartikkel; Peer reviewed, 2025-02-11)Accelerated Arctic warming and wetting has global impacts, as the region’s glaciers and ice caps respond to variations in temperature and precipitation, impacting global sea-level change. But as the observations needed to calibrate models are scarce, predictions cannot confirm if increases in snowfall can help offset melt. Here, we analyze two 14,000-year-long glacier-fed lake sediment records ... -
Lithospheric mantle heterogeneity beneath the Siberian craton: Evidence from garnet xenocryst database with implications for kimberlite compositions
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-22)This contribution reports some 16,000 major and minor element analyses of garnet xenocrysts derived from 18 (out of the 21 known) kimberlite fields of the Yakutian Kimberlite Province (YaKP) on the Siberian craton in Russia. Using TiO<sub>2</sub>–in–garnet as an indicator of heterogeneity within the subcontinental lithospheric mantle (SCLM), as well as garnet mg# (mg#=Mg<sup>2+</sup>/(Mg<sup>2+</s ... -
Carbon cycling during the India-Asia collision revealed by δ26Mg–δ66Zn–δ98Mo evidence from ultrapotassic volcanoes in NW Tibet
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-06-18)India-Asia continental collision–induced volcanic gas emissions are thought to have played an important role in driving Cenozoic atmospheric CO<sub>2</sub> variations, yet the details of how the deep carbon cycle may influence volcanic CO<sub>2</sub> degassing are not understood. We present a novel study employing Mg-Zn-Mo isotopic compositions of Cenozoic ultrapotassic lavas from NW Tibet. The ... -
Proglacial methane emissions driven by meltwater and groundwater flushing in a high-Arctic glacial catchment
(Journal article; Tidsskriftartikkel; Peer reviewed, 2025-02-06)Glacial groundwater is a conduit for geologic methane release in areas of glacier retreat on Svalbard, representing a large, climate-sensitive source of the greenhouse gas. Methane emissions from glacial melt rivers are known to occur in other regions of the Arctic, but such emissions have not yet been considered on Svalbard. Over the summer of 2021, we monitored methane concentrations in the ... -
Crustal Heterogeneity Onshore Central Spitsbergen: Insights From New Gravity and Vintage Geophysical Data
(Journal article; Tidsskriftartikkel; Peer reviewed, 2025-01-23)Gravity data provide constraints on lateral subsurface density variations and thus provide crucial insights into the geological evolution of the region. Previously, gravity data from the Norwegian Arctic archipelago of Svalbard comprised an onshore regional gravity database with coarse station spacing of 2–20 km, offshore gravity profiles acquired in some fjords, airborne gravity, and satellite ... -
Links between Calcite Kimberlite, Aillikite and Carbonatite in West Greenland: Numeric Modeling of Compositional Relationships
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-06-05)Textural, mineralogical and mineral compositional observations in a suite of Neoproterozoic aillikite and calcite kimberlite dykes from southern West Greenland point to consistent variations in melt major element compositions amongst these silica-undersaturated magma types. The aillikites have notably higher bulk SiO<sub>2</sub>/CO<sub>2</sub>, H<sub>2</sub>O/CO<sub>2</sub> and K<sub>2</sub>O compared ... -
The newly discovered Attu carbonatite of West Greenland: A Mesoproterozoic dyke intrusion enriched in primary Sr-Ba-REE minerals
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-06-22)A newly discovered ca. 1.5 Ga old carbonatite dyke in central West Greenland is characterized by very high contents of rare earth elements (REE), Sr and Ba (up to 12.4 wt% total REE, 14.6 wt% SrO and 12.4 wt% BaO). The dyke occurrence is named ‘Attu carbonatite’ after the nearby village Attu. The carbonatite is primarily composed of carbonate minerals such as Sr-rich calcite (CaCO<sub>3</sub>) and ...
RSS 1.0