Organické uloženiny fluviální výplně údolního dna řeky Bečvy u Oseku nad Bečvou a jejich vztah k vývoji sedimentace

Jan Vít, Eva Břízová, Tomáš Kolář, Michal Rybníček

Abstrakt

Organic matter, like pollen, plant detritus or subfossil woods can be found in sequences of fluvial sediments. Detail study of these remains help to assess age of accumulation processes, especially during the Holocene erosion/accumulation cycle. Two localities with exposed infill of the Bečva River valley were found near Osek nad Bečvou. The first outcrop is a gravel pit 1 km south of Osek nad Bečvou village. The second one is a river-cliff on the left bank of the Bečva River, 1 km westward of Oldřichov village, formed mostly during the extreme flood in 1997. Fluvial sediments, 4–5 m thick, of the the so called “lower flood-plain level” were exposed on both localities. At the base of the Oldřichov river-cliff was encountered a horizon of boggy soil with subfossil trunk at the base. In the gravel pit near Osek nad Bečvou was exposed layer of clay/silt with plant detritus. Up to 2 m thick middle/coarse grained gravel, situated beneath underground water level, underlie the organic-rich sediments in both localities. Badenian clay represents the bedrock of the river valley. Organic-rich layers are overlaid by middle/coarse grained gravel sediments passing gradually to sandy silt of the flood plain. Pollen analyses were made from the organic-rich layers and dendrological analysis, dendrochronology and radiometric dating from subfossil trunk.

Organic-rich layer from Osek (sample LS001) was assigned to the early Holocene based on pollen analysis and represents the oldest age found. The Oldřichov samples come from oxbow sediment. The sample LV030V was poor in pollen grains and inconclusive. The sample LV030Z indicates Holocene climate optimum (Atlantic). This supposed age is compatible with radiometric dating of the subfossil trunk from the base of the layer. Radiocarbon dating using wiggle matching method gave age of 7 070–6 775 BC.

Based on these data, repeated erosion/accumulation events during Late Pleistocene and Holocene are evident in Bečva River valley fill. Late Pleistocene accumulation was replaced with erosion during Late Pleistocene-Holocene transition. Erosion on the break of the Pleistocene and Holocene partly removed upper Pleistocene gravels so in places left reached level 2 m above the bedrock. The first third of Holocene (time of all interpreted data) seems to be very stable from erosion/accumulation evolution point of view. More dynamic evolution started with accumulation of “higher flood-plain level” (from cca 214 m a. s. l. up to 221 m a. s. l.). Subsequent erosion formed relatively deep cut in the northwest part of the flood plain which was filled relatively quickly by sediments as consequence of deforestation connected with a colonization of upper parts of Bečva River drainage area. This is supported by finds of much younger subfossil trunks dated from 1 century BC up to top of Middle-Age period in this accumulation (Vít et al. 2009). The surface of this accumulation is the so called “lower flood plain level” where periodicity of the inundation during floods is more regular then on the upper one.

Bibliografická citace

Vít, J., Břízová, E., Kolář, T., & Rybníček, M. (2019). Organické uloženiny fluviální výplně údolního dna řeky Bečvy u Oseku nad Bečvou a jejich vztah k vývoji sedimentace. Geologické výzkumy na Moravě a ve Slezsku, 26(1-2). doi:https://doi.org/10.5817/GVMS2019-1-2-66

Klíčová slova

Bečva River, Holocene, river sediments, palynology, dendrochronology, radiocarbon datting

Plný Text:

HTML

Reference

Zobrazit literaturu Skrýt literaturu

Baillie, M. G. L., Pilcher, J. R. (1973). A simple cossdating program for tree-ring research. – Tree-Ring Bulletin 33, 7–14.

Břízová, E. (1999). Late Glacial and Holocene development of the vegetation in the Labe (Elbe) River flood-plain (Central Bohemia, Czech Republic). – Acta Paleobot. Suppl. 2 - Proceedings 5th EPPC, 549–554. Kraków.

Czudek, T. (2005). Vývoj reliéfu krajiny České republiky v kvartéru. – 238 s., Moravské zemské muzeum. Brno. ISBN 8070282703

Čufar, K., Luis, M. D., Zupančič, M., Eckstein, D. (2008). 548-year tree-ring chronology of oak (Quercus spp.) for southeast Slovenia and its significance as a dating tool and climate archive. – Tree-Ring Research 64 (1), 3–15. https://doi.org/10.3959/2007-12.1

Dreslerová, D., Břízová, E., Růžičková, E., Zeman, A. (2004). Holocene environmental processes and alluvial archaeology in the middle Labe (Elbe) valley. – In: Gojda, M. (ed.): Ancient landscape, settlement dynamics and non-destructive archaeology. Academia, Praha, 121–171.

Drobníčková, H., Pavlík, J. (1995). Závěrečná zpráva o průzkumu nalezišť násypových materiálů pro výstavbu D 35 a obchvatu Lipníka nad Bečvou. – MS, Geotest, a.s., Brno.

Eckstein, D., Bauch, J. (1969). Beitrag zur Rationalisierung eines dendrochronologischen Verfahrens und zur Analyse seiner Aussagesicherheit. – Forstwissenschaft liches Centralblatt 88, 230–250. https://doi.org/10.1007/BF02741777

Erdtman, G. (1954). An introduction to pollen analysis. – Waltham (USA).

Hollstein, E. (1980). Mitteleuropäische Eichenchronologie. Trierer dendrochronologische Forschungen zur Archäologie und Kunstgeschichte. – Trierer Grabungen und Forschungen. Mainz am Rhein, 274 pp.

Kalicki, T., Krapiec, M. (1995). Problems of dating alluvium using buried subfossil tree trunks: lessons from the black oaks of the Vistula Valley, Central Europe. – The Holocene, 5, 243–50. https://doi.org/10.1177/095968369500500213

Kolář, T., Rybníček, M. (2011). Dendochronological and radiocarbon dating of subfossil wood from the Morava River basin. – Geochronometria 38(2), 155–161. https://doi.org/10.2478/s13386-011-0021-x

Kolář, T., Rybníček, M., Střelcová, M., Hedvábný, J., Vít, J. (2014). The changes in chemical composition and properties of subfossil oak deposited in Holocene sediments. – Wood Research, Vol. 59, No. 1, 149–165. Slovak Forest Products Research Institute. Bratislava.

Moravec, Č., Peichel, S., Ševčík, J., Špíchalová, D., Staňková, L. (1983). Povodí Bečvy. Úsek Hranice – Přerov. Souhrnná závěrečná zpráva. Surovina štěrkopísek. Etapa vyhledávací. – MS, Unigeo, závod Ostrava (ČGS Geofond, P054388).

Prokop, O., Kolář, T., Kyncl. T., Rybníček, M. (2017). Updating of the Czech millennia-long oak tree-ring width chronology. – Tree-ring Research 73(1): 47–52. https://doi.org/10.3959/1536-1098-73.1.47

Růžičková, E., Zeman, A. (1994). Paleogeographic development of the Labe river flood plain during the Holocene. – In: Růžičková E. et Zeman A. (eds): Holocene flood plain of the Labe river. Contemporary state of research in the Czech Republic. 104–112. Prague.

Rybníček, M., Koňas, P., Kolář, T. (2010). The benefits of tree-ring curves detrending for dating archaeological wood. – Geochronometria, 35, 85–90. https://doi.org/10.2478/v10003-010-0004-6

Rybníčková, E. (1985): Dřeviny a vegetace Československa v nejmladším kvartéru. – MS, disertační práce. Institut systematické a ekologické biologie, Brno.

Schweingruber, F. H. (1990). Anatomy of European woods. An atlas for the identification of European trees, shrubs and dwarf shrubs. – 800 s. Paul Haupt Publisher, Berne, Switzerland and Stuttgart, Germany.

Svoboda, R. (1987). Zpráva o výsledku předběžného průzkumu nalezišť násypového a konstrukčního materiálu pro stavbu dálnice D35 na lokalitách Rokytnice, Týn n. Bečvou, Osek n. Bečvou, Rybáře, Oldřichov. – MS, Geotest, Brno.

Tyráček J. (1957). Jihozápadní část Moravské brány mezi Lýskami a Lipníkem nad Bečvou na topografických sekcích 4259/1 a 4159/3. – Antropozoikum, VI, 166–171.

Teodoridis, V., Bruch, A. A., Vassio, E., Martinetto, E., Kvaček, Z., Stuchlik, L. (2017). Plio-Pleistocene floras of the Vildštejn Formation in the Cheb Basin, Czech Republic. – A floristic and palaeoenvironmental review. – Palaeogeography, Palaeoclimatology, Palaeoecology 467, 166–190. https://doi.org/10.1016/j.palaeo.2015.09.038

Vít, J., Kolář, T., Rybníček, M. (2009). Předběžné výsledky studia vztahu subfosilních kmenů a fluviálních sedimentů na lokalitách Osek nad Bečvou a Tovačov-Annín. – Geologické výzkumy na Moravě a ve Slezsku v r. 2008, 53–55. Brno.

https://doi.org/10.5817/GVMS2019-1-2-66%20