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Sediment gravity flows transport large volumes of sand and clay minerals into submarine systems, which store some of the world's major reserves of oil and gas. However, knowledge about grain‐coating clay mineral formation and its role in preserving reservoir quality in deep marine settings is poorly documented. Here we present a case study on the Agat Formation, a deep marine deposit interpreted as a series of turbidites, using a multimethod approach including petrographical, petrophysical and sedimentological data. This study investigates the occurrence and origin of chlorite coating and demonstrates how extensive chlorite coating substantially affects reservoir quality. The presence of green marine clay pellets suggests an initial shallow marine origin and sedimentological evidence reveals that the sediments were later remobilized by gravity flows and deposited at their present location. We suggest that the precursor clay coating was emplaced prior to sediment remobilization because of the presence of clay coating on grain contacts and all detrital components, the continuous nature of coating and the lack of clay bridges between the grains. Therefore, the origin of chlorite coating in deep marine environments may be recognized using the characteristic properties of inherited precursor clay coating. Chlorite coating thickness varies between an upper and lower sand unit, with an average of ca. 4.5 µm and ca. 24 µm, respectively. Permeability is significantly reduced in the interval with exceedingly thick chlorite coating but shows only a subtle decrease in helium porosity. This study enlightens the importance of crucially evaluating porosity in sandstones with thick chlorite coating using a multimethod approach. The results from this study can be useful in future exploration endeavours in the area and in other deep marine systems with a similar setting worldwide. [ABSTRACT FROM AUTHOR]

In order to improve the understanding of how the high northern latitudes responded to the escalating warming which led to the middle Cretaceous super greenhouse climate, more temperature proxy records from the High Arctic are needed. One of the current obstacles in obtaining such records is poor age control on the Lower Cretaceous strata in the Boreal region. Here, we provide a biostratigraphic framework for the Rurikfjellet and Helvetiafjellet formations representing the lower part of the Lower Cretaceous succession on Spitsbergen. We also attempt to date the boundary between the Agardhfjellet and the Rurikfjellet formations. This study is based on dinoflagellate cysts (dinocysts) from three onshore cores (DH1, DH2 and DH5R) and three outcrop sections (Bohemanflya, Myklegardfjellet and Ullaberget). Relatively abundant and well-preserved dinocyst assemblages from the Rurikfjellet Formation date this unit as early Valanginian – early Barremian. The dinocyst assemblages from the Helvetiafjellet Formation are significantly impoverished and are characterized by reworking, but collectively indicate a Barremian–Aptian age for this formation. [ABSTRACT FROM AUTHOR]

Aims: Cross-country comparisons of mortality and longevity patterns of Nordic populations could contribute with novel insights into the compositional changes of these populations. We investigated three metrics of population ageing: the proportion of the population aged 75+ and 90+ years, the proportion of birth cohorts reaching 75 and 90 years, and life expectancy (LE) at age 75 and 90 years in Sweden, Norway, Iceland, Denmark and Finland, in the period 1990–2014. Methods: Demographic information was collected from national statistical databases and the Human Mortality Database. Results: All metrics on population ageing increased during the study period, but there were some cross-country variations. Finland experienced a notably steep increase in the proportion of 75+ and 90+ year olds compared to the other countries. Regarding the proportion reaching old ages, the Finnish lagged behind from the beginning, but females decreased this difference. The Danes were more similar to the other countries at the beginning, but did not experience the same increase over time. Gender-specific LE at age 75 and 90 years was similar overall in the five countries. Conclusions: Developments in cross-country variation suggest that survival until old age has become more similar for Finnish females and more different for Danish males and females compared with the other countries in recent decades. This provides perspectives on the potential to improve longevity in Denmark and Finland. Similarities in LE in old age suggest that expected mortality in old age has been more similar throughout the study period. [ABSTRACT FROM AUTHOR]