The developmental history of peatlands at Muskiki and Marguerite lakes, Alberta

1989 ◽  
Vol 67 (12) ◽  
pp. 3534-3544 ◽  
Author(s):  
Helen Kubiw ◽  
Michael Hickman ◽  
Dale F. Vitt
Keyword(s):  
Species Composition ◽  
Radiocarbon Dating ◽  
Environmental Changes ◽  
Warm Period ◽  
Vegetation Changes ◽  
Developmental History ◽  
Peat Accumulation ◽  
Fire Activity ◽  
History Of ◽  
Peat Stratigraphy

The peat stratigraphy of fens at Muskiki Lake (52°50′N, 116°51′W) and Marguerite Lake (54°38′N, 110°43′W) in central Alberta was examined to determine the developmental history of the fens on the basis of radiocarbon dating and bryophyte macrofossil analyses. Peat accumulation at Muskiki Lake peatland began about 9000 years BP via lake filling. Expansion of the peatland by paludification and vegetation changes, including string and flark formation, are secondary occurrences, the latter occurring subsequent to environmental changes, including mid-Holocene thermal events. Peat inception at Marguerite Lake began about 2400 years BP via paludification. This delay, relative to Muskiki Lake peatland, may be related to the mid-Holocene warm period. Fire activity and increased wetness, as well as autogenic successional processes, altered species composition and abundance.

Stratigraphy and genesis of the Lake Sixteen peatland, northern Michigan

1986 ◽  
Vol 64 (12) ◽  
pp. 3008-3019 ◽  
Author(s):  
Richard P. Futyma ◽  
Norton G. Miller
Keyword(s):  
Basal Layer ◽  
Developmental History ◽  
Peat Accumulation ◽  
Hydrological Changes ◽  
Alkaline Lake ◽  
Temporal Relationships ◽  
History Of ◽  
Northern Michigan

The Lake Sixteen peatland is a 400-ha mire consisting principally of low-shrub (Chamaedaphne) bog and lesser areas of tree-covered (Picea – Larix) bog and sedge fen adjacent to a 55-ha alkaline lake. The sediments consist of the following superimposed deposits: gyttja, sedge peat, and Sphagnum–ericad–sedge peat. Near the edges of the peatland, highly humified, sometimes woody peat is present as the basal layer instead of gyttja. Radiocarbon-dated pollen stratigraphies from the lake and four sites in the peatland have elucidated the temporal relationships of the various sediment units and the developmental history of the peatland. During the mid-Holocene, probably in response to a change to cooler, moister climate, early Lake Sixteen underwent an expansion resulting in the deposition of gyttja over an increasingly larger area. About 3000 years BP, a sedge fen developed on the edge of the lake. Low-shrub bog replaced the sedge vegetation as the fen mat expanded into the lake. Swamping of bordering forests also allowed expansion of bog vegetation outward from the basin. Hydrological changes accompanying peat accumulation probably promoted vegetational changes within the peatland and the centrifugal spread of bog vegetation through swamping.

Postglacial vegetational history of Tonquin Pass, British Columbia

1983 ◽  
Vol 20 (5) ◽  
pp. 776-786 ◽  
Author(s):  
M. S. Kearney ◽  
B. H. Luckman
Keyword(s):  
British Columbia ◽  
National Park ◽  
Pinus Contorta ◽  
Radiocarbon Dating ◽  
Climatic Changes ◽  
Warm Period ◽  
Canadian Rockies ◽  
Jasper National Park ◽  
History Of ◽  
Cool Conditions

A pollen and macrofossil study of peat sediments in Tonquin Pass, British Columbia provides the oldest dated record of vegetational and climatic changes in the middle Canadian Rockies. Paleoecological interpretation of these events dated by tephrochronology and radiocarbon dating is facilitated by comparisons with other regional pollen profiles.Late Wisconsin ice receded from Tonquin Pass prior to 10 000 years BP. By 9700 years BP a Pinus contorta forest with an understory dominated by ferns had colonized the area. The climate of this period was cool and moist. Following this interval was a brief episode (9000–8040 years BP) of haploxylon pine dominance during which the climate became colder. A long warm period beginning by 8040 years BP was characterized by desiccation of local meadows and fens and invasions of these areas by trees, principally Picea. Dated fossil Picea and Abies logs from alpine bogs within Jasper National Park document that timberlines had advanced beyond present limits by 8770 years BP. These data indicate a considerable lag in the registration of this interval in the Tonquin record.During the last 4300 years the retreat of trees from meadows and increases in the representation of several alpine taxa indicate that generally moist and cool conditions have prevailed. Evidence for Holocene timberline fluctuations in the Jasper area suggests an overall lowering in timberline elevation and further cooling since 1700 years BP.

Studies in the vegetational history of Scotland IV. Pine stumps in Scottish blanket peats

1975 ◽  
Vol 270 (905) ◽  
pp. 181-226 ◽  
Keyword(s):  
Pollen Analysis ◽  
Radiocarbon Dating ◽  
Upland Forest ◽  
Pollen Diagrams ◽  
Blanket Peat ◽  
History Of ◽  
Peat Stratigraphy

The palaeoecology of six Scottish blanket peat profiles containing pine stumps was investigated by means of peat stratigraphy, pollen analysis, and radiocarbon dating. In addition, several other pine and birch remains from peat in other areas of Scotland were radiocarbon dated. Three peat profiles were selected in each of two contrasting regions. The Cairngorm area is within the distributional area of native pine today and pollen analysis has shown that pine has been a major component of the upland forest since about 7000 b.p. The Galloway region in southwest Scotland is south of the native pine area, and pollen analysis has shown that pine has never been a major component of the upland forest. Despite the limitations of the methods used, it has been established that there were several different circumstances for the growth and death of the pines studied, and that their ages are asynchronous within and between the two areas. Thus little regional climatic significance can be assumed from their occurrence, and they cannot be taken as evidence in support of dry Boreal and sub-Boreal periods in the Blytt and Sernander climatic scheme. In the northwest Highlands dates from pine stumps and major declines of pollen in pollen diagrams are consistently around 4000 b.p. This overall demise of pine may have a regional climatic cause in this area.

Origin of a postglacial kettle-fill sequence near Georgetown, Ontario

1991 ◽  
Vol 28 (12) ◽  
pp. 1965-1974 ◽  
Author(s):  
Barry G. Warner ◽  
Helen J. Kubiw ◽  
Paul F. Karrow
Keyword(s):  
Plant Communities ◽  
Fossil Record ◽  
Radiocarbon Dating ◽  
Developmental History ◽  
Wetland Plant ◽  
Pollen Diagram ◽  
Wetland Plant Communities ◽  
Kettle Hole ◽  
History Of ◽  
Fossil Records

Stratigraphic relationships, radiocarbon dating, and pollen and plant macrofossil analyses establish the origin and developmental history of a kettle near Georgetown, Ontario. The early inorganic sediments contain redeposited fossils, particularly from local vegetation. Fossils in peat younger than 10 000 BP largely represent past wetland plant communities in the basin. Although the fossil record probably began about 1300 years after deglaciation of the site, an additional 1700 years passed before the dead ice block melted; only then did sedimentation and biological activity stabilize in the basin and produce an accurate fossil record of past vegetation. Truncated fossil records, illustrated further here by a pollen diagram from nearby Heart Lake, should be expected from kettle-hole deposits, and the radiocarbon ages and fossils from the earliest parts of such sequences should be interpreted with caution.

Peat isotopic composition of a deep deposit of palsa mire for the reconstruction of environmental changes in permafrost domain of Northern Siberia

2021 ◽  
Author(s):  
Prokushkin Anatoly ◽  
Novenko Elena ◽  
Kupryanov Dmitry ◽  
Serikov Sergey
Keyword(s):  
Isotopic Composition ◽  
Radiocarbon Dating ◽  
Environmental Changes ◽  
Vegetation Changes ◽  
Northern Siberia ◽  
Plant Macrofossil ◽  
Peat Core ◽  
The Past ◽  
Diagenetic Alteration ◽  
C And N

<p>Palsa peatlands are a significant carbon pool in Northern hemisphere which is subjected to change due to accelerated permafrost thaw and peat decomposition with progressing global warming. On the other hand, peat deposits of palsas serve as an important conduit of information about variability of environment conditions in the past millennia and respective vegetation changes. In our study we applied the multi-proxy record to distinguish variation in hydrothermal regimes of palsa peatland in Northern Siberia and to trace the likely diagenetic alteration of accumulated peat.</p><p>The study site is located 10 km North-East of Igarka settlement (67<sup>o</sup>31’ N, 86<sup>o</sup>38’E) within the area underlain discontinuous permafrost. The peat core was obtained in the central intact part of elevated (ca. > 3.5 m above surrounding hollows) dry hummock. The active layer, thawed seasonally layer, at the coring site was about 0.6 m. The entire depth of peat deposit was 8.6 m, but interrupted with several relatively thin (0.1-0.2 m) ice-rich lenses. Thawed and frozen peat samples of 0.5-5.0 cm thickness (mean = 2.8 cm) were collected at 2.5-12.0 cm step (mean =5.4 cm) depending on the amount of peat material. Collected samples (n = 160) after drying at 60<sup>o</sup>C for 48 h were subjected to the analysis for C and N content, stable isotopic composition of C and N. These measurements will further accompany radiocarbon dating, loss on ignition, plant macrofossil and macro charcoal analyses.</p><p>The analyzed 8.6 m deep peat core demonstrated the large variation of C (17.3-54.7%) and N (0.37-3.26 %) contents as well as C:N ratios (14-134). The isotopic depth profile was in the range from -24.51 to -34.31 ‰ for d<sup>13</sup>C and from -1.77 to 6.96 ‰ for d<sup>15</sup>N. The highest enrichment in <sup>15</sup>N (2.69±1.60 ‰ d<sup>15</sup>N) was found in seasonally thawed layer (≤0.6 m). A layer close to the bottom (6.9-8.3 m) contained peat the most depleted by <sup>13</sup>C (<-30 ‰ d<sup>13</sup>C). Meanwhile, along the peat profile depth we detected significant fluctuations in these parameters suggesting the different periods with specific environmental conditions.</p><p>Further combined with radiocarbon dating and plant macrofossil analyses we will attempt to capture the changes occurred during the past epochs in an input matter (vegetation changes and/or its productivity), decomposition rates as well as hydrothermal regimes and permafrost processes like aggradation (e.g. hummock uplift and cryoturbation) and degradation (e.g. hummock collapse, shifts from minerotrophic to ombrotrohic conditions and vice versa).</p><p>This work was supported by the Russian Science Foundation, project № 20-17-00043.</p>

The role of climate on the developmental history of Frontenac Peatland, southern Quebec

2000 ◽  
Vol 78 (5) ◽  
pp. 668-684 ◽  
Author(s):  
Martin Lavoie ◽  
Pierre JH Richard
Keyword(s):  
Lake Level ◽  
Elevated Temperatures ◽  
Accumulation Rate ◽  
Critical Factor ◽  
Accumulation Rates ◽  
Developmental History ◽  
Peat Accumulation ◽  
Lake Water Level ◽  
History Of

The developmental stages, hydrological conditions, and net peat accumulation rates at three coring sites of Parc de Frontenac Peatland (Quebec) were reconstructed to examine the role of climate on peat accumulation. During the early to mid-Holocene, elevated temperatures proved to be a more critical factor for sustained peat production than precipitation, because peatland development occurred mostly under a dry climate according to a low lake-level stage lasting from 11 000 to 7000 calibrated (cal.) BP in a nearby lake. Between 7000 and 6000 cal. BP, elevated net peat accumulation rates roughly correspond with a rise in lake water level, suggesting that higher precipitation and (or) less evapotranspiration then favored peat growth. A decrease in peat accumulation occurred from 5000 to 2500-1500 cal. BP, while the lake level was high from 4400 cal. BP. An important increase in net peat accumulation rate is recorded for this entire peatland from 1500 cal. BP. Lack of close timing between lake level changes and changes in peat accumulation rates or surface hydrology suggest that temperature and autogenic processes were often more important than regional water balance in the developmental history of the peatland.Key words: peatlands, paleohydrology, pollen, plant macrofossils, rhizopods, Quebec.

scholarly journals Environmental change in Danish marine waters during the Roman Warm Period inferred from mollusc data

2007 ◽  
Vol 13 ◽  
pp. 21-24 ◽  
Author(s):  
Peter Rasmussen ◽  
Kaj Strand Petersen ◽  
David B. Ryves
Keyword(s):  
Cultural History ◽  
Environmental Changes ◽  
Plant Macrofossils ◽  
Warm Period ◽  
Sea Level Changes ◽  
Spatial And Temporal Patterns ◽  
Modern Times ◽  
Postglacial History ◽  
First Results ◽  
History Of

Modern geological research into the late and postglacial history of the inner Danish waters (i.e. Kattegat, Bælthavet and Øresund, plus the adjoining fjords and estuaries) began at the turn of the last century. Since then most investigations have focused on the timing of the initial marine inundation of the area, the early to mid-Holocene changes in land–sea confi- guration and sea level changes during the mid-Holocene Littorina period. Research on the late Holocene marine environment has received less emphasis, undoubtedly due to problems in finding continuous marine sediment records, as sedimentation in large areas of the Danish waters seems to have been characterised by complex spatial and temporal patterns of deposition and non-deposition (e.g. Lykke-An dersen et al. 1993). In an ongoing project we aim to ex- plore the continuous development of Dan ish coastal environments over the last 9000 years using a variety of proxy data, including molluscs, dia toms, foramini fera, algal pigments, plant macrofossils and physical properties of sedi ments. The project spans both environmental and cultural history, and addresses the important links between them, as the nature of the coastal environment has exerted major influences on cultural and societal expression and activity from Mesol ithic to modern times. This paper presents some of the first results from the project concerning environmental changes in the Roman Warm Period (c. 2000–1600 years B.P.) as shown by changes in molluscan faunas at two coring sites in Horsens Fjord and Tem pelkrog in southern Isefjord (Fig. 1).

Sign in / Sign up

Export Citation Format

Share Document