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AbstractThis paper compiles and correlates for the first time Cretaceous to Eocene palynostratigraphies across the Arctic. It focuses on Greenland and adjacent areas, including the Labrador–Baffin Seaway, onshore Nuussuaq Basin in central West Greenland, onshore southern East Greenland, central East Greenland, North-East Greenland, eastern North Greenland and the Danmarkshavn Basin, but also extends to the Canadian Arctic Archipelago and the Barents Sea region offshore Norway. The paper compiles data from more than three decades of detailed Arctic palynological analyses, based mainly on dinoflagellate cysts. It gives a historical overview of the Cretaceous to Paleogene palaeontological studies of Greenland and presents an overview of 85 palynological intervals and numerous bioevents. The palynological assemblages from the Labrador–Baffin Seaway, Nuussuaq Basin and north-east Baffin Bay reflect the opening of the Labrador–Baffin Seaway, from a brackish to freshwater environment in a large embayment in the Early Cretaceous to an open marine seaway in the Late Cretaceous. Assemblages reveal dinoflagellate cyst provincialism between the opening stages of the Labrador–Baffin Seaway and the already opened Greenland–Norwegian–Barents seaway. The Upper Cretaceous global Oceanic Anoxic Event 2 (OAE2) spanning the Cenomanian/Turonian boundary is recognised from Arctic Canada, north-east Baffin Bay, Nuussuaq Basin in central West Greenland, and North-East Greenland, and is mapped and correlated based on dinoflagellate cyst stratigraphy and carbon isotope (δ13Corg) curves. The dinoflagellate cyst assemblages of the Cretaceous/Paleogene boundary are correlated from the Labrador Sea across to the Nuussuaq Basin in central West Greenland; in both areas the earliest Danian palynological assemblage is represented by incoming warm-water species. The presence of the global Paleocene–Eocene Thermal Maximum (PETM) in the Paleogene successions in North-East Greenland and in exploration wells in the Labrador–Baffin Seaway is indicated by the incoming of the warm-water dinoflagellate cyst species Axiodinium augustum. [ABSTRACT FROM AUTHOR]

Reported ancient bottom current deposits in deep marine settings are scarce and most of them remain contentious. This study describes sedimentological, ichnological and petrographical characteristics of a drill core that covers ca 10 Myr of Upper Cretaceous stratigraphy at Hold with Hope, north‐east Greenland. The core is divided into four facies associations, which are interpreted to reflect deposition from bottom currents, turbidity flows and hemipelagic settling in slope and/or near slope environments. The evidence for bottom current influence is three‐fold. Firstly, pervasive indications of winnowing such as marine bioclast‐rich lags and outsized clasts on 'mud on mud' contacts are suggestive of low‐sediment concentration flows capable of transporting up to pebble‐sized clasts. Common Mn–Fe–Mg rich carbonate matrix cements and various types of hiatal chemogenic lag deposits showing glauconite, apatite and carbonate clasts also point to condensation, prolonged exposure at the sediment–water interface and recurrent phases of sea‐floor erosion. Secondly, such deposits can show indicators for tidal processes such as double mud‐drapes, tangential bottom sets in dune‐scale cross‐bedding and cyclic rhythmites. Thirdly, inverse to normal grading at various scales is common in fully marine, commonly seafloor‐derived sediments. Ichnological data indicate considerable taxonomic variability in the bottom current deposits, but recurrent fabrics are characteristically dominated by morphologically simple burrows such as Thalassinoides and Planolites, with secondary Phycosiphon, Nereites, Zoophycos and/or Chondrites. In general, opportunistic taxa are common whereas mature composite ichnofabrics are rare. The omission surfaces are locally burrowed with stiffground to firmground trace fossil suites. The results contribute to establishing sedimentological, ichnological and mineralogical criteria for recognition of bottom current deposits as well as to the understanding of the Late Cretaceous palaeoenvironmental evolution of the Arctic region. [ABSTRACT FROM AUTHOR]

The Lower Cretaceous succession in Svalbard is commonly considered as an important analogue to age-equivalent strata on the Barents Shelf which are sporadically targeted by exploration wells. In this study, the stratigraphic and genetic relationship between the Rurikfjellet (open marine), Helvetiafjellet (paralic) and Carolinefjellet (open marine) formations of the Lower Cretaceous succession in Svalbard is evaluated by combining sedimentological outcrop studies with well log and core data across Nordenskiöld Land, central Spitsbergen. Sedimentological characteristics and stratigraphic units are mapped within a refined dinocyst biostratigraphic framework, enabling relatively well-constrained palaeogeographic reconstructions. The Valanginian-lowermost Barremian Rurikfjellet Formation consists of a lower shale-dominated unit of offshore origin which grades upwards into storm-reworked lower shoreface sandstones displaying hummocky cross-stratification. Local occurrences of prodeltaic successions and thick successions of gravity flow deposits containing coal-bearing slump blocks of delta plain origin in some wells, reveal a late Hauterivian progradational pulse which has previously not been recorded in Svalbard. The lower Barremian-lower Aptian Helvetiafjellet Formation consists of fluvial braidplain and paralic deposits which rest unconformably on the Rurikfjellet Formation across the entire study area, reflecting regional uplift and widespread subaerial exposure prior to the onset of paralic deposition. The Helvetiafjellet Formation exhibits increased marine influence upwards, and in the investigated cores the uppermost part of the unit consists of wave-reworked mouth-bar deposits which are truncated by a transgressive conglomerate lag dominated by extrabasinal lithic clasts and intraformational siderite clasts. An up to 10 m-thick, regionally extensive, organic-rich (TOC up to 2.1 wt.%) shale unit of early Aptian age marks the base of the overlying Carolinefjellet Formation. The shale accumulated during a regional flooding event which drowned and eventually transformed the Helvetiafjellet Formation coastal plain into a shallow shelf. The organic facies of the shale unit (Type II-III kerogen) and a high Pr/Ph ratio (>2), in combination with abundant long-chained n-alkanes, suggest that the unit was deposited in a suboxic paralic marine environment strongly influenced by input of terrestrial organic matter. The investigated succession exhibits stratigraphic and petrographic resemblance to age-equivalent strata in NE Greenland, suggesting that these successions may have formed part of the same drainage system located on the northwestern margin of the Barents Shelf. Thus, by highlighting the Early Cretaceous palaeogeographic evolution in Svalbard, this study contributes to the regional stratigraphic understanding of the Lower Cretaceous succession on the wider northern Barents Shelf. [ABSTRACT FROM AUTHOR]

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 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.

Abstract: A new palynological event biostratigraphy for the Cretaceous–lower Palaeogene succession in the Kangerlussuaq Basin, onshore southern East Greenland is presented. Sixty-three biostratigraphical marker events are recognised, based on the first and last occurrences of dinoflagellate cysts and pollen from eleven key outcrop sections through the Sorgenfri, Christian IV, Sediment Bjerge and Vandfaldsdalen Formations of the Kangerdlugssuaq and Blosseville Groups. The palynological events are correlated with published event stratigraphies and with palynological zonations from North–East Greenland, West Greenland, North America, the North Sea and the Faroe–Shetland Basin. The palynological records date the Sorgenfri Formation as middle Albian to Coniacian or ?early Santonian, the Christian IV Formation as ?late Campanian to late Maastrichtian and the Sediment Bjerge Formation as late Danian to late Selandian. The biostratigraphic ranges of dinoflagellate cysts, pollen and macrofossils around the lower to upper Maastrichtian boundary are discussed and correlated. The palynological records and recent isotopic dating results (40Ar/39Ar) of volcanic rocks indicate that the youngest sediments of the Vandfaldsdalen Formation are of Thanetian or early Ypresian age. The study documents two major hiatuses in the area: the boundary between the Sorgenfri and Christian IV Formations spans the ?upper Coniacian–Santonian and Campanian, whilst the unconformity between the Christian IV and Sediment Bjerge Formations possibly spans the uppermost Maastrichtian and the lower Danian, indicating that the Cretaceous–Palaeogene boundary is represented by a major unconformity, as recognised widely around the northern North Atlantic. [Copyright &y& Elsevier]

The article presents a lithostratigraphic description of the Cretaceous-Paleocene Nuussuaq Group, Nuussuaq Basin in West Greenland. According to the author, the Nuussuaq Basin is a complex of interrelated rift basins that stretches from the Labrador Sea to northern Baffin Bay. These basins developed due to the opening of the Labrador Sea during the late Mesozoic to Early Cenozoic period. The Nuussuaq Group comprises ten formations which include the Kome Formation, the Upernivik Næs Formation, the Atana Formation and the Agatdal Formation.

Eleven cored boreholes, with depths up to c. 360 m were drilled in north-east Baffin Bay, a frontier area offshore West Greenland by the vessel Joides Resolution. The cores were part of the Baffin Bay scientific shallow coring program, expedition 344S in 2012, funded by a consortium of eight petroleum companies. The main drilling target was a succession of dipping strata in the Kap York Basin that proved to be of Cretaceous age. Here we report the results of comprehensive core analyses involving lithofacies interpretation, palynological dating, palynofacies studies, isotope geochronology, organic geochemistry and reservoir characterization. The Lower Cretaceous succession comprises sandstones, mudstones and few thin coal beds of Albian age. Terrestrial material and a sparse and low diversity assemblage of brackish-water dinoflagellate cysts (dinocyst) species dominate the organic particles. The sedimentary environments range from floodplain to deep bay and suggest deposition in a large non-marine to brackish embayment. The kerogen type is immature to marginally mature, type III/IV, with very restricted potential for generation of petroleum or gaseous petroleum. The Upper Cretaceous sedimentary succession of Cenomanian–Turonian age consists of black marine mudstone with varying amounts of discrete sand layers. The amorphous organic material and marine dinocysts suggest that most of the succession was deposited in an anoxic–dysoxic to oxygen restricted palaeoenvironment, probably ranging from outer shelf and prodelta fringe to lower delta front. The organic richness and petroleum potential are variable. The black mudstones include organic rich intervals with TOC of 3–6%, HI of 200–350 and SPI value of 3.0, comparable to well-known petroleum source rock successions of this age worldwide. The δ13C org curves for the Cenomanian–Turonian sections display values and trends characteristic of Oceanic Anoxic Event 2 (OAE2). A marine transgression between the Lower and Upper Cretaceous successions caused dramatic changes in depositional environments. • Eleven shallow cores from Baffin Bay, Greenland dated Albian–Turonian (Cretaceous). • Studies of lithofacies, palynology, palynofacies, isotopes, geochemistry, porosity. • Net sandstone thickness of 100 m with an average porosity of 25%. • TOC 3–6%, HI 200–350, SPI 3.0 values of organic-rich intervals indicate source rock. • δ13C org curves for the Cenomanian–Turonian corresponds to the Oceanic Anoxic Event 2. [ABSTRACT FROM AUTHOR]

The microfossil and palynofloral assemblages of the Paleocene to middle Eocene succession, offshore West Greenland, have been investigated. Several taxa, which are believed to reflect specific palaeoenvironments were selected, and their relative abundances measured. Subsequently, an interpretation of the changing depositional settings in the Hellefisk-1, Ikermiut-1, Kangaˆmiut-1, Nukik-1 and Nukik-2 boreholes through the lower Palaeogene has been made. [Copyright &y& Elsevier]

A new Palaeogene dinoflagellate cyst stratigraphy from offshore West Greenland has been described based on the strata from the Hellefisk-1, Ikermiut-1, Kangaˆmiut-1, Nukik-1, Nukik-2 and Qulleq-1 wells. Twenty-one palynological intervals are defined from the Late Eocene to the late Early Paleocene. This stratigraphy has been correlated with a new microfossil zonation and previous established North Sea zonations. The stratigraphy and well correlation are based on last appearance datum events and abundances of stratigraphically important species from 355 samples, 148 of which are sidewall core samples. A major middle Eocene hiatus spanning the early Lutetian and a major Early Paleocene hiatus spanning the Late Santonian, Late Cretaceous to the early Danian have been recognised from the offshore deposits. [Copyright &y& Elsevier]

Based on morphological observations carried out on the same material, but submitted to different processing, Trithyrodinium fragile Davey 1969 is herein demonstrated to be a junior synonym of Trithyrodinium evittii Drugg 1967. From both original descriptions, the only way that the two species can be separated is by the presence or the absence of a thick brown organic layer on the surface of the endocyst. The present study proves that this is an artificial separation caused by different processing techniques. As a result, T. evittii is emended in order to encompass specimens, wholly or partially exhibiting this brown organic layer and previously attributed to T. fragile. These new observations also have stratigraphic and palaeoenvironmental implications. Combination of both synonym lists reveals that T. evittii, which is regarded as a warm water species (58°N to 52°S) in the latest Cretaceous, migrated to higher latitudes (80°N to 75°S) in the earliest Paleocene. Consequently, an increase in oceanic circulation and/or temperature increase of the surface water is suggested during this epoch. In support of this contention, several peak occurrences of T. evittii are recorded just above the K/T boundary in high latitudes. [ABSTRACT FROM PUBLISHER]

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]

New interpretations are reported of the sedimentology and sequence stratigraphy of the Palaeogene sediments encountered by the boreholes Hellefisk-1, Ikermiut-1, Kangaˆmiut-1, Nukik-1 and Nukik-2 offshore southern West Greenland. These interpretations, together with new biostratigraphic and palaeoenvironmental interpretations, have been used to correlate the boreholes and to calibrate seismic sequences interpreted on a grid of reflection seismic data. The interpreted seismic sequences lie between major regional unconformities of Danian and mid-Eocene age.The new interpretations show that the area offshore southern West Greenland was subject to major uplift and erosion during the Danian when latest Cretaceous sediments were removed. Sedimentation restarted in the late Danian, coevally with major volcanism in central West Greenland and the start of sea-floor spreading in the Labrador Sea. Late Paleocene sediments were deposited in a predominantly extensional tectonic environment. The extensional stresses continued in most areas during the early Eocene, but in the northern and northwestern part of the basins, a transtensional system developed along the strike-slip faults that transferred sea-floor spreading movements between the Labrador Sea and Baffin Bay.Sediment input to the basins was predominantly from the north, possibly from a major river system flowing out of central Greenland. Lesser amounts of sediment came from the east, from the mainland of Greenland, and minor amounts from the west. The thickness of total sediment decreases substantially from north to south. The sediments were deposited in environments that ranged from fresh-water/marginal marine to upper bathyal. Proximal environments are probably generally sand-prone, but distal environments probably contain larger amounts of mud, some of which could contain a mature source rock for oil. Basin-floor fans, syn-tectonic wedges and turbidite channel complexes that could act as hydrocarbon reservoirs sealed by surrounding muds have been identified in many of the seismic sequences. [Copyright &y& Elsevier]

The groundwork for the northeast Atlantic opening was laid during the latest Jurassic to mid-Cenozoic. The period is well-investigated on the Norwegian and UK continental margins at which the tremendous petroleum potential to a large extent resulted from the latest Jurassic to mid-Cenozoic development. Harsh ice conditions have made investigations of the NE Greenlandic margin more difficult. Based on a large 2D seismic dataset tied to cored stratigraphic boreholes, three phases of rifting leading to continental breakup are documented: 1) latest Jurassic to mid-Cretaceous, 2) mid-Cretaceous to Maastrichtian and 3) Maastrichtian to early Eocene. This development is in many ways comparable to offshore Norway. However, Early Cretaceous rifting was more severe offshore NE Greenland compared to elsewhere in the northeastern Atlantic with more than 10 km downfaulting and accumulation of up to 16 km of Lower Cretaceous strata in the Danmarkshavn and Thetis basins. During the mid-Cretaceous, rifting ceased in most of the Danmarkshavn Basin and the inner Thetis Basin but continued in the outer Thetis Basin. This coincides with a shift in rifting taking place in the Barents Sea, offshore central Norway, and onshore NE Greenland. During the latest Cretaceous, rifting shifted seawards to the outermost NE Greenland margin and the eventual line of continental break-up, again mirroring the development at the central Norwegian margin. Coincident uplift of Greenland resulted in clinoform progradation across the central and southern Danmarkshavn Basin and incursion of Greenland-derived sand to offshore central Norway. The uplift and change in rifting may reflect the initial effects of the Icelandic mantle plume building up underneath Greenland. Shortly thereafter, magmatism commenced along parts of the NE Greenland margin followed by continental break-up. Subsequently, small amounts of compression on the outer margin formed subtle folds and small thrusts during presumably Oligocene to early Miocene times. • Seismic investigations of the NE Greenland margin tied with boreholes. • E Cretaceous, L Cretaceous and Maastrichtian–Eocene rift phases shaped NE Greenland. • Tremendous basins and intra-basin highs formed during the rifting. • The three rift phases recur across other northern N Atlantic margins. • The northern N Atlantic E. Cretaceous rift center was located offshore NE Greenland. [ABSTRACT FROM AUTHOR]

The Cenomanian–Turonian transition includes the youngest of the two so-called Cretaceous Oceanic Anoxic Events, sometimes also referred to as the "Bonarelli Event". This is an interval of global deposition of organic-rich oceanic deposits, including some of the most prolific petroleum source rocks of the World. However, in the greater North Atlantic realm, little direct evidence of notable volumes of rich Cenomanian–Turonian petroleum source rocks exists. As part of a major study of the Cretaceous succession in northeast Greenland between 2009 and 2012, a fully cored borehole (Nanok-1) on eastern Hold with Hope was drilled to penetrate a poorly or non-exposed stratigraphic succession including the Cenomanian–Turonian transition. The Nanok-1 penetrated 160.5 m of Cenomanian to Campanian clastic deposits and terminated at a TD of 168.35 m in an igneous intrusion. Although none of the deposits penetrated qualify as a petroleum source rock, a downwards increasing trend in petroleum source potential starting at c. 100m hint at the existence of such rocks at levels deeper than the TD of the well. The downwards increasing trend in petroleum generation potential is curtailed by maturation from c. 140m, but assuming the trend would have prevailed, were it not for the intrusion, the presence of at least a marginal source rock would be expected at the level of the sill and deeper. The presumed existence of petroleum source rocks below the TD of the borehole is supported by the presence of marked oil staining in sandstones (i.e. migrated petroleum) at shallower levels of the drilled succession. The hopane and sterane distributions and stable carbon isotopic compositions and age-specific nordiacholestane ratios of the oil stains are compatible with an origin from the Cretaceous succession, while the Jurassic can be ruled out. The oil stains recorded were probably generated from a marine shale source rock of Cretaceous age, containing a significant proportion of terrigenous organic matter. The possible presence of at least one marginal petroleum source rock in the mid-Cretaceous succession at the Nanok-1 location has implications for the exploration potential of the conjugate margin. Hence, comparison of sediment accumulation histories of the Møre and Vøring basins and northeast Greenland suggests that the presumed source rock was deposited before the accommodation space at the Nanok-1 location was exhausted. Thus, coeval sediment starvation and deposition of more condensed and richer petroleum source rocks may have prevailed in the offshore basins to the east during the mid-late Cenomanian. This potential source rock will thus be slightly older than Cenomanian–Turonian source rocks that are important worldwide. • The Nanok-1 fully cored borehole, Hold with Hope, NE Greenland, penetrated c.160m of Cenomanian–Campanian deposits and terminated in an intrusion. • The borehole did not encounter any petroleum source rocks, but prominent oil stains were found in sandstones drilled by the well.. • The oil stains were generated from a Cretaceous-age marine shale source rock. • The oil stains document the existence of a Cretaceous-age source rock with capacity for generation of liquid petroleum. • The results are important for the ongoing discussion of potential Cretaceous petroleum source rocks in the North Atlantic region. [ABSTRACT FROM AUTHOR]