Importance of the Radiocarbon Standard Deviation in Determining Relative Sea Levels and Glacial Chronology from East Baffin Island

Deals with the problem of error in estimating relative sea levels and glacial chronology in a small area where radiocarbon dates provide some chronological order, but where the precision of radiometric technique does not allow a clear-cut chronology to be developed on that basis alone. An equation is presented to predict postglacial uplift which is defined as the algebraic sum of the equation of the marine limit and the appropriate eustatic sea level correction. Using the head of Ekalugad Fiord as an example, author constructs postglacial uplift and emergence curves on the basis of the equation, and an equidistant diagram showing possible variation in relative sea level. Results indicate that glaciers lingered in the east and central Baffin Island valleys from 5700 to at least 4350 BP. Data for this study were gathered by Geographical Branch field parties during the Baffin Island Project, 1961-67.Importance de la déviation standard du radiocarbone dans la détermination des niveaux marins relatifs et dans les chronologies glaciaires : un exemple pour l'est de l'île de Baffin. L'auteur donne des exemples de l'importance de la déviation standard du radiocarbone dans l'évaluation des niveaux marins relatifs, de même qu'une chronologie glaciaire locale. Il décrit les techniques d'évaluation des données. Dans la première étape de l'émergence postglaciaire, des incertitudes sur l'âge radiocarbone d'un échantillon, qu'on présume dater la limite marine, peuvent conduire à une erreur de vingt pour cent dans l'altitude estimée des niveaux marins inférieurs. Aussi récemment que 4.300 années-radiocarbone avant aujourd'hui, des langues glaciaires alimentées par la calotte intérieure de l'île de Baffin atteignaient le niveau de la mer, tout au moins dans la région étudiée ici

University of Colorado 1976 Field Season in Eastern Baffin Island

A large programme was carried out during the summer of 1976 by faculty members and graduate students from the University of Colorado's Institute of Arctic and Alpine Research (INSTAAR) and Department of Geological Sciences. The research included studies of various aspects of Quaternary geology and chronology, investigations of micropalaeontological fauna from raised marine sediments, studies of weathering and of the role and significance of tors on hill summits (sometimes associated with erratics), and coring of lake sediments. Associated research included studies of cliff erosion, of changes in soils through time, on associations between microclimate and vegetation, and on Eskimo sites and archaeology. Research was concentrated in four primary areas: Broughton Island, including the area south to Canso Channel and north to Kivitoo; Pangnirtung and Kingnait fiords; Sunneshine Fiord and Cape Dyer; and the fiords and bays of the northern Hall Peninsula

Holocene Sediment Magnetic Properties Along a Transect from Isafjardardjup to Djupall, Northwest Iceland

Holocene changes in terrestrial provenance and processes of sediment transport and deposition are tracked along a fjord-to-shelf transect adjacent to Vestfirdir, Iceland, using the magnetic properties ofmarine sediments.Magnetic susceptibility (MS) profiles of 10 cores (gravity and piston) were obtained onboard using a Bartington MS loop. Remanent magnetizations were measured at 1-cm intervals from u-channel samples taken from six cores on a cryogenic magnetometer. Between six and nine alternating field demagnetization steps were used to isolate the characteristic magnetization directions. The chronologies of the cores used in this study were determined from AMS14 C dates on mollusks and foraminifera and contrained by the regional occurrance ofthe 10,200 6 60 cal yr. BP Saksunavatn tepha. Correlative fluctuations in magneticconcentration are noted between the fjord and shelf sites, though these fluctuations are partiallymasked by regional variations in carbonate content. The onset of Neoglaciation is interpreted by changes in magnetic properties including an increase in mass magneticsusceptibility that began approximately 3000 cal yr. BP. The maximum angular deviation and the median destructive field (generally 20 mT) suggest that the natural remanent magnetization is carried by a coarse ferrimagnetite mineralogy, likely magnetite or titano-magnetite. Reproducible paleomagnetic inclination values are observed in several records, including a nearly vertical inclination around 8000 cal yr. BP, suggesting that the magnetic pole may have been proximal to Iceland, followed by an interval of much shallower inclination (6000–7000 cal yr. BP)

University of Colorado: 1970 Summer Field Season in East Baffin Island

... Field work continued on [the late glacial and neoglacial chronology and recent crustal movements] program with the main emphasis being shifted to Narpaing Fiord and outer Okoa Bay. Marine limits were measured at many localities in the two areas and some samples of marine shells were collected for dating ... Studies continued on the task of subdividing the glacial deposits on the basis of a number of weathering criteria such as: depth of pitting, surface texture of boulders, soil development, X-ray analysis for clay minerals and Free-iron content. The combined results suggest several episodes of glaciation with a general decrease of glacier area and volume throughout the Wisconsin. ... A tentative lichen growth-curve is being developed based on a variety of evidence, and it is considered that the graph may usefully be extended back to 8,000 or 10,000 years ago. Work on a series of corrie moraines at the heads of Narpaing and Quajon fiords suggests that the outermost south-facing moraines at 600 m.a.s.l. may be 15,000 years old whereas the north-facing moraines at 550 m.a.s.l. are 8,000 to 10,000 years old. ... A series of 7 weather stations were established at different exposures and elevations in the area between the head of Quajon and Narpaing fiords. ... Mass budgets were measured in early June and mid-August using a variety of methods. Stakes, probing and pits were used to detail the progress of melting during the ablation season. In early June the specific net budget was + 0.42 cm ± 0.06 and in mid-August was + 0.38 ± 0.06 cm water equivalent. In complete contrast to 1969, no ice was showing on the glacier and the summer melt had been compensated by snowfalls throughout the "ablation" season. Surface lowering amounted to about 45 cm of snow and this was nearly identical to the mass added in the growth of superimposed ice. Because of low temperatures the glacier was acting nearly as a closed system. ..

A Study of Late-Quaternary Plant-Bearing Beds in North-Central Baffin Island, Canada

Plant-bearing beds, exposed by downcutting of the Isortoq River at the northern end of the Barnes Icecap, have been folded, apparently by east-west moving overriding ice, truncated and overlain by horizontal alluvial sediments. Radiocarbon dates for plant material from the Isortoq River (folded unit), Flitaway Lake, and Lewis Glacier localities are >30,000 to >40,000 yr BP, from the horizontal beds, 14,000 ± 400 yr BP. The vegetation was probably similar to that of southern Baffin Island today; the Isortoq beds are assigned to the Sangamon interglacial. Pollen diagrams and description of the present vegetation and climate are included.Étude des dépôts végétaux fini-quaternaires dans le centre-nord de l'île de Baffin, Canada. On a daté à plus de 38,830 et 40,000 ans av. p. respectivement des horizons végétaux enfouis le long de la rivière Isortoq, à l'extrémité nord de la calotte de Barnes, sur l'île de Baffin. Des études palynologique et paléobotanique indiquent la présence d'espèces (comme le bouleau nain) qui se retrouvent aujourd'hui à plusieurs centaines de kilomètres au sud de cette localité. En déduisant des conditions climatiques plus favorables qu'à présent, on assigne à ces horizons un âge interglaciaire (Sangamon). Le plissement des horizons par de la glace de recouvrement et l'orientation de ces plis indiquent que l'accumulation d'une calotte initiale s'est produite à l'est de la localité

University of Colorado 1974 Field Season in Eastern Baffin Island

The summer of 1974 saw one of the largest research parties the University of Colorado has been able to mount operating along the eastern coast of Baffin Island. The early and widespread break-up of sea ice greatly assisted in the completion of the field programme in which a total of sixteen persons were involved. In addition to members of the University staff, the following individuals from other institutions also participated. In the programme: a member of the Department of Micropalaeontology of the University of Aarhus, Denmark; a soil scientist from the University of Pennsylvania, U.S.A.; a Quaternary geologist from Brock University, Ontario, Canada; and a Quaternary geologist from Grand Valley State College, Michigan, U.S.A. ... Raised marine sediments and tills were investigated on Broughton Island and northwards along the coast to Quajon Fiord. Specific attention was focused on collecting samples for micro-faunal analysis and delimiting different marine episodes. In addition, a number of sites were revisited on Broughton Island and northwards along the coast to Kivitoo and Quajon Fiord. Large (1000-g and over) samples of marine shells were collected from sites previously given dates of over 30,000 years BP. ... One field party mapped the southern part of the Baffin Island National Park, giving particular attention to (a) the delimitation of glacial periods on the basis of surface weathering of boulders, and (b) determining the elevation of local marine limits and lower strandlines. The latter research was concentrated on the mapping of the southern shore of Cumberland Peninsula, from outer Kingnait Fiord westward to the head of Cumberland Sound. ... Soil scientists established a soil chronosequence, and investigated the range of soil types existing within the southern part of Cumberland Peninsula. They sent samples south from laboratory analysis. Plant collection: Specimens of vascular plants, mosses and lichens were collected from Broughton Island and from the head of Maktak Fiord, and sent to the University of Colorado Museum. By December 1974, a total of 86 vascular plants had been identified. Climatological studies in relation to fast ice: Work done during the summer of 1974 concludes the field-measurement phase of the University of Colorado's study of the surface energy budgets of fast ice at Broughton Island. A micrometeorological station was operated at a site approximately one kilometre south of Broughton settlement, from late May until local break-up in early July. The programme of observation consisted of the periodic taking of profiles of wind, temperature and relative humidity; the continuous measurement of temperature at two metres, and net radiation over both saturated and unsaturated surfaces; and transects of surface short-wave albedo. Salinity and temperature profiles in the ice and water were taken every 304 days. Comparative analysis of the data for 1972-74 is now in progress in relation to the observed ice regime. The 1974 data should provide better estimates of the turbulent flux components of the energy budget than it was possible to make in previous summers. Meteorological observations were continued near the base of the Broughton Island operations through mid-August. Results are now available of four summers and two winters of standard meteorological observations, and global solar and net radiation measurements as well. The Atmospheric Environment Service Cooperative Observer station, with its twice-daily measurements of maximum and minimum temperatures and of precipitation, is now into its fourth calendar year of operation. The summer of 1974 was unusually mild. The mean ablation seasonal temperature was 3.9°C at the Broughton DEW line weather station. In contrast, 1972 was the coldest (-1.2 C°). The early part of June 1974 was dominated by anticyclonic synoptic weather patterns which greatly accelerated the fast ice ablation rate to give the earliest break-up in five years. Satellite-observed conce ntrations of pack ice in Davis Strait in late May were less than at the same time in 1973. With the resurvey of the "Boas" Glacier (67 35 N, 65 16 W) in August 1974, the mass balance measurements were extended to five balance years. Accurate measurements were not possible, because most ablation poles melted out during the warm summer of 1974. However, it is estimated that the net specific balance for the 1973-74 budget year was approximately -0.5 m water equivalent (w.e.). ... Analysis of the past five budget years shows that (a) the "Boas" Glacier exhibited a two-year alternation of large mass gains and losses during the first four years, and (b) the estimated net specific mass balance for the five-year period was -0.16 m w.e., in spite of the total net mass gains of 0.38 m w.e. during the first four years. ..

Comparison of Elevations of Archaeological Sites and Calculated Sea Levels in Arctic Canada

Based on a study of postglacial uplift in the Canadian Arctic, it has been proposed that relative emergence can be estimated if the age and elevation of late-glacial marine limits are known. This suggestion is used to construct 5 maps showing the amounts of relative sea level emergence since 4000, 3200, 2400, 1600 and 800 BP. The archaeological sequence of coastal arctic Canada has been artificially divided into 5 corresponding 800-year periods. Eighty-four archaeological sites are examined; 71 of these appear to have been located with reference to contemporaneous sea level. The mean elevation of the 71 sites is only 5.2 m above the interpolated sea level for each period; the Spearman rank correlation between site elevations and interpolated sea level is 0.82. The maps can therefore be used to delimit area of search for cultural remains of specific ages in archaeological reconnaissance, but the relationship is not sufficiently close to allow the construction of a detailed chronological sequence using elevation data alone.Comparaison des altitudes de sites archéologiques et de niveaux marins calculés, dans l’Arctique canadien.  Sur la base d’une étude du relèvement post-glaciaire dans l’Arctique canadien, on a proposé que l’émergence relative peut être estimée si l’âge et l’altitude des limites marines fini-glaciaires sont connus.  A partir de cette suggestion, on construit 5 cartes montrant les niveaux d’émergence relative du niveau de la mer depuis 4000, 3200, 2400, 1600 et 800 ans.  Puis, on divise artificiellement la séquence archéologique du Canada arctique côtier en 5 périodes de 800 ans.  Des quatre-vingt-quatre sites archéologiques examinés, 71 semblent localisés par rapport au niveau marin qui leur était contemporain, car l’altitude moyenne de ces 71 sites n’est que 5,2 m au-dessus du niveau moyen interpolé pour chaque période; la corrélation de Spearman entre l’altitude des sites et le niveau marin interpolé est de 0,82.  Ces cartes peuvent ainsi servir à délimiter une aire de recherche de vestiges culturels d’âges spécifiques dans une reconnaissance archéologique d’une séquence chronologique détaillée n’utilisant que les seules données d’altitude

Radiocarbon Date List XI: Radiocarbon Dates from Marine Sediment Cores of the Iceland, Greenland, and Northeast Canadian Arctic Shelves and Nares Strait

Radiocarbon Date List XI contains an annotated listing of 178 AMS radiocarbon dates on samples from marine (169 samples) and lake (9 samples) sediment cores. Marine sediment cores, from which the samples for dating were taken, were collected on the Greenland Shelf, Baffin Bay, and the Eastern Canadian Arctic shelf. About 80% of the marine samples for dating were collected on the SW to N Icelandic shelf. The lake sediment cores were collected in northwestern Iceland. For dating of the marine samples, we submitted molluscs (117 samples), benthic and planktic foraminifera (45 samples), plant macrofauna (3 samples), and one serpulid worm. For dating of the lake cores, we submitted wood (8 samples) and one peat sample. The Conventional Radiocarbon Ages range from 294±9114C yr BP to 34,600±640 14C yr BP. The dates have been used to address a variety of research questions. The dates constrain the timing of high northern latitude late Quaternary environmental fluctuations, which include glacier extent, sea level history, isostatic rebound, sediment input, and ocean circulation. The dates also allowed assessment of the accuracy of commonly used reservoir correction. The samples were submitted by INSTAAR and affiliated researchers

Report on the Distribution of Dwarf Birches and Present Pollen Rain, Baffin Island, N.W.T., Canada

A distribution map for the dwarf birches is presented for the region from Frobisher Bay northward to Cumberland Peninsula. These shrubs are restricted to favourable habitats which, at the northern limit of the species (67 deg. 40 sec. N), are found on south-facing slopes above the immediate local cooling influence of the sea. Pollen studies within the zone of scattered dwarf birch indicate that pollen dispersal from these low, prostrate shrubs is minimal. Samples of moss collected beneath the bushes have 5-36% Betula pollen; whereas sites no more than 50 m away from Betula shrubs have percentages of <2%. These data will be useful in considering the Holocene and Pleistocene histories of these Low Arctic shrubs in the Eastern Canadian Arctic