Active anhydrite hydration during weathering leading to crystallisation of secondary gypsum and significant volume expansion was investigated and documented by the authors at three sites: the environs of Walkenried (Germany), Dingwall (Canada), and Pisky (Ukraine). As a result of these processes, peculiar landscape forms were created: hydration domes and ridges with empty internal chambers, some of them large enough to be called hydration caves (German: Quellungshöhlen). Currently, there are only four recognised sites on Earth featuring such a unique landscape and with a large group of hydration caves in one place (the fourth site is in the Alebastrovyye Islands, Russia). These sites constitute a particularly valuable geological and geomorphological heritage, including potential geosites and geomorphosites which require special protection. Actively growing hydration domes and caves change shape and size within a short time span, on the scale of months, years, or decades. Their study and proper protection require these changes to be monitored. Several different methods of documentation were applied in the field in order to document continuing morphological changes. The practical aspects of the use of each of these methods were assessed, demonstrating that the photogrammetric methods offer the greatest utility; not only are they the most efficient (fast and sufficiently precise) but also, compared with other methods, they yielded the most complete results. The key documentation of outcrops in Canada and Ukraine was executed with the application of terrestrial photogrammetry at Pisky (GoPro camera) and aerial photogrammetry at Dingwall (unmanned aerial vehicle). Application of these methods enabled the recording of the morphology associated with the hydration process in the form of 2.5D and 3D models as well as of orthophotomaps. The maps and the models were created using the Photoscan programme. The authors demonstrate that the photogrammetric models can be used for spatial morphological analysis of hydration forms in the ArcGIS programme. Repetition of this documentation in future will enable analysis of the morphological changes expected to occur during the progressive expansive hydration of anhydrite.
The biostratigraphic importance, current zonations, and potential for the recognition of the standard chronostratigraphic boundaries of five palaeontological groups (benthic foraminifers, ammonites, belemnites, inoceramid bivalves and echinoids), critical for the stratigraphy of the Santonian through Maastrichtian (Upper Cretaceous) of extra-Carpathian Poland, are presented and discussed. The summary is based on recent studies in selected sections of southern Poland (Nida Synclinorium; Puławy Trough including the Middle Vistula River composite section; and Mielnik and Kornica sections of south-eastern Mazury-Podlasie Homocline) and of western Ukraine (Dubivtsi). The new zonation based on benthic forams is presented for the entire interval studied. Zonations for ammonites, belemnites and inoceramid bivalves are compiled. All stage boundaries, as currently defined or understood, may easily be constrained or precisely located with the groups discussed: the base of the Santonian with the First Occurrence (FO) of the inoceramid Cladoceramus undulatoplicatus; the base of the Campanian with the Last Occurrence (LO) of the crinoid Marsupites testudinarius and approximated by the range of the foraminifer Stensioeina pommerana; and the base of the Maastrichtian approximated by the FO of the inoceramid bivalve Endocostea typica and the FO of the belemnite Belemnella vistulensis. The positions of substage boundaries, as currently understood, are constrained in terms of the groups discussed.
Unusual phosphatic casts of the ammonites Mortoniceras (Subschloenbachia) sp. and Stoliczkaia sp. from the upper Albian condensed phosphorite bed at Annopol, Poland, are discussed in terms of their taphonomic history. These specimens are interpreted as ‘secondary’ external casts of ammonite replicas preserved originally as attachment scars on oyster shells. The following genetic history is suggested for this previously undocumented mode of ammonite preservation: (1) settling of shells of dead ammonites on the seafloor; (2) colonization of these shells by oysters and formation of ammonite replicas on left valves of oysters; (3) dissolution of ammonite shells; (4) reworking and fragmentation of oyster shells; (5) casting of ammonite replicas by phosphatic material; and (6) separation of ammonite casts from oyster shells, either through mechanical disintegration or dissolution of the latter. The specimens studied were formed after dissolution of the ammonite conchs, not prior to this event as in the case of typical ammonite steinkerns (internal moulds). Therefore, they are here referred to as ‘pseudo‐steinkerns’. The time interval between loss of the original ammonite shells and the formation of oyster‐mediated pseudo‐steinkerns may be very extensive. Therefore, the pseudo‐steinkerns may potentially mislead in biostratigraphic dating of condensed phosphorite deposits.
The stratigraphical distribution of Porosphaera globularis, a common calcareous sponge in the Upper Cretaceous (mostly Campanian and Maastrichtian) of Poland was studied. The presented material, both new and from museum collections, comes from the Campanian of the Miechów Synclinorium, in southern Poland, and from the Lower Campanian of Mielnik in the south-eastern part of the Mazury-Podlasie Homocline, in eastern Poland. The significance of the species in extra-regional correlation, its palaeobiogeography and stratigraphical potential is critically reviewed.
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