This series of geochemical maps shows the distribution of lead in four sample media: (A) the oxide residue (the oxalic-acid-leachable fraction) of the stream sediment, (B) the minus-80-mesh stream sediment, (C) the ash of streambank sod (mixed organic and inorganic material) collected beneath the water level, and (D) the ash of aquatic bryophytes (mosses). The geochemical data are plotted on base maps showing generalized geology and the drainage pattern. The map symbols show the sample sites and ranges of values in the following manner: (1) open symbols denote background, (2) small black symbols represent weakly anomalous values, and (3) large black symbols denotes strongly anomalous values. Because the small black symbols represent weakly anomalous values, they are considered to be significant only where they are closely associated with strongly anomalous metal values either in the same sample medium or with anomalous values in other sample media. The ranges of values represented by the symbols are shown on the histograms which accompany the geochemical maps. An explanation of sampling, preparation, and analytical procedures is given in Circular 734, which accompanies this folio. Complete analytical data for geochemical samples collected by the U.S. Geological Survey in the Tanacross quadrangle are available in a U.S. Geological Survey open-file report (O'Leary and others, 1976).

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USGS1976

Geochemical maps showing the distribution and abundance of zinc in the Tanacross Quadrangle, Alaska

This series of geochemical maps shows the distribution of zinc in four sample media: (A) the oxide residue (oxalic-acid-leachable fraction) of the stream sediment, (B) the minus-80-mesh steam sediment, (C) the ash of streambank sod (mixed organic and inorganic material) collected beneath the water level, and (D) the ash of aquatic bryophytes (mosses). The map symbols show sample sites and ranges of values in the following manner: (1) open symbols denote background, (2) small black symbols represent weakly anomalous values, and (3) large black symbols denote strongly anomalous values. Because the small black symbols represent weakly anomalous values, we consider them to be significant only where they correlate with strongly anomalous metal values either in the same or in other sample media. The ranges of values represented by the symbols are shown on the histograms that accompany the geochemical maps. An explanation of sampling, preparation, and analytical procedures is given in Circular 734, which accompanies the folio. Complete analytical data for geochemical samples collected by the U.S. Geological Survey in the Tanacross quadrangle are available in a U.S. Geological Survey open-file report (O'Leary and others, 1976.)

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USGS1976

Geochemical maps showing the distribution and abundance of arsenic and mercury in the Tanacross Quadrangle, Alaska

This series of geochemical maps shows the distribution of arsenic and mercury in the minus-80-mesh stream sediment and of arsenic in the ash of streambank sod (mixed organic and inorganic material) collected beneath the water level. The geochemical data are plotted on a base map that shows generalized geology and the drainage pattern. The map symbols show the sample sites and ranges of values in the following manner: (1) open symbols denote background, (2) small black symbols represent weakly anomalous values, and (3) large black symbols denotes strongly anomalous values. Because the small black symbols represent weakly anomalous values, they are considered to be significant only where they are closely associated with strongly anomalous metal values either in the same sample medium or with anomalous values in other sample media. The ranges of values represented by the symbols are shown on the histograms that accompany the geochemical maps. An explanation of sampling, preparation, and analytical procedures is given in Circular 734, which accompanies this folio. Complete analytical data for geochemical samples collected by the U.S. Geological Survey in the Tanacross quadrangle are available in a U.S. Geological Survey open-file report (O'Leary and others, 1976).

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USGS1976

Geochemical maps showing the distribution and abundance of tin in the Tanacross Quadrangle, Alaska

This series of geochemical maps shows the distribution of tin in three sample media: (A) the oxide residue (the oxalic-acid-leachable fraction) of the stream sediment, (B) the minus-80-mesh stream sediment, and (C) the ash of aquatic bryophytes (mosses). The geochemical data are plotted on a base map that shows generalized geology and the drainage pattern. The map symbols show the sample sites and ranges of values in the following manner: (1) open symbols denote background, (2) small black symbols represent weakly anomalous values, and (3) large black symbols denotes strongly anomalous values. Because the small black symbols represent weakly anomalous values, they are considered to be significant only where they correlate with strongly anomalous metal values either in the same or other sample media. The ranges of values were determined from the histograms and other statistical data shown for each of the sample media. An explanation of sampling, preparation, and analytical procedures is given in Circular 734, which accompanies this folio. Complete analytical data for geochemical samples collected by the U.S. Geological Survey in the Tanacross quadrangle are available in a U.S. Geological Survey open-file report (O'Leary and others, 1976).

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USGS1976

Composite geochemical map of anomalous copper and molybdenum distribution in the Tanacross Quadrangle, Alaska

This geochemical map delineates drainage basins in which either anomalous copper, molybdenum, or both copper and molybdenum were detected in at least one of four sample media: (A) the oxide residue (the oxalic-acid-leachable fraction) of the stream sediment, (B) the minus-80-mesh stream sediment, (C) the ash of streambank sod (mixed organic and inorganic material) collected beneath the water level, and (D) the ash of aquatic bryophytes (mosses). The anomaly patterns were derived from the point-plot maps of copper and molybdenum distribution in the individual sample media (Curtain, Day, O'Leary, Marsh, and Tripp, 1976; Curtain, Day, Carten, Marsh, and Tripp, 1976). Background data were disregarded for each of the two metals. Weakly anomalous data for all media (small black symbols) were assigned the number 2; strongly anomalous data for all media (large black symbols) were assigned the number 3. These new data were then summed or "stacked" for each metal so that all sites showing anomalous values in one or more of the sample media had a numerical rating that ranged from 2 (weakly anomalous value in one sample medium) to a possible 12 (strongly anomalous values in all four sample media). The summed data were ranked into three groups shown in the explanation. The drainage basins showing anomalous values were outlined according to these groups. As a final step the composite copper anomaly map was superimposed on that of molybdenum to give this composite copper-molybdenum map.

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USGS1976

Distribution and abundance of gold in stream sediments and moraine debris, McCarthy quadrangle, Alaska

A geochemical survey was conducted in the McCarthy quadrangle Alaska, to identify areas containing anomalous concentrations of various metallic and nonmetallic elements. This study incorporates the results of analyses for gold from 764 stream sediment and glacial moraine debris samples collected in the quadrangle, and analyzed by the U.S. Geological Survey between 1961 and 1976 using atomic absorption spectrophotometry. No analytical results for gold are available for stream sediment samples from the White River area, located in the northeastern part of the quadrangle. The accompanying map shows the distribution and relative abundance of gold in stream sediment and glacial moraine debris samples. Geochemical analyses have been grouped and are represented by symbols on a base map, which includes topography and generalized geology. The range of analytical values and the symbol that represents it are shown on the histogram. Graphical representation of analytical values on the map permits easy observation of any large variation resulting from separate or duplicate samples collected at the same or nearby localites.

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USGS1976

Distribution and abundance of arsenic in bedrock, mineralized, vein, and altered rock samples, McCarthy quadrangle, Alaska

A geochemical survey was conducted in the McCarthy quadrangle Alaska, to identify areas containing anomalous concentrations of various metallic and nonmetallic elements. This study incorporates the results of analyses for arsenic from 827 rock samples collected in the quadrangle, and analyzed by the U.S. Geological Survey between 1961 and 1976 using semiquantitative emission spectrophotometry. The samples included both unaltered and hydrothermally altered rocks. The hydrothermally altered rock consist of ore grade material, gossans, fault gouge, vein materials, silica-rich boxworks, veins adjacent to faults, and fracture surfaces showing evidence of mineralization. Therefore, the analytical data set may be considered representative of most rock types known to occur in the study area. The accompanying map shows the distribution and relative abundance of arsenic in rocks collected. Geochemical analyses have been grouped and are represented by symbols on a base map, which includes topography and generalized geology. The range of analytical values and the symbol that represents it are shown on the histogram. Graphical representation of analytical values on the map permits easy observation of any large variation resulting from separate or duplicate samples collected at the same or nearby localites. All samples were crushed and ground to pass through a 180 micron opening sieve before being analyzed.

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USGS1976

Geochemical anomalies in the Willow Creek mining district, southern Talkeetna Mountains, Alaska

No abstract available.

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