They are a vital source of information about the glaciations that covered significant areas of Poland in the Pleistocene. They intrigue not only scientists, but also geotourists. So why do glacial erratics so frequently end up vandalized?
Quaternary sediments in the southwestern Nordenskiöld Land are described with particular emphasis put on distribution of erratics against their basset matrices. Results confirm previous suppositions on directions of past glacial advances from east westwards. The latter separated by sea submergences, caused translocations of the rock material. This process was most intensive in upstreams of large mountain valleys.
The glacial and glacio-marine sediments of the Oligocene Polonez Cove and Early Miocene Cape Melville Formations on King George Island (South Shetland Islands, West Antarctica) yield numerous erratic boulders of limestone, in particular archaeocyathan-algal boundstone, oolite, onkolite, and biomicrite. Some of these boulders are fossiliferous and contain archaeocyathans, sponges, inarticulate brachiopods, monoplacophorans, gastropods, hyolithids, trilobites, ostracodes and such enigmatic fossils as: Chancelloria, Coleolella. Dailyatia. Halkieria. Hadimopanella. Hyolithellus. "Lenastella", Mongolitubulus and Torellella. The small shelly fauna appears to be Early Cambrian (Botomian) in age. The boulders of fossiliferous limestones resemble the rocks of the Shackleton Limestone unit in the central Transantarctic Mts. The lithological composition of the boulder assemblage brought to King George Island during the Tertiary glaciations suggests that the Cambrian outcrops around the Weddell Sea are the source of the erratics. The Antarctic Lower Cambrian fauna resembles its analogues in Australia and Asia.
The present paper contains the results of geomorphological investigations carried out by the author during the llnd Polar Expedition of the Scientific Society of the Students of the Department of Geography and Regional Studies, Warsaw University, to the northwest part of Nordenskiöld Land (West Spitsbergen) in the summer of 1980. The present elaboration discusses the glacial forms and deposits which arose during previous stays of the glacier on this area. Particular attention was paid to the disposition of erratics, which permitted the determination of the directions of the transgression of the young Quaternary glaciations.
Fennoscandinavian erratics found in the glacial deposits till and in the glaciofluvial sediments within the main limit of the Odra glacier lobe (NW Poland and NE Germany), have been examined in two fractions: of 4-10 mm and 2060 mm. The most numerous in the fraction of 4-10 mm are: crystalline rocks (Cr; 35-40%) originating in the Protero zoic Baltic Shield as well as Lower Palaeozoic limestones (LPL; 35-40%) - from the sedimentary sheet covering the Proterozoic Baltic Shield in the area of central Baltic Sea. Percentage of sandstones (S) amounts to 10-15%. The re maining rock types (several percent each) are: Palaeozoic shales (PS), the outcrops of which are localized in Scania (Skane) and on Bornholm, Cretaceous limestones (CL) and flintstones (F) originating from the western part of the southern Baltic Sea as well as quartz (Q), milk quartz (MQ) and isolated grains of Devonian dolomites (DD). From the analysis of indicator erratics, which was carried out in the 20-60 mm fraction, it appears that mainly the outcrops localized in Smaland (e.g. red and grey Viixjo granites, Paskallavik porphyries or Tessini and Kalmarsund sandstones) as well as in Scania (Hoor and Hardeberga sandstones) and Region Blekinge-Bornholm (e.g. Karlshamn and Halen granites as well as Nexo and Bavnodde sandstones) had been subjected to the glacial plucking. Theoretical boulder centres (TBC, German: TGZ das Theoretische Geschiebezentrum, Uittig 1958), which were calculated for 23 samples, are localized mostly in a small area in Smiiland, between 15°E-16°E and 56.5°N-58.5°N. Apart from indicator erratics the statistical ones are numerous, that are first of all grey and red Lower Palaeozoic limestones with their outcrops localized at the bottom of the central Baltic Sea. Taking into account the TBC values of indicator erratics as well as high percentage of statistical erratics it can be pronounced that the section of central and western Baltic Sea as well as the one of south-eastern Sweden had been subjected to the heaviest glacial plucking by that part of the Pleistocene ice-sheet which reached the studied area during the Pomeranian Phase.
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