scholarly journals A Sixteen Thousand Year Old Organic Deposit, Northern Baffin Island, N.W.T., Canada: Palynology and Significance

2007 ◽  
Vol 42 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Susan K. Short ◽  
John T. Andrews
Keyword(s):  
Baffin Island ◽  
Pollen Assemblage ◽  
Radiocarbon Dates ◽  
Pollen Types ◽  
Rapid Accumulation ◽  
Terrestrial Sediments ◽  
Organic Deposit

ABSTRACT A 3 m exposure of sediment containing organics was sampled near the settlement of Arctic Bay, Baffin Island, N.W.T. A total of seven radiocarbon dates have been obtained from the deposit. Three dates between 182.5 and 290 cm depth gave radiocarbon ages between 14,185 ± 760 and 16,849 ± 860. A date from 82.5 to 87.5 cm resulted in an age of 8635 ± 565. An apparent reversal in 14C dates may reflect folding of the sediments associated with the downslope creep of the deposit or rapid accumulation of organics. The three basal dates are the first terrestrial sediments from Baffin Island to date from older than ca. 10,000 BP and less than 20,000 BP. Analysis of the sediment for pollen indicated that it is generally sparse. The pollen assemblage is dominated by Salix, Cyperaceae, and Gramineae pollen and exotic pollen types {Pinus, Picea, Betula, and Alnus) occur sporadically throughout the section.

The last interglacial–glacial cycle, Clyde foreland, Baffin Island, N.W.T.: stratigraphy, biostratigraphy, and chronology

1977 ◽  
Vol 14 (12) ◽  
pp. 2824-2857 ◽  
Author(s):  
G. H. Miller ◽  
J. T. Andrews ◽  
S. K. Short
Keyword(s):  
Amino Acid ◽  
Marine Sediments ◽  
Baffin Island ◽  
Buried Soils ◽  
Last Interglacial ◽  
Pollen Assemblage ◽  
Outlet Glacier ◽  
Radiocarbon Dates ◽  
Last Glaciation

A study of the stratigraphic sequence (14C and amino acid age control), marine bivalve faunal changes, and palynology of buried soils and organic-rich sediment collected from the Clyde Foreland Formation in the extensive cliff sections of the Clyde foreland, eastern Baffin Island, N.W.T., suggests the following last interglacial – Foxe (last glaciation) glacial – present interglacial sequence.(1) Cape Christian Member (ca. 130 000 years BP?)Consists of the Sledgepointer till overlain by the Cape Christian marine sediments. In situ molluscan fauna, collected from the marine sediments, contain a moderately warm bivalve assemblage. A well-developed soil that formed on the marine sediments (Cape Christian soil) contains an interglacial pollen assemblage dominated by dwarf birch. U-series dates of > 115 000 and ca. 130 000 years BP on molluscs from the Cape Christian marine sediments suggest that they were deposited during the last interglaciation, here termed the Cape Christian Interglaciation. The development of a subarctic pollen assemblage in the Cape Christian soil has not been duplicated during the present interglaciation, suggesting higher summer temperatures and perhaps a duration well in excess of 10 000 years for the last interglaciation.(2) Kuvinilk MemberConsists of fossiliferous marine sediments, locally divided by the Clyde till into upper and lower units. The Clyde till was deposited by the earliest and most extensive advance of the Foxe (last) Glaciation. Kuvinilk marine sediments both under- and overlying the Clyde till contain the pecten Chlamys islandicus, indicating that the outlet glacier advanced into a subarctic marine environment. Amino acid ratios from in situ pelecypod shells abovę and below the Clyde till are not statistically different, but contrast markedly with ratios obtained from the same species in the Cape Christian Member. Organic horizons within the Kuvinilk marine sediments contain a relatively rich pollen assemblage, although 'absolute' counts are low.(3) Kogalu Member (> 35 00014C years BP)Sediments of the Kogalu Member unconformably overlie those of the Kuvinilk Member, but are of a similar character. The dominant sediments are marine in origin, but in places are divided into upper and lower units by the Ayr Lake till. Amino acid ratios from in situ shells above and below the Ayr Lake till are indistinguishable, but substantially less than those in the Kuvinilk Member, suggesting the two members are separated by a considerable time interval. Radiocarbon dates on shells in the Kogalu marine sediments range from 33 000 to 47 700 years BP, but these may be only minimum estimates. The sea transgressed to a maximum level 70–80 m asl, coincident with the glacial maximum. Subarctic marine fauna of interstadial–interglacial character occur within the Kogalu marine sediments.(4) Eglinton Member (10 000 years BP to present)A major unconformity exists between the Kogalu and Eglinton Members. Ravenscraig marine sediments were deposited during an early Holocene marine transgression–regression cycle; the oldest dates on these sediments are ca. 10 000 years BP. Locally a vegetation mat occurs at the base or within the Ravenscraig unit. Pollen from these beds is sparse, but indicates a terrestrial vegetation assemblage as diverse as that of today. There is no evidence that Laurentide Ice reached the foreland during the last 30 000 years. Eolian sands that overlie a soil developed on the marine sediments record a late Holocene climatic deterioration. Pollen in organic-rich sediments at the base of, and within, the eolian sands record a vegetation shift in response to climatic change.

An Insect Assemblage of Early Flandrian Age from Lea Marston, Warwickshire, and its Bearing on the Contemporary Climate and Ecology

1974 ◽  
Vol 4 (4) ◽  
pp. 471-486 ◽  
Author(s):  
P.J. Osborne
Keyword(s):  
Pollen Assemblage ◽  
Insect Fauna ◽  
Radiocarbon Dates ◽  
Deciduous Woodland ◽  
Oceanic Climate ◽  
South Sweden ◽  
Contemporary Climate ◽  
Insect Assemblage ◽  
Alluvial Clay ◽  
Organic Deposit

An extensive insect fauna is described from an organic deposit occurring in a gravel pit at Lea Marston, Warwickshire, England. This organic deposit was lying beneath approximately 2.5 m of alluvial clay and directly above gravels which had provided organic material 14C dated at 11,700 ± 200 yr BP. The insect fauna was indicative of a temperate oceanic climate similar to that found today in southern England or south Sweden and suggested the presence of deciduous woodland. The six radiocarbon dates, however, agreed in giving the deposit an age of around 9500 yr BP which is earlier than the arrival of the principal broad-leaved trees. The pollen assemblage was consistent with the radiocarbon dates in showing, in addition to herbaceous pollen, only the presence of Betula, Salix, and small amounts of Pinus. As the insect faunas known from midland Britain at the close of the Devensian period, barely 500 yr before, are arctic in aspect and entirely devoid of thermophilous species a very rapid climatic amelioration is postulated which permitted the immigration of the very mobile insect fauna well in advance of the more slowly migrating trees.

The Use of Ecological Tolerances for the Reconstruction of Tertiary Palaeoclimates

1997 ◽  
Vol 45 (3) ◽  
pp. 475 ◽  
Author(s):  
Helene A. Martin
Keyword(s):  
Vegetation Types ◽  
Climatic Parameters ◽  
Salt Tolerant ◽  
Pollen Assemblage ◽  
Pollen Types ◽  
Living Species ◽  
Marine Influence ◽  
Lagarostrobos Franklinii ◽  
Single Living ◽  
Very High

The major vegetation types may be recognised from the pollen assemblage being deposited beneath them, hence the palaeovegetation may be reconstructed from fossil pollen assemblages. The climatic parameters of the vegetation may then be used to reconstruct palaeoclimates. The result, however, is very general. Most pollen types can only be affiliated with a family, a genus or a group of species and the ecological tolerances within these groups may not be uniform. There are, however, some distinctive pollen types that can be identified with a single living species and this paper examines the potential of these types in the reconstruction of palaeoclimates. Lagarostrobos franklinii (J.D.Hook) Quinn, Huon pine, has a long history and the fossil occurrences of it are compatible with the hypothesis that its ecological tolerances have not changed and it has always required very high humidity. Two sclerophyllous taxa,Eucalyptus spathulata Hook. and Dodonaea triquetra Wendl., however, coexisted with rainforest and then other vegetation types as the climate became drier, adapting to the prevailing conditions. The evidence suggests that the salt-tolerant E. spathulata may have evolved in small patches of coastal scrub, subjected to marine influence, within the dominant rainforest vegetation.

scholarly journals Episodic Neoglacial expansion and rapid 20th century retreat of a small ice cap on Baffin Island, Arctic Canada, and modeled temperature change

2017 ◽  
Vol 13 (11) ◽  
pp. 1527-1537 ◽  
Author(s):  
Simon L. Pendleton ◽  
Gifford H. Miller ◽  
Robert A. Anderson ◽  
Sarah E. Crump ◽  
Yafang Zhong ◽  
...  
Keyword(s):  
Temperature Change ◽  
Climate Model ◽  
Ice Age ◽  
The Arctic ◽  
Baffin Island ◽  
Radiocarbon Dates ◽  
The Past ◽  
Ice Cap ◽  
Climate Model Simulations ◽  
Glacier Advance

Abstract. Records of Neoglacial glacier activity in the Arctic constructed from moraines are often incomplete due to a preservation bias toward the most extensive advance, often the Little Ice Age. Recent warming in the Arctic has caused extensive retreat of glaciers over the past several decades, exposing preserved landscapes complete with in situ tundra plants previously entombed by ice. The radiocarbon ages of these plants define the timing of snowline depression and glacier advance across the site, in response to local summer cooling. Erosion rapidly removes most dead plants that have been recently exposed by ice retreat, but where erosive processes are unusually weak, dead plants may remain preserved on the landscape for decades. In such settings, a transect of plant radiocarbon ages can be used to construct a near-continuous chronology of past ice margin advance. Here we present radiocarbon dates from the first such transect on Baffin Island, which directly dates the advance of a small ice cap over the past two millennia. The nature of ice expansion between 20 BCE and ∼ 1000 CE is still uncertain, but episodic advances at ∼ 1000 CE, ∼ 1200, and  ∼ 1500 led to the maximum Neoglacial dimensions ~ 1900 CE. We employ a two-dimensional numerical glacier model calibrated using the plant radiocarbon ages ice margin chronology to assess the sensitivity of the ice cap to temperature change. Model experiments show that at least ∼ 0.44 °C of cooling over the past 2 kyr is required for the ice cap to reach its 1900 CE margin, and that the period from ∼ 1000 to 1900 CE must have been at least 0.25° C cooler than the previous millennium, results that agree with regional temperature reconstructions and climate model simulations. However, significant warming since 1900 CE is required to explain retreat to its present position, and, at the same rate of warming, the ice cap will disappear before 2100 CE.

Climate change and human disturbance of fynbos vegetation during the late Holocene at Princess Vlei, Western Cape, South Africa

The Holocene ◽  
2011 ◽  
Vol 21 (7) ◽  
pp. 1137-1149 ◽  
Author(s):  
F.H. Neumann ◽  
L. Scott ◽  
M.K. Bamford
Keyword(s):  
Anthropogenic Disturbance ◽  
Late Holocene ◽  
Climate Changes ◽  
Western Cape ◽  
Radiocarbon Dates ◽  
The Core ◽  
Pollen Types ◽  
Hydrological System ◽  
Vegetation And Climate ◽  
Floating Mat

Pollen analysis of a core in Princess Vlei in the Fynbos Biome near Cape Town gives a 4150 year record of vegetation and climate changes followed by disturbance by colonial settlers since c. 300 years ago. Their impact replaced climate as a major factor in changing the vegetation. The chronology is based on eight radiocarbon dates. Pollen types such as Restionaceae, Ericaceae, and Proteaceae reflect changes in fynbos. Pollen indicators at the bottom of the core suggest drier conditions followed by an increase in Morella, Cyperaceae and Carpacoce pollen, which might indicate moist conditions c. 3400–2600 cal. yr BP. Drier conditions prevail c. 2600–1900 cal. yr BP. Apparent light disturbance after c. 2000 cal. yr BP might be attributed to Khoi herders. Deeper water and damp surroundings are indicated c. 1900–1000 cal. yr BP. The top of the core shows an increase of Poaceae while Restionaceae decrease with anthropogenic disturbance, including the introduction of neophytes such as Pinus ( c. 300 years ago) and Zea mays. Charcoal percentages point to intense fires after the arrival of the Europeans. Water between 105 and 75 cm indicates the development of a floating mat resulting from changes in the hydrological system possibly connected to disturbances by settlers.

Spatial patterns of modern diatom distribution and multiple paleolimnological records from a small arctic lake on Baffin Island, Arctic Canada

1996 ◽  
Vol 74 (3) ◽  
pp. 435-449 ◽  
Author(s):  
Alexander P. Wolfe
Keyword(s):  
Late Holocene ◽  
Baffin Island ◽  
Diatom Assemblages ◽  
Arctic Canada ◽  
Habitat Specificity ◽  
Radiocarbon Dates ◽  
Numerous Species ◽  
Sediment Reworking ◽  
Clear Differentiation ◽  
Lake Ontogeny

The assumption that within-lake, deep-water sedimentary diatom assemblages are relatively uniform and that a single core is sufficient to depict lake ontogeny was tested for a small tarn on the southwestern Cumberland Peninsula of Baffin Island, Northwest Territories. Diatom transport and deposition were evaluated through analyses of periphytic, planktonic, and epipelic habitats. Diatom stratigraphies of four cores were used to test whether or not trends are comparable in different regions of the lake and throughout the Holocene. Among 12 surface-sediment stations, diatom distributions were alternately highly equitable or variable. Valves of evenly distributed genera (Aulacoseira and Achnanthes) are mixed in the water column prior to deposition. This is supported by plankton tow and periphyton samples, which were respectively dominated by Aulacoseira distans (and varieties) and Achnanthes altaica. Conversely, frequencies of several benthic taxa (e.g., Pinnularia biceps, species of Eunotia) varied up to 30% between stations, in patterns unrelated to water depth, and reflecting habitat specificity and minimal transport prior to burial. Of the four cores (38.0–95.5 cm), analysis of the two longest revealed three distinct zones: (i) a zone dominated by species of Fragilaria (> 9000 BP); (ii) a zone containing benthic acidophilic diatoms indicating natural acidification (9000–7000 BP); and (iii) a zone characterized by numerous species of Aulacoseira ranging from the mid to late Holocene. Clear differentiation of the lower two zones was impossible in the shorter cores, and radiocarbon dates suggest that sediment reworking truncated the earliest records of organic sedimentation at these sites. Correspondence analysis facilitated comparisons of the diatom stratigraphies and enabled the evaluation of core reproducibility. Central cores preserve the most useful paleolimnological records in this environment. Keywords: diatoms, paleolimnology, Arctic Canada, Baffin Island.

A 1100 year paleoclimatic record from Burton Bay – Tarr Inlet, Baffin Island

1982 ◽  
Vol 19 (3) ◽  
pp. 398-409 ◽  
Author(s):  
Susan K. Short ◽  
John D. Jacobs
Keyword(s):  
Grass Pollen ◽  
Baffin Island ◽  
Pollen Data ◽  
Pollen Assemblage ◽  
Bay Area ◽  
Pollen Records

Pollen studies were carried out in the upper Frobisher Bay area, Baffin Island, as part of joint paleoenvironmental–archaeological investigations in the area. Pollen data from southern Baffin Island are rare, and this paper expands this record.A shallow peat section and several recent pollen records are presented. They suggest a contrast between an earlier assemblage, dated 2000–1650 BP, which was characterized by a rich, diverse flora, especially birch shrubs, and a subsequent pollen assemblage dominated by grass pollen and interpreted as representing colder and drier conditions to 900 BP.

Holocene pollen assemblages from the Tiger Hills, Manitoba

1968 ◽  
Vol 5 (4) ◽  
pp. 873-880 ◽  
Author(s):  
J. C. Ritchie ◽  
Sigrid Lichti-Federovich
Keyword(s):  
Deciduous Forest ◽  
Pollen Assemblage ◽  
The Holocene ◽  
Radiocarbon Age ◽  
Arboreal Pollen ◽  
Pollen Types ◽  
Weedy Species ◽  
Zone Ii ◽  
Shepherdia Canadensis ◽  
Age Determinations

Coring of three kettle lakes in the moraine area known as the Tiger Hills, Manitoba, yielded sections of sediment which span the Holocene for this region. Detailed pollen analysis of two of the sections suggests five main pollen assemblage zones for the Holocene, numbered I to V from above. Zone V is interpreted as a spruce-dominated vegetation associated with such pioneering species as Shepherdia canadensis and Artemisia, a type found at present as local fragments and having no regional equivalent. Zone IV also has no analogue among recent pollen spectra, and is interpreted as a mosaic of mixed coniferous–broadleaved deciduous forest stands, and extensive scrub with Juniperus and grassland. Zone III is dominated by non-arboreal pollen types and suggests grassland, while Zone II has an oak component, which indicates a savanna type. Zone I is the modern assemblage, with prominent representation by weedy species. Radiocarbon age determinations suggest that the area was occupied by the Zone V assemblage from about 12 800 B.P.

scholarly journals Variability of pollen aperture heteromorphism in annual pansies (Viola Section Melanium)

2015 ◽  
Vol 74 (1) ◽  
pp. 43-52 ◽  
Author(s):  
Sara Magrini ◽  
Anna Scoppola
Keyword(s):  
Pollen Grains ◽  
Perennial Species ◽  
Pollen Assemblage ◽  
Significant Variability ◽  
Pollen Types ◽  
Pollen Heteromorphism

Abstract Pollen heteromorphism is frequent in the section Melanium of the genus Viola, in which over 80% of the species produces pollen morphs with 3 to 6 apertures. Some authors have pointed out that many factors can affect the proportion of the different pollen types in perennial species, and that this proportion can change among populations. This work focuses on the study of the polymorphic pollen assemblage of three annual pansies: Viola arvensis, V. kitaibeliana, and V. hymettia, and on the assessment of its variability both within a population and within the same plant. In all the species, with both large and small flowers, 3-, 4- and 5-aperturate pollen grains were observed, with a large prevalence of 4-aperturate types. No pollen grains with 6 apertures were found. No significant variability of the pollen assemblage among flowers of the same plant was observed. In addition, in these three Viola species the frequencies of the various pollen morphs are also fairly constant among plants of the same population.

scholarly journals Introduction to the Special Issue: Correlating changes for environmental, technological and societal transformation in prehistoric eastern Asia

The Holocene ◽  
2020 ◽  
pp. 095968362097025
Author(s):  
Ruiliang Liu ◽  
Guanghui Dong ◽  
Minmin Ma ◽  
A. Mark Pollard
Keyword(s):  
Environmental Science ◽  
Animal Husbandry ◽  
Local Environment ◽  
Agricultural Practice ◽  
Social Changes ◽  
Special Issue ◽  
Societal Transformation ◽  
Radiocarbon Dates ◽  
Disciplinary Boundaries ◽  
Rapid Accumulation

Identifying and explaining changes in the prehistoric material and social world is one of the greatest research interests in archaeology, palaeoclimate and environmental science. In the last two decades or so, a considerable number of studies have made significant contributions to the associated disciplines in eastern Asian archaeology. However, due to the more specialised scientific approaches and the rapid accumulation of new excavation materials, it becomes increasingly difficult for scholars to examine and correlate research outputs from different areas and achieve a holistic picture of the past. Using eastern Asian archaeology as an example, this Special Issue aims to break down the disciplinary boundaries and present the current research debate on how to correlate different climate, environmental and social changes and explain human past. One of the fundamental issues is the lack of adequate chronological resolution to order various archaeological events. To tackle this, a large number of radiocarbon dates, primarily derived from short- lived materials, are provided in the Special Issue. A great variety of changes in local environment, agricultural practice, animal husbandry, technologies, migration, demography and social organisations are revealed in the following papers but there are two profound drivers to all of these changes. One is the broad climate change since the start of the Holocene and the other is the communication between the West and the East.

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