Stuart A. Giles

Biogeochemical Characterization of an Undisturbed Highly Acidic, Metal-Rich Bryophyte Habitat, East-Central Alaska, U.S.A

ABSTRACT We report on the geochemistry of soil and bryophyte-laden sediment and on the biogeochemistry of willows growing in an undisturbed volcanogenic massive sulfide deposit in the Alaska Range ecoregion of east-central Alaska. We also describe an unusual bryophyte assemblage found growing in the acidic metal-rich waters that drain the area. Ferricrete-cemented silty alluvial sediments within seeps and streams are covered with the liverwort Gymnocolea inflata whereas the mosses Polytrichum commune and P. juniperinum inhabit the area adjacent to the water and within the splash zone. Both the liverwort-encrusted sediment and Polytrichum thalli have high concentrations of major and trace metal cations (e.g., Al, As, Cu, Fe, Hg, La, Mn, Pb, and Zn). Soils in the area do not reflect the geochemical signature of the mineral deposit and we postulate they are influenced by the chemistry of eolian sediments derived from outside the deposit area. The willow, Salix pulchra, growing mostly within and adjacent to the larger streams, has much higher concentrations of Al, As, Cd, Cr, Fe, La, Pb, and Zn when compared to the same species collected in non-mineralized areas of Alaska. The Cd levels are especially high and are shown to exceed, by an order of magnitude, levels demonstrated to be toxic to ptarmigan in Colorado. Willow, growing in this naturally occurring metal-rich Red Mountain alteration zone, may adversely affect the health of browsing animals.

An exploration hydrogeochemical study at the giant Pebble porphyry Cu-Au-Mo deposit, Alaska, USA, using high-resolution ICP-MS

A hydrogeochemical study using high resolution ICP-MS was undertaken at the giant Pebble porphyry Cu-Au-Mo deposit and surrounding mineral occurrences. Surface water and groundwater samples from regional background and the deposit area were collected at 168 sites. Rigorous quality control reveals impressive results at low nanogram per litre (ng/l) levels. Sites with pH values below 5.1 are from ponds in the Pebble West area, where sulphide-bearing rubble crop is thinly covered. Relative to other study area waters, anomalous concentrations of Cu, Cd, K, Ni, Re, the REE, Tl, SO42− and F− are present in water samples from Pebble West. Samples from circum-neutral waters at Pebble East and parts of Pebble West, where cover is much thicker, have anomalous concentrations of Ag, As, In, Mn, Mo, Sb, Th, U, V, and W. Low-level anomalous concentrations for most of these elements were also found in waters surrounding nearby porphyry and skarn mineral occurrences. Many of these elements are present in low ng/l concentration ranges and would not have been detected using traditional quadrupole ICP-MS. Hydrogeochemical exploration paired with high resolution ICP-MS is a powerful new tool in the search for concealed deposits.

Ultraviolet to near-infrared spectroscopy of REE-bearing materials

Increasing worldwide demand for many of our natural resources requires that we reassess our geologic models and expand our search for rare earth element (REE) resources in the United States. Currently, there is a lack of sufficient spectroscopic investigations characterizing surface materials associated with many of the potential REE-bearing deposit types. Understanding the spectral properties of these deposits using ultraviolet (UV) to near-infrared (NIR) spectroscopic methods will add significant information about how we assess such deposits in the future using laboratory spectrometers, core scanning systems, and imaging spectrometers. Spectra of lanthanide-bearing materials show fine structure in the UV to NIR wavelengths of the electromagnetic spectrum that are caused by 4/-4/ intraconfigurational electron transitions of lanthanide ions present in the material [1]. Lanthanide-bearing minerals produce sharp spectral absorptions that allow for accurate identification of these minerals when found in significant concentrations and can also be used to identify the type of lanthanides based on the position of their absorptions.

Hyperspectral surface materials map of quadrangles 3360 and 3460, Kawir-e Naizar (413), Kohe-Mahmudo-Esmailjan (414), Kol-e Namaksar (407), and Ghoriyan (408) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

HYPERSPECTRAL SURFACE MATERIALS MAP OF QUADRANGLES 3360 AND 3460, KAWIR-E NAIZAR (413), KOHE-MAHMUDO-ESMAILJAN (414), KOL-E NAMAKSAR (407), AND GHORIYAN (408) QUADRANGLES, AFGHANISTAN, SHOWING IRON-BEARING MINERALS AND OTHER MATERIALS By Trude V.V. King, Todd M. Hoefen, Raymond F. Kokaly, Keith E. Livo, Michaela R. Johnson, and Stuart A. Giles 2013 SCALE 1:250 000 5 5 0 10 15 20 25 30 35 40 KILOMETERS 10 5 0 5 15 20 MILES Cultural data from digital files from Afghanistan Information Management Service (http://www.aims.org.af) Projection: Universal Transverse Mercator, Zone 41, WGS 1984 Datum Figure 1.—Provinces and selected cities, towns, and villages in the map area. Topography is shown as shaded relief. EXPLANATION OF MATERIAL CLASSES USGS OPEN-FILE REPORT 2013–1203–B AGS OPEN-FILE REPORT (413/414/407/408) 2013–1203–B USGS Afghanistan Project Product No. 226 U.S. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY AFGHANISTAN MINISTRY OF MINES AFGHANISTAN GEOLOGICAL SURVEY Prepared in cooperation with the U.S. Geological Survey under the auspices of the U.S. Department of Defense Task Force for Business and Stability Operations

Hyperspectral surface materials map of quadrangles 3664 and 3764, Char Shengo (123), Shibirghan (124), Jalajin (117), and Kham-Ab (118) quadrangles, Afghanistan, showing iron-bearing minerals and other materials

124 123 3664 118 117 3764 REFERENCES CITED Clark, R.N., Swayze, G.A., Wise, R.A, Livo, K.E., Hoefen, T.M., Kokaly, R.F., and Sutley, S.J., 2007, USGS digital spectral library splib06a: U.S. Geological Survey Data Series 231. King, T.V.V., Kokaly, R.F., Hoefen, T.M., Dudek, K.B., and Livo, K.E., 2011, Surface materials map of Afghanistan; iron-bearing minerals and other materials: U.S. Geological Survey Scientific Investigations Map 3152–B, one sheet, scale 1:1,100,000. Kokaly, R.F., King, T.V.V., and Hoefen, T.M., 2013, Surface mineral maps of Afghanistan derived from HyMapTM imaging spectrometer data, version 2: U.S. Geological Survey Data Series 787. Kokaly, R.F., King, T.V.V., and Livo, K.E., 2008, Airborne hyperspectral survey of Afghanistan 2007; flight line planning and HyMapTM data collection: U.S. Geological Survey Open-File Report 2008–1235, 14 p. DATA SUMMARY This map shows the spatial distribution of selected iron-bearing minerals and other materials derived from analysis of airborne HyMapTM imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007 (Kokaly and others, 2008). This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan and is a subset of the version 2 map of the entire country showing iron-bearing minerals and other materials (Kokaly and others, 2013). This version 2 map improved mineral mapping from the previously published version (King and others, 2011) by refining the classification procedures, especially in areas having wet soils. The version 2 map more accurately represents the mineral distributions and contains an additional mineral classification (FeFe type 3). Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMapTM imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMapTM imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials (Clark and others, 2007). Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated. Minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Goethite and jarosite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra. Further information regarding the processing procedures is presented in King and others (2011) and Kokaly and others (2013). International boundary City, town, or village Peak; elevation in meters 3725

Hyperspectral surface materials map of quadrangles 3664 and 3764, Char Shengo (123), Shibirghan (124), Jalajin (117), and Kham-Ab (118) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

124 123 3664 118 117 3764 DATA SUMMARY This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMapTM imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007 (Kokaly and others, 2008). This map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan and is a subset of the version 2 map of the entire country showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials (Kokaly and others, 2013). This version 2 map improved mineral mapping from the previously published version (Kokaly and others, 2011) by refining the classification procedures, especially in areas having wet soils. The version 2 map more accurately represents the mineral distributions and contains modifications to the material class names, as well as an additional mineral classification (Carbonate and clay/muscovite). Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMapTM imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMapTM imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials (Clark and others, 2007). Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated. Minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra. Further information regarding the processing procedures is presented in Kokaly and others (2011, 2013).