scholarly journals Radiocarbon chronology of glacial lake sediments in the Retezat Mts (South Carpathians, Romania): a window to Late Glacial and Holocene climatic and paleoenvironmental changes

2009 ◽  
Vol 52 (3-4) ◽  
pp. 225-248 ◽  
Author(s):  
Enikõ K. Magyari ◽  
Mihály Braun ◽  
Krisztina Buczkó ◽  
Zoltán Kern ◽  
Péter László ◽  
...  
Radiocarbon ◽  
1994 ◽  
Vol 36 (2) ◽  
pp. 187-202 ◽  
Author(s):  
Anna Pazdur ◽  
M. F. Pazdur ◽  
Tomasz Goslar ◽  
Bogumił Wicik ◽  
Maurice Arnold

We obtained 14C ages on samples of lake marl and other sediments from cores taken in Gościąż Lake and its environs. Comparison of 14C dates of bulk samples of laminated sediment with varve chronology and available AMS dates of terrestrial macrofossils indicates a reservoir correction of 2000 ± 120 yr for the basal series of lake sediments. 14C dates obtained on peat layers underlying the oldest lacustrine sediments in Gościąż and other lakes consistently locate the beginning of organogenic sedimentation in this area at ca. 13 ka bp. We distinguished three periods of lacustrine gyttja sedimentation in cores taken in Gościąż and adjacent lakes: 11.8–10.2 ka, 8–7 ka and 2.7–2.1 ka bp. From the 14C dates of lithological boundaries in these cores, we reconstruct a pattern of lake-level changes during the last 12 ka, remarkably similar to Swedish lakes and generally agreeing with available records from European and American lakes. The behavior of Gościąż Lake during the last 12 ka fairly well reflects global climate changes in the temperate zone during the Late Glacial and Holocene periods.


Radiocarbon ◽  
2004 ◽  
Vol 46 (2) ◽  
pp. 745-754 ◽  
Author(s):  
Sergey K Krivonogov ◽  
Hikaru Takahara ◽  
Yaroslav V Kuzmin ◽  
Lyobov A Orlova ◽  
A J Timothy Jull ◽  
...  

New radiocarbon dates obtained from Late Pleistocene and Holocene deposits of the southern, eastern, and northern shores of Lake Baikal in 1995–2001 are presented, and the most important results of paleoenvironmental studies based on C data are discussed. The following paleogeographic events were verified with the help of C dating: 1) first Late Pleistocene glaciation (Early Zyryan); 2) Middle Zyryan interstadial; 3) loess formation during the Late Zyryan (Sartan) deglaciation; 4) warm and cold events in the Late Glacial; and 5) vegetation changes and forest successions during the Late Glacial and Holocene.


Radiocarbon ◽  
1999 ◽  
Vol 41 (1) ◽  
pp. 25-45 ◽  
Author(s):  
Kh A Arslanov ◽  
L A Saveljeva ◽  
N A Gey ◽  
V A Klimanov ◽  
S B Chernov ◽  
...  

We have studied 6 reference sections of bog and lake sediments in the Leningrad and Novgorod provinces to develop a geochronological scale for vegetational and paleoclimatic changes in northwestern Russia during the Late Glacial and Holocene. Every 10-cm layer along the peat and gyttja sections (4–8.5 m thick) was investigated palynologically and the great majority of them were radiocarbon dated. Using the data obtained, standard palynological diagrams were plotted and vegetation history reconstructed. The palynozones indicated on the diagrams were related to the climatic periods and subperiods (phases) of the Blytt-Sernander scheme. On the basis of 230 14C dates obtained, we derived the geochronology of climatic periods and phases, as well as the chronology for the appearance and areal distribution of forest-forming tree species. The uppermost peat layers were dated by using the “bomb effect”. We compared the stages of Holocene vegetation and paleoclimatic changes discovered for the Leningrad and Novgorod provinces with the those obtained for Karelia, which we had studied earlier using the same methodology.


2007 ◽  
Vol 42 (2) ◽  
pp. 171-179 ◽  
Author(s):  
Dana L. Naldrett

ABSTRACT Rhythmites overlying either cross-bedded sand or diamicton are found throughout the Ottawa Valley. Previously thought to be restricted glacial lake sediments, they are now known to be widespread, and represent a large proglacial lake which preceded the Champlain Sea. The rhythmites consist of thin silt and clay laminae which fine upwards and contain slump, flame, shear (ice-contact?) and fluid escape structures. Ice-rafted material is common. The ostracode Candona cf. C. subtriangulata occurs in low numbers and indicates a freshwater body with depth of approximately 200 m. The alternation of silt and clay rhythmite laminae is characteristic of deposition by underflow and overflow currents, respectively. To produce underflows with typical glacial outwash concentrations may require discharge into fresh rather than marine water. This evidence and the widespread occurrence of rhythmites throughout the Ottawa Valley and the Rideau Lakes area suggests a large proglacial lake as the sedimentary basin. The lake is tentatively correlated with the Belleville Phase of Glacial Lake Iroquois and the Ft. Ann Phase of Glacial Lake Vermont. These phases occurred at depths consistent with the requirements for Candona survival. The water body which existed in the Ottawa area is here called Lake Rideau after the type locality where rhythmites were first observed. Generation of such a lake favours the more conventional "window blind" model for déglaciation rather than the calving bay concept.


The Holocene ◽  
2020 ◽  
Vol 30 (6) ◽  
pp. 905-922 ◽  
Author(s):  
Jarosław Wilczyński ◽  
Maciej T Krajcarz ◽  
Magdalena Moskal-del Hoyo ◽  
Witold Paweł Alexandrowicz ◽  
Barbara Miękina ◽  
...  

The study of past environments, their ecology, and detailed changes through time has become an important task of environmental science. Records of paleoenvironment usually vary between regions owing to different influences of local climate, vegetation, relief, and depositional processes. Therefore, studying local sequences thoroughly allows paleoenvironmental and paleoecological reconstructions for particular regions, but it also provides important data that complement the global record. The Żarska Cave is an exceptional site, which owing to its thick and undisturbed Holocene sediments with very rich paleobotanical and paleozoological materials has become the most complete example of the uppermost Upper Pleistocene and Holocene cave deposits in the Polish uplands. The aim of our study was to understand paleoenvironmental changes in southern Poland, from the late Glacial to the late Holocene, which has been targeted by use of a detailed geological analysis accompanied by analysis of a wide range of paleobotanical, paleozoological, and archeological assemblages. All the results obtained have permitted characterization of the paleoenvironmental changes occurring in the area of the Polish Jura during the last >15 ka years. A particularly well-represented sequence covers the Allerød interstadial, which revealed the presence of forests with associated shade-loving mollusks and rodents. The beginning of the Holocene was clearly identified with an increase of shaded forest habitats, which developed in a still relatively cold climate with continental features, and with the first appearance of mesophilous deciduous trees. During the middle Holocene, unusual evidence for maple forests is documented, which developed before the formation of beech forests, typical for the late Holocene. The obtained sequence has great significance not only for the Polish Jura region, but also has wider implications for southern Poland and the vast area of the northern Carpathian foreland.


2020 ◽  
Author(s):  
Laura Parducci ◽  
Kevin Nota ◽  
Willy Tinner ◽  
Jacqueline van Leeuwen ◽  
Pim van der Knaap ◽  
...  

<p>We used shotgun DNA sequencing of the full metagenome preserved in varved lake sediments from southern Italy (Lago Grande di Monticchio) to investigate the whole diversity of taxonomic groups present. We combine sedimentary aDNA and pollen data as well as other biological multi-proxy data and tested if it was possible to correlate the relative abundances of plants and other biological communities to distinct climatic shifts that occurred between the Late Glacial and Holocene. In addition, we used the metabarcoding technique to compare the two sequencing approaches specifically for plants.</p><p>Our studies showed that the inhibition of DNA replication was almost absent in older (full glacial) sediment samples while it increased substantially in more recent samples. DNA provides a strong signal of plant community changes and a large number of new plant taxa were recorded. A comparison between sequencing approaches and proxies highlights differences and similarities and supports earlier findings that plants growing close to or within a lake are often recorded by DNA and that DNA provides important complementary information to that collected from palaeoecological analyses. Nevertheless, increasing DNA reference libraries and enrichment strategies prior to sequencing are necessary to improve the potential and accuracy of plant identification using the metagenomic approach.</p>


2016 ◽  
Author(s):  
Nathan Stansell ◽  
◽  
Donald T. Rodbell ◽  
Joseph M. Licciardi ◽  
Mark B. Abbott ◽  
...  

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