<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>Cynthia Dusel-Bacon</dc:contributor>
  <dc:contributor>Lawrence C. Rowan</dc:contributor>
  <dc:contributor>Robert G. Eppinger</dc:contributor>
  <dc:contributor>Larry P. Gough</dc:contributor>
  <dc:contributor>Warren C. Day</dc:contributor>
  <dc:creator>Bernard E. Hubbard</dc:creator>
  <dc:date>2007</dc:date>
  <dc:description>On July 8, 2003, the Advanced Spaceborne Thermal 
Emission and Reflection Radiometer (ASTER) sensor 
acquired satellite imagery of a 60-kilometer-wide swath 
covering a portion of the Bonnifield mining district within 
the southernmost part of the Tintina Gold Province, Alaska, 
under unusually favorable conditions of minimal cloud and 
snow cover. Although rocks from more than eight different 
lithotectonic terranes are exposed within the extended swath of 
data, we focus on volcanogenic massive sulfides (VMS) and 
porphyry deposits within the Yukon-Tanana terrane (YTT), 
the largest Mesozoic accretionary terrane exposed between the 
Denali fault system to the south of Fairbanks and the Tintina 
fault system to the north of Fairbanks. 
Comparison of thermal-infrared region (TIR) 
decorrelation stretch data to available geologic maps indicates 
that rocks from the YTT contain a wide range of rock types 
ranging in composition from mafic metavolcanic rocks to 
felsic rock types such as metarhyolites, pelitic schists, and 
quartzites. The nine-band ASTER visible-near-infrared 
region--short-wave infrared region (VNIR-SWIR) reflectance 
data and spectral matched-filter processing were used to map 
hydrothermal alteration patterns associated with VMS and 
porphyry deposit types. In particular, smectite, kaolinite, 
opaline silica, jarosite and (or) other ferric iron minerals 
defined narrow (less than 250-meter diameter) zonal patterns 
around Red Mountain and other potential VMS targets. Using 
ASTER we identified some of the known mineral deposits 
in the region, as well as mineralogically similar targets that 
may represent potential undiscovered deposits. Some known 
deposits were not identified and may have been obscured by 
vegetation or snow cover or were too small to be resolved.</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.3133/sir20075289E</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>U.S. Geological Survey</dc:publisher>
  <dc:title>Mapping known and potential mineral occurrences and host rocks in the Bonnifield Mining District using minimal cloud- and snow-cover ASTER data: Chapter E in &lt;i&gt;Recent U.S. Geological Survey studies in the Tintina Gold Province, Alaska, United States, and Yukon, Canada--results of a 5-year project&lt;/i&gt;</dc:title>
  <dc:type>reports</dc:type>
</oai_dc:dc>