UID:
kobvindex_GFZ20201111110304
Umfang:
vii, 62, A4, B2, C2 Seiten
,
Illustrationen
Serie:
Research report / Cold Regions Research and Engineering Laboratory 26
Inhalt:
Summary: The results of temperature, density, ram-hardness and grain-size measurements at 118 test sites along a 300-mi. traverse, ranging in elevation from 2000 to 8000 ft, are reported in detail, and their meteorological and climatic implications are discussed. Four types of diagenetically produced facies were recognized: ablation facies, extending from the snout of the glacier to the firn line; soaked facies, extending from the firn line to the saturation line; percolation facies, extending from the saturation line to the dry-snow line; and dry-snow facies, extending across the glacier above the dry-snow line. The well defined saturation line shows marked discontinuities in temperature, density, and ram hardness, while the dry-snow line is a transition 1 zone 10-20 mi. wide. The recognition of facies allows greater resolution of glacier characteristics than Ahlmann's classification, permitting quantitative subdivision of all types of large glaciers. Regional precipitation (entirely from cyclonic storms) is about 5 times greater than at Thule; and the prevailing katabatic winds control the vertical component of the temperature gradient in the snow and firn. The depth density curve of the firn at elevations where melt is negligible is invariant with time, as in Sorge's law, so that the densification can be treated as a steady-state situation with load as the only significant variable.
Anmerkung:
CONTENTS
Preface
Summary
Chapter I. Introduction
Greenland
Glaciers and stratigraphy
The Greenland ice sheet - a rock formation
Region of investigation
Chapter II. Methods of investigation
Stratigraphy
Accumulation measurements
Work program at pit stations
General description of pits
Temperature
Hardness
Density, stratigraphy, and grain size
Accuracy of density measurements
Photography
Core drilling
Air permeability and mechanical tests
Elevation measurements
Barometric altimetry
Transit leveling
Chapter III. Basic concepts and definitions
Summer melt
Soaking
Complete soaking
Localized percolation
Stability
Diagenetic facies
Chapter IV. Presentation and discussion of results
Grain size and morphology
Grain size
Morphology
Temperature
Seasonal variation and mean annual temperature
Thermal effect of an open pit
Constancy of climate
Facies in terms of temperature data
Hardness
Continuity of strata
Effect of wind
Increase in R with depth below snow surface
Facies in terms of hardness data
Density
Depth vs density data
Depth vs load data
Attempts to formulate depth vs density
Facies in terms of density data
Glacier facies - a classification of glaciers
Chapter V. Stratigraphy and accumulation
Stratigraphy
Stratigraphic interpretation at station 1-0
Correlation between stratigraphic and meteorological
records
Accumulation
Integrated qepth-density curves
Measurement of accumulation on surface marker plates
Pole-marker measurements
Stratigraphic correlation
Selection of a reference datum in the annual stratigraphic sequence
Correlation across the traverse
Effects of topography
Chapter VI. Meteorological and climatological implications
Winds
Precipitation
Annual heat exchange
References
Appendix A: Stratigraphy, meteorology and glaciology
Appendix B: Logistics and development of the research program
Appendix C: Tables
In:
Research report / Cold Regions Research and Engineering Laboratory, 26
Sprache:
Englisch
Schlagwort(e):
Forschungsbericht
URL:
https://hdl.handle.net/11681/2724
