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.

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.

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.

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.

scholarly journals Lichen Growth on Supraglacial Debris and its Implications for Lichenometric Studies

1978 ◽  
Vol 20 (82) ◽  
pp. 163-172 ◽  
Author(s):  
Nigel J. Griffey
Keyword(s):  
Glacial Deposits ◽  
Southern Norway ◽  
Past Conditions ◽  
Lichen Growth

AbstractLichens were found growing on some of the supraglacial debris of six small, active, retreating valley glaciers in southern Norway. The circumstances permitting their growth are discussed, as is the possibility of their surviving pro-glacial deposition under current and past conditions. Their occurrence does not appear to present a problem to careful lichenometric surveys of Holocene glacial and fluvio-glacial deposits.

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.

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.

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