Chapter 8B. Analysis of Imaging Spectrometer Data for the 

Katawas Area of Interest

By Trude V.V. King and Michaela R. Johnson

Abstract

Computer analysis of the HyMap spectroscopic data of the Katawas area of interest (AOI) in the 

east-central part of Afghanistan used spectrum matching techniques to identify the occurrence of 

selected materials at the surface based on characteristic absorption features (absorption bands) in the 

HyMap data compared to a library of spectral standards. Although there are no known mineral 

occurrences in the AOI, several areas warranting additional studies are recognized.

Iron (Fe 2+

A northeast-trending, fault-bounded linear feature bisects the area, and mineralization occurs 

along and adjacent to the linear feature and an associated northeast-trending ridge. Minerals along and 

adjacent to the linear feature include epidote and chlorites, calcite and calcite mineral mixtures, 

serpentines, and Fe-bearing carbonates. Well-defined clusters of Fe

)-bearing minerals, chlorite or epidotes, and calcite and calcite mixtures dominate the 

AOI. The area has three potential areas that, based on the HyMap data, suggest areas with potential 

epithermal mineralization.

3+

The southern part of the fault-bounded area is characterized by carbonates, epidotes and 

chlorites, and smaller amounts of Fe-bearing carbonates that are seemingly bedded and lithologically 

controlled. In the northwestern part of the AOI, complex terrain that appears to be folded is 

characterized by calcite, epidotes or chlorites, and Fe-bearing carbonates, suggesting possible 

hydrothermal activity. 

-bearing minerals are also present 

in the fault-bounded area. 

The presence of a known geochemical mercury anomaly (Peters and others, 2007) and the 

mapped mineral assemblages make this a very attractive area for future detailed exploration.

8B.1 Introduction

Previous U.S. Geological Survey (USGS) analyses of existing geologic data of Afghanistan 

revealed numerous areas with indications of potential mineral resources of various types (Peters and 

others, 2007). From these areas of interest, several were selected for follow-on studies using modern 

imaging spectrometer remote sensing data to further characterize surface materials. One of those areas is 

the Katawas area of interest (AOI) in east-central Afghanistan.

The Katawas AOI is approximately 150 km south-southwest of Kabul (fig. 8B–1) and is believed 

to have the potential for hot-springs gold, mercury, and base-metal deposits. To help assess these 

potential resources, high-resolution imaging spectrometer data were analyzed to detect the presence of 

selected minerals that may be indicative of past mineralization processes. This report contains the results 

of those analyses for the main Katawas AOI and the Katawas gold subarea. Katawas gold subarea 

mineral maps are subsets extracted from the same data as the Katawas AOI maps, but are presented at a 

larger scale, thus showing the mineral distribution patterns in more detail. Within the Katawas area, two 

areas deserving further investigation, especially detailed geological mapping and geochemical studies, 

are highlighted in King, Johnson, and others (2011). 
618 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Figure 8B–1. The Katawas area of interest is located about 150 km south of Kabul in the Ghazni and Paktika 

Provinces and is believed to have the potential for hot-springs gold, mercury, and base-metal deposits.

8B.1.1 Imaging Spectrometer Data Collection and Processing

In 2007, imaging spectrometer remote sensing data were acquired over most of Afghanistan with 

the HyMap imaging spectrometer (Cocks and others, 1998), as part of the USGS Oil and Gas Resources 

Assessment of the Katawas and Helmand Basins project (Kokaly and others, 2008). These data were 

acquired from August 22, 2007 to October 2, 2007. There were 207 north-south flight lines and 11 

cross-cutting calibration lines collected over Afghanistan, for a total of 218 flight lines covering a 

surface area of 438,012 km2 (Kokaly and others, 2008). These data provide a means for characterizing 

surface materials in support of assessments of resources (coal, water, minerals, and oil and gas) and 

earthquake hazards in the country. Imaging spectrometers measure the reflectance of visible and nearinfrared light from the Earth’s surface in many narrow channels, producing a reflectance spectrum for 

each image pixel. These reflectance spectra can be interpreted to identify specific chemical transitions 

and molecular bonds that provide compositional information about specific materials occurring at the 

surface. The imaging spectrometer sensor data can only be used to characterize the upper surface 

materials and not subsurface composition or structure. 

After undergoing a complex and rigorous data calibration process, the georeferenced and 

calibrated reflectance data were processed. The reflectance spectrum of each pixel of HyMap data was 

compared to the spectral features of reference entries in a spectral library of minerals, vegetation, water, 
Chapter 8B. Analysis of Imaging Spectrometer Data for the Katawas Area of Interest 619

and other materials (King, Kokaly, and others, 2011; Kokaly and others, 2011). The best spectral 

matches were determined, and the results were clustered into classes of materials discussed below.

8B.1.2 Calibration Process

To ensure the utility of the imaging spectrometer dataset, a rigorous calibration process to 

remove atmospheric absorptions and residual instrument artifacts was applied. Before the calibration 

process started, each flight line was georeferenced to Landsat base imagery in UTM projection (Davis, 

2007). Because of the extreme topographic relief and restricted access to ground-calibration sites, 

modifications to the traditional USGS calibration procedures were required to calibrate the 2007 

Afghanistan HyMap dataset (Hoefen and others, 2010). Radiance data were converted to apparent 

surface reflectance using the radiative transfer correction program Atmospheric CORrection Now 

(ACORN; ImSpec LLC, Palmdale, Calif.). ACORN was run multiple times for each flight line, using 

average elevations in 100-m increments, covering the range of minimum to maximum elevation within 

the flight line. A single atmospherically corrected dataset was assembled from the ACORN results in 

100-m increments. This was done by determining the elevation of each pixel and selecting the 

atmospherically corrected pixel from the 100-m increment closest to the elevation of the pixel. The 

atmospherically corrected dataset was further empirically adjusted using ground-based reflectance 

measurements from the Kandahar Air Field, Bagram Air Base, and Mazar-e-Sharif Airport, as well as 

soil samples from two fallow fields. To improve the data quality, new calibration techniques were 

developed to address the atmospheric differences within a flight line. 

To refine data quality of ground-calibrated reflectance, a multiplier correction, computed by 

cross-calibrating north-south flight lines with a flight line that passed over a ground-calibration site, was 

applied. For each north-south flight line, the pixels in overlap regions of north-south and cross-cutting 

calibration lines, subject to slope, vegetation cover, and other restrictions, were used to develop these 

cross-calibration correction factors (Hoefen and others, 2010). The cross-calibration multiplier corrected 

any residual atmospheric contamination in the imaging spectrometer data that was not present in the 

spectra of the ground-calibration site.

8B.1.3 Materials Maps and Presentation

HyMap reflectance data were processed using Material Identification and Characterization 

Algorithm (MICA), a module of the U.S. Geological Survey Processing Routines in Interactive Data 

Language (IDL) for Spectroscopic Measurements (PRISM) software (Kokaly, 2011). MICA compared 

the reflectance spectrum of each pixel of HyMap data against entries in a reference spectral library of 

minerals, vegetation, water, and other materials. The library included 97 reference spectra of 

well-characterized mineral and material standards. The resulting maps of material distribution, 

resampled to a 23 × 23 m2

HyMap data were analyzed twice. MICA was first run using the set of minerals with absorption 

features in the visible and near-infrared wavelength region, producing the 1-micron (μm) map of ironbearing minerals and other materials (King, Kokaly, and others, 2011). MICA was run again using the 

minerals with absorption features in the shortwave infrared, producing the 2-μm map of carbonates, 

phyllosilicates, sulfates, altered minerals, and other materials. For clarity of presentation, some 

individual classes in these two maps were bundled by combining selected specific mineral types (for 

example kaolinites, montmorillonites, and hematites) to reduce the number of mineral classes. The ironbearing minerals map has 27 classes. Iron-bearing minerals with different mineral compositions but 

similar spectral features are difficult to classify as specific mineral species. Thus, generic spectral 

classes, including several minerals with similar absorption features, such as Fe

pixel grid, were used to prepare maps of mineral, vegetation, and other 

material occurrences.

3+ Type 1 and 

Fe 3+ Type 2, are depicted on the map. The carbonate, phyllosilicates, sulfates, and altered minerals map 

has 31 classes. Minerals with slightly different mineral compositions but similar spectral features are 

less easily discriminated; thus, some identified classes consist of several minerals with similar spectra, 
620 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

such as the chlorite or epidote class. When comparisons with reference spectra produced no viable 

match, a designation of “not classified” was assigned to a pixel.

Although the occurrence of certain minerals (pyrophyllite, buddingtonite, dickite, and jarosite) 

may suggest that mineralization processes may have once operated in the area, many of the minerals that 

were identified are also common rock-forming minerals. Consequently, the distribution patterns of the 

identified minerals are extremely important in understanding the causes of mapped mineral occurrences 

and evaluating the possible potential for related mineral deposits. 

8B.1.4 Data Limitations

It should be noted that geographic registration between various datasets is not always possible, 

because of differences in collection methods and resolution. The geographic accuracy and quality of 

each dataset is limited by the original source. Significant efforts were made to ensure the geographic 

accuracy of the HyMap data (Kokaly and others, 2008; Hoefen and others, 2010). However, exact 

registration between previously published known mineral occurrences, fault traces, geologic units, and 

structural boundaries in comparison to the HyMap data may not be ideal. To resolve additional details, 

the digital versions of these maps can be viewed at higher spatial resolution than what is possible in a 

single-page printed map. 

8B.2 Geologic Setting of the Katawas Area of Interest

The Katawas hot-springs gold, mercury, and base-metals deposits are located in the Ghazni and 

Paktika Provinces of Afghanistan (fig. 8B–1). The Katawas AOI is approximately 478 km2 and the 

Katawas gold subarea is approximately 143 km2

. The elevation in the AOI ranges from 2,079 to 3,052 m 

(fig. 8B–2). High northeast-trending terrain dominates the central portion of the AOI, and lower terrain 

occurs in the northern, northeastern, and western parts. Landsat Enhanced Thematic Mapper (TM) data 

for the AOI (fig 8B–3) show that the rocks range from light colors to greenish, red, and black. Two 

subparallel faults that strike southwest to northeast extend three-quarters of the extent of the AOI, and 

rocks range in age from Paleocene to Recent (fig. 8B–4). Small cultivated plots of land and a lake occur 

in the northern part of the AOI. 

8B.3 Imaging Spectrometer Material Maps of the Katawas Area of Interest

Spectroscopic analysis of the HyMap imaging spectrometer data of the Katawas AOI resulted in 

the identification of a variety of surficial minerals. These minerals have been identified by the presence 

and wavelength position of absorption features in the 0.45–2.48 μm wavelength. Two general categories 

of minerals are recognized: (1) iron-bearing minerals that have characteristic spectral absorption features 

that occur at wavelengths near 1 μm, and (2) a wide variety of minerals, including carbonate, mica, and 

clay minerals, and sulphates that have diagnostic spectral absorptions near 2-μm wavelength. Although 

the occurrence of certain minerals may suggest mineralization processes may have operated in the area, 

many of the minerals identified and mapped are also common rock-forming minerals or minerals that 

can be derived from the weathering of a variety of rock types. Consequently, the distribution patterns of 

the identified minerals and the geologic content where they occur are extremely important in 

understanding the causes of the mapped mineral occurrences and assessing the potential for related 

mineral deposits.

A companion report and geodatabase of potential mineral resource anomalies (areas of potential 

economic mineral resource occurrence) that have not been previously recognized or where the HyMap 

data has expanded the geologic understanding of the prospect can be found in King, Johnson, and others 

(2011). 
Chapter 8B. Analysis of Imaging Spectrometer Data for the Katawas Area of Interest 621

8B.3.1 Katawas Area of Interest

Figures 8B–5 and 8B–6 show the distribution of identified surficial minerals and other materials 

for the entire Katawas AOI. Figure 8B–5 shows the distribution of Fe-bearing minerals and other 

materials (28 possible classes), and figure 8B–6 shows the distribution of carbonates, phyllosilicates, 

sulphates, altered minerals, and other materials (32 possible classes). Because of the large number of 

mineral classes represented and the subtleties of the distribution patterns in these maps, it is more 

instructive to display these results as a series of topical images depicting a group of minerals that are 

commonly related or occur together in special geologic environments (figs. 8B–7 to 8B–11). Figure 8B–7 

shows the distribution of carbonate minerals in the AOI; figure 8B–8 shows the distribution of clays and 

micas; figure 8B–9 shows the distribution of iron oxide and hydroxide minerals; figure 8B–10 shows the 

distribution of secondary minerals; and figure 8B–11 shows the distribution of minerals commonly 

found in hydrothermally altered rocks. 

Figure 8B–2. Shaded relief map showing elevations in the Katawas area of interest (AOI). High northeasttrending terrain dominates the central portion of the AOI, and lower terrain occurs in the northern, northeastern, and 

western parts.

8B.3.1.1 Carbonate Minerals

The calcite and calcite + muscovite/illite mineral groups are the primary carbonate minerals in 

the AOI (fig. 8B–7). The calcite group minerals preferentially occur in the fault-bounded central portion 

of the area. A fewer number of dolomites and dolomite mixtures are present in the area and occur both 

in the southwest portion of the image (Paleocene rocks) and in the central fault-bounded area. A 

scattering of dolomitic minerals occur in the Eocene and Pliocene rocks on the east side of the central 
622 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

fault-bounded area. In the northwestern part of the image, near lat 68°37′28.73′′Ε., long 33°14′48.56′′Ν., 

is an area that is free of calcite and montmorillonite mixtures, but exhibits well-defined distributions of 

calcite. A small Eocene unit on the northwest side of the AOI, adjacent to the boundary, is dominantly 

calcite, but also has minor amounts of calcite and montmorillonite. Fe-bearing carbonates occur along 

the length of the central fault-bounded region as well as along an east-northeast-trending ridge near lat 

68°

38′45′′Ε., long 33°12′10′′Ν. that originates within the central fault-bounded region. 

Figure 8B–3. Several northeast-striking faults occur in the Katawas area of interest. The Landsat Enhanced 

Thematic Mapper (TM) images show that the rocks range from light colors to greenish, red, and black. (Davis, 

2007).

8B.3.1.2 Clays and Micas

The clays and micas are mapped in all ages of rocks within the AOI (fig 8B–8). 

Muscovites and illites are the most abundant minerals. Pixels of chlorite and epidote and illitic 

minerals dominate the central fault-bounded area that cross-cuts the AOI. The portion of the AOI east of 

the central fault-bounded area is dominated by spatially coherent groups of illite and muscovite with 

lesser amounts of chlorite and epidote. The bedded rocks of Eocene age that appear in the “greenish” 

colored areas in the TM image of the AOI (fig 8B–3) are mapped as illite with lesser amounts of epidote 

and chlorite. Some illitic rocks occur in the northeast portion of the AOI in Pliocene, late Quaternary, 

and Recent rocks. Illite, muscovite, and chlorite and epidote occur in the southwestern portion of the 

AOI and appear to be eroded from the fault-bounded portion of the central ridge. Strong concentrations 

of chlorite or epidote and illite occur in the Eocene rocks in the area adjacent to the northern terminus of 

the central fault-bounded area near lat 68°

37′28′′E., long 33°14′48 ′′N. These rocks appear dark in the 
Chapter 8B. Analysis of Imaging Spectrometer Data for the Katawas Area of Interest 623

TM image and have a morphology commonly associated with extrusive rocks. Montmorillonite-rich 

surficial materials are present near lat 68°43′27′′E., long 33°17′38′′N., in Quaternary and Recent rocks. 

Figure 8B–4. Within the Katawas area of interest, the prominent faults strike southwest to northeast and rocks 

range in age from Paleocene to Recent. Geologic map is taken from Doebrich and others (2006).

8B.3.1.3 Iron Oxides and Hydroxides

Figure 8B–9 shows iron-bearing and other alteration minerals in the Katawas AOI. The central, 

fault-bounded region of the AOI primarily contains epidote with lesser amounts of goethite-bearing 

minerals and minor amounts of hematite associated with the east-northeast-trending ridge near lat 

68°

38′35′′E., long 33°12′11′′N. Chlorite or epidote pixels occur in the extrusive rocks near lat 

68°

38′29′′E., long 33°14′48′′N., and in the southern half of the AOI where chlorite or epidote is both 

lithologically controlled and represents erosional material of Paleocene, Eocene, and late Quaternary 

rocks (figs. 8B–6 and 8B–9).

8B.3.1.4 Common Secondary Minerals

The occurrence and distribution of common secondary minerals for the Katawas AOI are shown 

in figure 8B–10. The dominant secondary minerals in the AOI are epidote and the chlorite or epidote 

group. Pixels of epidote-bearing minerals are spatially distributed over the area as well as in spatially 

coherent clumps and part of intermingled mineral groups. 

Serpentine pixels are present in the central, fault-bounded area as spatially coherent clusters 

between lat 68°

34′50′′E., long 33°9′57′′N. and lat 68°38′47′′E., long 33°12′9′′N., in Eocene rocks. 
624 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Figure 8B–5. Distribution of iron-bearing and other alteration minerals in the Katawas area of interest detected in 

the HyMap data.

8B.3.1.5 Common Alteration Minerals

Most of the minerals in this group are commonly present in hydrothermally altered rocks 

associated with epithermal processes. Consequently, where they occur in distinct clusters is of great 

interest in terms of potential mineral deposits. However, only chlorite or epidote group minerals and 

Fe-bearing carbonate minerals were mapped in the area (fig 8B–11). 

8B.3.2 Katawas Gold Subarea

There are no known mineral occurrences in the Katawas gold subarea. The topography in the 

area ranges from 2,087 to 2,715 m. High terrain dominates the central portion and lower terrain occurs 

in the northern and northeast part of the subarea (fig. 8B–12). The surficial materials in the TM data 

(fig. 8B–13) show a range in colors including very light, red, greenish, and dark rocks. Small cultivated 

plots of land occur in the northern part of the AOI. The geologic map of the area (fig. 8B–14) shows 

rocks ranging from Paleocene to Recent that do not appear to be well correlated with the color variations 

shown in the TM data. Figures 8B–15 and 8B–16 show the distribution of carbonate, sulphate, 

phyllosilicate and other alteration minerals, and the distribution of Fe-bearing minerals in the subarea.
Chapter 8B. Analysis of Imaging Spectrometer Data for the Katawas Area of Interest 625

Figure 8B–6. Distribution of clays, carbonates, phyllosilicates, sulphates, and other alteration minerals for the 

entire Katawas area of interest detected in the HyMap data.

8B.3.2.1 Katawas Gold Subarea: Carbonate Minerals

The calcite and calcite + muscovite/illite mineral groups are the primary carbonate minerals in 

the subarea (fig 8B–17). The calcite group minerals occur in the fault-bounded central portion of the 

subarea but are also present in well-defined clusters to the east, and in less well defined patterns in the 

northern part of the image. Scattered dolomitic minerals occur on the eastern side of the subarea in the 

Eocene and Pliocene rocks. Iron-bearing carbonates occur along the length of the central fault-bounded 

region as well as along an east-northeast-trending ridge near lat 68°38′7′′Ε., long 33°12′8′′Ν. that 

originates within the central fault-bounded region.

8B.3.2.2 Katawas Gold Subarea: Clays and Micas 

On the basis of the HyMap data, figure 8B–18 shows the enrichment of clays and micas in the 

Katawas gold subarea. The subarea is dominated by chlorite and epidote and illite minerals with lesser 

amounts of muscovite and a very minor amount of montmorillonite. The chlorites and epidotes and 

illites and montmorillonites occur in rocks of all ages. However, the largest concentration of chlorites 

and epidotes occurs in Eocene rocks on the western side of the subarea. 
626 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Figure 8B–7. Distribution of carbonate-bearing minerals detected in the HyMap data.

8B.3.2.3 Katawas Gold Subarea: Iron Oxide and Hydroxide Minerals

The central, fault-bounded region and the east-northeast-trending ridge near lat 68°38′7′′Ε., long 

33°

12′8′′N. primarily contain epidote and goethitic minerals (fig. 8B–19) in Paleocene and Eocene rocks. 

Far less epidote and goethitic minerals are generally present in the younger rock units. However, a welldefined cluster of goethitic minerals ringed by epidote occurs in the northwest part of the image in 

Pliocene rocks near lat 68°40′E., long 33°16′10′′W.

8B.3.2.4 Katawas Gold Subarea: Common Secondary Minerals

The distribution of common secondary minerals (fig. 8B–20) occurs in the central fault-bounded 

area, the associated east-northeast-trending ridge, and the Eocene rocks adjacent to the fault-bounded 

central area. Some epidote or chlorite and epidote group minerals are present in the Eocene, late 

Quaternary, and Recent rocks in the western part of the subarea. Serpentine minerals extend from near 

lat 68°34′50′′E., long 33°9′57′′N. to lat 68°38′47′′E., long 33°12′9′′N. in Paleocene and Eocene rocks. 

Only a few scattered occurrences of the secondary minerals are seen in rocks younger than Pliocene in 

the northern part of the subarea.

8B.3.2.5 Katawas Gold Subarea: Common Alteration Minerals

Common alteration materials detected in the HyMap data (fig. 8B–21) for the subarea are 

chlorite or epidote or Fe-bearing carbonates.
Chapter 8B. Analysis of Imaging Spectrometer Data for the Katawas Area of Interest 627

Figure 8B–8. Occurrence of spatially distinct pixels of clays and micas identified in the HyMap data for the 

Katawas area of interest. 

8B.5 Summary 

The Katawas AOI and the Katawas gold subarea have no known mineral occurrences. However, 

the HyMap data for the AOI and subarea show several locations of potential epithermal activity that 

warrant additional field sampling and geochemical and geophysical studies. Two large areas within the 

AOI have been identified as anomalous regions and are included in the USGS anomalies report (King, 

Johnson, and others, 2011). 

Large concentrations of chlorite or epidote group minerals and muscovites and illites occur in the 

southern part (south of approximately lat 33°9′Ν.) of the AOI (figs. 8B–6, 8B–8; 8B–10; 8B–11) within 

and adjacent to the central fault-bounded area. Figures 8B–8, 8B–10 and 8B–11 suggest that the chlorite 

and epidote mineral occurrences may in part be lithologically controlled in bedded rocks. The 

distribution of muscovites and illites does not appear to be associated with bedded rocks. A small 

concentration of Fe-bearing carbonates within the muscovites and illites further emphasizes the need for 

additional studies. 
628 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Figure 8B–9. Distribution of Fe-hydroxides and oxides mapped using the HyMap data for the Katawas area of 

interest. 

The Katawas AOI and the Katawas gold subareas both contain Fe 3+, Type 1 minerals (figs. 8B–5 

and 8B–16) in the northern part of the study areas in rocks ranging in age from Paleocene to Recent.

Well-defined clusters of the Fe 3+, Type 1 minerals occur in the fault-bounded block in the central 

portion of the AOI along the northeast-trending linear feature where they occur with a concentration of 

goethite-rich surficial material. The Fe 3+, Type 1 minerals appear to be associated with eroded material 

(figs 8B–3 and 8B–13) in rocks younger than Paleocene. 

A large dark area in the TM data (fig 8B–3) also warrants additional geochemical and geological 

sampling. The area situated near lat 68°

37′28.73′′Ε., long 33°14′48.58′′N. shows well-defined clusters of 

chlorite or epidote, epidote, muscovite, illite, calcite, and Fe-bearing carbonates (figs. 8B–5 to 8B–11).

The proximity of the Fe-bearing carbonates and chlorite- and epidote-rich alteration assemblage 

minerals areas makes the area noteworthy as a potential area of mineralization. 
Chapter 8B. Analysis of Imaging Spectrometer Data for the Katawas Area of Interest 629

Figure 8B–10.

Previous remote sensing studies using ASTER data (Mars and Rowan, 2007) suggested the 

potential of mineralization within the Katawas AOI. As in the HyMap data, Bernard Hubbard (written 

commun., 

Occurrence and distribution of common secondary minerals detected in the HyMap data.

in Peters and others, 2007) has also identified (based on ASTER classifications) potential 

areas of mineralization along a linear trend in the Katawas gold subarea. According to Peters and others 

(2007), the subarea mineralization occurs within a mercury geochemical halo. The HyMap data for the 

gold subarea (figs. 8B–15 to 8B–21) best shows the extensive area of alteration along the northeasttrending linear feature and associated east-northeast-trending ridge. The linear feature is primarily in 

fault-bounded Paleocene rocks. Fe 2+-bearing minerals are the dominant surficial material (fig. 8B–16), 

although large amounts of Fe 3+-bearing minerals (discussed above) and chlorite or epidote, epidote, and 

goethitic minerals are present. Lesser amounts of Fe-bearing carbonate and serpentine pixels are also 

detected in the area (figs. 8B–15, 8B–17, 8B–20, and 8B–21). Both the Fe-bearing carbonates and 

serpentine minerals occur in spatially well-defined clusters along the length of the linear feature and 

associated east-northeast-trending ridge. The detection and association of these phyllic-altered minerals 

and groups of minerals suggest the possibility of polymetallic copper, gold, and lead deposits (Mars and 

Rowan, 2007). 
630 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Figure 8B–11. Distribution of common alteration minerals in the Katawas AOI.
Chapter 8B. Analysis of Imaging Spectrometer Data for the Katawas Area of Interest 631

Figure 8B–12. Shaded relief map showing elevation in the Katawas gold subarea. The darker brown tones 

indicate the higher elevations and the lower elevations are represented by the blue tones. 
632 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Figure 8B–13. Northeast-striking faults in the Katawas gold subarea. The fault traces (Peters and others, 2007) 

are placed on a Landsat Enhanced Thematic Mapper (TM) image (Davis, 2007).
Chapter 8B. Analysis of Imaging Spectrometer Data for the Katawas Area of Interest 633

Figure 8B–14. Geologic map of the Katawas gold subarea is from Doebrich and others (2006). 
634 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Figure 8B–15. Distribution of clays, carbonates, phyllosilicates, sulphates, and other alteration minerals for the 

Katawas gold subarea.
Chapter 8B. Analysis of Imaging Spectrometer Data for the Katawas Area of Interest 635

Figure 8B–16. Map showing he iron-bearing and other alteration minerals detected in the HyMap data for the 

Katawas gold subarea.
636 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Figure 8B–17. Distribution of carbonate-bearing minerals in the Katawas gold subarea detected in the HyMap 

data.
Chapter 8B. Analysis of Imaging Spectrometer Data for the Katawas Area of Interest 637

Figure 8B–18. Distribution of clays and micas detected using the HyMap data.
638 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Figure 8B–19. Distribution of Fe-hydroxides and oxides for the Katawas gold subarea.
Chapter 8B. Analysis of Imaging Spectrometer Data for the Katawas Area of Interest 639

Figure 8B–20. Distribution of common secondary minerals for the Katawas gold subarea.
640 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Figure 8B–21. Common alteration materials detected in the HyMap data for the Katawas gold subarea.
Chapter 8B. Analysis of Imaging Spectrometer Data for the Katawas Area of Interest 641

8B.6 References Cited

Cocks, T., Jenssen, R., Stewart, A., Wilson, I., and Shields, T., 1998, The HyMap airborne hyperspectral 

sensor—The system, calibration and performance, in Schaepman, M., Schlapfer, D., and Itten, K.I., 

eds., Proceedings of the 1st EARSeL Workshop on Imaging Spectroscopy, 6–8 October 1998, Zurich: 

Paris, European Association of Remote Sensing Laboratories, p. 37–43. 

Davis, P.A., 2007, Landsat ETM+ false-color image mosaics of Afghanistan: U.S. Geological Survey 

Open-File Report 2007–1029, 22 p. (Also available at http://pubs.usgs.gov/of/2007/1029/.) 

Doebrich, J.L., and Wahl, R.R., comps., with contributions by Doebrich, J.L., Wahl, R.R., Ludington, 

S.D., Chirico, P.G., Wandrey, C.J., Bohannon, R.G., Orris, G.J., Bliss, J.D., Wasy, Abdul, and 

Younusi, M.O., 2006, Geologic and mineral resource map of Afghanistan: U.S. Geological Survey 

Open File Report 2006–1038, scale 1:850,000, available at http://pubs.usgs.gov/of/2006/1038/. 

Hoefen, T.M., Kokaly, R.F., and King, T.V.V., 2010, Calibration of HyMap data covering the country 

of Afghanistan, in Proceedings of the 15th Australasian Remote Sensing and Photogrammetry 

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