Chapter 11B. Analysis of Imaging Spectrometer Data for the 

Nalbandon Area of Interest

By Trude V.V. King

Abstract

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

the west-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. Carbonate minerals dominate the large 

Nalbandon AOI as well as the Nalbandon District and Gharghanaw-Gawmazar subarea. Iron oxides and 

hydroxides are present throughout the AOI with Fe2+ minerals dominating in the Proterozoic rocks north 

of the Hari Rud fault zone. Bedding planes consisting of assemblages of iron-bearing minerals and 

goethites can be traced for tens of kilometers across the AOI. The known mineral occurrences in the 

Gharghanaw-Gawmazar subarea seemingly correspond to areas containing Fe3+, iron hydroxide, and 

goethitic minerals. The majority of the known lead-zinc and polymetallic-vein occurrences in the 

Nalbandon District are not associated with any particular mineral or group of minerals, with the 

exception of the Minora and Zawar polymetallic occurrences, which show an affinity with hematitic 

minerals. The only occurrence of groups of minerals associated with epithermal deposits (alunite, 

kaolinite, jarosite, pyrophyllite, and hydrated silica) is in the most northern part of the Nalbandon 

District (north and east of the Minora known mineral occurrence). The horizontally bedded rock units 

(little horizontal surface expression), the alteration mineral assemblages and patterns associated with 

lead-zinc deposits, and the presence of abundant dry vegetation, which may have masked the surficial 

minerals in a significant and geologically important part of the area, have reduced the utility of the 

imaging spectrometer data for overall site characterization in the Nalbandon AOI. 

11B.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 Nalbandon area in west-central Afghanistan.

The Nalbandon area is about 460 kilometers (km) west and south of Kabul (fig. 11B–1) and is 

believed to have the potential for sandstone-hosted lead-zinc, Phanerozoic sedex zinc, lead-silver-gold, 

Mississippi Valley-type lead-zinc, and bedded barite 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 and 

identifies numerous sites with the Nalbandon area that could merit further investigation, especially 

detailed geological mapping and geochemical studies.

11B.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 project “Oil and Gas 

Resources Assessment of the Katawaz and Helmand Basins” (Kokaly and others, 2008). These data 

were acquired from August 22 to October 2, 2007. There were 207 north-south flight lines and 
896 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

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

surface area of 438,012 square kilometers (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 near-infrared 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, 

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

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

Figure 11B–1. The Nalbandon area of interest is located about 460 kilometers west and south of Kabul in the 

Ghor and Herat Provinces of Afghanistan.

11B.1.2 Calibration

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, 
Chapter 11B. Analysis of Imaging Spectrometer Data for the Nalbandon Area of Interest 897

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 passes 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. 

11B.1.3 Materials Maps and Presentation

HyMap reflectance data were processed using MICA (Material Identification and 

Characterization Algorithm), a module of the USGS PRISM (Processing Routines in IDL for 

Spectroscopic Measurements) software (Kokaly, 2011). MICA compared the reflectance spectrum of 

each pixel of HyMap data entries in a reference spectral library of minerals, vegetation, water, and other 

materials. The HyMap data were compared to 97 reference spectra of well-characterized mineral and 

material standards. The resulting maps of material distribution, resampled to 23×23-square-meter (m

2

) 

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

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

features in the visible and near-infrared wavelength region producing a 1-micrometer (μm) map of ironbearing minerals and other materials (King and others, 2011b), and again using the minerals with 

absorption features in the shortwave infrared producing a 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 iron-bearing 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 Fe3+ type 1 and Fe3+ type 2 are depicted on the 

map. The carbonates, 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, such as the chlorite or epidote 

class. When comparisons with reference spectra have 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. 
898 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

11B.2 Geologic Setting of the Nalbandon Area

The main Nalbandon lead-zinc area is located in the Ghor and Herat Provinces of Afghanistan 

(fig. 11B–1). The main Nalbandon lead-zinc area is 6,150.55 km2, and within this area of interest (AOI) 

lies the subareas of Nalbandon District (554 km2) and Gharghanaw-Gawmazar (385 km2). The elevation 

in the AOI ranges from 1,435 to 3,488 meters (m) (fig. 11B–2). The area is cut by two rivers that flow 

east-west. Numerous faults and fractures of different orientations and extent occur in the area 

(fig. 11B–3). Within the Nalbandon area, the prominent faults strike southwest to northeast. Known 

mineral occurrences commonly occur along the fracture systems.

11B.2.1 Lithology and Structure

The Nalbandon AOI has stratified rocks that range in age from Paleoproterozoic to Holocene and 

intrusive rocks of Mississippian, Late Triassic, Early Cretaceous, and Oligocene age (fig. 11B–4).

A series of intrusive rocks are exposed in the northern part of the AOI along the Hari-Rud fracture zone. 

11B.2.2 Known Mineralization

Figure 11B–5 shows 16 locations where reconnaissance field geology and geologic literature 

identified mineralization that suggests a potential for mineral resources. The mineralogical 

characteristics of the mineralized locations are summarized in Table 11B–1. These mineralization 

occurrences are of two types: (1) polymetallic veins and (2) Mississippi Valley-type lead-zinc deposits. 

Many of the noted mineral occurrences are relatively small and are at or below the spatial resolution of 

the HyMap data.

The geology of the Nalbandon area was first investigated by the German Geological Mission in 

1963. The mineralization is located on the northern flank of the large syncline striking west-east (Peters 

and others, 2007). 

Figure 11B–2. Shaded relief map showing range of elevations in the Nalbandon area of interest. 
Chapter 11B. Analysis of Imaging Spectrometer Data for the Nalbandon Area of Interest 899

Figure 11B–3. Numerous faults and fractures of different orientations and extent occur within the Nalbandon area 

of interest. The fault traces (Peters and others, 2007) are placed on Landsat TM images (Davis, 2007).

Figure 11B–4. Geologic map of the Nalbandon area of interest, from Doebrich and others (2006).
900 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

In the Nalbandon District, the lead-zinc occurrences are associated with shear zones and faults 

(Peters and others, 2007) . The Sarghul lead-zinc occurrence is within Lower to Middle Jurassic 

limestone and contains galena and sphalerite within sandstone lenses, accompanied by chalcopyrite and 

pyrrhotite (German Geological Mission, unpub. data, 1969). The Minora II polymetallic vein is in 

Triassic porous siltstone along a fault zone containing ferruginous quartz veins with traces of zinc and 

copper (Dronov and others, 1972). The Palang-Khana polymetallic occurrence is hosted in Lower to 

Middle Jurassic shale within two brecciated ferruginous zones containing silica veinlets and sparse 

galena.

The Gharghanaw-Gawmazar subarea is located in the northern part of the Nalbandon AOI. The 

Gharghanaw I and II lead-zinc mineral occurrences are hosted in lower Middle Jurassic sedimentary 

rocks within bedding-plane shear zones and contain zinc and traces of copper (Dronov and others, 

1972). The Hasan-Sansalaghay lead-zinc occurrence is in a shear zone within Lower to Middle Jurassic 

sandstone and limestone (Dronov and others, 1972) and contains lead, zinc, copper, and traces of 

antimony. The Gawmazar I and II polymetallic deposits occur in silicified and carbonated, ferruginous 

shear zones in Upper Triassic sandy slate rocks that reportedly contain copper and gold. The Gawamazar 

III polymetallic-vein occurrence is in Upper Permian slaty sandstone in a wide shear zone that contains 

lead and minor zinc. 

Table 11B–1. Deposit name, deposit type, mineralogy, and alteration of the known sites of mineralization in the 

Nalbandon area of interest. Name Deposit type Mineralogy Alteration

Kajnaw Vein hematite Hematite; limonite

Zawar Polymetallic vein Chalcopyrite; galena; malachite Silicification

Sulfides; secondary mineral of 

Minora Polymetallic vein cooper Oxidation; silicification

Unnamed Polymetallic vein Sulfides Silicification; carbonatization

Sphalerite; galena; pyrite; 

Nalbandon Mississippi Valley Zn-Pb chalcopyrite; boulangerite

Ustoowa Polymetallic vein Galena; limonite Limonitization; quartz alteration

Gawmazar IV Polymetallic vein Limonite Silicification; limonitization

Silicification; carbonatization; 

Gawmazar I & II Polymetallic vein Limonite limonitization

Gawmazar III Polymetallic vein No data Silicification

Shekhlawast Polymetallic vein No data Silicification

Hasan Sansalaghay Mississippi Valley Zn-Pb No data

Gharghanaw II & III Mississippi Valley Zn-Pb Galena Silicification

Minora II Polymetallic vein Limonite; Silicification; limonitization

Palang-Khana Polymetallic vein Galena Quartz alteration

Galena; sphalerite; chalcopyrite; 

Sarghul Mississippi Valley Zn-Pb boulangerite

Tilak Unknown Hg Cinnabar Carbonatization; dickitization

11B.3 Imaging Spectrometer Material Maps of the Nalbandon Area

Computer analysis of the HyMap data of the Nalbandon AOI using spectral mapping techniques 

resulted in the identification of a variety of surficial minerals. These minerals have been identified on 

the presence and wavelength position of absorption features in the 0.45–2.48 μm wavelength region.

Two general categories of minerals are recognized: (1) iron-bearing minerals that have characteristic 

spectral absorption features that occur at wavelengths near the 1-μm region, and (2) a wide variety of 

minerals, including carbonates, mica and clay minerals, and sulfates, that have diagnostic spectral 

absorptions near the 2-μm region. Although the occurrence of certain minerals 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 rocks where they occur are 
Chapter 11B. Analysis of Imaging Spectrometer Data for the Nalbandon Area of Interest 901

extremely important in understanding the causes of the mapped mineral occurrences and assessing the 

possible potential for related mineral deposits.

Two general types of maps are included: (1) complete AOI maps showing the entire mapped 

suite of minerals that have absorption in the 1- and 2-μm-wavelength regions, and (2) topical maps that 

are subsets of the complete AOI maps. The topical maps, which depict selected groups of minerals that 

are mineralogically related or commonly occur together, are presented to show subtleties in the mineral 

distribution (figs. 11B–6 to 11B–12). A set of maps has been produced for the full Nalbandon AOI and 

each of the Nalbandon District and Gharghanaw-Gawmazar subareas.

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. Great efforts were made to ensure the 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. 

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

potential economic mineral resource occurrence) that have not been previously known or where the 

HyMap data have expanded the knowledge or surficial coverage can be found in King and others 

(2011b).

Figure 11B–5. Map showing location of known mineral occurrences in the Nalbandon area of interest (AOI). The 

map consists of four data layers: a shaded relief base map; a transparency of the geologic map (Doebrich and 

others,2006); fault traces (Peters and others, 2007); and known mineral occurrences (Peters and others, 2007). 

The map shows the overall AOI and two subareas: Nalbandon District and Gharghanaw-Gawmazar.
902 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

11B.3.1 Nalbandon Area of Interest

Figures 11B–6 and 11B–7 shows the distribution of carbonates, phyllosilicates, sulfates, altered 

minerals, other materials (32 possible classes), and the iron-bearing minerals (28 possible classes) for 

the entire Nalbandon AOI. HyMap data are also a powerful tool to use in the identification and mapping 

of faults and fractures (see fig. 11B–9); note the large Hari-Rud fracture system in the northern part of 

the image. The presence of clouds in an AOI is unusual because less than 5 percent of the total mapped 

area of Afghanistan is cloud covered in the HyMap dataset. 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. 11B–8 to 11B–13). Figure 11B–8 

shows the distribution of carbonate minerals in the AOI, whereas figure 11B–9 shows where the clays 

and micas were mapped. The distribution of iron oxide and hydroxide minerals are displayed in 

figure 11B–10. Secondary minerals are shown in figure 11B–11, and minerals commonly found in 

hydrothermally altered rocks are mapped in figure 11B–12. 

11B.3.1.1 Carbonate Minerals

The calcite and calcite + muscovite/illite groups cover more than 90 percent of the mapped area 

and are continuous across most geologic boundaries. The widespread occurrence of carbonate minerals 

limits their usefulness for detecting areas characterized by calcite alteration (table 11B–1; fig. 11B–8).

Although difficult to see because of the small number of pixels, dolomite and dolomite mixtures are 

present throughout the area, with small concentrations in the western and northeastern portion of the 

mapped area. The dolomite commonly occurs along or near fault/fracture boundaries. 

11B.3.1.2 Clays and Micas

The phyllosilicates are the second most dominant group of minerals mapped in the AOI (fig. 

11B–9). Muscovites and illites are the dominate minerals. Epidote and chlorite, when present, occur 

primarily in the western half of the area. The largest concentration of epidote and chlorite occurs in the 

Permian stratified rocks and intrusive units in the northernmost part of the AOI. Scattered and small 

clusters of epidote also occur in the Lower to Middle Jurassic, Permian, and Proterozoic geologic units. 

A small cluster of epidote pixels is present in the northeastern part of the area that cross-cuts geologic 

boundaries. 

The kaolinite group of minerals primarily occur in the northern (Proterozoic and Carboniferous–

Permian units) and southernmost portions of the area (see subarea maps for more detail). Although 

minor amounts of kaolinite group minerals occur in the Carboniferous–Lower Permian rocks in the 

west-central portion of the AOI. 
Chapter 11B. Analysis of Imaging Spectrometer Data for the Nalbandon Area of Interest 903

Figure 11B–6. Distribution of clays, carbonates, phyllosilicates, sulfates, altered minerals, and other materials 

detected in the HyMap data for the entire Nalbandon area of interest. The identification of the specific minerals is 

based on the presence of characteristic absorption features resulting from the vibrational process in the mineral.

The map area was analyzed to detect the presence of 32 possible specific minerals or groups of minerals.

11B.3.1.3 Iron Oxides and Hydroxides

Figure 11B–10 shows the iron-bearing minerals in the Nalbandon AOI. These iron-bearing 

minerals can be roughly grouped into three zones that correlate with the geologic units (fig. 11B–4). The 

northern portion of the area, along and north of the Hari-Rud fracture zone, is dominated by Fe2+- and 

Fe3+-bearing minerals with minor amounts of hematite that occur along fractures and faults in the 

undifferentiated Pliocene rocks. The central portion of the map is dominated by the presence of dry 

vegetation and unclassified materials (see fig11B–6 for comparison) with lesser amounts of hematite 

(red), goethite (dark orange), and iron hydroxide minerals (light orange). Bedded units in the Lower–

Middle Jurassic sedimentary rocks can be mapped, over tens of kilometers, by the presence of Fe3+

minerals (green). The southern (lower) portion of the map illustrates the lithologic control of the Fe2+- 

and Fe3+-bearing minerals in the Upper Jurassic to Lower Cretaceous rocks. Hematite minerals (red) 

occur along and between narrowly separated fractures and faults. Mineral occurrence and distribution 

may be masked in the central part of the AOI because of the presence of vegetation.
904 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Figure 11B–7. Image showing iron-bearing minerals and other materials in the Nalbandon area of interest that 

were detected in the HyMap data.

11B.3.1.4 Common Secondary Minerals

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

11B–11. This map shows information taken from both the 1- and 2-μm-wavelength datasets. A coherent 

grouping of secondary minerals occurs adjacent and north of the Hari-Rud fracture zone. In the central 

part of the AOI (adjacent to the Nalbandon District subarea), a small concentration of serpentine and 

serpentine or calcite + dolomite was mapped. Common secondary minerals in the southern half of the 

AOI fail to show a coherent distribution. 

11B.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 a single pixel or small number of pixels of 

the individual minerals were mapped in the area (fig. 11B–12). Occurrence of two or more minerals 

associated with hydrothermal alteration processes are observed in the Proterozoic rocks in the 

northernmost portion of the AOI. In the northern part of the AOI, epidote or chlorite are shown to be 

spatially related to the occurrence of the kaolinite group of minerals.
Chapter 11B. Analysis of Imaging Spectrometer Data for the Nalbandon Area of Interest 905

Figure 11B–8. Distribution of carbonate-bearing minerals detected by the HyMap data in the Nalbandon area of 

interest. 

11B.3.2 Gharghanaw Gawmazar Subarea:

The known mineral occurrence map (semitransparent geologic map overlain on a shaded relief 

image) shows the position of reported mineral occurrences in the Gharghanaw Gawmazar area (fig. 

11B–13). The topography in the area ranges from 2,020 to 3,308 m and no rivers are present in the area 

(fig. 11B–14). 

The geologic map of the area (fig. 11B–15) shows rocks ranging in age from Mesoproterozoic to 

middle Quaternary age. Early Cretaceous intrusive rocks occur in the northern part of the area along the 

Hari Rud fault. The majority (7 of 10) of the known mineral occurrence in Gharghanaw-Gawmazar 

occur south of the Hari Rud fault zone in rocks of Early–Middle Jurassic age.

The Upper Triassic (Norian–Rhaetian) and Oligocene geologic units in the central part of the 

area are easily recognized by their bluish-purple shades in the Landsat Enhanced Thematic Mapper 

(TM) data (Davis, 2007) (fig.11B–15). The Hari Rud fracture zone is readily identified in the central 

part of the image.

Figures 11B–17 and 11B–18 show the distribution of iron-bearing and carbonate, sulphate, 

phyllosilicate, and altered minerals, respectively. The map of iron-bearing minerals (fig. 11B–17) also 

shows a variation in the mineral assemblages on either side of the large fault zone. Fe2+ and Fe3+

minerals are pervasive in the Proterozoic rocks. South of the Hari-Rud fault zone, the surficial 

mineralogy is dominated by iron hydroxides and goethites. 
906 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Figure 11B–9. Distribution of clays and micas identified in the HyMap data for the Nalbandon area of interest. 

11B.3.2.1 Gharghanaw-Gawmazar Subarea: Carbonate Minerals

Calcite-rich rocks are widespread and occur over the entire subarea (fig.11B–19). A lesser 

number of pixels representing dolomite and dolomite mixtures are present throughout the area with 

small concentrations in the western and northeastern portion of the mapped area. The dolomite occurs in 

Devonian rocks in the western part of the area and along or near fault traces or edges of intrusive bodies 

in the northeast part of the image. 

11B.3.2.2 Gharghanaw-Gawmazar Subarea: Clays and Micas

On the basis of the HyMap data, figure 11B–20 shows the enrichment of clays and micas in the 

Proterozoic rocks and Norian–Rhaetian age rocks in the Gharghanaw-Gawmazar subarea. The clays and 

micas are associated with the Mesoproterozoic rocks north of the Hari Rud fault zone. The muscovites 

are present in the Proterozoic rocks. Polymetallic veins and lead-zinc deposits are known to occur along 

the boundary of the Norian–Rhaetian and Early–Middle Jurassic age rocks (fig. 11B–13) and show no 

correlation with the phyllosilicate minerals.
Chapter 11B. Analysis of Imaging Spectrometer Data for the Nalbandon Area of Interest 907

Figure 11B–10. Distribution of iron hydroxides and oxides mapped using the HyMap data for the Nalbandon area 

of interest. 

11B.3.2.3 Gharghanaw–Gawmazar Subarea: Iron Oxide and Hydroxide Minerals

Figure 11B–21 shows the distribution of iron oxides and hydroxides in the GharghanawGawmazar subarea. Hematite is primarily mapped adjacent to contact zones of the Early Cretaceous 

intrusive rocks and the Proterozoic country rocks. However, a cluster of hematite is also present in the 

southern part of the area at the terminus of a fault zone (King and others, 2011a). Mineral occurrence 

and distribution may be somewhat masked in the central portion of the area because of the presence of 

dry vegetation. 

11B.3.2.4 Gharghanaw-Gawmazar Subarea: Common Secondary Minerals

There are few occurrences and scattered distribution of common secondary minerals 

(fig.11B–22) in the area. The largest number of pixels of secondary minerals occurs in the Pliocene 

rocks in the northernmost part of the area.
908 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Figure 11B–11. Occurrence and distribution of common secondary minerals detected in the HyMap data.

11B.3.2.5 Gharghanaw-Gawmazar Subarea: Common Alteration Minerals

Common alteration materials detected in the HyMap data (fig. 11B–23) in the area are primarily 

kaolinite group minerals that are present in the Mesoproterozoic rocks. The few pixels of chlorite or 

epidote minerals are present in Pliocene rock in the northernmost part of the image (fig. 11B–23). 

11B.3.3 Nalbandon District Subarea

The known mineral occurrence map (fig. 11B–24) shows the position of reported mineral 

occurrences in the Nalbandon District subarea. The topography in the area ranges from 1,435 to 3,488 m 

and two rivers, one flowing east-west and one north-south, are present in the area (fig. 11B–25). Figure 

11B–26 shows that the district is composed of dominantly Early–Middle Jurassic age rocks with some 

of Carboniferous–Early Permian age units. 

In the Landsat TM data (Davis, 2007 ), the Early–Middle Jurassic age rocks in the central part of 

the area are easily recognized by their distinct bedding and bluish-brown color (fig.11B–27). The 

majority (5 of 6) of the known mineral occurrence in the Nalbandon District occur in rocks of Early–

Middle Jurassic age (fig. 11B–24). 
Chapter 11B. Analysis of Imaging Spectrometer Data for the Nalbandon Area of Interest 909

Figure 11B–12. Distribution of common alteration minerals in Nalbandon area of interest. 

The overall-inclusive imaging spectrometer data for the area (figs. 11B–28 and 11B–29) show 

the distribution of iron-bearing minerals and carbonate, phyllosilicate, sulphate, alteration minerals, and 

other materials respectively. Dry vegetation (brown) is abundant throughout the entire subarea, but is 

most pervasive in the eastern half. The presence of the dry vegetation (figs. 11B–28 and 11B–29) masks 

much of the area and reduces the mineral identification in areas with significant vegetation cover.

11B.3.3.1 Nalbandon District Subarea: Carbonate Minerals

Figure 11B–30 shows widespread distribution of carbonate-rich rocks over the entire AOI. 

Calcite and calcite and muscovite or illite are by far the dominant mineral groups.

11B.3.3.2 Nalbandon District Subarea: Clays and Micas

Figure 11B–31 shows the enrichment of phyllosilicates in the Nalbandon District subarea. 

Muscovite (lighter orange) occurs throughout the area. Although chlorite or epidote is mapped 

throughout the area in scattered pixels, a large concentration of pixels is located adjacent and east of the 

Oligocene intrusive outcrop in rocks mapped as Early–Middle Jurassic age (fig. 11B–26). These chlorite 

or epidote rocks are not reported as common occurrences in the Jurassic age rocks and warrant 

additional consideration (King and others, 2011a). An anomalous occurrence of kaolinite group minerals 

occurs in the northernmost part of the district. 
910 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Figure 11B–13.

11B.3.3.3 Nalbandon District Subarea: Iron Oxides and Hydroxides

 Known mineral occurrences in the Gharghanaw-Gawmazar subarea of the Nalbandon area of 

interest. 

The distribution of iron oxides and hydroxides is shown figure 11B–32. Hematite is primarily 

present adjacent to contact zones of Early Cretaceous intrusive rocks and Proterozoic country rocks.

However, a cluster of hematite is also present in the southern part of the area at the terminus of a fault 

zone (King and others, 2011a). Mineral occurrence and distribution may be somewhat masked in the 

central portion of the AOI because of the presence of dry vegetation.

11B.3.3.4 Nalbandon District Subarea: Common Secondary Minerals

There are few occurrences of common secondary minerals (fig.11B–33), with the exception of 

the chlorite or epidote group, which seems to be present throughout the subarea with concentrated areas 

along the south-central portion of the AOI. A coherent grouping of secondary minerals occurs in the 

northern part of the AOI. These occurrences are related to geologic units adjacent and north of the 

Hari-Rud fracture zone. Small concentrations of serpentine and serpentine or calcite and dolomite were 
Chapter 11B. Analysis of Imaging Spectrometer Data for the Nalbandon Area of Interest 911

mapped in the central portion of the area, and the southern half of the AOI shows only scattered 

occurrences.

Figure 11B–14. Shaded relief map showing that elevation in the Gharghanaw-Gawmazar subarea of the 

Nalbandon area of interest ranges from 2,020–3,308 meters. The darker brown tones indicate the higher elevations 

and the lower elevations are represented by the blue tones.

11B.3.3.5 Nalbandon District Subarea: Common Alteration Minerals

The only significant common alteration minerals that do not have a seemingly random 

distribution are the kaolinite group minerals, which map along the northeastern portion of the AOI and 

the previously mentioned chlorite or epidote group (fig. 11B–34). In addition, a cluster of alunites and 

kaolinites is seen north of the Minora mineral occurrence and is discussed in the USGS anomaly report 

(King and others, 2011a).
912 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

11B.4 Summary 

The horizontally bedded geologic units (little horizontal surface expression in areas with steep 

terrain), the alteration mineral assemblages and patterns associated with lead-zinc deposits, and the 

presence of abundant dry vegetation that may have masked the surficial minerals in a significant and 

geologically important part of the area have reduced the utility of the imaging spectrometer data for 

overall site characterization in the Nalbandon AOI. 

Figure 11B–15. Numerous faults and fractures of different orientations and extent occur in the GharghanawGawmazar subarea of the Nalbandon area of interest. The fault traces (Peters and others, 2007) are placed on 

Landsat TM images (Davis, 2007). Marked color differences in the TM data are associated with rocks of different 

ages.

The imaging spectrometer data for the Nalbandon District subarea suggest that the known 

mineral occurrence at Palang-Khana, Nalbandon, and Sarghul are in mappable lithologic units consisting 

of a mixture of Fe3+ minerals, iron hydroxide, and goethite. It is believed that additional field 

verification would confirm this observation as this type of mineral assemblage extends across the area. 
Chapter 11B. Analysis of Imaging Spectrometer Data for the Nalbandon Area of Interest 913

The HyMap data show that the Gawmazar polymetallic-vein mineral occurrences and the 

Gharghanaw II and III lead-zinc mineral occurrences (fig. 11B–13) are preferentially in units that were 

mapped as enriched concentrations of iron hydroxide, although there was not a high correlation. 

Attempts to verify areas of hydrothermal alteration identified in field studies by the Lithuanians 

(Motza and Silaupa, 2010) using the HyMap data did prove effective. There were no indications of 

minerals associated with hydrothermal alteration (fig. 11B–12) in the HyMap data. Again, this may be 

due to the size of the reported field observations or the location of the alteration in the geologic 

sequence. If the alteration is bedded in steep-sided exposures with little horizontal exposure, the HyMap 

data may not have detected the occurrence.

Figure 11B–16. Geologic map of the Gharghanaw-Gawmazar subarea of the Nalbandon area of interest from 

Doebrich and others (2006).
914 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Figure 11B–17. The iron-bearing and other alteration minerals detected in the HyMap data for the GharghanawGawmazar subarea of the Nalbandon area of interest are shown in this image.
Chapter 11B. Analysis of Imaging Spectrometer Data for the Nalbandon Area of Interest 915

Figure 11B–18. Distribution of clays, carbonates, phyllosilicates, sulfates, altered minerals, and other materials 

for the Gharghanaw-Gawmazar subarea of the Nalbandon area of interest based on the HyMap data. 
916 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Figure 11B–19. Distribution of carbonate-bearing minerals in the Gharghanaw-Gawmazar subarea detected in 

the HyMap data.
Chapter 11B. Analysis of Imaging Spectrometer Data for the Nalbandon Area of Interest 917

Figure 11B–20. Distribution of clays and micas detected using the HyMap data. The figure shows the occurrence 

of muscovites and illites and epidote and kaolinite group of minerals. 
918 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Figure 11B–21. Distribution of Fe-hydroxides and oxides for the Gharghanaw-Gawmazar subarea.
Chapter 11B. Analysis of Imaging Spectrometer Data for the Nalbandon Area of Interest 919

Figure 11B–22. This image shows the very limited occurrence and scattered distribution of common secondary 

minerals detected in the HyMap data. A coherent grouping of secondary minerals occurs in the northern part of the 

Nalbandon area of interest. 
920 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Figure 11B–23. Common alteration materials detected in the HyMap data are limited primarily to kaolinite group 

minerals.
Chapter 11B. Analysis of Imaging Spectrometer Data for the Nalbandon Area of Interest 921

Figure 11B–24. This map shows the known mineral occurrences in the Nalbandon District subarea of the 

Nalbandon area of interest. The district includes four polymetallic-vein occurrences (Palang-Khana, Zawar, Minora, 

and Minora II) and two lead-zinc occurrences (Nalbandon and Sarghul).
922 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Figure 11B–25. Shaded relief map shows elevation of the Nalbandon District subarea ranges from 1,435 to 

3,488 meters. The darker brown tones indicate the higher elevations, and the lower elevations are represented by 

the blue tones. Two rivers dissect the area; one flows east-west and the other roughly north-south.
Chapter 11B. Analysis of Imaging Spectrometer Data for the Nalbandon Area of Interest 923

Figure 11B–26. The geologic map of the Nalbandon District subarea of the Nalbandon area of interest is from 

Doebrich and others (2006).
924 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Figure 11B–27. The fault traces (Peters and others, 2007) are placed on a Landsat TM images (Davis, 2007).

Color difference in the TM data correlate with different geologic units. The central part of the image (bluish-brown 

rocks) correlates with the Early–Middle Jurassic age rocks. The dark brown unit in the southeast portion of the 

image is associated with Early Cretaceous age rocks. 
Chapter 11B. Analysis of Imaging Spectrometer Data for the Nalbandon Area of Interest 925

Figure 11B–28. The iron-bearing and other alteration minerals detected in the HyMap data of the Nalbandon 

District subarea are shown in this image.
926 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Figure 11B–29. Distribution of clays, carbonates, phyllosilicates, sulfates, altered minerals and other materials for 

the Nalbandon District subarea of the Nalbandon area of interest using the HyMap data.
Chapter 11B. Analysis of Imaging Spectrometer Data for the Nalbandon Area of Interest 927

Figure 11B–30. Distribution of carbonate-bearing minerals in the Nalbandon District subarea detected in the 

HyMap data. Although difficult to see because of the small number of pixels, dolomite and dolomite mixtures are 

present throughout the area, with small concentrations in the western and north-eastern portion of the mapped 

area.
928 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Figure 11B–31. Distribution of clays and micas in the Nalbandon District subarea that were mapped using the 

HyMap data. The figure shows the occurrence of muscovites and illites and epidote and kaolinite group minerals. 
Chapter 11B. Analysis of Imaging Spectrometer Data for the Nalbandon Area of Interest 929

Figure 11B–32. Distribution of iron hydroxides and oxides for the Nalbandon District subarea.
930 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

Figure 11B–33. Image showing very limited occurrence and scattered distribution of common secondary 

minerals detected in the HyMap data for the Nalbandon District subarea of the Nalbandon area of interest. 
Chapter 11B. Analysis of Imaging Spectrometer Data for the Nalbandon Area of Interest 931

Figure 11B–34. Common alteration materials detected in the HyMap data (fig. 11B–23).
932 Summaries of Important Areas for Mineral Investment and Production Opportunities of Nonfuel Minerals in Afghanistan

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