scholarly journals Smykiv – the new key section of the upper pleistocene of the Volyn Upland

Formulation the problem. The new section at Smykiv in the Volyn Upland has an informative stratigraphic record, showing details of climatic phases in the Late Pleistocene. The site is located in the Rivne Oblast, 40 km south of Lutsk, on slope of the River Dezha (the tributary of the River Styr). Review of previous publications and studies. The loess-palaeosol sequence of the Volyn’ Upland has been intensively studied by Ukrainian, Russian and Polish researchers such as A. Bogucki, M. Lanczont, P. Voloshyn, A. Tsatskin, V. Nechaev, T. Morozova, L. Bezusko, J. Kusiak, S. Fedorowicz, J. Nawrocki, R. Dmytruk and many others. Methods. The section has been studied using lithostratigraphic, palaeopedological, palaeocryological, grain size, micromorphological and partial chemical methods, which enable the reconstruction of past climate and environment. The stratigraphy is applied follows the Quaternary Framework of Ukraine (Veklitch et al., 1993). All the stratigraphical units of the Upper Pleistocene are represented in the section; and, herein, these divided into smaller parts characterized by distinct environmental histories. The purpose of the article is to study the detailed stratified sequence at Smykiv by various methods in order to clarify the regional Quaternary palaeogeographical scheme. Results. The periglacial alluvium of the Dnipro unit, at the base of the sequence, and the analysis of the position of the site in the relief indicate the interpretation that it is located on the Dezha river’s terrace. The alluvium bed is distorted by syngenetic involutions. The overlying Kaydaky unit truncates the alluvium, and is inclined parallel to the present valley slope. Three pedogenetic phases during the Kaydaky times are identifiable: pedosediments formed in the first phase (kda), pedosediments of forest soil formed in the early optimum (kdb1) and a Retisol formed in the late optimum (kdb2). During the Tyasmyn cold event, a network of small soil veins formed. Renewed, but less intense than in the Kaydaky unit, erosion processes started in Pryluky times. It can be demonstrated that the Pryluky polygenetic soil was formed in three phases, divided by a cold event in mid Pryluky times (pl2). A Chernozem with signs of slight podzolisation and biogenic aggregation was formed during the first phase (pl1b2). The soil is disturbed by cryogenic features formed during pl2. An incipient Cambisol was enriched with a fine organic matter during the phase pl3b1. An incipient Calcic Cambisol (pl3b2), aggregated and slightly gleyed, formed at the end of the Pryluky time. Erosion processes were not strongly developed during Pleniglacial. At the beginning of the stadials (in Uday and Bug times), solifluction processes occurred. At the beginning of these stadials, other cryogenic features, such as soil veins, frost fissures and ice-wedges, were also formed. Upper Pleistocene loess beds show slight pedogenesis, particularly very weak humus accumulation and biogenic aggregation. Furthermore, all Pleniglacial units are enriched in carbonates in diverse forms: however, the most common is disperse powdery lime. These last are frequently interpreted as being the result of calcite crystallization under cryogenic processes. During Vytachiv and Dofinivka interstadial times, boreal soils were formed – Gleyic Cambisol and Calcic Gleyic Cambisol, respectively. The first is mostly represented by pedosediments (indicating intense erosion), whereas the second soil is preserved in situ and it is enriched in fine organic matter and is well-microaggregated. The last loess unit of the Upper Pleistocene, the Prychornomorsk loess unit, is subdivided into two loess subunits (pc1 and pc3) which are connected with cryogenic events, and a Gleysol (pc2), indicating a relatively warm period.

Oecologia ◽  
2012 ◽  
Vol 172 (4) ◽  
pp. 1105-1115 ◽  
Author(s):  
Christopher J. Patrick ◽  
Dylan H. Fernandez

1983 ◽  
Vol 49 (S2) ◽  
pp. mf55-mf57
Author(s):  
Richard Macphail

Layer 3 was examined in the fiela and provisionally interpreted as a Bt horizon. A sample (locaxion shown on fig.5) was examined in thin section in order to throw further light on how the layer had formed. It can be described as follows using the method and terminology of Brewer 1964, Bullock and Murphy 1979:- Homogeneous; well developed fine and meciium subangular blocky; total macrovoids (> 20 μm) 13.1%; smoothed orthovughs and channels occur intrapedally; silt-size mineral grains dominantly quartz; includes fine gravel-size flint; coarse grains angular; small grains moderately rounded; many fine void argillans (few medium); few compound ferri-argillans; few embedded argillans; common to many fine to medium matrans and matri-argillans; common to many irregular, and linear intrapedal clay concentrations; few fine to medium distinct ferromanganiferous nodules; finely mixed organic matter and medium organic matter fragments in matrix; fine organic matter and charcoal fragments in matrans; silt layers within compound matrans ana matri-argillans; silasepic; porphyroskelic.


2020 ◽  
Author(s):  
Amanda H. Schmidt ◽  
◽  
Melinda Quock ◽  
Alexandra Grande ◽  
Lee B. Corbett ◽  
...  

2010 ◽  
Vol 7 (11) ◽  
pp. 3473-3489 ◽  
Author(s):  
J. Holtvoeth ◽  
H. Vogel ◽  
B. Wagner ◽  
G. A. Wolff

Abstract. Organic matter preserved in Lake Ohrid sediments originates from aquatic and terrestrial sources. Its variable composition reflects climate-controlled changes in the lake basin's hydrology and related organic matter export, i.e. changes in primary productivity, terrestrial plant matter input and soil erosion. Here, we present first results from lipid biomarker investigations of Lake Ohrid sediments from two near-shore settings: site Lz1120 near the southern shore, with low-lying lands nearby and probably influenced by river discharge, and site Co1202 which is close to the steep eastern slopes. Variable proportions of terrestrial n-alkanoic acids and n-alkanols as well as compositional changes of ω-hydroxy acids document differences in soil organic matter supply between the sites and during different climate stages (glacial, Holocene, 8.2 ka cooling event). Changes in the vegetation cover are suggested by changes in the dominant chain length of terrestrial n-alkanols. Effective microbial degradation of labile organic matter and in situ contribution of organic matter derived from the microbes themselves are both evident in the sediments. We found evidence for anoxic conditions within the photic zone by detecting epicholestanol and tetrahymanol from sulphur-oxidising phototrophic bacteria and bacterivorous ciliates and for the influence of a settled human community from the occurrence of coprostanol, a biomarker for human and animal faeces (pigs, sheep, goats), in an early Holocene sample. This study illustrates the potential of lipid biomarkers for future environmental reconstructions using one of Europe's oldest continental climate archives, Lake Ohrid.


2013 ◽  
Vol 10 (1) ◽  
pp. 67-80 ◽  
Author(s):  
W. R. Hunter ◽  
A. Jamieson ◽  
V. A. I. Huvenne ◽  
U. Witte

Abstract. The Whittard Canyon is a branching submarine canyon on the Celtic continental margin, which may act as a conduit for sediment and organic matter (OM) transport from the European continental slope to the abyssal sea floor. In situ stable-isotope labelling experiments were conducted in the eastern and western branches of the Whittard Canyon, testing short-term (3–7 days) responses of sediment communities to deposition of nitrogen-rich marine (Thalassiosira weissflogii) and nitrogen-poor terrigenous (Triticum aestivum) phytodetritus. 13C and 15N labels were traced into faunal biomass and bulk sediments, and the 13C label traced into bacterial polar lipid fatty acids (PLFAs). Isotopic labels penetrated to 5 cm sediment depth, with no differences between stations or experimental treatments (substrate or time). Macrofaunal assemblage structure differed between the eastern and western canyon branches. Following deposition of marine phytodetritus, no changes in macrofaunal feeding activity were observed between the eastern and western branches, with little change between 3 and 7 days. Macrofaunal C and N uptake was substantially lower following deposition of terrigenous phytodetritus with feeding activity governed by a strong N demand. Bacterial C uptake was greatest in the western branch of the Whittard Canyon, but feeding activity decreased between 3 and 7 days. Bacterial processing of marine and terrigenous OM were similar to the macrofauna in surficial (0–1 cm) sediments. However, in deeper sediments bacteria utilised greater proportions of terrigenous OM. Bacterial biomass decreased following phytodetritus deposition and was negatively correlated to macrofaunal feeding activity. Consequently, this study suggests that macrofaunal–bacterial interactions influence benthic C cycling in the Whittard Canyon, resulting in differential fates for marine and terrigenous OM.


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