This data set provides a comprehensive assessment of groundwater partial pressure CO2 (pCO2) across Denmark, spanning more than three decades (1988–2024). Using groundwater chemistry data from the national borehole database, Jupiter, pCO2 levels were calculated and compared using two distinct approaches: (1) geochemical modelling via PHREEQC; and (2) simplified carbonate equilibria using only pH and alkalinity. While the latter is widely used for its simplicity, the PHREEQC method offers more accurate estimates by accounting for ionic strength and complexation. Despite Denmark’s extensive public archive of groundwater chemistry, pCO2 values have remained largely unavailable to the scientific community due to data complexity. This data set addresses this data gap through rigorous cleaning and the flagging of potentially contaminated samples to ensure high data fidelity. The resulting long-term, large-scale overview is essential for elucidating the role of groundwater in the carbon cycle and its spatiotemporal dynamics. Furthermore, these data establish critical baseline conditions necessary for monitoring and protecting groundwater resources in the context of the future CO2 injection and storage in deep geological reservoirs.
We present a point-based inventory of landslide events at Møns Klint, Denmark. It is compiled from a Danish Nature Agency (Naturstyrelsen) event list, quality-controlled by adding sources where possible and georeferenced from the listed place names to derive best-estimate cliff localities representing potential source areas. The dataset is provided as a GeoPackage and an Excel file containing metadata on date/temporal precision, location, event type, size class and source. The inventory contains 63 events, spanning from 1801 to 2024. Limitations include locality name uncertainty, variable temporal precision, uncertainty in landslide size and type, and reporting bias related to spatial accessibility and uneven documentation through time. The inventory suggests that landslides are relatively evenly distributed across the cliff. They occur throughout the year but cluster in winter and spring. The inventory provides a baseline for operational monitoring and hazard communication at Møns Klint and supports further research on event frequency, spatial distribution and links between landsliding and potential drivers such as coastal erosion, hydro-meteorological forcing and freeze–thaw processes. The dataset may also serve as a template for developing a national landslide-event inventory for Denmark.
Anthophyllite- and garnet-bearing metapelites from the Nunatarsuaq domain, located north of the UNESCO World Heritage site Ilulissat Icefjord (Kangiata Sullua) in Greenland at the northern margin of the Nagssugtoqidian orogen, enable a first quantitative assessment of the conditions of metamorphism in the area. Geothermobarometry undertaken on metapelites from a representative section of the domain indicates peak metamorphic conditions of c. 700–750°C and c. 8–9.5 kbar implying burial to mid–lower-crustal depths during deformation. The high-temperature range is consistent with the occurrence of widespread textural evidence for partial melting in the rocks. Retrograde chlorite, epidote and actinolite along with reverse zoning of Mn in garnet rims record subsequent cooling and hydration during exhumation into lower amphibolite to greenschist facies conditions, although the timing is unclear. The recognition of upper-amphibolite facies metamorphic conditions indicates that the Nunatarsuaq domain likely shared a common Palaeoproterozoic 1.82–1.81 Ga metamorphic event, probably associated with crustal thickening during collision of the Rae and North Atlantic cratons in the Nagssugtoqidian orogen. These findings reveal that the Nunatarsuaq domain preserves a higher-grade metamorphic imprint than previously recognised and refine the metamorphic architecture of the northern Nagssugtoqidian orogen.
This study presents a first-order assessment of reservoir pressure regimes across onshore Denmark, focusing on hydrostatic conditions and occurrences of natural overpressure. Using a newly compiled database of brine salinity measurements from 28 wells, hydrostatic pressures were estimated based on salinity-derived density profiles. Validation against in situ pressure measurements confirms the reliability of this approach. Additional analysis of historical artesian deep wells documents local overpressured reservoirs within specific units such as the Zechstein Group, Bunter Sandstone and Ørslev Formations. These overpressured compartments suggest that reservoirs may be hydraulically isolated, potentially impacting storage capacity in CO2 sequestration projects. Overpressure is also observed in the overburden within the Chalk Group. We suggest that regional Neogene uplift has further shaped hydraulic heads in the Chalk Group, introducing semi-regional pressure compartments. The main objective of this study was to establish a robust regional baseline for hydrostatic pressure conditions while highlighting historically underappreciated overpressure phenomena relevant to risk assessment in subsurface CO2 storage, geothermal utilisation and underground energy storage. We calculate the pressure required to lift brine to the surface, potentially allowing interaction with groundwater and thereby providing practical constraints for risk assessments and subsurface pressure management in prospective CO2 storage sites. In order to distinguish between open versus closed aquifer behaviour and identify potential brine discharge pathways, the sealing capacity of the Quaternary cover above the sparse natural outcrops of the Gassum and Skagerrak Formations, together with the conductivity of fault systems, must be assessed. These results establish a pressure baseline and provide critical input for future pressure communication models, supporting site selection, operational safety and coordinated subsurface resource management during Denmark’s green energy transition.
Geothermal heat flow (GHF) influences ice sheet thermal conditions, affecting ice flow by sliding and deformation. However, GHF distribution under polar ice sheets remains poorly constrained, with few direct borehole-derived estimates and large discrepancies between glaciological and geophysical models caused by methodological differences and data limitations. As a result, many ice sheet models rely on uniform GHF estimates, ensemble averages or outdated fields that oversimplify reality. The choice of GHF product can lead to significantly different thermal conditions simulated at the ice-bed interface, which affects the projected evolution of ice sheets under climate warming. Therefore, we conducted an expert elicitation survey to identify the most suitable GHF fields for use as basal boundary conditions in ice sheet modelling, particularly for the Ice Sheet Modelling Intercomparison Project for CMIP7 (ISMIP7). GHF fields generally fall into three categories: (1) outdated due to improved data availability, (2) overly simplified parameterisations and (3) current and preferred. For GHF fields that rank highly in the survey, we discuss uncertainty and data dependency and guide their use in different applications. Finally, we recommend two Antarctic and one Greenlandic GHF fields for ISMIP7.
Denitrification is the most important process for nitrate removal in groundwater. Although carbonate aquifers are important for drinking water supply, the denitrification process in these systems is less understood than for unconsolidated sedimentary aquifers. We reviewed studies that (1) provide evidence for denitrification in carbonate aquifers, (2) discuss the specific location where it occurs, and (3) quantify denitrification rates. Literature sources were identified by a systematic search of scientific databases and follow-up reference tracking.The key finding is that denitrification in carbonate aquifers is possible, supported by microbiologic and/or isotopic evidence for several locations. Pore size and connectivity are major limiting factors for denitrification within the matrix. Denitrification in fissures/fractures would be limited by electron donor availability and unfavourable redox conditions. However, it has also been hypothesised that denitrification could occur in micro-anaerobic environments and biofilms. Denitrification rates for carbonate aquifers varied by several orders of magnitude (0.01–36 792 mg N/L/y). High concentrations and very reactive organic carbon from waste-water contamination and high groundwater temperatures are characteristic for some of the studies. Thus, rates may not be transferable to cooler oligotrophic conditions. Future research is needed to fill identified knowledge gaps.
Newly collected ammonites from Campanian and Maastrichtian strata in East and North-East Greenland are described. An early early Campanian fauna from Hold with Hope includes Neophylloceras, Pseudophyllites, Gaudryceras (Gaudryceras) mite (Hauer 1866) and Baculites. A latest early Campanian fauna from Geographical Society Ø comprises Pseudophyllites latus (Marshall 1926), Hoploscaphites cobbani (Birkelund 1965), and Baculites sp. Late Campanian assemblages from Geographical Society Ø and Traill Ø include Hoploscaphites greenlandicus (Donovan 1953) and Hoploscaphites compressus (Roemer 1841). In the Kangerlussuaq Basin, East Greenland, an early early Maastrichtian fauna contains Acanthoscaphites (Acanthoscaphites) tridens (Kner 1848), together with Anagaudryceras politissimum (Kossmat 1895) and other taxa. A later fauna is characterised by Discoscaphites angmartussutensis Birkelund (1965). Generally, early Maastrichtian faunas of the Kangerlussuaq Basin are dominated by Diplomoceras cylindraceum (Defrance 1816), and also contain Anagaudryceras, Saghalinites, and Baculites, together with the nautiloid Eutrephoceras. Maastrichtian faunas also occur reworked into the Paleocene. Most of these taxa are reported for the first time from eastern Greenland in this study, and their occurrence supports the existing stratigraphy.
Most operational flood forecasting systems provide predictions of pluvial and fluvial floods, often neglecting groundwater flooding. Groundwater-induced floods can occur when prolonged rainfall, high river stages or elevated sea levels raise the groundwater table above the surface of the land, often occurring in low-lying areas or areas with specific soil and land-surface conditions. This study presents an operational, national-scale, integrated flood forecasting system that combines surface water and groundwater components – such as river discharge and high groundwater levels – to assess flood risk in Denmark. The system has been proven to effectively capture peak river flows and elevated groundwater levels, as it did across the country during the winter of 2024, and provide local-scale insights, as exemplified during a specific flood event in Varde, west Denmark. This study demonstrates how groundwater flooding, often neglected in operational forecasting, can be effectively incorporated at a national scale to support more informed flood management.
The 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.
A 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.
This study provides a detailed structural analysis of a selected part of the Fanø Bugt Glaciotectonic Complex in the south-eastern part of the Danish North Sea. The 200 km2 study area was mapped in 3D using high-resolution, 2D multichannel seismic data. The interpretation of seismic profiles demonstrates an architecture markedly separated into a lower and an upper thrust fault level, separated by the upper décollement surface. The lower level is characterised by >15 thrust sheets, with crests that form subsurface ridges with reliefs up to 150 m, scattered over c. 15 km. The upper level is characterised by thrust sheets grouped in imbricate complexes with thrust faults connecting to the upper décollement. The structural style changes in the direction of transport, possibly related to the position of the ice-sheet margin responsible for the thrusting and changes in the properties of the basal décollement. The structural style is generally large-scale thrusting and folding, suggesting proglacial deformation. However, the hinterland of the upper thrust fault level displays heavily folded layers or a chaotic reflection pattern associated with subglacial deformation. Special attention is drawn to two exceptional structural frameworks containing a hidden hill-hole pair: SF1, an imbricate thrust fault fan in a 5 km long and 2.5 km wide basin, developed above an extensional normal fault imbricate, and SF2, a frontal ramp uplifting an imbricated fan c. 90 m above the average level of thrusting. Restored cross-sections demonstrate a shortening of the lower thrust fault level between 9–43% and 44–49% of the upper level across SF1 and SF2, respectively. We suggest that the glaciotectonic complex was formed proglacially due to gravity spreading in front of an ice margin. Gravity gliding due to an inclined décollement surface of 0.5° and elevated porewater pressure at the décollement might also have facilitated the deformation.
We 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.
Pesticides and degradation products are a major challenge for groundwater management in Europe, and in Denmark where drinking water relies entirely on groundwater. To protect drinking water resources, local Danish authorities must take groundwater-protective measures in areas designated as sensitive to pollution; however, official zonation for pesticides is lacking. Nitrate-sensitive groundwater abstraction areas have been used instead. The goal of our study was to test the appropriateness of this groundwater protection strategy. We used Køge municipality (Denmark) as a focus area and tested how our findings upscale to the national level. The data for Køge municipality included 1070 individual groundwater samples, analysed for at least one of 366 pesticide compounds during the period 2012–2022, which were aggregated at the well-screen level by the median. Four pesticide compounds (2,6-dichlorobenzamide (BAM), desphenylchloridazon (DPC), N,N-dimethylsulphamide (DMS), 1,2,4-triazole) and three pesticide groups (phenoxyalcanoic acids, triazines and dimethachlor and its metabolites) were found with the highest detection frequency in the study area. We found that groundwater pollution with pesticide compounds was not limited to nitrate-sensitive areas in Køge municipality or in Denmark as a whole. Therefore, nitrate-sensitive areas can only be used partially for identifying pesticide-sensitive groundwater abstraction areas. The management implication is that placing protective measures only within nitrate-sensitive areas would be insufficient to fully address the risk of future groundwater pesticide pollution. We identified knowledge gaps and discussed a potential way forward with a more integrated management of groundwater protection in Denmark.
This 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.
Meltwater rivers in Greenland transport large quantities of freshwater from the Greenland ice sheet and local glaciers to the ocean, significantly influencing marine ecosystems and global biogeochemical cycles. With accelerating ice melt due to climate change, understanding the biogeochemistry of these rivers is critical. Here, we present a data set providing comprehensive biogeochemistry data from 28 meltwater rivers in south-western Greenland. Spanning a period from 2017 to 2021, it includes data on nutrients and other ions, trace metals, sediment, radio and water isotopes, microbiology and cyanotoxins, sampled during field campaigns in June and August–September. This data set offers valuable insights for research on glacial meltwater, biogeochemistry and microbiology, addressing key knowledge gaps in these fields.
In June 2021, a novel Danish national carbon capture and storage strategy was ratified by the Danish Parliament, and this was followed by the initiation of the project ‘CCS2022–2024’, led by the Geological Survey of Denmark and Greenland. In collaboration with other institutions, we acquired and interpreted new 2D seismic data between 2022 to 2024 to investigate and mature eight sites for potential subsurface storage of CO2 in Danish onshore and offshore areas. This Bulletin contains a series of papers that present important results of the work. In this introduction paper, we provide an overview of seismic acquisitions and the interpretation of seismic data together with existing deep wells. The study sites selected are large subsurface structures located in onshore Jylland, Sjælland and Lolland and offshore Denmark in the eastern North Sea. The onshore targets are the Gassum, Havnsø, Rødby, Stenlille and Thorning structures, while the offshore sites comprise the Inez, Jammerbugt and Lisa structures. The project work comprises a series of reports regarding extensive seismic acquisition, processing and interpretation of the new and pre-existing seismic data as well as other publications emanating from the project. This Bulletin and the technical reports present an improved understanding of the formation, composition and geometry of the investigated structures. The studies include the mapping of the reservoir and seal formations, identification of principal faults, interpretation of the stratigraphic and structural development, reservoir and seal characterisation and estimates of the static storage capacity. Hence, this research provides a significant step forward concerning characterisation of the geology and maturation of the potential storage sites. In addition, it has inspired new ideas, including an updated regional stratigraphic interpretation of the Triassic succession of the Danish Basin and correlation with adjacent basins.
CO2 storage presents new risks and challenges, where the properties of formation water play an important role. These challenges include reduced injectivity and storage capacity due to salt precipitation, viscous fingering caused by viscosity contrasts between CO2 and brine and diminished CO2 solubility in formation waters. Understanding these factors and developing predictive models for pressure distribution are essential for successful CO2 storage projects. This study presents salinity (Cl and total dissolved solids), density, temperature, pressure, halite (NaCl) saturation, CO2 solubility and viscosity of formation waters across five CO2 storage sites in Denmark (Stenlille, Gassum, Rødby, Lisa and Inez), covering eight reservoirs (one in the Frederikshavn Formation, four in the Gassum Formation and three in the Bunter Sandstone and Skagerrak Formations). Salinity assessments are based on existing brine data or, where unavailable, a reference salinity model developed from a water chemistry database with 77 analyses from 28 wells in the Danish Basin and adjacent regions. The model was created using Partial Least Squares regression, accounting for local geological developments and subsurface salts. We report high chloride levels (182 000–202 000 mg/L) and densities (1.21–1.23 kg/L) in the Bunter Sandstone and Skagerrak Formations, while the Gassum and Frederikshavn Formations are undersaturated with halite, exhibiting lower chloride levels (99 000–148 000 mg/L) and densities (1.11–1.17 kg/L). These differences suggest a higher risk of mineral precipitation due to brine evaporation in dry CO2, and a higher risk of density override due to significant density contrast, which will hamper filling efficiency in older reservoirs. Modelling shows that CO2 solubility reaches 33.9 g CO2/L, with a 37% reduction due to chemical and pressure–temperature variations. Conceptual fluid flow modelling is recommended to further assess brine–rock–CO2 interactions. The salinity model has implications for geothermal reservoir assessment and can be applied regionally.
The renewable energy transition has increased the demand for offshore construction in the Danish North Sea energy sector. This development underpins the need for further investigation of potential geological hazards and associated risks to avoid accidents involving people, the environment or infrastructure. A scientific approach to de-risking requires an understanding of the seabed and the buried geosystems. Understanding geosystems is the first step in the de-risking process of offshore construction. In this study, we review three key geosystem elements in the Danish North Sea, represented by (1) shallow stratigraphy and geomorphology, (2) glacial tectonics and salt movement and (3) subsurface fluid migration. We summarise the current state of knowledge of these geosystem elements and identify multiple risks associated with each geosystem in the region. Such investigations are critical for understanding the geotechnical behaviour of the subsurface and identifying and de-risking of potential geohazards during the construction of future energy developments in the Danish North Sea region.
The biostratigraphy of the Jurassic in East Greenland is historically based on macroscopic fossils. Stratigraphy based on palynomorphs (spores, pollen and dinoflagellate cysts) has progressed more slowly and sporadically. The Scriniodinium crystallinum dinoflagellate cyst Zone is identified in middle - upper Oxfordian strata of Ilimananngip Nunaa (Milne Land), central East Greenland. The lower boundary is defined by the last occurrence of Trichodinium scarburghense in the Cardioceras tenuiserratum ammonite Zone. The upper boundary is defined by the last occurrence of S. crystallinum in the uppermost Amoeboceras rosenkrantzi ammonite Zone. However, the subzonal division of the S. crystallinum Zone recorded in North-West Europe is not identified in Greenland. Eighteen characteristic dinoflagellate cyst events are considered stratigraphically significant and useful in East Greenland. Fifteen of these events provide an informal, detailed stratigraphical subdivision of the S. crystallinum Zone into 10 subunits. Identification of the zone is an addition to the previously defined upper Bathonian - middle Oxfordian zonation, where the uppermost palynostratigraphical event was recorded to be the last occurrence of T. scarburghense. With this study, the correlation of dinoflagellate cyst and ammonite stratigraphy in the lower and middle Oxfordian is slightly modified. The S. crystallinum Zone documented here, in combination with the zonation used forthe stratigraphy of the Blokelv-1, R & oslash;dryggen-1 and Brorson Halv & oslash;-1 cores of the Upper Jurassic to Lower Cretaceous, completes the dinoflagellate cyst stratigraphy ofthe marine Jurassic in East Greenland. Together with previous studies of spores and pollen in less marine units, the first complete palynological Jurassic stratigraphy is thus established forthe Jurassic succession in East Greenland.
The Portfjeld Formation, as originally defined, is the lowermost lithostratigraphic unit of the mainly Lower Palaeozoic Franklinian Basin in southern Peary Land, central North Greenland. The unit crops out semi-continuously from Valdemar Glückstadt Land to Nordenskiöld Fjord but is also recognised locally in northern parts of Peary Land and Wulff Land (western North Greenland). Regionally, it provides a key record of the early, pre-break-up history of the basin. The type succession in southern Peary Land has thus been the focus of recent biostratigraphical, sedimentological and geochemical study. This has demonstrated the composite nature of the unit, a lower interval (c. 190 m thick) of carbonate ramp deposits of Neoproterozoic (late Ediacaran) age being overlain at a karstic unconformity by a shallow marine, mixed carbonate–siliciclastic interval (c. 100 m thick) of probable earliest Cambrian age. Lithostratigraphic revision of this succession is presented here. The Portfjeld Formation throughout North Greenland is elevated to the rank of group, and two new formations are defined in this group in southern Peary Land and immediately adjacent areas: the Ediacaran carbonate-dominated unit is referred to the Slusen Formation, the upper mixed siliciclastic–carbonate unit to the Glaciologelv Formation.
