Tracking Lateglacial and early Holocene environmental change: a palaeolimnological study of sediment at Preluca Tiganului, NW Romania (original) (raw)
Related papers
2012
Abstract High resolution analyses of pollen, mineral magnetic properties, loss of ignition, lithostratigraphy and AMS 14C measurements of lake sediments and peat deposits accumulated in the former crater lake of Steregoiu (Gutâiului Mts., NW Romania), gave new and important information about vegetation and climate changes from the period GS-2 to the present. During the Lateglacial, three cold events were recorded: before 14,700 cal. years BP (GS-2), 14,050–13,800 cal. years BP (GI-1d), 12,900-11,500 cal.
Quaternary Science Review, 2001
High resolution pollen, plant macrofossil, charcoal, mineral magnetic and sedimentary analyses, combined with AMS 14 C measurements, were performed on multiple sediment sequences along a transect through the former crater lake Preluca-Tiganului in northwestern Romania in order to reconstruct the climatic and environmental changes during the early part of the Last Termination. Lake sediments started to accumulate at 14,700calyrBP.InitiallytheuplandvegetationconsistedofanopenforestwithmainlyBetulaandSalixandfewPinussp.,butfrom14,500calyrBPonwards,Pinusmugo,P.sylvestrisandPopulusandlateronalsoLarixbecameestablishedaroundthelake.Between14,150and13,950calyrBP,PinuscembraseemstohavereplacedP.mugoandP.sylvestris.At14,700 cal yr BP. Initially the upland vegetation consisted of an open forest with mainly Betula and Salix and few Pinus sp., but from 14,500 cal yr BP onwards, Pinus mugo, P. sylvestris and Populus and later on also Larix became established around the lake. Between 14,150 and 13,950 cal yr BP, Pinus cembra seems to have replaced P. mugo and P. sylvestris. At 14,700calyrBP.InitiallytheuplandvegetationconsistedofanopenforestwithmainlyBetulaandSalixandfewPinussp.,butfrom14,500calyrBPonwards,Pinusmugo,P.sylvestrisandPopulusandlateronalsoLarixbecameestablishedaroundthelake.Between14,150and13,950calyrBP,PinuscembraseemstohavereplacedP.mugoandP.sylvestris.At13,950 cal yr BP the tree cover increased and Picea appeared for the first time, together with Pinus cembra, P. mugo and Larix. From $13,750 cal yr BP onwards, a Picea forest developed around the site. Based on the combined proxy data the following climatic development may be inferred:
Journal of Quaternary Science, 2004
Macrofossil, pollen, lithostratigraphy, mineral magnetic measurements (SIRM and magnetic susceptibility), loss-on-ignition, and AMS radiocarbon dating on sediments from two former crater lakes, situated at moderate altitudes in the Gutaiului Mountains of northwest Romania, allow reconstruction of Late Quaternary climate and environment. Shrubs and herbs with steppe and montane affinities along with stands of Betula and Pinus, colonised the surroundings of the sites prior to 14 700 cal. yr BP and the inferred climatic conditions were cold and dry. The gradual transition to open Pinus-Betula forests, slightly higher lake water temperatures, and higher lake productivity, indicate more stable environmental conditions between 14 700 and 14 100 cal. yr BP. This development was interrupted by cooler and drier climatic conditions between 14 100 and 13 800 cal. yr BP, as inferred from a reduction of open forests to patches, or stands, of Pinus, Betula, Larix, Salix and Populus. The expansion of a denser boreal forest, dominated by Picea, but including Pinus, Larix, Betula, Salix, and Ulmus started at 13 800 cal. yr BP, although the forest density seems to have been reduced between 13400 and 13200cal.yrBP. Air temperature and moisture availability gradually increased, but a change towards drier conditions is seen at 13400cal.yrBP. A distinct decrease in temperature and humidity between 12900 and 11500cal.yrBP led to a return of open vegetation, with patches of Betula, Larix, Salix, Pinus and Alnus and individuals of Picea. Macrofossils and pollen of aquatic plants indicate rising lake water temperatures and increased aquatic productivity already by ca. 11800cal.yrBP, 300 years earlier than documented by the terrestrial plant communities. At the onset of the Holocene, 11500cal.yrBP, forests dominated by Betula, Pinus and Larix expanded and were followed by dense Ulmus forests with Picea, Betula and Pinus at 11250cal.yrBP. Larix pollen was not found, but macrofossil evidence indicates that Larix was an important forest constituent at the onset of the Holocene. Moister conditions were followed by a dry period starting about 10600cal.yrBP, which was more pronounced between 8600 and 8200cal.yrBP, as inferred from aquatic macrofossils. The maximum expansion of Tilia, Quercus, Fraxinus and Acer between 10700 and 8600cal.yrBP may reflect a more continental climate. A drier and/or cooler climate could have been responsible for the late expansion (10300cal.yrBP) and late maximum (9300cal.yrBP) of Corylus. Increased water stress, and possibly cooler conditions around 8600cal.yrBP, may have caused a reduction of Ulmus, Tilia, Quercus and Fraxinus. After 8200cal.yrBP moisture increased and the forests included Picea, Tilia, Quercus and Fraxinus. Copyright
Review of Palaeobotany …, 2007
Romania has for a long time been lacking good palaeoenvironmental records, particularly for the Late Quaternary. A chronological framework had been nearly absent and the vegetation development had been reconstructed entirely from pollen data. Data sets from this part of Europe are important for assessing the spatial variability of past vegetation and climatic changes and to reconstruct tree migration routes at the end of the last glacial period. New palaeobotanical evidence has enabled us to address this gap and to provide a more comprehensive picture of the Lateglacial and early Holocene continental environment. This paper reviews results from radiocarbon dated sequences in Romania with the aim to place them in a larger perspective with regard to glacial refugia and tree immigration, and to asses the vegetation response to climatic oscillation from the end of the Last Glacial Maximum (LGM) to the early Holocene. This study documents that some coniferous and broad-leaved trees were present prior to 14,700 cal. yr BP in Romania, and thus it appears that this region may have been a refugial area for some tree species. During the Lateglacial, the vegetation shows a distinct response to climatic oscillations at all elevations, although the response is stronger at mid altitude (800-1100 m. a.s.l) than at high altitudes. Moreover, smaller climatic oscillations are only recorded at sites situated at mid altitudes, probably because these areas were located close to the tree line ecotone.
Central European Geology, 2009
As a first piece in a series of Late Quaternary paleoecological studies on the glacial lake sediments of the Retezat Mountains, this study discusses radiocarbon chronology and sediment accumulation rate changes in two sediment profiles in relation to lithostratigraphy, organic content, biogenic silica and major pollenstratigraphic changes. A total of 25 radiocarbon dates were obtained from sediments of two lakes, Lake Brazi (TDB-1; 1740 m a.s.l.) and Lake Gales (Gales-3; 1990 m a.s.l.). Age-depth modeling was performed on TDB-1 using calibrated age ranges from BCal and various curve-fitting methods in psimpoll. Our results suggest that sediment accumulation began between 15,124-15,755 cal yr BP in both lakes and was continuous throughout the Late Glacial and Holocene. We demonstrated that local ecosystem productivity showed delayed response to Late Glacial and Early Holocene climatic changes in the subalpine and alpine zones most likely attributable to the cooling effect of remnant glaciers and meltwater input. However, regional vegetation response was without time lag and indicated forestation and warming at 14,450 and 11,550 cal yr BP, and cooling at ca. 12,800 cal yr BP. In the Holocene one major shift was detected, starting around 6300 cal yr BP and culminating around 5200 cal yr BP. The various proxies suggested summer cooling, shorter duration of the winter ice-cover season and/or increasing size of the water body, probably in response to increasing available moisture.
2002
Pollen analyses and AMS 14C measurements were performed on lacustrine sediments and peat sequences from two former crater lakes (Preluca Tiganului, Steregoiu) situated in the Gutaiului Mountains in northwestern Romania, in order to reconstruct the vegetation development during the Lateglacial and Early Holocene. Before c. 14,700 cal. years BP (GS-2) open vegetation with shrubs (Salix, Juniperus), grasses and herbs (eg Artemisia and Chenopodiaceae) prevailed in the area. Around c. 14,700 cal.
Quaternary International, 2015
ABSTRACT Pollen datasets from central-eastern Europe, a region that for long time has been lacking quality palaeoecological records, are becoming increasingly available and these allow an evaluation of past vegetation sensitivity to climate change. Here, we use a new pollen and non-pollen palynomorph (NPP) record supported by eight AMS radiocarbon measurements from the Ic Ponor peat sequence, NW Romania, covering the end of the Lateglacial to mid-Holocene to examine the vegetation dynamics and associated climatic conditions. The vegetation at the Lateglacial to Holocene transition was composed of mixed forest (Pinus dominated) -tundra-steppe vegetation. Following the decline of Pinus from 11,200 cal BP, Ulmus and Picea abies expanded and formed dense forests, then by Corylus avellana and Quercus from 10,200 cal BP. The forests were mainly composed of C. avellana and P. abies along with Ulmus, Quercus and Fraxinus between 9800 and 7440 cal BP. Starting with 7200 cal BP, P. abies dominated the landscape in the area probably favored by the increasingly cooler and moist conditions. After a considerable hiatus between 5830 and 40 cal BP, the most recent changes in the forest composition in the area were primarily related to forest clearings and grazing. The absence of relevant occurrences of Fagus sylvatica and Carpinus betulus in our sequence prior to 8800 cal BP, fail to give support to the glacial survival of these two taxa in the Apuseni Mountains, as hypothesized in the previous pollen and genetic studies. However, their continuous occurrence in small percentages after 8800 cal BP most probably reflects locally present, small populations of these taxa. Short-term phases of changes in the vegetation composition that appeared to be the response to cooler and/or wetter climate were recorded between 11,800 and 11,700, 11,500e11,200, 10,300e10,200, 9350e9250, 8250e8140, 7700e7400, 6800e6600 and 6100e5900 cal BP. These intervals correlate well to other centennial-scale excursions recorded in Romania and Europe.
Late-Glacial and Holocene forest dynamics at Steregoiu in the Gutaiului Mountains, Northwest Romania
Review of Palaeobotany and Palynology, 2003
Pollen analyses and AMS 14C measurements were performed on lacustrine sediments and peat deposits from the former crater lake Steregoiu in a mid-altitude area in the Gutaiului Mountains in NW Romania in order to provide a detailed reconstruction of the vegetational development of the area during the Late-Glacial and Holocene. The bottom sediments are siliciclastic and were deposited probably during the Full Glacial, which is characterised by open patchy vegetation consisting of a mosaic of shrubs, herbs, and ungrown grounds. Around 14 700 cal yr BP an open Pinus–Betula forest expanded, at the same time as organic-rich lake sediments started to be deposited. This change was likely a response to the first deglacial warming phase at the beginning of the Bølling period, or GI-1e, in the GRIP event stratigraphy. Between 13 750 and 12 950 cal yr BP an open forest dominated by Betula, Picea, Pinus, and Ulmus developed in the area. The forest composition implies rather warm climatic conditions, which may correspond to the Allerød, or GI-1c–GI-1a. Around 12 950 cal yr BP the forest retracted, and at 12 600 cal yr BP open patchy vegetation became re-established. These changes imply a return to significantly colder conditions, which may correspond to the Younger Dryas, or GS-1. At 11 500 cal yr BP Betula, Pinus, and Alnus quickly responded to the temperature rise, characterising the beginning of the Holocene. Within a few hundred years, around 11 300 cal yr BP, Ulmus and Picea became re-established and a mixed forest type expanded. Quercus, Tilia, and Fraxinus likely arrived at around 10 750 cal yr BP, and from about this time Betula, and Pinus started to diminish. Around 10 500 cal yr BP a dense mixed forest dominated by Ulmus, Picea, Quercus, Tilia, and Fraxinus had developed in the area. Corylus probably became locally established around 10 500 cal yr BP, but it did not expand until 10 200 cal yr BP. Tilia and Fraxinus were locally important until 8600 cal yr BP, when Picea gained renewed importance and the lake became completely overgrown. Picea was probably an important constituent in the carr forest at the site as well as in the upland forest. Around 4800 cal yr BP Fagus and Carpinus became important in the local stand, apparently without any major disturbance of the forest. Until around 3400 cal yr BP the forest was highly diverse, but when Fagus eventually expanded, Ulmus, Tilia, Picea, and Corylus diminished. From about 2200 cal yr BP onwards Fagus has been the local forest dominant, but some Quercus and Carpinus individuals have been present as well. Pollen evidence for human influence on the local vegetation is comparatively scant. The area may have been used for forest grazing from about 1050 cal yr BP, but the grazing pressure was probably low until ca. 300 cal yr BP.
Hungarian Geographical Bulletin, 2021
The research area is located in the Eastern Carpathians, Romania. This region is rich in various formations and indicates significant potential for paleo-environmental reconstruction. The present research was carried out on sediment cores collected at lake Bolătău-Feredeu, Feredeului Mountains (Eastern Carpathians, Romania). Preliminary examination of the sediment confirmed the possibility for data analysis with high temporal resolution. The aim of the research was to clarify and supplement the findings of previous research at this site, to explore the relationships between proxy parameters and to elucidate the cause for the changes. Core dating was carried out using 210Pb and radiocarbon isotopes and indicated that sediment cores span the past 500 years. The research uses a wide range of methodologies, including organic geochemistry with calculated n alkane indices (Phw and Pwax). Based on these proxies, the changes of woody and herbaceous coverage in the catchment can be estimated...