The peatlands of the Karwia Barrier and Karwia Lowland as a potential archive of extreme storm floods

Torfowiska zlokalizowane w obrębie Mierzei i Niziny Karwieńskiej stanowią potencjalne archiwum ekstremalnych wezbrań sztormowych. W trakcie badań terenowych dokonano rozpoznania utworów podpowierzchniowych w celu weryfikacji doniesień o możliwości występowania w tym rejonie współczesnych osadów sztormowych. Wykonano liczne sondowania, z których najważniejsze zaprezentowano w artykule. Wyraźny zapis sedymentacyjny procesów sztormowych zachował się jedynie w obrębie torfowiska najbardziej eksponowanego w kierunku morza, przy ujściu rzeki Czarnej Wdy. Cechą charakterystyczną osadów sztormowych okazała się malejąca miąższość osadów piaszczystych w kierunku lądu oraz ostra granica erozyjna w spągu. Obserwacja cech teksturalnych piasku wskazuje na pochodzenie osadu z plaż i wydm Mierzei Karwieńskiej. W obrębie zaplecza bariery nie znaleziono osadów, które mogłyby być powiązane ze sztormami. W związku z tym stwierdzono, że w przeszłości nie doszło do znaczących powodzi sztormowych, które pozostawiłyby w obrębie Niziny Karwieńskiej łatwo wyróżnialną warstwę osadów piaszczystych.Karwia Barrier peatlands are a potential archive of extreme storm floods. During the field work, the subsurface sediments of the investigated area were surveyed to verify the hypothesis of a presence of storm surge deposits within the barrier and accompanying peatlands. Numerous shallow drillings were performed and the most essential of them are presented in this paper. A distinguishable sedimentological mark of storm surge processes was recognized only in a peatland exposed directly to the sea, in close neighbourhood to the Czarna Wda river mouth. Thickness of sandy deposits decreasing landward and a sharp erosive boundary in the base were the most common features. Textural characteristics of sandy grains revealed a beach and dune source of these sediments. Peatlands located at the back of the barrier lacked sediments, which could be linked to the storm processes. This leads to a conclusion that none of historical storm floods left an easily disti nguishable sandy layer within the Karwia Lowland

Handheld gamma-ray spectrometry at geological exposures : methods and applications

Handheld gamma-ray spectrometry (hGRS) is a valuable method for geological studies. It may be applied in correlations between well-logging and outcrop strata, enhance interpretations of sedimentological data, prospect radiogenic ores and geothermal resources, and identify radiogenic hazards for society. This paper aims to review and popularize one of the research methods based on a mobile device (hGRS) equipped with a BGO (bismuth germanium oxide) scintillator. The general concept of the research method is presented in this paper. The method's perspectives and limits based on reviewed literature. Advantages of hGRS include, e.g., low cost, short data acquisition time, the possibility of studying natural exposures, and a broad set of research applications. The main disadvantages comprise relatively modest resolution of acquired data and their difficult interpretation in complex geological formations. The review is backed by sample measurements performed in various geological exposures at Bornholm Island (Baltic Sea). Measurements comprised igneous rocks exposed in several quarries and sedimentary profiles near Liesti Valley and Muleby

River response to climate and sea level changes during the Late Saalian/Early Eemian in northern Poland – a case study of meandering river deposits in the Chłapowo cliff section

Fluvial sediments in the Chłapowo cliff section were studied in order to reconstruct their palaeoflow conditions and stratigraphical position. Lithofacies, textural and palaeohydraulic analyses as well as luminescence dating were performed so as to achieve the aim of study. Sedimentary successions were identified as a record of point bar cycles. The fluvial environment probably functioned during the latest Saalian, shortly after the retreat of the Scandinavian Ice Sheet. Discharge outflow was directed to the northwest. The river used the older fluvioglacial valley and probably was directly connected to the Eem Sea. Good preservation and strong aggradation of point-bar cycles were related to a rapid relative base level rise. The meandering river sediments recognised showed responses to climate and sea level changes as illustrated by stratigraphical, morphological and sedimentological features of the strata described. The present study also revealed several insights into proper interpretation of meandering fluvial successions, in which the most important were: specific lithofacies assemblage of GSt (St, Sp) → Sl → SFrc → Fm (SFr) and related architectural elements: channel/sandy bedforms CH/SB → lateral accretion deposits LA → floodplain fines with crevasse splays FF (CS); upward-fining grain size and decreasing content of denser heavy minerals; estimated low-energy flow regime with a mean depth of 1.6–3.3 m, a Froude number of 0.2–0.4 and a sinuosity of 1.5

Application of in situ cosmogenic nuclides in dating glacial till : research potential, limitations and prospects

Determination of numerical age for glacial till is one of the most intriguing issues in glacial geology and geomorphology. Till layers are unequivocal evidence of ice sheets advances and retreats, and therefore they are very important for Quaternary palaeoclimatic reconstructions. Herein, we present a review dedicated to the methodology of glacial till dating with in situ cosmogenic nuclides. This relatively novel approach enables direct dating of deposition of till and its exposure after deglaciation. Getting reliable numerical age (in years) of till opens a new prospect for reconstructions of past glaciations and palaeogeographic studies. Despite some limitations of applying in situ cosmogenic exposure and burial dating, we argue that this technique may be successfully employed in studies of glacial deposits in Poland