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The Nuussuaq Basin is the only exposed Cretaceous–Paleocene sedimentary basin in West Greenland and is one of a complex of linked rift basins stretching from the Labrador Sea to northern Baffin Bay. These basins developed along West Greenland as a result of the opening of the Labrador Sea in Late Mesozoic to Early Cenozoic times. The Nuussuaq Basin is exposed in West Greenland between 69°N and 72°N on Disko, Nuussuaq, Upernivik Ø, Qeqertarsuaq, Itsaku and Svartenhuk Halvø and has also been recorded in a number of shallow and deep wells in the region. The sediments are assigned to the more than 6 km thick Nuussuaq Group (new) which underlies the Palaeogene plateau basalts of the West Greenland Basalt Group. The sediment thickness is best estimated from seismic data; in the western part of the area, seismic and magnetic data suggest that the succession is at least 6 km and possibly as much as 10 km thick. The exposed Albian–Paleocene part of the succession testifies to two main episodes of regional rifting and basin development: an EarlyCretaceous and a Late Cretaceous – Early Paleocene episode prior to the start of sea-floor spreading in mid-Paleocene time. This exposed section includes fan delta, fluviodeltaic, shelfal and deepmarine deposits. The Nuussuaq Group is divided into ten formations, most of which have previously been only briefly described, with the exception of their macrofossil content. In ascending stratigraphic order, the formations are: the Kome Formation, the Slibestensfjeldet Formation (new), the Upernivik Næs Formation, the Atane Formation (including four new members – the Skansen, Ravn Kløft, Kingittoq and Qilakitsoq Members – and one new bed, the Itivnera Bed), the Itilli Formation (new, including four new members: the Anariartorfik, Umiivik, Kussinerujuk and Aaffarsuaq Members), the Kangilia Formation (including the revised Annertuneq Conglomerate Member andthe new Oyster–Ammonite Conglomerate Bed), the Quikavsak Formation (new, including three new members: the Tupaasat, Nuuk Qiterleq and Paatuutkløften Members), the Agatdal Formation, the Eqalulik Formation (new, including the Abraham Member), and the Atanikerluk Formation (new, including five members: the Naujât, Akunneq (new), Pingu (new), Umiussat and Assoq (new) Members).

Large structural highs and sedimentary basins are identified from mapping of the West Greenland continental margin from the Labrador Sea to the Baffin Bay. We present a new tectonic elements map and a map of thickness from the seabed to the basement of the entire West Greenland margin. In addition, a new stratigraphic scheme of the main lithologies and tectonostratigraphy based on ties to all offshore exploration wells is presented together with seven interpreted seismic sections. The work is based on interpretation of more than 135 000 km of 2D seismic reflection data supported by other geophysical data, including gravity- and magnetic data and selected 3D seismic data, and is constrained by correlation to wells and seabed samples. Eight seismic mega-units (A-H) from the seabed to the basement, related to distinct tectonostratigraphic phases, were mapped. The oldest units include pre-rift basins that contain Proterozoic and Palaeozoic successions. Cretaceous syn-rift phases are characterised by development of large extensional fault blocks and basins with wedge-shaped units. The basin strata include Cretaceous and Palaeogene claystones, sandstones and conglomerates. During the latest Cretaceous, Paleocene and Eocene, crustal extension followed by oceanic crust formation took place, causing separation of the continental margins of Greenland and Canada with north-east to northward movement of Greenland. From Paleocene to Eocene, volcanic rocks dominated the central West Greenland continental margin and covered the Cretaceous basins. Development of the oceanic crust is associated with compressional tectonics and the development of strike-slip and thrust faults, pull-apart basins and inversion structures, most pronounced in the Davis Strait and Baffin Bay regions. During the late Cenozoic, tectonism diminished, though some intra-plate vertical adjustments occurred. The latest basin development was characterised by formation of thick Neogene to Quaternary marine successions including contourite drifts and glacial related shelf progradation towards the west and south-west. [ABSTRACT FROM AUTHOR]

The Late Cretaceous Oceanic Anoxic Event 2 (OAE2) represents a major perturbation of the global carbon cycle caused by the widespread deposition of organic-rich black shales. Although the paleoceanographic response and the spatial extent of bottom-water anoxia in low and mid-paleolatitudes are reasonably well constrained for OAE2, similar data from high paleolatitudes are lacking. Here, we present palynostratigraphy and organic-carbon isotope stratigraphy from the Sverdrup Basin, Axel Heiberg Island (Canada). It is shown that episodes of high marine organic-carbon burial at paleolatitudes of ~70°N is contemporaneous with the widely observed occurrence of black shale deposition during OAE2. Paleontological, lithological, and geochemical data indicate normal marine conditions with persistent anoxic bottom waters during OAE2. The results imply that the high marine primary productivity pulse during OAE2 may have caused massive organic-carbon burial on the Arctic shelf in general, with important implications for hydrocarbon source-rock distribution in the Arctic region. [ABSTRACT FROM AUTHOR]

The article presents a case study of spectral gamma-ray characterisation of the deltaic Cretaceous Atane Formation in Nuussuaq Basin, Greenland. It states that gamma-ray logs are used for lithology indicator and petrophysical model which are emitted by three elements such as potassium, thorium, and uranium. The case study reportedly fails to resolve the grain-size variation of the formation because of the presence of the elements.

The generally warm Cretaceous (c. 145-66 Ma) climate culminated in the mid Cretaceous Hot Greenhouse climate (95-85 Ma). Another characteristic feature of the Cretaceous period is a high number of Oceanic Anoxic Events (OAE) related with major carbon cycle perturbations. While the Lower Cretaceous successions from equatorial region and middle latitudes are relatively well studied, sections from High Arctic settings are sparse and occasionally suffering from poor age constrains.The present study was performed within the LoCrA (Lower Cretaceous Basin Studies in The Arctic) consortium and focused on the Lower Cretaceous succession on Spitsbergen (this study) and the Barents Sea. The Lower Cretaceous succession on central Spitsbergen is divided into: the Rurikfjellet, Helvetiafjellet and Carolinefjellet formations. Each formation was deposited under different environmental conditions, ranging from open to shallow marine (Rurikfjellet and Carolinefjellet formations) to fluvio-deltaic (Helvetiafjellet Formation). Our improved age model (based on palynology, macrofossils and organic stable carbon isotopes) for the Rurikfjellet and Helvetiafjellet formation confirms that these two units span the Valanginian to lower Aptian. Dinoflagellate cysts (dinocysts) are excellent for biostratigraphy as well as paleoecology. Dinoflagellates, forming the primary component of marine plankton, are sensitive to various environmental factors: temperature, salinity, nutrient availability, etc. Within the studied interval a number of dinocyst events occurs, which appears to be synchronous between Spitsbergen and other high-Arctic basins (e.g. in Greenland and Arctic Canada). However, some of the characteristic Early Cretaceous dinocyst taxa, are either absent or only observed locally. Here, we investigate if the changes in the dinocyst assemblages are an effect of the local environmental changes or an effect of the regional to global climate perturbations. [ABSTRACT FROM AUTHOR]