Geologos, 2009, 15, 1

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    Soft-sediment deformation structures in siliciclastic sediments: an overview
    (Bogucki Wydawnictwo Naukowe, 2009) van Loon, A.J. (Tom)
    Deformations formed in unconsolidated sediments are known as soft-sediment deformation structures. Their nature, the time of their genesis, and the state in which the sediments occur during the formation of soft-sediment structures are responsible for controversies regarding the character of these deformations. A definition for soft-sediment deformation structures in siliciclastic sediments is therefore proposed. A wide variety of soft-sediment deformations in sediments, with emphasis on deformations in siliciclastic sediments studied by the present author, are described. Their genesis can be understood only if their sedimentary context is considered, so that attention is also paid to the various deformational processes, which are subdivided here into (1) endogenic processes resulting in endoturbations; (2) gravity-dominated processes resulting in graviturbations, which can be subdivided further into (2a) astroturbations, (2b) praecipiturbations, (2c) instabiloturbations, (2d) compagoturbations and (2e) inclinaturbations; and (3) exogenic processes resulting in exoturbations, which can be further subdivided into (3a) bioturbations – with subcategories (3a’) phytoturbations, (3a’’) zooturbations and (3a’’’) anthropoturbations – (3b) glaciturbations, (3c) thermoturbations, (3d) hydroturbations, (3e) chemoturbations, and (3f) eoloturbations. This subdivision forms the basis for a new approach towards their classification. It is found that detailed analysis of soft-sediment deformations can increase the insight into aspects that are of importance for applied earth-scientific research, and that many more underlying data of purely scientific interest can, in specific cases, be derived from them than previously assumed. A first assessment of aspects that make soft-sediment deformation structures in clastic sediments relevant for the earth sciences, is therefore provided.
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    Early Permian solitary rugose corals from Kruseryggen (Treskelodden Fm., Hornsund area, southern Spitsbergen)
    (Bogucki Wydawnictwo Naukowe, 2009) Chwieduk, Edward
    A collection of solitary rugose corals collected from the Treskelodden Formation of the Kruseryggen Hill, Hornsund area, south Spitsbergen, consists of 30 specimens representing the Bothrophyllidae family with the genera Bothrophyllum, Caninophyllum, Hornsundia, and Timania (5 species), and an indeterminate family with the genus Svalbardphyllum (one species). These large, dissepimental forms, dating from the Early Sakmarian (Tastubian), indicate a warm-water environment. The lithology, the thickness of the succession, the reddish hue and the abrasion of the fossils indicate that the area of the inner Hornsund showed a relief that enabled considerable erosion of the elevated areas and redeposition of the fossils at remote locations. The changing morphology of this area during the Early Permian was probably influenced by synsedimentary block tectonics.