Borehole locations and permafrost depths, Alaska, USA, Version 1
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The methods utilized by the U.S. Geological Survey to measure subsurface temperatures have evolved considerably over the years. Although some of the early measurements were obtained using thermistor strings frozen into permafrost, the vast majority of the measurements were made in fluid-filled holes using a custom temperature sensor. A typical sensor used in Alaska prior to 1989 consisted of a series-parallel network of 20 thermistors; see Sass et al. [1971] for a more detailed description. During a logging experiment, the resistance of the thermistor network was determined using a Wheatstone bridge prior to 1967. After that time, a 4-wire resistance measurement was made using a commercial 5.5-digit multimeter (DMM). Before 1984, boreholes were logged in the 'incremental' or 'stop-and-go' modes; the vertical spacing of the measurements was typically 3-15 m. Beginning in 1984, the depth/resistance measurements were automatically stored on magnetic tape, allowing boreholes to be logged in the 'continuous' mode; the typical data spacing for the continuous temperature logs was 0.3 m (1 ft). Many of the Alaskan boreholes were re-logged several times to quantify the thermal disturbance caused by drilling the holes (see Lachenbruch and Brewer [1959]). A review of current temperature measuring techniques used by the USGS in the polar regions is given by Clow et al. [1996]. Data from 1950-1989 are included on the CAPS CD-ROM Version 1.0, June 1998.
Canadian Geothermal Data Collection: Deep permafrost temperatures and thickness of permafrost, Version 1
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Precision temperature measurements have been made in some 150 deep wells and holes drilled in the course of natural resource exploration in the permafrost regions of Northern Canada. In most cases, holes were logged by lowering a probe containing a regions of Northern Canada. In most cases, holes were logged by lowering a probe containing a thermistor incrementally down the well, in other cases multi-thermistor cables were left in the holes and periodic measurements taken. In the 1990's, a few holes were logged by a automatic quasi- continuous logging system. Most holes were logged annually for 5-10 years after drilling completion, and measured temperatures show the disturbance due to drilling and the gradual recovery to near-undisturbed conditions. Some holes in the collection are of depth less than 125 m. Permafrost thicknesses are estimated at each well or hole from the depth of the 0 degree Celsius isotherm. This data collection provides the highest quality of permafrost temperature and permafrost thickness information available for Northern Canada. Other data are the large number of downhole temperature and permafrost thickness estimates taken during commercial well logging of petroleum exploration wells, and are by nature of lesser quality. These data are not included in this data set, but references to compilations of this data are provided. A short text (2000 words), tables of site locations and permafrost thicknesses with small-scale maps, and an extensive bibliography accompany the data collection. The file structure and contents of each file are well described. The text is sufficient to locate the data of interest, and the file description is adequate for a user to recover the parameters of interest. The data are presented on the CAPS Version 1.0 CD-ROM, June 1998.
Permafrost Map of Alaska, USA, Version 1
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This data set consists of a geo-referenced digital map and attribute data derived from the publication 'Permafrost map of Alaska'. The map is presented at a scale of 1 to 2,500,000 and shows the correlation of physiographic province to presence of permafrost across the state of Alaska. The digital data were prepared under the U.S. Geological Survey Global Change Program, Land Data Systems - Arctic Land Processes Studies for display and analysis of terrain. The line work was captured by hand digitizing the source map, Ferrians, O.J., 1965, Permafrost map of Alaska - U.S. Geological Survey Miscellaneous Geologic Investigations Map I-445. Scale 1 to 2,500,000. The digital map was assembled and edited in ARC/INFO. The source map projection is polyconic. It is based on the Clarke 1866 ellipsoid with a central meridian of 150 W longitude. The data were geo-referenced from digitizer coordinates to the polyconic projection and then projected into an Albers Equal Area projection. The coastline was taken from the U.S Geological Survey, 1 to 2,000,000 scale Digital Line Graph data (U.S. Geological Survey, 1987). Attributes for the permafrost map were assigned. Metadata documentation was completed in 1996. The map units are closed polygons that are generalized in shape and size. They are defined in terms of their physiographic characteristics and association with permafrost. Each unit differs with respect to all other units and is uniquely identified as follows. 11 Mountainous Area underlain by continuous permafrost 12 Mountainous Area underlain by discontinuous permafrost 13 Mountainous Area underlain by isolated masses of permafrost 21 Lowland and Upland Area underlain by thick permafrost 22 Lowland and Upland Area underlain by moderately thick to thin permafrost 23 Lowland and Upland Area underlain by discontinuous permafrost 24 Lowland and Upland Area underlain by numerous isolated masses of permafrost 25 Lowland and Upland Area underlain by isolated masses of permafrost 26 Lowland and Upland Area generally free of permafrost Use constraints - The U.S. Geological Survey should be acknowledged as the data source in products derived from these data. The data are general in nature and should not be used at a scale larger than 1 to 2,500,000, that of the original map. Users must assume responsibility to determine the usability of this data for their purposes. The use of these data is not restricted and may be interpreted by organizations, agencies, units of government or others; however, they are responsible for its appropriate application. Digital data files are periodically updated. Files are dated and users are responsible for obtaining the latest revisions of the data. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made by the agency regarding the utility of the data on any other system, nor shall the act of distribution constitute any such warranty. A copy of this map is presented on the CAPS Version 1.0 CD-ROM, June 1998.
Borehole temperatures in deep wells of Western Siberia, Russia, 1960-1995, Version 1
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This data set is a database of the permafrost and geothermal conditions of the oil and gas deposits of Western Siberia. Data were taken from 736 plots, each having from one to ten wells. The data set includes soil and rock temperatures at 20, 50, 100, 200, 300, 400, 500, 1000, and 3000 meters; depth of the bedding of the top and bottom of permafrost layers; size of the thermal flows in the subpermafrost; and thickness of frozen layers and underlying thawed layers. Additional information includes the geographical coordinates of the sites, the air temperature, permafrost-geothermal geological sections, maps of thermal flows, and the distribution of the temperatures at each depth (down to 5000 meters). The data are presented on the CAPS Version 1.0 CD-ROM, June 1998.
Borehole permafrost data, Kumtor and Taragai Valleys, Tienshan, Kazakhstan, Version 1
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This dataset includes observations of the permafrost temperatures in the Inner Tien Shan were started in 1986 by Kazakhstan Alpine Permafrost Laboratory. Observations are carried out on more than 40 boreholes, at altitudes between 3300-4200 m. The depths of the boreholes vary from 30 to 600 m. The boreholes are located in both loose (moraines) sediments and bedrock. Several boreholes are situated in the territory of the 'Kumtor' goldmine. The geocryological conditions of goldmine 'Kumtor' and nearby territory have been discussed in scientific reports 1988, 1989 and articles (see references). Two boreholes were drilled in body of glacier 'Davydov' and located in the central and lateral parts of the glacier (depth - 30 m). A third borehole passed through the glacier, moraine and bedrock to a depth of 600 m. In the Kumtor and Taragai valleys, permafrost temperature in 14 boreholes from 25 to 50 m depth, between 3300-3750 m ASL were observed. The distance between outermost boreholes is about 40 km. Temperature measurements in 9 geological prospecting adits [tunnels] (lengthwise 1500-1900 m) located in the four neighboring valleys (altitudes from 3920 to 4010 m) were carried out. At the same sites, but in natural conditions, the thermal conductivity of the bedrock was determined by the cylindrical sounding method. Grain size, soil moisture content, cryogenic structure and depth of seasonal thaw were also obtained from 15 pits located in differing altitudinal levels and exposures. At two further sites, ground temperatures measurements at depths of 0, 2, 5, 10, 15, 20 and 40 cm were taken every hour during daylight hours every 5 days over a two year period. Air temperature, wind velocity and duration of daylight were measured at the same time as the ground temperature measurements. These data are presented on the CAPS Version 1.0 CD-ROM, June 1998.