The U.S. Geological Survey, is required by the Alaskan National Interests Lands Conservation Act (Public Law 96-487, 1980), to survey certain Federal lands to determine their mineral values, if any. Results from the Alaskan Mineral Resource Assessment Program (AMRAP) must be made available to the public and be submitted to the President and the Congress. This report presents analytical results of a geochemical survey of the Circle quadrangle, Alaska. o would be produced by using a Frantz Isodynamic Separator set at a slope of 15 and a tilt of 10° with a current of 0.1 ampere to remove the magnetite and ilmenite, and a current of 1.0 ampere to split the remainder of the sample into paramagnetic and nonmagnetic fractions. Sample Analysis Spectrographic method The stream-sediment and heavy-mineral-concentrate samples were analyzed for 31 elements using a semi quantitative, direct-current arc emission Spectrographic method (Grimes and Marranzino, 1968). The elements analyzed and their lower limits of determination are listed in Table 1. Spectrographic results were obtained by visual comparison of spectra derived from the sample against spectra obtained from standards made from pure oxides and carbonates. Standard concentrations are geometrically spaced over any given order of magnitude of concentration as follows: 100, 50, 20, 10, and so forth. Samples whose concentrations are estimated to fall between those values are assigned values of 70, 30, 15, and so forth. The precision of the analytical method is approximately plus or minus one reporting interval at the 83 percent confidence level and plus or minus two reporting intervals at the 96 percent confidence level (Motooka and Grimes, 1976). Values determined for the major elements (iron, magnesium, calcium, and titanium) are given in weight percent; all others are given in parts per million (micrograms/gram). Analytical data for samples from the Circle quadrangle are listed in Tables 3 and 4. Chemical Methods Other methods of analysis used on stream-sediment samples from the Circle quadrangle are summarized in Table 2. Analytical results for the streamsediment samples are listed in Table 3. ROCK ANALYSIS STORAGE SYSTEM Upon completion of all analytical work, the analytical results were entered into a computer-based file called Rock Analysis Storage System (RASS). This data base contains both descriptive geological information and analytical data. Any or all of this information may be retrieved and converted to a binary form (STATPAC) for computerized statistical analysis or publication (VanTrump and Miesch, 1977). DESCRIPTION OF DATA TABLES Tables 3 and 4 list the analyses for the samples of stream sediment and heavy-mineral concentrate, respectively. For the two tables, the data are arranged so that column 1 contains the USGS-assigned sample numbers. These numbers correspond to the numbers shown on the site location map (plate 1), however, the prefix "CI" and the suffix "s" or "c" were not included on the map. Columns in which the element headings show the letter "...

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We collected samples at 1066 sites (plate 1). At nearly all of those sites, we collected both a stream-sediment sample and a heavy-mineral concentrate. We analyzed 1064 stream-sediment samples and 1045 panned-concentrate samples, for a sampling density of about 1 sample site per 6 mi^ for the stream sediment and heavy-mineral concentrate. The drainage basins sampled ranged from 3 to 6 mi. Stream-sediment samples Analyses of the stream-sediment samples represent the chemistry of the rock material eroded from the drainage basin upstream from each sample site. Such information is useful in identifying those basins which contain concentrations of elements that may be related to mineral deposits. The stream-sediment samples consisted of active alluvium collected primarily from first-order (unbranched) and second-order (below the junction of two first-order) streams as shown on USGS topographic maps (scale = 1:63,360). Where stream sediments were not available due to glacial ice cover in the drainage basin, a glacial-debris sample was collected. The sample consists of detrital material that has been mechanically introduced into a moraine from the bedrock and colluvium. Like the stream sediment, the glacial debris represents the chemistry of the rock material eroded from the drainage basin Glacial-debris samples and heavy-mineral concentrates of glacial-debris samples were collected at the following sites: 143-150, 156-157, 217-233, 488-490, 704-705, and 748-750. Heavy-mineral-concentrate samples We panned heavy-mineral-concentrate samples from the same active alluvium as the stream-sediment samples. Each bulk sample was passed through a 2.0-mm (10-mesh) screen to remove the coarse material. The sediment passing through the screen was panned until most of the quartz, feldspar, organic material, and clay-sized material was removed. The sample was oven dried at 16°C.

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