Anomalou s Unfrozen Zone Caribou Peak, Alaska

The field studies were done with the assistance of Allen Delaney, while Bruce Brockett provided valuable information on the borehole unfrozen zone. Dr. Patrick Black conducted the NMR analysis and Alan Hewitt conducted the ion chromatography analysis. Paul Sellmann and Lawrence Gatto provided useful technical reviews of the report manuscript. The authors thank all of the above individuals, who made this investigation successful. The contents of this report are not to be used for advertising or promotional purposes. Citation of brand names does not constitute an official endorsement or approval of the use of such commercial products. CONTENTS Preface Introduction 1 Background 1 Field site 1 Borehole and radar profile locations 1 Radar instrumentation 3 Borehole geology 5 Results and discussion 6 Radar profiles 6 Downhole temperatures 12 Vegetation patterns and fracture locations 18 Groundwater origin 19 Conclusion 21 Literature cited 21 Abstract 25 ILLUSTRATIONS Figure 1. Location map showing the Caribou-Poker Creeks Research Watershed within the Fairbanks region of Interior Alaska 2 2. Enlargement of USGS Livengood Quadrangles Α-1 and Α-2 in the Caribou Peak vicinity, with the 1985 boreholes located 2 3. A part of transect 3 3 4. Typical waveform of the radar pulse emitted from either the Model 3105 or 3102 antenna units 4 5. Wiggle trace display of a single scan and equivalent graphic record should these scans remain constant with profile distance 5 6. Summary of geologic logs for boreholes Κ20, K20Α and Κ2 6 7. Processed radar profiles of transect 1 8 8. 330-MHz profile of transect 1, with additional stacking and filtering, to better illustrate features of interest as interpreted on the right 9 9. Processed radar profiles of transects 2, 3 and 4 10 10. Spatial distribution of fractures relative to radar transects and boreholes 12 11. Downhole temperatures for 1989 13 12. Aerial photograph of the Caribou Peak area on 12 July 1977, showing the approximately parallel linear arrangement to the vegetation 18 13. Idealized diagram showing a possible relationship between water-bearing fractures and vegetative lineations 19 14. Schematic model of the apparent relationship between fractures 21 TABLE Table 1. Ground temperature data from thermistor strings installed in boreholes INTRODUCTION presents the results of this survey in light of existing geological and related data, and hypothesizes on the origin of the unfrozen zone. The distribution of permafrost is controlled by a number of interrelated environmental factors and processes. The relationship …