mineral mapping studies such as those done at well known 
localities like Cuprite, Nevada, this exercise tried to simulate a 
operational situation often encountered in mineral exploration, 
in which remote sensing is used as the first tool for defining 
targets before the geologist sets foot on the ground. Therefore, 
techniques that do not require a priori input of ground data 
were favored and assessed in their ability to convert image data 
to ground reflectance and for identifying surface materials. 
3. STUDY AREA 
The area selected for this study is the Bodie mining district and 
part of the neighboring Paramount district located in Mono 
County, California, USA (Figure 1). AVIRIS data for this area 
were acquired in August 1992 by NASA's ER-2 aircraft. The 
scene used in this study consists of 614 x 512 pixels (10.44 x 
9.70 km) in 224 bands, at 16-bit radiometric resolution, 
corresponding to approximately 141 MBytes of data. It covers 
the Bodie district almost entirely and the eastern portion of the 
Paramount district between Atastra and Rough creeks. 
  
  
  
  
  
  
  
r 382 12’ 
  
  
  
119° 00’ 
  
  
Figure 1 - Location of the study area. The rectangle around Bodie marks the outline of the AVIRIS scene and the locations marked 
as PA, SH and BB are refered in the text. 
4. GEOLOGY AND MINERALIZATION OF THE 
BODIE AND PARAMOUNT DISTRICTS 
Bodie was an important gold-silver mining district in the 
second half of the nineteenth century and a mercury mine was 
exploited in the Paramount district. Tertiary (7.8 to 9.4 Ma) 
intermediate to basic volcanic rocks (dacitic, andesitic and 
rhyolitic lavas, plugs, tuffs and breccias) underlie both districts. 
Hydrothermal alteration associated with precious metal 
concentration at Bodie is probably the result of intense thermal 
spring activity, some of which can still be found in this region 
along fault zones (Silberman et al., 1995). 
Bodie has mixed characteristics of a bonanza-type lode quartz 
vein deposit and a large-scale stockwork system, with gold 
162 
occurring in quartz veins and quartz-adularia-chalcedony 
stockworks in the center of the district. Petrographic work by 
Herrera et al. (1993) showed vertical and lateral zoning in the 
alteration with silicification in the center surrounded by zones 
of potassic, argillic and sericitic alteration and an outer zone of 
propylitic alteration. Little information is available for the 
Paramount district due to the lack of important mineralization, 
but the district has recently been prospected for bulk tonnage 
precious metal mineralization (Herrera et al., 1993). Geological 
characteristics observed at Paramount are very similar to those 
in Bodie and the origin of the alteration is believed to be similar 
(Silberman et al., 1995). 
5. DATA CALIBRATION TO SURFACE REFLECTANCE 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B7. Vienna 1996