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Aperiodic-Seismic-Arrays
No full textJupyter Notebooks to compute, plot and save as figures, text files or KML files several aperiodic tilings and layouts for seismic arrays
Dependencies:
numpy
scipy
matplotlib
pandas
scienceplots
geopandas
shapely
pykml
utm # UTM for converting between latitude/longitude and UTM coordinates
simplekml # simplekml for creating KML file
Supplementary Files for: A multidisciplinary biostratigraphic framework for the Lower to Middle Miocene of the Norwegian North Sea – the siliceous succession of the Valhall–Hod area
No full textA new multidisciplinary biostratigraphic framework, combining dinoflagellate cysts, microfossils, calcareous nannofossils, diatoms and silicoflagellates, is established for the Early to Middle Miocene deep marine clay and siliceous ooze in the southern Norwegian sector of the North Sea, based on core samples from the Valhall and Hod hydrocarbon fields. The framework was successfully tested on the equivalent chronostratigraphic level of several wells based on ditch cutting samples. New biostratigraphic events for the Danish and Norwegian North Sea resulting from this study are successfully used to correlate between the Valhall and Hod areas and supplement published zonation schemes. To our knowledge, this is the first time that diatoms and silicoflagellates from the fine fraction of microfossil samples have been used as correlation tools in the North Sea Basin. Dating of the siliceous/diatomite-rich interval results in a high-resolution (5–15 m intervals) biostratigraphic subdivision. The successful application of the new framework across the Valhall and Hod areas implies that it could also be useful in a more regional context. The new biostratigraphy
enables the correlation of the lithostratigraphic units recently defined for the Danish offshore Neogene succession to the study area and the correlation of the sequence stratigraphic surfaces defined for the Danish sector to the southern Norwegian sector
Supplementary files for: Lithostratigraphy of the Neogene succession of the Danish North Sea
No full textThe Neogene of the Danish North Sea is more than 1200 m thick. Despite being penetrated by numerous wells, formal lithostratigraphic subdivision of this succession has previously been restricted to the lowermost part. This monograph presents a comprehensive lithostratigraphy of the offshore Neogene of Denmark, in part extending recognised onshore units into the offshore realm. The mainly Lower Miocene deltaic deposits are referred to the Ribe Group, which is subdivided into six formations: the Klintinghoved, Bastrup, Arnum, Odderup, Dany (new) and Nora (new) Formations. The lowermost Miocene Vejle Fjord and Billund Formations known from the onshore
lithostratigraphy are absent in the offshore wells. The dominantly fully marine Middle and Upper Miocene sediments are referred to the Måde Group, subdivided into the Hodde, Ørnhøj, Gram, Marbæk and Luna (new) Formations; the Luna Formation includes the Lille John Member (new). The Pliocene deltaic deposits are referred to the Eridanos Group (new), which is subdivided into the Vagn (new), Emma (new) and Elin (new) Formations.
The depositional history of the Neogene of the Danish North Sea sector is presented based on a detailed reconstruction of subsurface morphology by the mapping of stratigraphical surfaces dated by biostratigraphy. During the Early Miocene, deposition in the Danish North Sea was dominated by progradation from Scandinavia; large deltas built out into the Danish onshore area from the north and north-east. West of the main deltas, muddy contourites periodically accumulated on the slope, accentuating shelf progradation. The Middle and Late Miocene period was mostly characterised
by fully marine conditions and deposition of mud. By the end of the Miocene, progradation of delta systems from Scandinavia into the North Sea resumed, and the shoreline reached the westernmost part of the Danish North Sea sector. During the Pliocene, new source areas in central and eastern Europe, such as the Carpathian Mountains, were activated and a huge delta system, the so-called Eridanos Delta, began to fill the North Sea Basin from the east and the south-east. Due to increased subsidence of the basin associated with the loading of sediments of the Eridanos
Delta, the northern systems were flooded. Although the Danish North Sea thus mainly received sediments from central Europe during the Pliocene, progradation from Scandinavia resumed at the end of the Pliocene
Supplementary basic data on danish groundwater bodies
No full textSupplementary basic data on danish groundwater bodies. The dataset was produced by GEUS on a contract with the Danish Agency for Green Transition and Aquatic Environment and is related to the Water Framework Directive River Basin Management Planing (2025-11-25
Modeled brightness temperatures at 1.4-18.7 GHz at 19 Greenland Ice Sheet sites using the SMRT and GEUS snow models
No full textThis dataset was produced under the European Space Agency Climate Change Initiative research fellowship Water Under Snow Cover.
The GEUS snow model (Vandecrux et al., 2018, 2020a, 2020b) was run at 19 sites on the Greenland Ice Sheet accumulation area using the Copernicus Arctic Regional Reanalysis (CARRA) as forcing. The Snow Microwave Radiative Transfer (SMRT) model from Picard et al. (2018) calculated the daily (6 AM) brightness temperature (TB) at four frequencies using as input the simulated profiles of snow temperature, density, and grain size from the GEUS snow model. The coupling between these two models was optimized through the adjustment of two parameters for each site and year. First, the number of pure ice layers to be considered in the SMRT input—based on the ice content simulated by the GEUS snow model—was optimized to maximize the match between observed and simulated winter vertically polarized TB at 1.4 GHz. Then, a multiplicative correction factor applied to the GEUS snow model's simulated grain diameter was also optimized each year and site to maximize the match between observed and simulated vertically polarized TB at 6.9, 10.7, and 18.7 GHz. Observations from the Soil Moisture and Ocean Salinity (SMOS) satellite and Advanced Microwave Scanning Radiometers (AMSR-E, AMSR2) were used as the observed TB.
Please refer to, and cite:
Vandecrux, B., Picard, G., Zeiger, P., Leduc-Leballeur, M., Colliander, A., Hossan, A., & Ahlstrøm, A. (submitted). Estimating the depth of subsurface water on the Greenland Ice Sheet using multi-frequency passive microwave remote sensing, radiative transfer modeling, and machine learning. Remote Sensing of Environment
Supplementary files for: Traverse Route from Pituffik to Warming Land, North Greenland
No full textWe examine the feasibility of an overland motorised traverse from Pituffik to Greenland’s oldest ice outcrop in Warming Land, North Greenland. We assess a 778 km overland traverse that departs Pituffik via the Nunatarssuaq Take-Off Ramp, which is an alternative to the more frequently used, but more heavily crevassed, Thule Take-Off Ramp. The traverse route includes brief sea ice and primitive road conditions, each c. 4% of the route length, and a lengthy ice sheet segment (c. 92% of the route length). This study outlines challenges for each of these traverse segments, including primitive road conditions and snow cover, seasonality of extreme cold conditions (air temperatures below –30°C), seasonality of surface melting and softening (air temperatures above 0°C), sea-ice thickness and potential ridging hazards, and ice dynamics and potential crevasse hazards. Ongoing work is required for annual vetting of the traverse route to ensure operational safety. The optimal operational window for such a traverse is departing Pituffik in mid-April and returning in mid-May. In comparison to aircraft-supported ice-sheet fieldwork, scientific traverses offer the opportunity for more intensive ground-based science, while significantly reducing carbon emissions. Based on previously reported traverse fuel consumptions, a ground traverse from Pituffik to Warming Land would use 90% less fuel than aircraft supported fieldwork. This assessment underscores the potential for sustainable ground-based access to Greenland’s oldest ice outcrop and other science sites within the region
Supplementary data for: The Kangâmiut dyke swarm in West Greenland: a new map and insights into their tectonic evolution
No full textThis contribution presents a new map of the Palaeoproterozoic Kangâmiut dyke swarm in Central West Greenland. The map is based on publicly available aerial imagery, the scale and quality of which allowed for quick and efficient interpretation across a large area. The Kangâmiut dyke swarm has played a pivotal role in the identification and characterisation of the southern margin of the Nagssugtoqidian orogen. Change in dyke orientation from NNE-trending in the south to ENE-trending farther north is accompanied by increasing deformation in both dykes and host rocks. The zone where dykes and host rocks are totally parallelised defines the southern structural and metamorphic front of the Nagssugtoqidian orogen. We document variable changes in orientation of the dykes and their density to estimate the crustal extension accompanying dyke emplacement. The average width of the 123 dykes is 25 m (80% are <50 m). These dykes occur with an average frequency of 3.4 dykes per km and make up 6–11% of the outcrops. These data reveal subordinate groups of dykes with ESE and NE orientations and track regional changes. At present, their ages relative to the dominant NNE-trending swarm are not known. The swarm generally extends from south of Maniitsoq northwards to the Ikertooq shear zone; however, we identified features north of the Ikertooq shear zone, which we speculatively interpret to represent the northernmost occurrence of the Kangâmiut dyke swarm. The tectonic consequences of this interpretation – if correct – allow us to estimate the amount of shortening across the Ikertooq shear zone during the Nagssugtoqidian orogeny to be more than 150 km. If the other major tectonic boundaries in the orogen, including the Nordre Strømfjord shear zone, were the loci of similar shortening, the current extent of the orogen may represent only a fraction of pre-Nagssugtoqidian crust in Central West Greenland
Snow line altitude for A. P. Olsen Ice Cap
No full textThis dataset gives an average snow line altitude for the part of A. P. Olsen Ice Cap that falls within the hydrological catchment of Zackenberg River. The snow/ice boundary has been mapped manually from the Sentinel image from August that has no clouds and the highest snow line altitude. The snow line altitude is extracted at 100 m intervals at along the snow/ice boundaries from the same DEM (the Greenland DEM from the Danish Agency for Climate Data (https://dataforsyningen.dk/data/4780) which is a combination between ArcticDEMv3, GIMP og TREx
GPR derived snow depth over A. P. Olsen Ice Cap (2008-2024)
No full textThis dataset contains ground-penetrating radar (GPR)-derived end-of-winter snow depths over A.P. Olsen Ice Cap for the period 2008–2024. GPR data were collected using a MALÅ Geoscience ProEx unit with 500 MHz (2008–2011) or 800 MHz (2012–2024) shielded antennas. Data were processed using the ReflexW-2D software package.
Raw GPR data can be found in GPR_raw_2008_2024.zip. Processed GPR data, including ReflexW files, are available in GPR_processed_2008_2024.zip.
The yyyy_GPR_snowdepth.txt files contain the picked reflection of the last summer surface (using ReflexW), converted to snow depths for each survey year. The variables are:
ProfName: Profile Name
TraceNr: GPR trace number as recorded along the profile
lon: Longitude, degrees East (GPS coordinates recorded with handheld unit, interpolated)
lat: Latitude, degrees North (GPS coordinates recorded with handheld unit, interpolated)
Elev: Elevation, meters above sea level (GPS coordinates recorded with handheld unit, interpolated)
X: Easting, kilometers, EPSG:3413
Y: Northing, kilometers, EPSG:3413
dist: Profile distance, meters
twt: Two-way travel time to the picked reflector, nanoseconds
depth: Snow depth, meters
v_snow: Radar velocity used for time-to-depth conversion, m/ns
rho_snow: Snow density used to calculate radar velocity, kg/m3
Amp: Amplitude of the picked reflector
The yyyy_GPR_snowdepth_ds.txt files contain snow depth data downsampled to a 2 m interval for each survey year.
2008_2024_GPR_snowdepth_ds.txt contains all downsampled data from the years 2008–2024.
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GREENMAG - Magnetic anomaly map of Greenland
No full textGreenland Magnetic Compilation (GREENMAG)
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The development of this new magnetic compilation from Greenland (GREENMAG) was initiated by the working group of Satellite- and Aerogeophysics at the Christian-Albrechts-University (CAU) in Kiel, Germany, and GEUS as part of the ESA project GOCE+Greenland in 2021. The here presented magnetic anomaly map covers whole Greenland including the Inland Ice and the adjacent shelf regions.
It is built out of all accessible modern regional aeromagnetic surveys from Greenland but also uses older datasets without GPS positioning in areas where modern data are lacking. Magnetic data are currently taken from the surveys of the projects AEROMAG, AEM, GICAS, EASTMAR, ICEBRIDGE, GAP91/92, AWI93-96, LOMGRAV, NOO-73, several projects from the German Federal Institute for Geosciences and Natural Resource (BGR), Geological Survey of Canada (GSC) and Alfred Wegener Institute (AWI) and from offshore datasets acquired by the TGS-NOPEC TGS GEOPHYSICAL COMPANY. Since long wavelength components in aeromagnetic data are often considered as unreliable, they are replaced by the ones from the LCS-1 satellite model (Gaussian coefficients with degrees n = 13 – 133).
The magnetic anomaly map is generated by a methodology that combines equivalent source modelling and a spherical harmonic expansion. The datapoints at their actual measuring locations are used as data input and magnetic dipoles are employed as equivalent sources that are arranged in three uniform grids with different source spacing and depths (coarsest spacing: 10 x 10 km; finest spacing: 0.7 x 0.7 km). The presented magnetic anomaly map is simulated from the dipole responses at a constant height of 2000 m asl and with a grid spacing of 400 x 400 m. Regularizations in the inversion for the different equivalent source grids are chosen such that the resulting resolution is flexible and adapted to the largely varying magnetic data coverage in Greenland.
Data Download
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Downloadable data include (1) the GREENMAG magnetic anomaly map as ArcView Binary Raster Grids (files *.flt, *.hdr) and in a column based ASCII-table (files *.XYZ) and (2) a table with the locations of used data points. The magnetic anomaly maps are provided as two versions. One is simulated from all three equivalent source grids, but the other is simulated only from the coarse and medium equivalent source grids