Acta Palaeobotanica 48(1): 3–130, 2008 Vegetation and climate of the Eemian and Early Vistulian lakeland in northern Podlasie* MIROSŁAWA KUPRYJANOWICZ Department of Botany, Institute of Biology, University of Białystok, PL-15-950 Białystok, Świerkowa 20b, Poland; e-mail: [email protected] Received 10 September 2007; accepted for publication 25 April 2008 ABSTRACT. Material for the study comes from 22 palaeolakes and palaeobogs in three macroregions – Białystok Upland, Sokółka Hills and Bielsk Upland – of northern Podlasie (north-eastern Poland). Six hundred and four- teen samples from 28 cores were examined by means of pollen analysis, and 300 samples from two most impor- tant profi les – Solniki and Dzierniakowo – using lithological analyses of the sediments were carried out, namely magnetic susceptibility, grain size distribution, concentration of 13C and 18O isotopes, organic carbon and calcium carbonate content. The results of the pollen analysis are presented graphically on diagrams. In each of them biostratigraphical units at the level of local pollen assemblage zones (L PAZ) were distinguished. On that basis it was determined that the studied sediment sequences span the closing phase of the late glacial of Wartanian (Saalian) glaciation, the Eemian interglacial and the early glacial of the Vistulian (Weichselian). Correlation of local pollen zones from all investigated profi les allowed to distinguish 14 regional pollen assemblage zones (R PAZ). They were correlated with pollen zones recognized in other pollen profi les from Poland and Europe, and also with bio- and chronostratigraphical units marked with various methods in Greenland’s ice cores and sea sediments. The results of investigation were used to reconstruct vegetation succession and climate changes across the great part of the last interglacial-glacial cycle, from the fi nal stage of the Wartanian glaciation to the end of the Early Vistulian. Two sites – Solniki and Dzierniakowo – play vital role in this reconstruction. Profi le from Solniki contains very well developed record of environmental changes during the Eemian interglacial. From the data obtained it occurs that this record registers two intra-Eemian fl uctuations of the climate. The fi rst of them fell to the middle part of the hornbeam zone (ENP5 Carpinus R PAZ) being probably manifested only by a signifi cant decrease in precipitation with no fl uctuations in temperature level. Hiatus, that in the numerous profi les from northern Podlasie contains a younger part of the hornbeam phase of the Eemian interglacial and the entire spruce phase (ENP6 Picea-Pinus-(Abies) R PAZ), is probably the effect of that climate change. Addition- ally, as a result of that change water level in lakes and bogs decreased. It was then followed by a temporal stop- ping of sediment accumulation in those basins or even through deposit decomposition (through drying) of what was earlier accumulated there. The paper deals also with other hypothetical causes of such abrupt decrease in water level, such as melting of permafrost, lowering of riverine erosion level, or other local conditions. The second climate fl uctuation took place in the middle part of the pine phase (subzones b and c of the ENP7 Pinus R PAZ). The decrease in forested areas and the increase in open plant communities of a cold step type with domination of the Artemisia genus was a result of environment change into a cool continental climate. Profi les from Dzier- niakowo and Solniki contain a high-resolution record of the early glacial stage of the Vistulian glaciation. This permitted a detailed reconstruction of environment changes during that period to be done. Cold fl uctuation of the climate appeared in the Brørup interstadial sensu lato. It seems likely that it represented the cooling that separated the Amersfoord and Brørup sensu stricto interstadials. KEY WORDS: pollen analysis, palaeoecological reconstructions, palaeoclimate, vegetation history, Wartanian, Eemian inter- glacial, Early Vistulian (Weichselian), Brørup interstadial, Odderade interstadial, Podlasie, Poland * The palaeobotanical investigations were supported by the Institute of Biology in University of Białystok (project No. BST-109), Ministry of Science and Higher Education (project No. 3 P04C 025 25) and Polish Geological Institute (the Detailed Geological Map of Poland in the scale 1:50 000). 4 CONTENTS Development of terrestrial vegetation in northen Podlasie . 75 Introduction. 4 Late glacial of the Wartanian glaciation . 75 The Eemian interglacial . 76 Research area . 7 Early glacial of the Vistulian glaciation . 85 Location . 7 Herning stadial . 85 Geology, geomorphology and hydrology . 7 Amersfoort interstadial. 86 Climate. 9 Cold oscillation (Montaignu event) . 87 Soils . 10 Brørup interstadial sensu stricto . 87 Plant cover. 10 Rederstall stadial . 88 Previous palaeobotanical researches in northern Odderade interstadial . 88 Podlasie and its vicinity . 10 Changes of the climate. 89 Material and methods . 10 General remarks . 89 Borings and sediments description . 10 Late glacial of the Wartanian glaciation . 90 Pollen analysis . 12 The Eemian interglacial . 91 Suplementary analyses. 13 Changes in climate of northern Podlasie 91 Background to the palaeoecological interpreta- Synthesis of climate data from northern tions . 13 Podlasie. 94 Białystok Upland . 13 Discussion – Was the climate of the Solniki . 13 Eemian interglacial stable?. 94 Dzierniakowo . 17 Early Vistulian . 97 Pieszczaniki . 20 Changes in climate of northern Podlasie 97 Kruszyniany. 21 Global changes in climate after the end of the Eemian interglacial. 98 Hieronimowo . 24 Małynka . 27 Development of mire and aquatic vegetation in Lesznia-Łuchowa Góra . 29 northern Podlasie – selected aspects. 99 Sokółka Hills . 31 Succession of water vegetation in the Solniki palaeolake . 99 Sokółka. 31 The Eemian interglacial . 99 Poniatowicze . 33 Early Vistulian . 102 Podkamionka . 36 Some remarks on the occurrence Starowlany . 37 of the Lobelia lakes during the Eemian Bohoniki . 40 interglacial and Early Vistulian. 103 Drahle. 41 Water level fl uctuation in lakes during Chwaszczewo . 42 the Eemian interglacial . 104 Trzcianka . 43 Record of water level changes in northern Gilbowszczyzna . 45 Po dlasie . 104 Harkawicze . 46 Methodical remarks . 104 Bielsk Upland . 49 Description of changes . 105 Proniewicze . 49 Registration of water level decrease during Wólka . 50 the Carpinus zone in Poland and central Śliwowo . 53 Europe . 110 Skupowo . 56 Probable reasons of intra-Eemian drop Boćki. 57 in water level . 111 Choroszczewo . 61 Changes in climate . 111 Regional pollen stratigraphy and its chrono- Melting of deep permafrost. 111 stratigraphy for northern Podlasie . 63 Lowering of riverine base level of erosion 112 General remarks . 63 Local conditions . 112 Late glacial of the Wartanian glaciation . 63 Final conclusions and summary . 113 The Eemian interglacial . 68 Acknowledgements . 115 Early glacial of the Vistulian glaciation . 72 References . 116 INTRODUCTION Rapid changes in climate that were observed interglacial, named in Europe as the Eemian at the world’s scale during the last decade interglacial, plays a crucial part in recognition prompted questions about possible causes. of climate change that was not related to the The possibilities of distinguishing between the human activity. Through numerous compari- natural causes and those being infl uenced by sons between that interglacial stage and the economic development were discussed. major part of the Holocene it was indicated Analysis of the environment of the last that many natural phenomena already took 5 place in both of those periods in similar man- profi les indicated the successive course of cli- ner (cf. Iversen 1954, Tobolski 1976). That mate changes during the Eemian interglacial allows to assume that recognition of climate (Zagwijn 1961, Mamakowa 1989, Jozuel et al. change in the fi nal part of the Eemian inter- 1993, Keigwin et al. 1994, McManus et al. glacial may enable prediction of other analo- 1994, Fauquette et al. 1999). Only few profi les gous natural changes that most likely occur in proved that the process might have under- the late Holocene in separation from anthropo- gone in a different manner (Müller 1974, de genic changes. Beaulieu & Reille1989, 1992, Guiot et al. 1993, In the context of contemporary rapid climate Field et al. 1994). change the main task is to answer the question During the study held in the last decade, whether there occurred a rapid climate fl uc- based on the Detailed Geological Map of tuations during the last interglacial or else if it Poland in the scale 1: 50 000, about 30 new was as in old and commonly accepted sequence sites of the lacustrine-mire deposits from the of successive climate changes – with cool Eemian interglacial were discovered in north- beginning of the interglacial, through constant ern Podlasie, north-eastern Poland (Kupry- warming culminated with the stage of optimal janowicz 1999a, b, c, 2000a, b, c, d, e, f, 2001a, conditions, and then back again to the begin- b, 2002a, b, c, d, e, f, Brud & Kupryjanowicz ning of another glaciation – a model that prob- 2000, 2002, Kupryjanowicz & Drzymulska ably better fi ts any period free from the human 2000, 2002, Brud 2001, Kmieciak 2001, 2003, presence (Iversen 1954, Tobolski 1976). Kurek & Preidl 2001a, b, Boratyn 2003, 2006, The issue of environmental stability during Kwiatkowski & Stepaniuk 1999, 2003, Krzy- the past interglacials, especially the Eemian wicki 2003, Noryśkiewicz