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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]

Sedimentological models for rift shoulders have poorly documented the effect of adjacent fault systems on drainage patterns. In this study we investigate the Loppa High, an ancient tilted rift shoulder located in the southwestern Barents Sea. We use seismic and well data, sedimentological log descriptions, and biostratigraphic information to understand the drainage patterns and the Early Cretaceous geological history of the Loppa High. This study provides an example of how the drainage systems in low-gradient flanks of a rift shoulder can be modified and confined by normal faults occurring almost orthogonal to the main fault system. These orthogonal faults might have acted as preferential sediment routes. Thus, potential deposits of the main drainage systems directed to the low gradient flank are found almost exclusively associated with grabens formed due to these orthogonal faults. The Early Cretaceous evolution of the Loppa High is summarized as follow: 1) during the Boreal Berriasian/Volgian to early Barremian, the Asterias and the Bjørnøyrenna fault complexes were active. Diachronous shallow to eventually deep-marine fans and incised valleys were developed along the southern and western flanks of the Loppa High; 2) late Barremian–Aptian fault activity is interpreted along the Ringvassøy Loppa Fault Complex. A second generation of incised valleys and their related shallow-marine fans were formed in the western flank of the Loppa High; and 3) during late Aptian–early Albian the Loppa High and the Hammerfest Basin were tilted eastwards. The latter event triggered a switch in depocenter location and development of shelf-margin clinoforms downlapping in close proximity to the eastern flank of the high. [ABSTRACT FROM AUTHOR]