Radosław Dobrowolski

INTERDISCIPLINARY STUDIES OF SPRING MIRE DEPOSITS FROM RADZIKÓW (SOUTH PODLASIE LOWLAND, EAST POLAND) AND THEIR SIGNIFICANCE FOR PALAEOENVIRONMENTAL RECONSTRUCTIONS

The paper presents the results of interdisciplinary (multiproxy) palaeoenvironmental studies of peat — calcareous tufa depositional sequences of spring mire from Radzików site (east Poland). Analyses of three biotic proxies (plant macrofossils, pollen, molluscs) were supplemented with sedimentological, geochemical, oxygen and carbon stable isotopes analyses and radiocarbon dating and used for reconstruction of environmental changes in Late Glacial and Holocene. The obtained results enable us to (1) reconstruct main phases of mire development and (2) determine environmental factors influencing changes of water supply.The object started to develop in Allerød. The Late Glacial and Early Holocene deposit sequence is relatively thick (about 1.0 m), with good palaeoecological record. The boundary between Younger Dryas and Preboreal is especially well confirmed by palynological and malacological analyses as well as radiocarbon dating. The Mesoholocene deposits are considerably worse preserved. Mire development was evaluated in terms of general mire ecology.

Multi-proxy evidence of Holocene climate variability in Volhynia Upland (SE Poland) recorded in spring-fed fen deposits from the Komarów site

Radiocarbon-dated spring-fed fen deposits from the Komarów site (Volhynia Upland, SE Poland) with its multi-proxy data (macrofossils, molluscs, geochemistry, pollen, stable isotopes of oxygen and carbon) enable us (1) to distinguish four main stages of fen evolution, which reflected a distinct variability of water supply conditions and (2) to reconstruct the Holocene humidity–temperature changes. The beginning of peat–tufa deposition took place in a Boreal phase, after a significant cool fluctuation of climate occurring ca. 9.4 ka cal. BP. We suggest that climate was the most important factor conditioning the development of the spring-fed fen. Permafrost degradation, and then wet periods, intensified the activity of ascending springs. The impact of humans was possible since the Neolithic period and increased during the Middle Ages: therefore, the anthropogenic influence could have partially overlapped with the regional tendencies of climate changes. Autogenic development of deposit succession in the studied fen was definitely conditioned by hydrological changes induced by climate. Based on the multi-proxy data, 12 cold events of different ranks were identified. They are also recorded in other Polish and European sites. A record of distinct variability of depositional conditions at ca. 9.4, 8.2, 5.9, 4.6, 2.8, 1.4 and 0.55 ka cal. BP corresponds to quasi-periodical global climate changes in the Holocene named the Bond events. The majority of the cold events recorded in δ13C and δ18O of carbonates can be correlated to the Greenland oxygen isotope curve.

Environmental changes and human impact on Holocene evolution of the Horodyska River valley (Lublin Upland, East Poland)

Environmental Changes and Human Impact on Holocene Evolution of the Horodyska River Valley (Lublin Upland, East Poland) Interdisciplinary palaeoenvironmental studies, conducted near the multi-cultural archaeological sites in the Horodyska River valley (Lublin Upland, East Poland), enable to reconstruct natural and anthropogenic changes of fluvial landscape in the Holocene. The changes are evidenced by the results of archaeological, geological, sedimentological and palynological investigations, as well as radiocarbon and thermoluminescence dating. The Horodyska fluvial system started functioning at the turn of the Late Vistulian and Preboreal. From the beginning of the Subatlantic the record of environmental changes in valley deposits bears the mark of human impact. Main phases of settlement on the river valley bottom (higher terrace) correspond to rather dry periods (Neolithic, Bronze Age, Halstadt period, period of Roman influence, early Middle Ages). Moistening of climate and its associated rise of groundwater level forced people to move settlement on the loess plateau and found a stronghold at the turn of the 11th and 12th centuries.

RADIOCARBON AGE AND GEOCHEMISTRY OF THE INFILLINGS OF SMALL CLOSED DEPRESSIONS FROM WESTERN POLESIE (POLAND SE, UKRAINE NW)

Radiocarbon Age and Geochemistry of the Infillings of Small Closed Depressions from Western Polesie (Poland Se, Ukraine Nw) In this paper we report the results of interdisciplinary investigations of deposits filling small closed depressions in the Western Polesie region. There were reconstructed the environmental changes and the main evolution phases of four morphometrically similar forms (=research sites) situated in the Lublin and Volhynia parts of the Polesie region. The gathered sedimentological, chronostratigraphical, palynological and geochemical data evidence great lithological (peats, gyttja, calcareous tufa) and age (Late Glacial, Neoholocene) differences between the deposits filling individual forms and indirectly suggest their karstic origin.

Origin and evolution of the Bezedna lake-mire complex in the Lublin area (East Poland): a case study for permafrost lakes in karstic regions

The Bezedna site represents a unique lake–mire complex in the Lublin chalkland, eastern Poland. This karst region contains Upper Cretaceous carbonate rocks under the influence of continental climate. Using sedimentologic, palaeobotanical, and fossil ostracode analyses as well as radiocarbon dating on cores, we were able: (1) to reconstruct the morphogenetic mechanisms related to lake formation, (2) to describe the main stages of lake evolution, and (3) to identify the environmental conditions during this evolution. The first stage was the formation of an accumulation basin in a periglacial setting related to permafrost thawing in the last phase of the Weichselian and at the beginning of the Holocene. During the second stage, in the successive phases of the Holocene, lake evolution was determined by climate changes and local conditions, and in the youngest Subatlantic period—also by human activity in several settlement phases. Natural water bodies in a karstic region create unique conditions for water circulation, especially for groundwater. During the change from the periglacial to temperate climate of the Holocene in the Lublin chalkland, the response of substratum (deeply frozen during the Weichselian) was influential in the development of surface water conditions in the study area. The strong fracturing of the Upper Cretaceous bedrock and general change of groundwater circulation associated with the activation of an ascending groundwater supply favored the intensive dissolution of carbonate and the progressive ground subsidence. Based on the reconstruction and correlation with paleoenvironmental investigations of the adjacent Volhynia chalkland, we were able to estimate and compare the influences of local (morphologic and geologic) conditions versus global climate changes on the paleoenvironmental record. Climate-driven lake-level fluctuations coincided over great areas of the Northern Hemisphere and are well reflected in changes of the Ostracoda fauna.

Multi-proxy reconstruction of mire development in the Poręby Wojsławskie Ecosystem (Sandomierz Basin, Southeastern Poland)

Multi-proxy analysis (sedimentological, palaeobotanical, geochemical data and results of radiocarbon dating) of the biogenic sediments from a small mire ecosystem in the Sandomierz Basin (SE Poland) is presented. The ecosystem contains a full hydroseral sequence from minerotrophic to ombrotrophic wetland. It is one of the few sites in this region which is so thoroughly investigated in terms of the palaeoenvironmental record. Changes in the water supply of the mire area, and consequently the changes in the plant and sediment succession, were well correlated with the regional tendencies in precipitation and temperature during the Late Glacial/Holocene transition and in the Holocene. Human impact is very well recorded in pollen diagram from the Subboreal period.