Darius Valunas - Academia.edu (original) (raw)

Papers by Darius Valunas

Research paper thumbnail of The Lateglacial and Early Holocene vegetation dynamics: New multi-proxy data from the central Belarus

Quaternary International, 2021

Abstract Detailed knowledge of the periglacial flora is essential to assess the vegetation dynami... more Abstract Detailed knowledge of the periglacial flora is essential to assess the vegetation dynamics in deglaciated regions of northern and north eastern Europe, previously covered by the ice sheet of the Late Weichselian Glaciation. Therefore, the territory of Belarus, which stretches in the periglacial zone of the Last Glaciation and the most part of which was free of ice during the Last Glacial maximum, is off particular importance in analysing the postglacial floral establishment and the subsequent vegetation dynamics in this part of the continent. In this study, results of palaeobotanical (pollen and plant macrofossil), lithological (measurements of magnetic susceptibility, MS) and isotopic (14C) investigations were obtained to fill the existing gap in reconstructing the peculiarities of the terrestrial and aquatic vegetation dynamics throughout the Lateglacial - Early Holocene period in the central Belarus. The investigated sediment profile, comprising organically enriched gyttja at 13,400–13,100 cal yr BP, carbon enriched and sandy gyttja at 13,100–9700 cal yr BP and unconsolidated mud after 9500 cal yr BP, provides clear evidence proving the flourishing of a pine-birch predominated forest with occasional spruce stands during the Allerod in area. Three occasions of change in the vegetation structure were noted within the Younger Dryas, i.e. 12,900–12,700 cal yr BP, 12,200–12,000 cal yr BP and 11,900–11,700 cal yr BP, suggesting negative climatic excursion taken place in area and facilitating flourishing of a Picea-predominating forest that culminated at about 12,300 and 12,000 cal yr BP. Pollen record suggests the Early Holocene vegetation shifts occurring at about 11,300–11,200 cal yr BP, 10,800–10,600 cal yr BP and 10,300–10,100 cal yr BP evidence the general response to the global-scale climatic events i.e. Preborael Oscillation or “10,2 ka” while fluctuations triggered by local or regional-scale climatic events have been identified as well. About 10,800–10,700 cal yr BP, formation of the forest with an increasing representation of thermophilous taxa (Ulmus, Tilia, Quercus) started in area.

Research paper thumbnail of New insight into the palaeoenvironmental dynamics as a background of the human history in the Nemunas River delta region, W Lithuania, throughout the Lateglacial and Early Holocene

Baltica, 2021

A new reconstruction of the Lateglacial – Early Holocene paleoenvironmental dynamics as a backgro... more A new reconstruction of the Lateglacial – Early Holocene paleoenvironmental dynamics as a background of the habitation history in the territory of the Nemunas River Delta (NRD) was based on the geological-geomorphological, grain-size, isotope (14C), pollen and diatom data supplemented by archaeological information obtained within the framework of the project „Man and Baltic Sea in the Meso-Neolithic: Relict Coasts and Settlements Below and Above Present Sea Level. ReCoasts&People“. The existence of extended proglacial lakes formed during the onset of the Lateglacial was succeeded by a period of low water estuaries or freshwater lagoons as early as 13.8 cal kyr BP. Simultaneously, groups of the Final Palaeolithic population, representing the classic Swiderian culture, inhabited the area. As shores of the Yoldia Sea and Ancylus Lake were situated further westwards (-11 to -24 – -29 m NN), wetlands and lake systems alongside with shallow boggy basins and fluvial streams predominated in...

Research paper thumbnail of Learners' Perceptions of E- Learning

Societal Studies, 2012

This article describes how students perceive the usefulness of e-learning of English for Specific... more This article describes how students perceive the usefulness of e-learning of English for Specific Purposes (ESP) at tertiary level. The research is based on the analysis of data obtained from the survey on learner attitudes to integrating online activities in the traditional English language classroom. The respondents are of five different specializations and study ESP either at University or College. The level of English proficiency is B2 or C1 according to the Common European Framework of Reference for Languages. The learner responses to the statements of a specially designed questionnaire are analyzed by a means of Software Package for Social Sciences (SPSS) with the aim of determining correlations among different specializations, data reliability and statistical significance. The implications of the findings are discussed.

Research paper thumbnail of E-learning from Learners‘ Perspective

Santalka, 2012

The concept of "e-learning" is ambivalent. On the one hand, it is used to describe the "distant l... more The concept of "e-learning" is ambivalent. On the one hand, it is used to describe the "distant learning", on the other hand, it refers to "blended learning". This article focuses on classic "blended learning", which means combination of face-to-face instruction with online activities. The study examines students' attitudes to integrating online activities into the traditional English language classroom. The respondents are the University students of three different specializations who study English for Specific Purposes. The frequencies of positive and negative responses to a specially designed questionnaire are analyzed. Not all the students enjoy e-learning in spite of its advantages, which might be expressed due to individual likes and dislikes. Statistical treatment of the students' responses by means of Software Package for Social Sciences (SPSS) includes the computations of correlation coefficients, which indicate the strength of relationships, and their statistical significance.

Research paper thumbnail of The Lateglacial and Early Holocene vegetation dynamics: New multi-proxy data from the central Belarus

Quaternary International, 2021

Abstract Detailed knowledge of the periglacial flora is essential to assess the vegetation dynami... more Abstract Detailed knowledge of the periglacial flora is essential to assess the vegetation dynamics in deglaciated regions of northern and north eastern Europe, previously covered by the ice sheet of the Late Weichselian Glaciation. Therefore, the territory of Belarus, which stretches in the periglacial zone of the Last Glaciation and the most part of which was free of ice during the Last Glacial maximum, is off particular importance in analysing the postglacial floral establishment and the subsequent vegetation dynamics in this part of the continent. In this study, results of palaeobotanical (pollen and plant macrofossil), lithological (measurements of magnetic susceptibility, MS) and isotopic (14C) investigations were obtained to fill the existing gap in reconstructing the peculiarities of the terrestrial and aquatic vegetation dynamics throughout the Lateglacial - Early Holocene period in the central Belarus. The investigated sediment profile, comprising organically enriched gyttja at 13,400–13,100 cal yr BP, carbon enriched and sandy gyttja at 13,100–9700 cal yr BP and unconsolidated mud after 9500 cal yr BP, provides clear evidence proving the flourishing of a pine-birch predominated forest with occasional spruce stands during the Allerod in area. Three occasions of change in the vegetation structure were noted within the Younger Dryas, i.e. 12,900–12,700 cal yr BP, 12,200–12,000 cal yr BP and 11,900–11,700 cal yr BP, suggesting negative climatic excursion taken place in area and facilitating flourishing of a Picea-predominating forest that culminated at about 12,300 and 12,000 cal yr BP. Pollen record suggests the Early Holocene vegetation shifts occurring at about 11,300–11,200 cal yr BP, 10,800–10,600 cal yr BP and 10,300–10,100 cal yr BP evidence the general response to the global-scale climatic events i.e. Preborael Oscillation or “10,2 ka” while fluctuations triggered by local or regional-scale climatic events have been identified as well. About 10,800–10,700 cal yr BP, formation of the forest with an increasing representation of thermophilous taxa (Ulmus, Tilia, Quercus) started in area.

Research paper thumbnail of New insight into the palaeoenvironmental dynamics as a background of the human history in the Nemunas River delta region, W Lithuania, throughout the Lateglacial and Early Holocene

Baltica, 2021

A new reconstruction of the Lateglacial – Early Holocene paleoenvironmental dynamics as a backgro... more A new reconstruction of the Lateglacial – Early Holocene paleoenvironmental dynamics as a background of the habitation history in the territory of the Nemunas River Delta (NRD) was based on the geological-geomorphological, grain-size, isotope (14C), pollen and diatom data supplemented by archaeological information obtained within the framework of the project „Man and Baltic Sea in the Meso-Neolithic: Relict Coasts and Settlements Below and Above Present Sea Level. ReCoasts&People“. The existence of extended proglacial lakes formed during the onset of the Lateglacial was succeeded by a period of low water estuaries or freshwater lagoons as early as 13.8 cal kyr BP. Simultaneously, groups of the Final Palaeolithic population, representing the classic Swiderian culture, inhabited the area. As shores of the Yoldia Sea and Ancylus Lake were situated further westwards (-11 to -24 – -29 m NN), wetlands and lake systems alongside with shallow boggy basins and fluvial streams predominated in...

Research paper thumbnail of Learners' Perceptions of E- Learning

Societal Studies, 2012

This article describes how students perceive the usefulness of e-learning of English for Specific... more This article describes how students perceive the usefulness of e-learning of English for Specific Purposes (ESP) at tertiary level. The research is based on the analysis of data obtained from the survey on learner attitudes to integrating online activities in the traditional English language classroom. The respondents are of five different specializations and study ESP either at University or College. The level of English proficiency is B2 or C1 according to the Common European Framework of Reference for Languages. The learner responses to the statements of a specially designed questionnaire are analyzed by a means of Software Package for Social Sciences (SPSS) with the aim of determining correlations among different specializations, data reliability and statistical significance. The implications of the findings are discussed.

Research paper thumbnail of E-learning from Learners‘ Perspective

Santalka, 2012

The concept of "e-learning" is ambivalent. On the one hand, it is used to describe the "distant l... more The concept of "e-learning" is ambivalent. On the one hand, it is used to describe the "distant learning", on the other hand, it refers to "blended learning". This article focuses on classic "blended learning", which means combination of face-to-face instruction with online activities. The study examines students' attitudes to integrating online activities into the traditional English language classroom. The respondents are the University students of three different specializations who study English for Specific Purposes. The frequencies of positive and negative responses to a specially designed questionnaire are analyzed. Not all the students enjoy e-learning in spite of its advantages, which might be expressed due to individual likes and dislikes. Statistical treatment of the students' responses by means of Software Package for Social Sciences (SPSS) includes the computations of correlation coefficients, which indicate the strength of relationships, and their statistical significance.