scholarly journals Holocene Environmental Change in the Frobisher Bay Area, Baffin Island, N.W.T.: Deglaciation, Emergence, and the Sequence of Vegetation and Climate

2007 ◽  
Vol 39 (2) ◽  
pp. 151-162 ◽  
Author(s):  
J. D. Jacobs ◽  
W. N. Mode ◽  
C. A. Squires ◽  
G. H. Miller
Keyword(s):  
Late Holocene ◽  
Late Glacial ◽  
Pollen Record ◽  
Baffin Island ◽  
Bay Area ◽  
Modern Pollen ◽  
Moist Environment ◽  
Organic Fractions ◽  
Late Glacial And Holocene ◽  
Inland Ice

ABSTRACT The late-glacial and Holocene paleoenvironmental sequence for the Frobisher Bay area is outlined using glacial, sea level, and palynological evidence. A rapid retreat of ice from the late Foxe glacial maximum in the lower part of the bay after 11,000 BP was followed by a series of stillstands or minor readvances between ca. 8500 and 7000 BP and possibly later, before the final disappearance of the inland ice centred near Amadjuak Lake. Lithostratigraphy of three buried organic sections which together represent deposition occurring over the period from 5500 to 400 BP indicates a change from a relatively warm, moist environment before 5500 BP to neoglacial conditions, with the coldest phases centred around 5000, 2700, 1200 BP and probably sometime after 400 radiocarbon years BP. As evidenced by peat growth and pollen data, milder, wetter conditions prevailed from 4500 to 3000 BP and again from ca. 2600 to 1800 BP. Peat growth and soil organic fractions point to lesser mild intervals ca. 900 BP and 400 BP, but these are not apparent in the pollen assemblage. The pollen record does not extend to the last four centuries; however, lichenometric studies of neoglacial moraines by DOWDESWELL (1984) show that the maximum late Holocene advance of glaciers in the area occurred within the last century. Modern pollen samples indicate that the present vegetation of the inner Frobisher Bay area is comparable to that of the milder intervals of the late Holocene.

scholarly journals Geochronology of vegetation stages of south-east Baltic coast (Kaliningrad region) during the middle and Late Holocene

2011 ◽  
Vol 38 (2) ◽  
pp. 172-181 ◽  
Author(s):  
Khikmatulla Arslanov ◽  
Olga Druzhinina ◽  
Larisa Savelieva ◽  
Dmitry Subetto ◽  
Ivan Skhodnov ◽  
...  
Keyword(s):  
Late Holocene ◽  
Late Glacial ◽  
Natural Object ◽  
Raised Bog ◽  
Baltic Coast ◽  
Kaliningrad Region ◽  
Late Glacial And Holocene ◽  
Peat Formation ◽  
Middle And Late Holocene

Abstract The raised bog sediments that have been continuously accumulated over time represent the most suitable natural object which enables us to reconstruct Late Glacial and Holocene vegetation and palaeoclimates. Bog peat consists of organic carbon formed in situ. It contains moss, plant fragments and microfossils that are necessary for the study of palaeovegetation and palaeoclimate. However, a successful study of palaeoenvironment can be carried out on the basis of investigation of a great quantity of samples along the whole peatbog thickness. In the present paper, the authors present the results of palynological, botanical investigations and radiocarbon dating of 31 peat samples taken from the raised bog Velikoye, located in the eastern part of Kaliningrad Region. The data obtained have enabled us to reconstruct the palaeovegetation, reveal the evolution of the bog and determine rate of peat formation at different evolutional stages over the last 7500 cal BP.

scholarly journals Late Glacial and Holocene changes in vegetation cover and climate in southern Siberia derived from a 15 kyr long pollen record from Lake Kotokel

2009 ◽  
Vol 5 (1) ◽  
pp. 127-151 ◽  
Author(s):  
P. E. Tarasov ◽  
E. V. Bezrukova ◽  
S. K. Krivonogov
Keyword(s):  
Late Glacial ◽  
Time Interval ◽  
Pollen Record ◽  
Time Intervals ◽  
Southern Siberia ◽  
Noticeable Increase ◽  
Modern Analogue ◽  
Quantitative Characteristics ◽  
Late Glacial And Holocene ◽  
Vegetation And Climate

Abstract. In this study a radiocarbon-dated pollen record from Lake Kotokel (52°47´ N, 108°07´ E, 458 m a.s.l.) located in southern Siberia east of Lake Baikal was used to derive quantitative characteristics of regional vegetation and climate since about 15 kyr BP (1 kyr=1000 cal. yr) until today. Quantitative reconstruction of the late glacial vegetation and climate dynamics suggests that open steppe and tundra communities predominated in the study area prior to ca. 13.5 kyr BP and again during the Younger Dryas interval, between 12.8 and 11.6 kyr BP. The pollen-based climate reconstruction suggests lower-than-present mean January (~–38°C) and July (~12°C) temperatures and annual precipitation (~270–300 mm) values during these time intervals. Boreal woodland replaced the primarily open landscape around Kotokel three times at about 14.8–14.7 kyr BP, during the Allerød Interstadial between 13.3–12.8 kyr BP and with the onset of the Holocene interglacial between 11.5 and 10.5 kyr BP, presumably in response to a noticeable increase in precipitation, and in July and January temperatures. The maximal spread of the boreal forest (taiga) communities in the region is associated with a warmer and wetter-than-present climate (Tw~17–18°C, Tc~–19°C, Pann~500–550 mm) occurred ca.\\ 10.8–7.3 kyr BP. During this time interval woody vegetation covered more than 50% of the area within a 21×21 km window around the lake. The pollen-based best modern analogue reconstruction suggests a decrease in woody cover percentages and in all climatic variables about 7–6.5 kyr BP. Since that time our results demonstrate gradual decrease in precipitation and mean January temperature towards their present-day values in the region around Lake Kotokel.

scholarly journals Late Glacial and postglacial seismicity in the Northeastern Fennoscandian Shield: tectonic position and age of paleo-earthquakes near Murmansk

2021 ◽  
Vol 93 (1) ◽  
pp. 53-72
Author(s):  
Svetlana B. Nikolaeva ◽  
◽  
Mikhail V. Rodkin ◽  
Sergey V. Shvarev ◽  
◽  
...  
Keyword(s):  
Late Holocene ◽  
Estimation Method ◽  
Late Glacial ◽  
Velocity Estimation ◽  
Fennoscandian Shield ◽  
Peak Ground Velocity ◽  
Seismic Events ◽  
Tectonic Position ◽  
History Of ◽  
Late Glacial And Holocene

Earthquake-induced deformations located near Murmansk City were investigated for information on the age, tectonic position and spatial occurrence of paleo-earthquakes. The main earthquake-generating zone is identified to be the system of strike slip faults and reverse-oblique faults trending NNW along the Kola River valley. We used radiocarbon analysis and paleogeographic reconstructions and revealed three episodes of increased seismic activity: from 9500 to 10500 cal BP, from 892 to 1182 cal BP, and from 200 to 300 cal BP. Based on the peak ground velocity estimation method we suggest that an earthquakes with a maximum moment magnitude up to Mw ≈ 6.0–6.5 may have taken place in the studied area. The recorded location of seismogenic deformation near faults indicates area of strong Late Glacial and Holocene earthquakes occurring in the northern Kola Peninsula; this is also consistent with observations concerning the historical events of 1772 and 1873, which took place near the area.Combined with previous data on palaeoseismicity in Kola region, our studies indicate a longer lasting and more complex spatial and temporal history of postglacial seismicity in the Northeastern Fennoscandian Shield area. In contrast to the generally accepted opinion, strong seismic events occurred not only during the deglaciation period or immediately after it, but continued until the late Holocene and the last centuries. Glacial isostasy as a factor giving rise to stresses has become minimal by the present time, while the tectonic factor continues to be felt.

scholarly journals Late Glacial and Holocene changes in vegetation cover and climate in southern Siberia derived from a 15 kyr long pollen record from Lake Kotokel

2009 ◽  
Vol 5 (3) ◽  
pp. 285-295 ◽  
Author(s):  
P. E. Tarasov ◽  
E. V. Bezrukova ◽  
S. K. Krivonogov
Keyword(s):  
Late Glacial ◽  
Time Interval ◽  
Pollen Record ◽  
Time Intervals ◽  
Southern Siberia ◽  
Noticeable Increase ◽  
Modern Analogue ◽  
Quantitative Characteristics ◽  
Late Glacial And Holocene ◽  
Vegetation And Climate

Abstract. In this study a radiocarbon-dated pollen record from Lake Kotokel (52°47´ N, 108°07´ E, 458 m a.s.l.) located in southern Siberia east of Lake Baikal was used to derive quantitative characteristics of regional vegetation and climate from about 15 kyr BP (1 kyr=1000 cal. yr) until today. Quantitative reconstruction of the late glacial vegetation and climate dynamics suggests that open steppe and tundra communities predominated in the study area prior to ca. 13.5 kyr BP and again during the Younger Dryas interval, between 12.8 and 11.6 kyr BP. The pollen-based climate reconstruction suggests lower-than-present mean January (~−38°C) and July (~12°C) temperatures and annual precipitation (~270–300 mm) values during these time intervals. Boreal woodland replaced the primarily open landscape around Kotokel three times at about 14.8–14.7 kyr BP, during the Allerød Interstadial between 13.3–12.8 kyr BP and with the onset of the Holocene interglacial between 11.5 and 10.5 kyr BP, presumably in response to a noticeable increase in precipitation, and in July and January temperatures. The maximal spread of the boreal forest (taiga) communities in the region is associated with a warmer and wetter-than-present climate (Tw~17–18°C, Tc~−19°C, Pann~500–550 mm) that occurred ca. 10.8–7.3 kyr BP. During this time interval woody vegetation covered more than 50% of the area within a 21×21 km window around the lake. The pollen-based best modern analogue reconstruction suggests a decrease in woody cover percentages and in all climatic variables about 7–6.5 kyr BP. Our results demonstrate a gradual decrease in precipitation and mean January temperature towards their present-day values in the region around Lake Kotokel since that time.

scholarly journals Aspects of the Postglacial Climate of Alberta: Calibration of the Pollen Record

2007 ◽  
Vol 40 (2) ◽  
pp. 153-160 ◽  
Author(s):  
Robert E. Vance
Keyword(s):  
Growing Season ◽  
Late Glacial ◽  
Climatic Data ◽  
Pollen Record ◽  
Current Position ◽  
Middle Holocene ◽  
Modern Pollen ◽  
Vegetational Change ◽  
Calibration Equations ◽  
Herbaceous Pollen

ABSTRACT This reconstruction of the postglacial climate of Alberta is based on a review of pollen studies within the province and the application of calibration equations to a pollen record from central Alberta. Regional palynological studies indicate that the late glacial vegetation, dominated by non-arboreal taxa and, on occasion, Populus, was replaced by a Picea dominated assemblage between 12,000 and 10,000 BP. In central Alberta, increased herbaceous pollen representation suggests that grassland was established north of its current position in early to middle Holocene time. By 3500 BP, the grassland boundary had retreated southward. Little vegetational change is evident during the last 3500 years. Calibration equations, derived from modern pollen and climatic data in the western interior of Canada and applied to an 11,400 year pollen record, suggest growing season temperature was 1.5°C greater than at present while growing season precipitation was 50 mm below current values during the middle Holocene.

scholarly journals Holocene plant diversity dynamics shows a distinct biogeographical pattern in temperate Europe

2020 ◽  
Author(s):  
Jan Roleček ◽  
Vojtěch Abraham ◽  
Ondřej Vild ◽  
Helena Svitavská Svobodová ◽  
Eva Jamrichová ◽  
...  
Keyword(s):  
Plant Diversity ◽  
Late Holocene ◽  
Time Window ◽  
Fossil Pollen ◽  
Pollen Record ◽  
Diversity Patterns ◽  
The Holocene ◽  
Modern Pollen ◽  
Biogeographical Region ◽  
Temperate Europe

AbstractAimsReconstruction of the Holocene diversity changes in a biogeographically complex region. Description of major diversity patterns, testing their predictors, and their interpretation in the palaeoecological and biogeographical context. Testing the assumption that pollen record is informative with respect to plant diversity in our study area.MethodsFossil pollen extracted from 18 high-quality profiles was used as a proxy of past plant diversity. Pollen counts of tree taxa were corrected by pollen productivity, and pollen assemblages were resampled to 100 grains per sample and 150 grains per 500-years time window. SiZer analysis was used to test and visualize multi-scale diversity patterns. Linear modelling was used to identify the best predictors. SiZer maps and pollen composition were analysed using non-metric multidimensional scaling. K-means clustering and indicator species analysis were used to interpret ordination results.ResultsMean Holocene plant diversity is significantly predicted by latitude, while its temporal pattern followed the biogeographical region and elevation. Major differences were found between the Mesic and Montane Hercynia (lower diversity, increasing only in the Late Holocene) and Pannonia, the Carpathians and Warm Hercynia (higher diversity, increasing from the Early or Middle Holocene on). Low diversity in the Middle and Late Holocene is associated with the prevalence of woody and acidophilic taxa. High diversity is associated with numerous grassland and minerotrophic wetland taxa, crops and weeds. Fossil-modern pollen diversity and modern pollen-plant diversity show significant positive relationships.ConclusionsPlant diversity and its changes during the Holocene are geographically structured across temperate Europe. Main causes appear to be differences in past dynamics of the landscape openness and vegetation composition, driven mainly by changes in climate and human impact and their different timing. Fossil pollen, if appropriately treated, is a useful proxy of past plant diversity.

The postglacial history of three Picea species in New England, USA

2003 ◽  
Vol 59 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Matts Lindbladh ◽  
George L. Jacobson ◽  
Molly Schauffler
Keyword(s):  
New England ◽  
Late Holocene ◽  
Classification Tree ◽  
Population Expansion ◽  
Pollen Grains ◽  
Late Glacial ◽  
Early Holocene ◽  
Pollen Record ◽  
Recent Population Expansion ◽  
Picea Species

AbstractGiven the difficulty of separating the three Picea species—P. glauca, P. mariana, and P. rubens (white, black, and red spruce)—in the pollen record, little is known about their unique histories in eastern North America following deglaciation. Here we report the first use of a classification tree analysis (CART) to distinguish pollen grains of these species. It was successfully applied to fossil pollen from eight sites in Maine and one in Massachusetts. We focused on the late glacial/early Holocene (14,000 to 8000 cal yr B.P.) and the late Holocene (1400 cal yr B.P. to present)—the two key periods since deglaciation when Picea has been abundant in the region. The result shows a shift from a Picea forest of P. glauca and P. mariana in the late glacial to a forest of P. rubens and P. mariana in the late Holocene. The small number of P. rubens grains identified from the late glacial/early Holocene samples (<5%) suggests that that species was either absent or rare at most of the sites. The occurrence and distribution of the three species do not reveal any geographic or temporal trend during late glacial time, but the data suggest that they were distributed in local patches on the landscape. The results of this study indicate that the recent population expansion of Picea (1000 to 500 cal yr B.P.) was likely the first time since deglaciation that P. rubens was abundant in the region.

scholarly journals An ice-core pollen record showing vegetation response to Late-glacial and Holocene climate changes at Nevado Sajama, Bolivia

2013 ◽  
Vol 54 (63) ◽  
pp. 183-190 ◽  
Author(s):  
C.A. Reese ◽  
K.B. Liu ◽  
L.G. Thompson
Keyword(s):  
Ice Core ◽  
Late Glacial ◽  
Pollen Record ◽  
Vegetation Response ◽  
Sparse Vegetation ◽  
Ice Cap ◽  
Pollen Concentrations ◽  
Dry Conditions ◽  
High Concentrations ◽  
Late Glacial And Holocene

AbstractWe present the results of pollen analysis performed on an ice core recovered from Nevado Sajama, Bolivia, dated to 25 ka BP. Low pollen concentrations from 25 to 15 ka BP are consistent with the scenario of an expanded ice cap surrounded by sparse vegetation and cold conditions on the Altiplano during the Last Glacial Maximum. After 15 ka BP, more pollen is present and percentages show vegetation response to climate fluctuations during the late Pleistocene. Initially, high concentrations of Poaceae pollen are replaced by Asteraceae pollen, suggesting the occurrence of dry conditions towards the end of the Bølling–Allerød/Guantiva interstadial. A deglacial climatic reversal is registered in the pollen record by an abrupt decline in Asteraceae and maximum percentages of Poaceae, indicating wet conditions during 14–12 ka BP. The climate changed abruptly to warm and dry after 12 ka BP, but vegetation remained in disequilibrium with climate until 10 ka BP. Pollen results indicate dry conditions at the beginning of the Holocene, with humidity increasing steadily until 8.5 ka BP. Decreased pollen concentration values (used as a moisture availability proxy) place the mid-Holocene dry period between 8 and 5 ka BP. This was followed by wetter conditions to the present day.

Evolution of a debris-covered glacier in the Kerguelen Archipelago (49°S, 69°E) over the past 15,000 years constrained by in situ cosmogenic 36Cl dating

2021 ◽  
Author(s):  
Vincent Jomelli ◽  
Joanna Charton ◽  
Irene Schimmelpfennig ◽  
Deborah Verfaillie ◽  
Vincent Favier ◽  
...  
Keyword(s):  
Late Holocene ◽  
Ice Cores ◽  
Late Glacial ◽  
Substantial Part ◽  
Individual Response ◽  
Specific Response ◽  
Ice Dynamics ◽  
Late Glacial And Holocene ◽  
Kerguelen Archipelago

&lt;p&gt;Debris-covered glaciers constitute a substantial part of the worldwide cryosphere (Scherler et al. 2018). However, their long-term response to multi-millennial climate variability has rarely been studied, in particular in the Southern Hemisphere. The presence of both debris-covered and debris-free glaciers on Kerguelen Archipelago (49&amp;#176;S, 69&amp;#176;E) offers therefore an excellent opportunity to investigate and compare long-term evolution of these two types of glaciers. To do so, we used the cosmogenic &lt;sup&gt;36&lt;/sup&gt;Cl surface dating method on moraine boulders that allows to establish temporal constraints of glacier oscillation. We provide here the first Late Glacial and Holocene glacier chronology of a still active debris-covered glacier from the archipelago: the Gentil Glacier. Results show that the Gentil Glacier advanced once at ~14.3 ka, i.e. during the Late Glacial (19.0 &amp;#8211; 11.6 ka), and re-advanced during the Late Holocene at ~2.6 ka (Charton et al., 2020). Both debris-covered and debris-free glaciers experienced a broadly synchronous advance during the Late Glacial, that may be assigned to the Antarctic Cold Reversal event (14.5 &amp;#8211; 12.9 ka) (Jomelli et al., 2017; 2018). This suggests that both types (debris-covered and debris-free) of glaciers at Kerguelen were sensitive to large amplitude temperature fluctuations recorded in Antarctic ice cores (WAIS divide Project Members, 2013), associated with increased precipitations (Van der Putten, 2015). However, during the Late Holocene, the advance at about ~2.6 ka was not observed on other glaciers and seems to be a specific response of the debris-covered Gentil Glacier, either related to distinct ice dynamics or an individual response to precipitation changes.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Charton et al., 2020 : Ant. Sci. 1-13&lt;/p&gt;&lt;p&gt;Jomelli et al., 2017 : Quat. Sci. Rev. 162, 128-144&lt;/p&gt;&lt;p&gt;Jomelli et al., 2018 : Quat. Sci. Rev. 183, 110-123&lt;/p&gt;&lt;p&gt;Scherler et al., 2018 : GRL. 45, 11,798-11,805&lt;/p&gt;&lt;p&gt;Van der Putten et al., 2015&amp;#160;: Quat. Sci. Rev. 122, 142-157&lt;/p&gt;&lt;p&gt;WAIS Divide Project Members, 2013: Nature. 500, 440-444&lt;/p&gt;

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