scholarly journals Holocene Glacier Fluctuations in the Torngat Mountains, Northern Labrador

2007 ◽  
Vol 37 (2) ◽  
pp. 211-216 ◽  
Author(s):  
William D. McCoy
Keyword(s):  
Growth Curve ◽  
Local Area ◽  
Baffin Island ◽  
Relative Age ◽  
Glacier Fluctuations ◽  
Glacier Recession ◽  
Rhizocarpon Geographicum ◽  
Lichen Growth

ABSTRACT Lichen measurements and other relative-age data were collected from deposits of several cirque glaciers in the Torngat Mountains of northern Labrador. Lichen growth stations were established, but no lichen-growth curve has yet been determined for the local area. However, moraines can be correlated between valleys on the basis of the largest diameter thallus of Rhizocarpon geographicum sensu lato combined with other relative-age data. These data suggest several discrete periods of Holocene glacier recession. If the R. geographicum s. I. growth curve established for the northern Cumberland Peninsula of Baffin Island (MILLER, 1975) is valid for similar environments in the Torngat Mountains, then glacier recession occurred < 150, 400, 550-750, 950, ≥ 1850, > 1850, ≥ 2800, > 2800, ≥ 4000, and > > 4000 yr BP. The latest three periods of glacier recession may correlate with periods of glacier recession on the Cumberland Peninsula of Baffin Island.

scholarly journals Recent Glacial History of an Alpine Area in the Colorado Front Range, U.S.A.: I. Establishing a Lichen-Growth Curve

1967 ◽  
Vol 6 (48) ◽  
pp. 817-832 ◽  
Author(s):  
James B. Benedict
Keyword(s):  
Growth Curve ◽  
Average Rate ◽  
Colorado Front Range ◽  
Ground Moraine ◽  
Front Range ◽  
Exposure Age ◽  
Rhizocarpon Geographicum ◽  
Valley Glacier ◽  
History Of ◽  
Lichen Growth

A lichen-growth curve has been developed for dating Recent glacial and periglacial deposits in the Indian Peaks area of the Colorado Front Range.Rhizocarpon geographicumwas selected for the study because of its long life span and consistent size-age relationship. The species grows at different rates in different micro-environments, with moisture, stability of substrate and length of snow-free growing season having the greatest effect. Growth rates were determined indirectly, by measuring the maximum diameters of circular or nearly circular thalli growing on surfaces of known exposure age. Measurements were made on 24 historically dated surfaces, ranging in age from 25 to 69 yr., and on three radiocarbon-dated surfaces, including (1) mudflow levees younger than 180 yr., (2) a rock wall built by prehistoric Indians about 970 yr. ago, and (3) ground moraine deposited by a retreating valley glacier about 2,460 radiocarbon years ago.R. geographicurrzgrows very rapidly (14. mm./100 yr.) during the First 100 yr. of its life. Growth then slows to an average rate of 3.3 mm./100 yr. The completed growth curve is believed to be suitable for dating deposits at least as old as 3,000 yr.

scholarly journals Recent Glacial History of an Alpine Area in the Colorado Front Range, U.S.A.: I. Establishing a Lichen-Growth Curve

1967 ◽  
Vol 6 (48) ◽  
pp. 817-832 ◽  
Author(s):  
James B. Benedict
Keyword(s):  
Growth Curve ◽  
Average Rate ◽  
Colorado Front Range ◽  
Ground Moraine ◽  
Front Range ◽  
Exposure Age ◽  
Rhizocarpon Geographicum ◽  
Valley Glacier ◽  
History Of ◽  
Lichen Growth

A lichen-growth curve has been developed for dating Recent glacial and periglacial deposits in the Indian Peaks area of the Colorado Front Range. Rhizocarpon geographicum was selected for the study because of its long life span and consistent size-age relationship. The species grows at different rates in different micro-environments, with moisture, stability of substrate and length of snow-free growing season having the greatest effect. Growth rates were determined indirectly, by measuring the maximum diameters of circular or nearly circular thalli growing on surfaces of known exposure age. Measurements were made on 24 historically dated surfaces, ranging in age from 25 to 69 yr., and on three radiocarbon-dated surfaces, including (1) mudflow levees younger than 180 yr., (2) a rock wall built by prehistoric Indians about 970 yr. ago, and (3) ground moraine deposited by a retreating valley glacier about 2,460 radiocarbon years ago. R. geographicurrz grows very rapidly (14. mm./100 yr.) during the First 100 yr. of its life. Growth then slows to an average rate of 3.3 mm./100 yr. The completed growth curve is believed to be suitable for dating deposits at least as old as 3,000 yr.

Late Holocene Glacier Fluctuations and Vegetation Changes at Maktak Fiord, Baffin Island, N.W.T., Canada

1976 ◽  
Vol 8 (4) ◽  
pp. 343 ◽  
Author(s):  
G. S. Boulton ◽  
J. H. Dickson ◽  
H. Nichols ◽  
M. Nichols ◽  
S. K. Short
Keyword(s):  
Late Holocene ◽  
Vegetation Changes ◽  
Baffin Island ◽  
Glacier Fluctuations

scholarly journals Using Lichenometry, Dendrochronology, and Historical Data to Establish the Relative Age of an Abandoned Cemetery in Northern Arkansas

2018 ◽  
Vol 9 (2) ◽  
pp. 253-262
Author(s):  
Brandy Garrett Kluthe ◽  
Margaret Guiccioni ◽  
Steven L. Stephenson
Keyword(s):  
Growth Rate ◽  
Historical Data ◽  
Private Ownership ◽  
Historical Records ◽  
Relative Age ◽  
Johnson County ◽  
Study Support ◽  
Time Periods ◽  
Louisiana Purchase ◽  
Lichen Growth

Folklore surrounding an abandoned cemetery located in Johnson County, Arkansas (a part of the Louisiana Purchase) suggested that it was used by early settlers. Historical records were combined with several dating techniques to determine the approximate time periods that Cedar Grove Cemetery was established and abandoned. Cores extracted from trees located adjacent to or on graves provided evidence that the cemetery was abandoned in the 1920s. These results coincide with the last burial event in 1922. The approximate age of undated gravesites was determined using lichenometry. A lichen growth rate of 0.0685 cm/year was determined for lichens present on two gravestones with known dates. This growth rate was then applied to the undated graves to establish their approximate ages. Death dates from historical records of individuals buried in the cemetery matched the dates established by the lichen growth rate. Our results show that many of the unmarked graves date prior to the first documented private ownership of the land. The results of this study support local folklore passed down over several generations about the origin of the cemetery.

scholarly journals Lichen Growth on an Active Medial Moraine, Jotunheimen, Norway

1973 ◽  
Vol 12 (65) ◽  
pp. 305-313 ◽  
Author(s):  
J. A. Matthews
Keyword(s):  
Population Dynamics ◽  
Rhizocarpon Geographicum ◽  
Southern Norway ◽  
Lichen Growth

AbstractAbundant specimens of lichens, includingRhizocarpon geographicum, are reported from an active medial moraine on Storbreen, southern Norway. The size and distribution of two crustose and two foliose species are described. Inferences are made regarding the age, origin and population dynamics of the lichens. Some implications of the observations for lichenometric dating and use of lichens as indicators of moraine stability are discussed.

Sizes and Growth-Rates of Thalli of the Lichen Rhizocarpon Geographicum on the Moraines of the Glacier De Valsorey, Valais, Switzerland

1983 ◽  
Vol 15 (3) ◽  
pp. 249-261 ◽  
Author(s):  
M. C. F. Proctor
Keyword(s):  
Growth Rates ◽  
Radial Growth ◽  
Growth Curves ◽  
Field Measurements ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Rhizocarpon Geographicum ◽  
Constant Rate ◽  
Maximum Parameters ◽  
Lichen Growth

AbstractMeasurements of thalli of Rhizocarpon geographicum on the recent moraines of the Glacier de Valsorey and their surroundings are considered in relation to thallus growth rates and colonization following glacial recession. Photographs taken in 1975 and 1979 show that up to c. 3.5 cm diam the relation of maximum growth-rate to thallus size is approximated by a growth curve of the kind derived by Aplin and Hill, rising asymptotically towards a constant rate of radial growth (here c. 0.5 mm year−1). Growth-rates of many individual thalli fall well below the maximum. Parameters of the fitted growth curves are used to construct curves of thallus radius against time. Taken in conjunction with the field measurements these suggest two main phases of colonization, one from about 1880 to 1910, and one from about 1930 onwards. Some general considerations relating to lichenometry and lichen growth curves are discussed.

Etching of Hornblende Grains in Arctic Soils: An Indicator of Relative Age and Paleoclimate

1979 ◽  
Vol 11 (2) ◽  
pp. 197-212 ◽  
Author(s):  
William W. Locke
Keyword(s):  
Soil Moisture ◽  
Canadian Arctic ◽  
Unfrozen Water ◽  
Soil Profiles ◽  
Baffin Island ◽  
Climatic Parameter ◽  
Relative Age ◽  
Arctic Soils ◽  
The Mean ◽  
Eastern Canadian Arctic

The degree of etching of hornblende grains in soils is defined as the mean depth of maximum etching on 100 grains per sample and is a function of: (1) the depth in the profile; (2) the age of the deposit on which the soil is formed; and (3) the climate since deposition. In soils formed on moraines in the eastern Canadian Arctic, etching decreases logarithmically with increasing depth in the profile, and the rate of etching at a given depth decreases logarithmically with increasing age. The most important climatic parameter with respect to etching appears to be the effective precipitation. Equally important in terms of soil moisture regimen is the presence of unfrozen water. Both affect the rate of etching as a function of depth and age. The inferred climate of northern Cumberland Peninsula, Baffin Island, N.W.T., Canada, preceding, during, and following the last (Foxe) glaciation, is indicated by the degree of etching of hornblende grains in soil profiles of various ages as follows: pre-Foxe—warm/wet; early to middle Foxe—mild/moist; middle to late Foxe—cold/arid; Hypsithermal—mild/moist; Neoglacial—cool/dry.

scholarly journals Palaeo-ice streams in the northern Keewatin sector of the Laurentide ice sheet

2005 ◽  
Vol 42 ◽  
pp. 135-144 ◽  
Author(s):  
Hernán De Angelis ◽  
Johan Kleman
Keyword(s):  
Potential Role ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Baffin Island ◽  
Ice Streams ◽  
Relative Age ◽  
Ice Stream ◽  
Deep Interior ◽  
Ice Sheet Dynamics ◽  
Streaming Flow

AbstractEvidence for ice streams in the Laurentide ice sheet is widespread. In the region of northern Keewatin and the Boothia Peninsula, Nunavut, Canada, palaeo-ice streams have been recognized, but their location, size and potential role in ice-sheet dynamics are poorly constrained. Based on the interpretation of satellite imagery, we produce a palaeo-ice-stream map of this region. Glacial directional landforms, eskers and moraines were mapped and integrated into landform assemblages using a glacial geological inversion model. Palaeo-frozen bed areas were also identified. Relative age of the geomorphic swarms was assessed by cross-cutting relationships and radiocarbon ages where available. Using this information we obtained a glaciologically plausible picture of ice-stream evolution within the northernmost Laurentide ice sheet. On the M’Clintock Channel corridor, three generations of pure ice streams are found. On Baffin Island and the Gulf of Boothia, glaciation was dominated by frozen-bed zones located on high plateaus and ice streams running along the troughs, i.e. topographic ice streams. A massive convergent pattern at the head of Committee Bay drained ice from both the Keewatin and Foxe sectors and was probably one of the main deglaciation channels of the Laurentide ice sheet. Finally, our results indicate that streaming flow was present in the deep interior of the Laurentide ice sheet, as recently shown for the Greenland and Antarctic ice sheets.

Lichenometric dating using Rhizocarpon subgenus Rhizocarpon in the Patagonian Andes, Argentina

2009 ◽  
Vol 71 (3) ◽  
pp. 271-283 ◽  
Author(s):  
Irene Adriana Garibotti ◽  
Ricardo Villalba
Keyword(s):  
Tree Ring ◽  
Growth Rates ◽  
Growth Curves ◽  
The Past ◽  
Glacier Fluctuations ◽  
Andean Cordillera ◽  
Latitudinal Difference ◽  
Patagonian Andes ◽  
Over Time ◽  
Lichen Growth

AbstractThis study represents the first attempt to develop and apply lichenometric dating curves of Rhizocarpon subgenus Rhizocarpon for dating glacier fluctuations in the Patagonian Andes. Six glaciers were studied along the Patagonian Andes. Surfaces of known ages (historical evidences and tree-ring analyses) were used as control sites to develop indirect lichenometric dating curves. Dating curves developed for the studied glaciers show the same general logarithmic form, indicating that growth rate of subgenus Rhizocarpon decreases over time. The strong west–east precipitation gradient across the Andean Cordillera introduces statistically significant differences in the growth curves, with faster growth rates in the moist west sites than the drier eastern sites. Latitudinal difference among the studied glaciers does not appear to be a major factor regulating lichen growth rates. Therefore, we developed two lichenometric curves for dating glacier fluctuations in wetter and drier sites in the Patagonian Andes during the past 450 yrs. Application of the developed curves to moraine dating allowed us to complement glacial chronologies previously obtained by tree-ring analyses. A first chronosequence for moraine formation in the Torrecillas Glacier (42°S) is presented. Our findings confirm the utility of lichenometry to date deglaciated surfaces in the Patagonian Andes.

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