Prepared in cooperation with the Task Force for Business and Stability Operations, under

the auspices of the U.S. Department of Defense and the Afghanistan Geological Survey

Rare Earth Element Mineralogy, Geochemistry, and 

Preliminary Resource Assessment of the Khanneshin 

Carbonatite Complex, Helmand Province, Afghanistan

Robert D. Tucker, Harvey E. Belkin, Klaus J. Schulz, Stephen G. Peters, and Kim P. Buttleman

Open-File Report 2011–1207

USGS Afghanistan Project Product No. 200

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2011

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Suggested citation:

Tucker, R.D., Belkin, H.E., Schulz, K.J., Peters, S.G., and Buttleman, K.P., 2011, Rare earth element mineralogy, 

geochemistry, and preliminary resource assessment of the Khanneshin carbonatite complex, Helmand Province, 

Afghanistan: U.S. Geological Survey Open-File Report 2011–1207, 50 p.

Any use of trade, product, or firm names is for descriptive purposes only and does not imply 

endorsement by the U.S. Government.

Although this report is in the public domain, permission must be secured from the individual 

copyright owners to reproduce any copyrighted material contained within this report.
iii

Contents

Abstract ......................................................................................................................................................................... 1

1.0 Introduction ........................................................................................................................................................... 2

2.0 Geology of the Khanneshin Carbonatite Complex ................................................................................................ 2

2.1 Geologic Setting ................................................................................................................................................ 2

2.2 Geology............................................................................................................................................................. 3

2.2.1 Rocks of the Central Vent........................................................................................................................... 3

2.2.2 Volcanic and Volcano-Sedimentary Rocks ................................................................................................. 8

2.2.3 Satellitic Vents, Dikes, and Minor Intrusive Rocks ...................................................................................... 9

2.3 History of Igneous Activity ................................................................................................................................. 9

2.4 Metallogeny ......................................................................................................................................................10

3.0 The Zone of LREE Enrichment ............................................................................................................................10

3.1 Styles of LREE Mineralization ..........................................................................................................................21

3.2 Whole-Rock Geochemistry...............................................................................................................................21

3.3 Mineralogy........................................................................................................................................................30

3.4 Structural Control on Alkaline Igneous Magmatism and LREE Mineralization..................................................41

4.0 Estimation of LREE Resources............................................................................................................................42

4.1 Analysis of the Soviet-Defined Zone.................................................................................................................42

4.2 Analysis by Remote Sensing............................................................................................................................47

5.0 Conclusions .........................................................................................................................................................48

6.0 References Cited .................................................................................................................................................49

Figures

1. Maps of southern Afghanistan showing the location of the Khanneshin carbonatite complex and the 

permissive tract of uranium-phosphorus-rare earth element mineralization in the Helmand Basin................... 4

2. Geologic map of the Khanneshin carbonatite complex..................................................................................... 5

3. Cross-sections through the Khanneshin carbonatite complex .......................................................................... 6

4. Field photographs showing the key rock types and relationships within the intrusive central vent and 

volcanic apron of the Khanneshin carbonatite complex.................................................................................... 7

5. Photographs of examples of type-1 rare earth element mineralization in the marginal zone of 

the intrusive central vent of the Khanneshin carbonatite complex ...................................................................22

6. Photographs of examples of type-2 mineralized dikes in the zone of light rare earth element 

enrichment of the Khanneshin carbonatite complex ........................................................................................26

7. Ternary diagrams of major-element concentration data at the Khanneshin carbonatite complex....................27

8. Variation diagrams illustrating the difference in major and trace element concentrations among 

igneous rocks of the Khanneshin carbonatite complex....................................................................................28

9. Graphs showing the magnitude of rare earth element enrichment in the marginal zone of the intrusive 

central vent of the Khanneshin carbonatite complex .......................................................................................30

10. Mineralogy and crystallization sequence of sample RT-11K-2, type-1 mineralization of the Khanneshin 

carbonatite complex ........................................................................................................................................32

11. Mineralogy and crystallization sequence of sample RT-11K-5, type-1 mineralization of the Khanneshin 

carbonatite complex ........................................................................................................................................35

12. Mineralogy and crystallization sequence of fluorite-bearing rocks of the Khanneshin carbonatite 

complex ...........................................................................................................................................................36

13. Mineralogy and crystallization sequence of the fluorine-rich intrusive dikes of the Khanneshin 

carbonatite complex ........................................................................................................................................38
iv

14. Mineralogy and crystallization sequence of the apatite-rich intrusive dikes of the Khanneshin 

carbonatite complex ........................................................................................................................................40

15. Maps showing the area of the identified light rare earth element prospect in the northeastern part 

of the central intrusive vent and the digital elevation topography of the northern part of the Khanneshin 

carbonatite complex ........................................................................................................................................45

Tables

1. Whole-rock major-, trace-, and rare earth element (REE) concentration data, traverses 1A and 1B, 

Khanneshin carbonatite complex, Afghanistan................................................................................................11

2. Major-, trace-, and rare earth element (REE) concentration data, traverse 2, Khanneshin carbonatite complex, 

Afghanistan......................................................................................................................................................13

3. Major- and trace- , and rare earth element (REE) concentration data, traverse 3, Khanneshin carbonatite 

complex, Afghanistan. .....................................................................................................................................17

4. Table of minerals containing rare earth elements (REE), Sr, and Ba as major elements, Khanneshin 

carbonatite complex, Afghanistan....................................................................................................................26

5. Summary of barium, strontium, and light rare earth element (LREE) concentrations, barite-ankerite alvikite, 

Khanneshin carbonatite complex, Afghanistan................................................................................................43

6. Estimated light rare earth element (LREE) resources, Khanneshin carbonatite complex, Afghanistan...........44
v

Conversion Factors

Multiply By To obtain

Length

centimeter (cm) 0.3937 inch (in.)

millimeter (mm) 0.03937 inch (in.)

micrometer (μm) 0.0003937 inch (in.)

meter (m) 3.281 foot (ft) 

kilometer (km) 0.6214 mile (mi)

meter (m) 1.094 yard (yd) 

Area

square meter (m2) 0.0002471 acre 

square kilometer (km2) 247.1 acre

square centimeter (cm2) 0.001076 square foot (ft2)

square meter (m2) 10.76 square foot (ft2) 

square centimeter (cm2) 0.1550 square inch (ft2) 

square kilometer (km2) 0.3861 square mile (mi2)

Volume

cubic centimeter (cm3) 0.06102 cubic inch (in3) 

cubic meter (m3) 35.31 cubic foot (ft3)

cubic meter (m3) 1.308 cubic yard (yd3) 

cubic kilometer (km3) 0.2399 cubic mile (mi3) 

Mass

gram (g) 0.03527 ounce, avoirdupois (oz)

kilogram (kg) 2.205 pound avoirdupois (lb)

metric ton (t) 1.1023 short ton (2,000 lbs)

million metric tons (Mt) 1.1023 million short tons

Density

gram per cubic centimeter (g/cm3) 62.4220 pound per cubic foot (lb/ft3)

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

°F=(1.8×°C)+32
1

Rare Earth Element Mineralogy, Geochemistry, and 

Preliminary Resource Assessment of the Khanneshin 

Carbonatite Complex, Helmand Province, Afghanistan

Robert D. Tucker, Harvey E. Belkin, Klaus J. Schulz, Stephen G. Peters, and Kim P. Buttleman

Abstract

The Khanneshin carbonatite is a deeply dissected igneous complex of Quaternary age that rises 

approximately 700 meters (m) above the Neogene sedimentary rocks of the Registan Desert, Helmand 

Province, Afghanistan. The complex consists almost exclusively of carbonate-rich intrusive and 

extrusive igneous rocks, crudely circular in outline, with three small hypabyssal plugs of leucite 

phonolite and leucitite outcropping in the southeast part of the complex. The igneous complex is broadly 

divisible into a central intrusive vent (or massif), approximately 4 kilometers (km) in diameter, 

consisting of coarse-grained sövite and brecciated and agglomeratic barite-ankerite alvikite; a thin 

marginal zone (<1 km wide) of outwardly dipping (5°–45°) and alkali metasomatized Neogene 

sedimentary strata; and a peripheral apron of volcanic and volcaniclastic strata extending another 3–5 

km away from the central intrusive vent. Small satellitic intrusions of biotite-calcite carbonatite and rare 

leucite phonolite, no larger than 400 m in diameter, crop out on the southern and southeastern margin of 

the central intrusive vent.

A zone of prospective light rare earth element (LREE) enrichment was delineated by Soviet 

geological teams in the mid-1970s. The area of LREE-enrichment is situated in extensively veined and 

dike-intruded barite-ankerite alvikite in the outer part of the central vent near its northeast contact with 

Neogene sedimentary rocks. In addition to having very high concentrations of LREE, the barite-ankerite 

alvikites are also highly enriched in barium and strontium. 

Three reconnaissance scoping missions to the Khanneshin carbonatite were led by scientists of 

the U.S. Geological Survey (USGS). Two of these were to LREE area of interest which is the primary 

subject of this report. 

Two types of LREE mineralization occur. Type-1 LREE mineralization consists of 

semiconcordant, symmetrically banded veins and discontinuous seams, as much as 0.5–0.7 m thick and 

several tens of meters long. These occur throughout a vertical thickness of at least 150 m. Type-1 

banded veins and seams are yellow-weathering zones, symmetric about a dark central zone, that are 

enriched in khanneshite-(Ce), barite, strontianite, and secondary LREE minerals (synchysite-(Ce) and 

parisite-(Ce)). The dark central zone, consisting primarily of ankeritic dolomite, barite, apatite, and 

strontianite, also has trace khanneshite-(Ce). These type-1 veins and seams alternate with dark, meterthick layers of ankerite-barite alvikite (wall rock) over a vertical distance of approximately 150 m. In 

some veins LREE carbonate minerals form dense spherically shaped aggregrates (100 micrometers 

diameter), presumably crystallized from immiscible droplets, which constitute as much as 30 percent 

(by volume) of the vein. Type-1 veins and seams average 19.92 weight percent (wt. percent) Ba, 3.61 

wt. percent Sr, and 2.78 wt. percent total LREE. The values of ∑ LREE (∑ LREE is the sum of La, Ce, 

Pr, and Nd) for eight average whole-rocks range from 6.23 to 1.83 wt. percent. 
2

Type-2 LREE mineralization occurs in discordant dikes and tabular sheets, as much as tens of 

meters wide and hundreds of meters long, which are composed of primary igneous minerals that 

crystallized directly from magma or a late-stage hydrothermal fluid. Type-2 discordant dikes are of two 

types—those enriched in fluorine, and those enriched in phosphorus. The igneous rocks enriched in 

fluorine have as their LREE-bearing minerals idiomorphic phenocrysts of khanneshite-(Ce) and 

monazite-(Ce), together with synchysite-(Ce), bastnäsite-(Ce), and calkinsite-(Ce) of likely secondary 

(late hydrothermal) origin. The igneous rocks enriched in phosphorus have as their LREE-enriched 

bearing minerals idiomorphic phenocrysts of carbocernaite, together with parisite-(Ce) of secondary 

origin. The type-2 LREE–enriched discordant dikes average 11.1 wt. percent Ba, 5.36 wt. percent Sr, 

and 3.28 wt. percent ∑ LREE. The values for ∑ LREE of fourteen average whole-rocks range between 

5.98 and 0.49 wt. percent. 

A magmatic origin is indicated for the type-2 LREE-enriched discordant dikes. On the basis of 

textural and field evidence, we suggest that the semiconcordant veins and discontinuous seams (type-1 

LREE mineralization) may have formed in the presence of LREE-rich hydrothermal fluids. It is possible 

that both types of LREE mineralization may be penecontemporaneous, having formed in the marginal 

zone adjacent to a carbonate-rich magma that was highly charged with volatile constituents (for 

example, carbon dioxide, fluorine, and phosphorus) and strongly enriched in Ba, Sr, and LREE. 

Both types of LREE-enriched rocks are comparable in grade to the world-class Bayan Obo 

(China) and Mountain Pass, Calif. (United States) deposits, which are also enriched in LREE. On the 

basis of several assumptions and employing a simple geometry for the zone of LREE enrichment, we 

estimate that at least 1 million metric tonnes (Mt) of LREE may be present in the Khanneshin Area of 

Interest. This comports well with the probabilistic estimate of 1.4 Mt of undiscovered REE resources in 

all of south Afghanistan (Peters and others, 2007). In addition to LREE, the Khanneshin carbonatite is 

also enriched in barium (>10 wt. percent), strontium (>6 wt. percent), phosphorus (~2 wt. percent), and 

uranium (>0.05 wt. percent). 

1.0 Introduction

There is increased concern about the future availability of rare earth elements (REE) because of 

China’s dominance as the supplier of more than 95 percent of world REE output, their decision to 

restrict exports of rare earth products, and the rapid increase in world-wide consumption of rare earth 

product. As a result, countries such as the United States, Japan, and member nations of the European 

Union face a future of tight supplies and high prices for rare earth products unless other sources of REE 

are found and developed (Long and others, 2010; U.S. Geological Survey, 2011, p. 128–129, 184–185). 

We report and describe a significant new deposit of light rare earth elements (LREE), estimated at 1 Mt, 

within the Khanneshin carbonatite complex of south Afghanistan. The potential resource is located in a 

remote and rugged part of the igneous complex in a region previously identified by Soviet geologists in 

the 1970s. This report reviews the geologic setting of LREE deposit, presents new geochemical data 

documenting the grade of LREE mineralization, briefly describes the mineralogy and mineralogical 

associations of the deposit, and presents a preliminary estimate of LREE resources based on our current 

understanding of the geology. 

2.0 Geology of the Khanneshin Carbonatite Complex

2.1 Geologic Setting

The Khanneshin carbonatite is a deeply dissected alkaline igneous complex of Quaternary age 

that rises approximately 700 m above the Neogene sedimentary rocks of the Sistan basin, Helmand 
3

Province, Afghanistan (fig. 1A). The carbonatite is one of eight proposed centers of alkaline igneous 

activity in southern Afghanistan (fig. 1B); all of these igneous centers except the Khanneshin complex 

are buried under Holocene-age sand and gravel of the Registan desert. These complexes, all of Neogene 

and younger age, are situated within the accreted terranes of the Helmand block south of the Har-i Rod 

fault. The terranes were accreted to south Asia in Mesozoic and younger time, but they are presently 

undergoing southwestward translation, and locally internal dilation, in response to continued northward 

thrusting of the Indian Plate (Krumsiek, 1980). Soviet geologists recognized the existence of both northnortheast- and west-northwest-striking regional faults in the Sistan basin, and they suggested that the 

Khanneshin carbonatite is distinctly linked to the crossing node of these faults in a region of relative 

dilation (Yeremenko, 1975; Cheremitsyn and Yeremenko, 1976; Alkhazov and others, 1978). 

2.2 Geology

The igneous complex is broadly divisible into four parts (figs. 2 and 3): (1) a central vent, 

approximately 4 km in diameter; (2) a thin marginal zone (<1 km wide) of alkali metasomatized and 

outwardly dipping (5°–45°) Neogene sedimentary strata that form the basement rocks to the igneous 

complex; (3) a peripheral apron of volcanic and volcaniclastic strata extending another 3–5 km away 

from the central vent; and (4) small satellitic intrusions of sub-volcanic origin, no larger than 400 m in 

diameter, that crop out on the southern and southeastern periphery of the central intrusive massif 

2.2.1 Rocks of the Central Vent

The igneous rocks of the central vent consist exclusively of holocrystalline, indurated 

carbonatite that forms the major topographic massif of the complex. The rocks of the central vent 

consist of medium- and coarse-grained carbonatite (sövite, Qisf), confined to a stock approximately 2–3 

km in diameter in the core of the massif, as well as fine- to medium-grained ankerite-barite alvikite 

(Qesf) that forms a near continuous ring, 0.8–1.5 km wide, surrounding the central stock of sövite. At the 

margin of the central vent, where the intrusive rocks are in contact with Neogene sedimentary rocks, the 

Neogene strata are strongly altered, brecciated, and dike invaded, forming an outwardly dipping 

sequence of discolored and metasomatized albite- and calcite-rich fenites (fig. 2, Na ; fig, 4A).

The sövites of the central stock are light-gray to reddish brown, spotted rocks, composed of 

calcite (70–95 percent) biotite (2–10 percent) strongly pleochroic amphibole (0–7 percent), acmite (0–5 

percent), barite (0–4 percent), magnetite (0–5 percent), and apatite (0–4 percent). Important accessory 

minerals include zircon and pyrochlore. 

In addition to sövite, the peripheral ring of the central vent is composed of black to dark gray, 

very dense, medium- to fine-grained carbonatite (alvikite, fig. 2, Qisf). These alvikites are composed 

primarily of ankerite, dolomite, barite, and strontianite. The alvikites are described as agglomeratic (for 

example, Yeremenko, 1975; Cheremitsyn and Yeremenko, 1976; Alkhazov and others, 1978) because 

they contain abundant xenoliths of altered, mica-rich xenoliths (fenites, glimmerites, and camoforites) 

as well as blocks of coarse-grained sövite of the central massif (fig. 4A,D). They may also be fluidally 

banded, owing to the low viscosity of the CO2-charged magma, and thus they locally have the 

appearance of layered volcanic rocks (that is, lava flows). Although some of the alvikites may be of 

extrusive volcanic origin, most of them are holocrystalline and fine-grained, with abundant fenitized 

xenoliths. We interpret them, therefore, to be of intrusive igneous origin. The alvikites consist mostly of 

calcite (10–15 percent), ankerite (5–50 percent), and dolomite (5–25 percent); however, an unusual 

variety of alvikite, very enriched in barium and strontium, crops out in the northeast part of the marginal 

zone. In these rocks, strontianite (5–20 percent), barite (5–50 percent), yellow-weathering REEcarbonate minerals, and celestine (0–10 percent) are common. Important accessory minerals in all 

varieties of alvikite are magnetite, phlogopite, galena, and hydrated iron oxides. 
4

Figure 1. A, LANDSAT image of southern Afghanistan showing the location of the Khanneshin carbonatite complex within the Sistan basin. Inset 

map indicates the Har-i Rod fault (HRF), Chaman fault (CF), Farah fault (FF), the accreted terranes of the Helmand block (HB), and the Khanneshin 

carbonatite complex (K). Location of figure 1A shown by the black rectangle. B, Aeromagnetic map of south Afghanistan (Sweeney and others, 

2006) showing the permissive tract of uranium-phosphorus-rare earth element (U-P-REE) mineralization (cb01) in the Helmand Basin. Numbers one 

through eight (1–8) refer to possible carbonatite centers within the tract based on the aeromagnetic data. These centers formed the basis of the 

quantitative estimate in Peters and others (2007). The single exposure of carbonatite is the Khanneshin complex of this report. Shown in B are the 

volcanoes of Quaternary age discussed in the text: KB (Koh-i Bazman), KT (Koh-i Taftan), KS (Koh-i Sultan), and K (Khanneshin).
5

Figure 2. Geologic map of the Khanneshin carbonatite complex, Afghanistan, after Cheremitsyn and Yeremenko (1976), showing its principal 

bedrock divisions: (1) Neogene sedimentary strata, partly metasomatized, that form an upturned section of outwardly dipping strata away from the 

central intrusive vent. (2) The central intrusive vent (or massif) composed of sövite and medium- to fine-grained alvikite. The zone of light rare earth

element (LREE) enrichment is located in the northeast part of the central vent (green box). (3) The apron of volcanic and volcano-sedimentary strata 

extending 5 km beyond from the central vent. (4) Small satellitic intrusive rocks and volcanic plugs, mostly on the southern peripheral margin of the 

complex, include alvikite agglomerate and leucite phonolite. The three traverses, 1 (A and B), 2, and 3, as well as the regions of rare earth element 

(REE), uranium (U), and phosphorus (P) enrichment, are indicted by labels. 
6

Figure 3. Two cross-sections through the Khanneshin carbonatite complex, Afghanistan, after Cheremitsyn and Yeremenko (1976), shown in 

figure 2: Line A-B-C, a northeast-southwest line of section through the zone of light rare earth element (LREE) enrichment and the zone of uranium 

(U) mineralization. Line D-E-F, a northwest-southeast line of section through the intrusive central vent and the plugs of leucite phonolite.
7

Figure 4. Field photographs showing the key rock types and relationships within the intrusive central vent and 

volcanic apron of the Khanneshin carbonatite complex, Afghanistan. A, Northwest view from the zone of rare earth

element (REE) enrichment showing the Neogene strata (background) dipping modestly north and away from the 

intrusive rocks of the central vent (foreground). Vertical relief is approximately 150 m (note person for scale). B, 

Unconformable relationship between LREE-enriched alvikite (above) and typical alvikite of the marginal zone, 

intrusive central vent. Note that the underlying alvikite was cooled and intruded by a carbonatite dike before

emplacement of the overlying LREE-enriched alvikite. C, Fine-grained alvikite at the margin of the central vent 

contains abundant xenoliths of fenitized country rock (“glimmerite”) and sövite. D, Alvikite of the central vent, here 

also with xenoliths, is intruded by fine-grained dikes of carbonatite (compare with fig. 4b). E, Relationships 

observed in traverse 1B (fig. 2). View of the volcanic rocks (1 in circle) of the western apron (Q1-3b) showing their 

relationship to older Neogene strata (2 in circle, N) and younger Quaternary gravels (3 in circle, Q4).

The barium- and strontium-enriched alvikites (Qesf) are located within a part of the vent that is 

bounded by north-northeast-trending faults with apparent normal displacement (fig. 2). It is best 

interpreted as a down-dropped block (graben) in which volcanic strata of the upper rim are juxtaposed 

against the intrusive rocks of the central vent without an intervening section of Neogene sedimentary 
8

strata. In contrast, rocks northwest and southeast of the block are strongly fenitized Neogene strata. It is 

conceivable, therefore, that the low-viscosity fluids or magma with extreme enrichments in Ba, Sr, and 

REE were focused by regional structures into this part of the central vent. 

2.2.2 Volcanic and Volcano-Sedimentary Rocks

Pyroclastic and volcano-sedimentary rocks form an apron of stratified rocks that extends as 

much as 5 km beyond the central vent. The volcanic apron is best developed on the northeast and 

southeast margin of the carbonatite complex, but the apron is rather poorly developed on the western 

margin. Geologic mapping of the volcanic strata identified at least four volcano-sedimentary formations 

(fig. 2; Cheremitsyn and Yeremenko, 1976), each interpreted to correspond to a discrete eruptive and 

sedimentary stage. None of the volcanic formations has been studied in a modern-day petrologic sense, 

and their linkage to any plutonic part of the central vent is tentative at best. What is clear, however, is 

that the vast majority of the volcanic emissions are composed of some variety of carbonatite. The only 

known silicate-rich igneous rocks are three small plugs and lava flows of leucite phonolite in the 

southeastern part of the volcanic apron. 

Part of the volcanic deposits near the central vent are composed of stratified dark red rocks that 

vary from very fine-grained tuff, some of them finely porphyritic, to sandstone-like rocks (fig. 2, Q1-2c). 

Many of the fine grained rocks are composed of ferruginous carbonate that may represent volcanic 

emissions of thin carbonate ash. In addition to thin ferruginous carbonatite, the more coarse-grained 

rocks contain lithoclasts of ankeritic sövite and detrital quartz, plagioclase, and potassium feldspar. The 

amount of detrital material varies greatly, and ranges from as much as 10 to 70 modal percent. These 

rocks are best described as volcano-sedimentary tuffites, because of their high degree of sedimentary 

rounding and sorting. 

The higher part of the volcanic section consists of bright orange-red rocks characterized by 

markedly higher iron content and, on the whole, a finer grain size (fig. 2, Q1-2b). They are also highly 

sorted and occasionally cross bedded, indicating they are likely reworked and redeposited sediments of 

a primary volcanic source.

In the northern part of the volcanic field (fig. 2, Q1-1), a mantle-like apron of coarse-grained 

agglomerate is mapped. The blocks are primarily sövite and ankerite-barite alvikite that range in size 

from a few centimeters to several meters in diameter. These blocks are cemented with very fine-grained 

greenish-brown carbonate. In some localities, signs of stratification are found amongst the blocks which 

are crudely stratified to form a macroscopic layering. The predominance of ankerite-barite carbonatite 

(alvikite) within the fragments suggests this unit formed as explosive eruption of ankerite-barite 

carbonatite.

Apparently linked to this eruption are coarsely laminated lithic tuffs on the western flank of the 

near-vent area (fig. 4E; fig. 2, Q1-3b). Their lithic fragments include biotite sövite (similar to rocks of the 

central vent), barite carbonatite, magnetite-apatite alvikite, and phlogopitic “glimmerites.” 

Unconformably overlying the laminated lithic tuffs are brick-red carbonatite tuffites. The southeastern 

part of the volcanic apron consists of green carbonatite tuffs, which form lenticular laminations 

overlying the brick-red tuffites. These are crystallo-lithoclastic, poorly cemented tuffs with fragments of 

ankerite sövite (30–70 percent), calcite (5–10 percent), phlogopite (2–8 percent), apatite (2–3 percent), 

potassium feldspar, and plagioclase.

The rock types described above constitute the near-vent rocks of the volcanic apron. In the distal 

parts of the apron, to the north and southeast, the volcanic strata are thin and strongly reworked by 

fluvial processes; they are best described as tuffaceous sedimentary deposits.
9

2.2.3 Satellitic Vents, Dikes, and Minor Intrusive Rocks

Five large plugs and several small extrusive masses of coarse-grained carbonatite crop out in the 

south, southeast, and west part of the Khanneshin carbonatite complex (fig. 2, Qaa). These plugs and 

small extrusive masses are heterogeneous in composition and texture, but, in general, they are all 

holocrystalline igneous rocks consisting mostly of banded and spotted biotite-calcite sövite. The largest 

of the intrusive plugs consists of medium-grained alvikite with coarse- and very coarse-grained 

xenoliths of sövite, biotite-rich “glimmerites” (mica-rich inclusions) and potassium feldspar-rich 

country rock (fenites). In contrast, many of the smaller satellitic vents are dominated by mediumgrained alvikite. In some of these plugs, very large (>1 m diameter) inclusions of coarse-grained sövite 

and “glimmerite” are abundant and large, and some outcrops have the appearance of giant intrusive 

breccias.

Three small plugs of leucitite and leucite phonolite also crop out in the southeast part of the 

volcanic apron (fig. 2, Qlp). These are the only bodies of silicate rock in the Khanneshin complex. The

leucite phonolites are dense, massive green-grey rocks with a thinly banded, finely spotted structure and 

porphyritic texture. Locally, they exhibit a spheroidal parting. The phenocrysts (50–70 percent) consist 

of leucite crystals 0.2–0.5 mm in diameter. The groundmass consists of sanidine, fine acicular aegerine 

aggregates, and minute crystals of nepheline, leucite, and carbonate. 

Two groups of carbonatite dikes can be distinguished: (1) those composed of massive alvikite, 

ankerite-barite carbonatite, tuff-breccias of alvikite and (2) those composed of porous fine-grained 

carbonatite. The last type of dike is one of the youngest generations of igneous rocks in the complex. 

These dikes are composed of rhombic calcite phenocrysts in a fine-grained calcite matrix with very 

small crystals of disseminated magnetite, apatite, and rare aegerine and chlorite.

2.3 History of Igneous Activity

According to Cheremitsyn and Yeremenko (1976) and Vikhter and others (1976, 1978), igneous 

activity began with explosive eruption of ankerite alvikite from the central vent at Khanneshin 

carbonatite complex. This event was followed by forceful emplacement of coarse-grained sövite into the 

same vent. The presence of strongly metasomatized “glimmerites” and fenites within the central vent 

suggests the activity of fluorine-, sulfate- and phosphate-enriched fluids at depth. This initial phase was 

completed by the emplacement of REE enriched ankerite-barite carbonatite of the peripheral vent. 

The succeeding phases commenced as an explosive eruption of common alvikite of the satellitic 

extrusive stocks and vents. These include various lava flows, volcanic tuffs, and volcanogenic 

sedimentary rocks of the volcanic apron. Emplaced into all of these are fine-grained carbonatites of the 

radial dykes. The final phase of activity was the eruption and emplacement of critically undersaturated 

silicate magma. These are represented by lava flows of leucite phonolite and intrusive brecciated plugs 

of leucitite in the southeastern part of the complex (figs. 2 and 3). 

The Khanneshin complex was considered Pliocene to early Quaternary in age (Vikhter and 

others, 1978) because of the eroded appearance of the young, central vent, and the unpublished isotopic 

ages of between 1.4 and 2.8 to 5.0 million years reported by Abdullah and others (1977). However, 

Whitney (2006) cites an unpublished K-Ar age of 0.61 ± 0.05 million years (Richard Marvin, USGS, 

written commun. to Whitney), obtained on leucite from a plug of phonolite in the southeastern part of 

the complex. These phonolites are the youngest igneous rocks of the Khanneshin complex. Thus, we 

assign an early Quaternary age for the entire igneous complex, which is consistent with the unpublished 

K-Ar age, the fact that the central vent intrudes the Sistan beds of late Miocene age (Whitney, 2006), 

and the youngest volcanic strata are overlain by unconsolidated deposits of middle-upper Quaternary 

age (fig. 2, Q4).
10

2.4 Metallogeny

The main nonfuel resources related to alkaline igneous rocks include barite, fluorspar, nepheline, 

REE, phosphate niobium, tantalum, zirconium, copper, uranium, and thorium. The Khanneshin 

carbonatite is the area of interest for three prospective nonfuel resources—REE, uranium (U) and 

phosphorus (P)—first identified and delineated by Soviet geologists in the 1970s (Chmyrev, 1976; 

Vikhter and others, 1976, 1978). Rare-earth element mineralization occurs mostly within the northeast 

marginal zone of the central vent, outlined in green in figure 2. Modestly high uranium and thorium 

concentrations (>200 parts per million, ppm) are reported in many rocks throughout the complex, but 

the greatest uranium concentrations are confined to silicified zones in the Neogene strata about 750 m 

southwest of the central vent. Finally, phosphorus is present in significant amounts, principally as 

apatite in rudaceous agglomerate, fenite xenoliths, and alvikite (fig. 2, Q1-3b). Other commodities may 

be present in significant, but as yet undetermined, amounts; these include barite, fluorite, nepheline, 

niobium, tantalum, zirconium, and copper. In addition to the Khanneshin carbonatite, alkali syenite 

intrusive igneous rocks, consisting of volcanoes and intrusive plugs and dikes, are identified in south 

Afghanistan (Abdullah and others, 1977; Vikhter and others, 1976, 1978). On the basis of regional 

geologic considerations and Monte Carlo calculations, the USGS estimates that there is a 50-percent

chance of one or more undiscovered deposits of REE and niobium in south Afghanistan. The mean 

estimated tonnage of these undiscovered resources is 1.4 Mt of REE and 3.5 Mt of niobium (Peters and 

others, 2007). 

3.0 The Zone of LREE Enrichment

A high content of LREE is characteristic of the sövitic rocks, as well as of the barium- and 

strontium-rich rocks of the ankerite-barite alvikites. In the 1970s, Soviet geologists identified a 

polygonal area, underlain by rocks having extreme REE enrichment, in the northeast margin of the 

central vent (fig. 2, Qesf). Within this area, outlined in green, several discordant dikes that are 

particularly rich in fluorite and LREE-carbonate minerals were identified. These dikes are tens of meters 

wide and as much as hundreds of meters long, and they contain as much as several wt. percent LREE.

Three 1-day scoping missions were completed by a team of USGS scientists and U.S. 

Department of Defense Task Force for Business and Stability Operations (TFBSO) personnel to the 

Khanneshin complex. Traverse 1, consisting of two different legs (1A and 1B) and completed in 

September 2009, examined the volcanic rocks in the southwestern part of the complex. In 2010 and 

2011, two missions were made to the zone of LREE enrichment (fig. 2). Traverse 2, completed in 

August 2010 with 6 hours of allowed field time, intersected the southern boundary of LREE zone of 

enrichment and transected the contact between metasomatized Neogene strata and rocks of the central 

intrusive vent. Traverse 3, completed in February 2011, traversed the northern apron of volcanic strata 

and intersected the northwestern corner of the zone of LREE enrichment. Because of security concerns 

in this rugged part of the complex, the USGS-TFBSO field team was allowed less than two hours to 

complete traverse 3. Over the course of both missions, the field teams collected more than 50 rock 

samples representing the principal rocks of the mineralized zone; these were submitted for major-, trace,

and rare earth element whole-rock geochemical analysis (tables 1–3). Polished thin-sections were made 

for each of the rock samples, and scanning-electron microscopy was conducted on a subset of these 

thin-sections.
11

Table 1. Whole-rock major-, trace-, and rare earth element (REE) concentration data, traverses 1A and 1B, Khanneshin carbonatite complex, 

Afghanistan. [wt. %, weight percent; ppm, parts per million]

Unit Description Northing Easting

Major elements

SiO2 Al2O3 Fe2O3(t) MgO CaO Na2O K2O TiO2 P2O5 MnO LOI

wt. % wt. % wt. % wt. % wt. % wt. % wt. % wt. % wt. % wt. % wt. %

KH09002R volcanic tuff 30.45918 63.57663 2.63 0.41 2.72 0.83 45.30 0.16 0.40 0.10 0.72 1.20 35.6

KH09003R carbonatite dike 30.45901 63.57749 3.40 1.05 1.83 1.25 47.90 0.36 0.43 0.03 1.69 0.90 34.4

KH09004RP alvikite agglomerate 30.45939 63.57956 14.30 3.02 7.98 2.19 35.80 0.37 2.61 0.20 1.97 0.33 27.7

KH09005R alvikite agglomerate 30.45890 63.57753 17.60 3.79 9.42 2.66 34.90 0.74 2.06 0.21 2.32 0.33 23.4

KH09006R alvikite agglomerate 30.45997 63.57998 14.30 2.42 8.43 2.81 36.00 0.41 2.62 0.17 3.72 0.49 24.8

KH09007R alvikite agglomerate 30.46043 63.57931 28.80 6.85 9.90 2.34 25.30 0.40 5.58 0.45 1.38 0.43 17.1

KH09008R alvikite agglomerate 30.45936 63.57565 11.50 1.89 8.92 2.94 39.40 0.63 0.72 0.15 3.63 0.40 27.4

KH09010R alvikite agglomerate 30.45918 63.57666 15.80 3.27 8.37 2.41 36.60 0.78 1.74 0.19 2.45 0.38 24.6

KH09011RP alvikite agglomerate 30.48074 63.54637 22.30 5.58 11.40 4.46 34.90 0.26 1.94 0.44 3.56 0.28 12.5

KH09012R alvikite agglomerate 30.48082 63.54713 22.30 5.61 11.50 4.40 34.40 0.43 1.80 0.45 3.48 0.28 13.6

KH09013R alvikite agglomerate 30.48086 63.54830 34.90 8.35 17.40 0.90 23.10 0.78 6.17 0.64 1.64 0.31 3.58

KH09014R sandstone 30.48079 63.54882 60.10 5.76 1.44 0.71 14.60 0.75 3.50 0.19 0.12 0.03 11.9

KH09101R volcanic tuff 30.46076 63.58070 31.30 8.45 8.18 2.77 21.70 0.77 6.64 0.34 1.01 0.49 15.6

KH09104R carbonatite dike 30.45922 63.57607 14.60 3.13 7.92 2.07 36.00 0.29 3.30 0.19 2.07 0.33 28.5

KH09105 volcanic tuff 30.48179 63.54846 34.80 5.79 6.52 3.42 21.00 0.50 5.55 0.29 1.51 0.17 18.8

Unit Description Northing Easting

Trace elements

Sc Be V Co Zn Ga Ge As Rb Sr Y Zr Nb Mo

ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm

KH09002R volcanic tuff 30.45918 63.57663 <5 46 157 2.1 279 17 NA NA 15.5 >10,000 162.0 13.1 165 NA

KH09003R carbonatite dike 30.45901 63.57749 <5 16 147 2.5 201 10 NA NA 20.2 7,140 81.8 39.2 64 NA

KH09004RP alvikite agglomerate 30.45939 63.57956 <5 14 115 11.8 158 13 NA NA 87.2 >10,000 223.0 296.0 37 NA

KH09005R alvikite agglomerate 30.45890 63.57753 <5 18 152 14.8 241 14 NA NA 62.0 >10,000 151.0 435.0 41 NA

KH09006R alvikite agglomerate 30.45997 63.57998 6 57 264 12.6 481 12 NA NA 70.1 >10,000 203.0 339.0 65 NA

KH09007R alvikite agglomerate 30.46043 63.57931 6 29 407 10.7 182 15 NA NA 99.0 2,750 226.0 756.0 120 NA

KH09008R alvikite agglomerate 30.45936 63.57565 6 19 200 11.3 159 11 NA NA 54.1 7,520 175.0 456.0 59 NA

KH09010R alvikite agglomerate 30.45918 63.57666 <5 17 165 12.7 208 13 NA NA 67.7 >10,000 163.0 606.0 51 NA

KH09011RP alvikite agglomerate 30.48074 63.54637 13 15 199 26.1 141 16 NA NA 111.0 8,360 118.0 809.0 40 NA

KH09012R alvikite agglomerate 30.48082 63.54713 13 14 185 25.5 141 16 NA NA 119.0 8,350 118.0 755.0 39 NA

KH09013R alvikite agglomerate 30.48086 63.54830 9 7 469 5.2 66 19 NA NA 145.0 2,630 731.0 2,790.0 31 NA

KH09014R sandstone 30.48079 63.54882 <5 <5 41 4.0 20 5 NA NA 86.0 1,160 8.0 183.0 5 NA

KH09101R volcanic tuff 30.46076 63.58070 8 19 288 9.5 176 16 NA NA 107.0 6,970 193.0 519.0 111 NA

KH09104R carbonatite dike 30.45922 63.57607 <5 14 116 11.4 156 12 NA NA 83.3 9,060 219.0 284.0 38 NA

KH09105 volcanic tuff 30.48179 63.54846 7 12 70 14.1 96 11 NA NA 164.0 4,310 64.7 347.0 26 NA
12

Unit Description Northing Easting

Trace elements—Continued

U

ppm

9.87

7.52

7.45

15.3

8.57

7.47

10.4

26.6

14.7

14.8

12.7

3.16

16.7

7.35

5.37

Ba

ppm

Bi

ppm

Lu Hf Ta W Tl

ppm ppm ppm ppm ppm

Pb

ppm

Th

ppm

KH09002R

KH09003R

KH09004RP

KH09005R

KH09006R

KH09007R

KH09008R

KH09010R

KH09011RP

KH09012R

KH09013R

KH09014R

KH09101R

KH09104R

KH09105

volcanic tuff

carbonatite dike

alvikite agglomerate

alvikite agglomerate

alvikite agglomerate

alvikite agglomerate

alvikite agglomerate

alvikite agglomerate

alvikite agglomerate

alvikite agglomerate

alvikite agglomerate

sandstone

volcanic tuff

carbonatite dike

volcanic tuff

30.45918

30.45901

30.45939

30.45890

30.45997

30.46043

30.45936

30.45918

30.48074

30.48082

30.48086

30.48079

30.46076

30.45922

30.48179

63.57663

63.57749

63.57956

63.57753

63.57998

63.57931

63.57565

63.57666

63.54637

63.54713

63.54830

63.54882

63.58070

63.57607

63.54846

>10,000

>10,000

3,060

3,180

5,090

4,320

5,220

3,610

2,880

2,720

760

345

5,410

2,690

1,610

2.8

8.2

0.8

1.2

5.0

2.3

1.6

1.6

0.6

0.4

0.2

0.1

3.1

0.8

0.4

0.92

1.36

2.63

1.22

1.48

1.71

1.64

1.32

0.95

0.96

7.94

0.26

1.32

2.44

0.57

<1

<1

9

5

10

19

12

6

17

16

49

3

10

8

8

2

0.7

2.7

2.4

2.2

3.8

2.8

2.9

1.9

1.9

7.8

<0.5

8.6

2.6

1.3

30

22

3

2

4

50

6

1

6

5

<1

2

36

3

2

9.2

2.5

1.4

4.7

6.2

4

1.4

10.5

1.8

1.9

1.2

0.7

2.7

1.3

1.4

626

837

79

121

309

167

124

149

68

57

26

13

193

79

42

100

24.9

102

106

107

78.9

123

105

59.6

59.9

116

3.5

118

96.7

34.9

Unit Description Northing Easting

REEs

La

ppm

Ce

ppm

Pr

ppm

Nd

ppm

Sm

ppm

Eu

ppm

Gd

ppm

Tb

ppm

Dy

ppm

Ho

ppm

Er

ppm

Tm

ppm

Yb

ppm

KH09002R

KH09003R

KH09004RP

KH09005R

KH09006R

KH09007R

KH09008R

KH09010R

KH09011RP

KH09012R

KH09013R

KH09014R

KH09101R

KH09104R

KH09105

volcanic tuff

carbonatite dike

alvikite agglomerate

alvikite agglomerate

alvikite agglomerate

alvikite agglomerate

alvikite agglomerate

alvikite agglomerate

alvikite agglomerate

alvikite agglomerate

alvikite agglomerate

sandstone

volcanic tuff

carbonatite dike

volcanic tuff

30.45918

30.45901

30.45939

30.45890

30.45997

30.46043

30.45936

30.45918

30.48074

30.48082

30.48086

30.48079

30.46076

30.45922

30.48179

63.57663

63.57749

63.57956

63.57753

63.57998

63.57931

63.57565

63.57666

63.54637

63.54713

63.54830

63.54882

63.58070

63.57607

63.54846

1700

922

492

491

430

320

484

544

352

351

156

12.4

376

457

162

2550

1400

1040

964

1140

713

1140

1060

701

690

451

21.6

760

1050

329

268

135

119

119

105

82.5

116

128

87.1

86.8

83.6

2.79

90.2

113

41

821

412

450

442

399

332

441

482

335

335

458

10.3

344

428

157

105

48.9

82.2

80.1

79.4

78.7

83.6

85.5

61.2

62.3

176

2

72.2

78.9

29.5

21.3

8.82

18.9

18.1

18.7

19.9

19

18.8

13.4

13.4

50.8

0.49

17.6

17.6

6.55

70.2

26.3

64.6

60.9

66.1

73.1

64

63.4

47.7

47.9

198

1.73

61.1

60.8

23.4

9.7

3.43

8.98

7.94

9.27

10.9

8.81

8.3

6.16

6.31

31.8

0.25

9.05

8.3

3.05

42.8

14.8

45.2

36.4

45.2

55.6

41.2

37.6

28.1

28.3

172

1.46

45.3

42.6

14.6

6.44

2.71

8.63

6.01

7.52

9.15

6.86

6.23

4.58

4.55

30.5

0.28

7.55

8.2

2.45

13.2

7.6

22.4

13.6

17.2

20.6

16.7

14.1

10.2

10.2

73.8

0.82

16.5

21.9

5.61

1.32

1.15

3 

1.52

1.97

2.23

2.05

1.56

1.13

1.14

9.39

0.09

1.8

2.99

0.65

6.6

8.6

17.5

8.2

10.5

11.6

11

8.7

6.1

6.1

52.5

0.9

9

17.4

3.7
13

Table 2. Major-, trace-, and rare earth element (REE) concentration data, traverse 2, Khanneshin carbonatite complex, Afghanistan. [%, percent; ppm, parts per million]

Unit Description Northing Easting

Major elements

SiO2 Al2O3 Fe2O3(t) MgO CaO Na2O K2O TiO2 P2O5 MnO LOI

% % % % % % % % % % %

AC-10-KH-05 alvikite 30.46884 63.59335 NA 0.45 NA NA NA NA NA NA 0.708 0.759 NA

RT-10K-03 fluorite-REE dike 30.47290 63.59799 NA 0.14 NA NA NA NA NA 0.003 0.082 >1.3 NA

RT-10K-13 alvikite 30.47363 63.60064 NA 3.98 NA NA NA NA NA >0.17 0.914 >1.3 NA

AC-10-KH-01 alvikite 30.47013 63.59568 NA 0.30 NA NA NA NA NA 0.087 0.936 >1.3 NA

RT-10K-2B carbonatite dike 30.47407 63.60501 NA 0.36 NA NA NA NA NA 0.028 0.165 1.252 NA

RT-10K-4B carbonatite dike 30.47035 63.59533 NA 1.40 NA NA NA NA NA 0.065 1.14 0.684 NA

FH-10-KH-02 alvikite 30.46884 63.59355 NA 0.10 NA NA NA NA NA 0.009 >2.3 >1.3 NA

FH-10-KH-04 alvikite 30.47354 63.59877 NA 1.08 NA NA NA NA NA 0.036 1.346 0.969 NA

FH-10-KH-05 alvikite 30.46816 63.59297 NA 0.22 NA NA NA NA NA 0.024 0.099 0.307 NA

FH-10-KH-08 alvikite 30.46858 63.59299 NA 0.12 NA NA NA NA NA 0.008 0.366 >1.3 NA

AC-10-KH-04 alvikite 30.46884 63.59335 NA 5.85 NA NA NA NA NA >0.17 1.17 1.209 NA

RT-10K-5A sövite 30.46884 63.59361 NA 1.37 NA NA NA NA NA 0.068 0.481 0.547 NA

RT-10K-5B alvikite 30.46884 63.59361 NA 0.09 NA NA NA NA NA 0.022 >2.3 >1.3 NA

RT-10K-5C apatite alvikite 30.46884 63.59361 NA 0.17 NA NA NA NA NA 0.014 >2.3 >1.3 NA

RT-10K-5D apatite alvikite 30.46884 63.59361 NA 0.13 NA NA NA NA NA 0.023 1.365 >1.3 NA

RT-10K-09 sövite 30.47087 63.59591 NA 1.25 NA NA NA NA NA 0.059 >2.3 0.931 NA

RT-10K-12 alvikite dike 30.47388 63.59966 NA 0.32 NA NA NA NA NA 0.024 1.678 1.015 NA

RT-10K-5E alvikite 30.46884 63.59361 NA 0.11 NA NA NA NA NA 0.015 1.721 >1.3 NA

FH-10-KH-03 alvikite 30.46726 63.59227 NA >9.4 NA NA NA NA NA >0.17 1.885 0.593 NA

FH-10-KH-06 alvikite 30.46806 63.59283 NA >9.4 NA NA NA NA NA >0.17 0.163 0.595 NA

FH-10-KH-07 alvikite 30.47056 63.59573 NA 1.28 NA NA NA NA NA 1.012 0.418 0.657 NA

RT-10K-6A alvikite tuff 30.46719 63.59228 NA 3.59 NA NA NA NA NA 0.149 1.057 0.415 NA

RT-10K-6B alvikite tuff 30.46719 63.59228 NA 3.63 NA NA NA NA NA 0.152 2.063 1.105 NA

RT-10K-6C alvikite tuff 30.46719 63.59228 NA 0.15 NA NA NA NA NA 0.016 0.242 >1.3 NA

RT-10K-6D alvikite tuff 30.46719 63.59228 NA >9.4 NA NA NA NA NA >0.17 0.437 0.535 NA

RT-10K-6E alvikite tuff 30.46719 63.59228 NA 2.49 NA NA NA NA NA 0.096 0.391 0.16 NA

RT-10K-1A alvikite agglomerate 30.47335 63.60572 NA 2.88 NA NA NA NA NA 0.142 0.777 >1.3 NA

RT-10K-07 alvikite 30.46859 63.59301 NA 0.24 NA NA NA NA NA 0.017 0.221 >1.3 NA

RT-10K-08 alvikite agglomerate 30.46975 63.59528 NA 7.69 NA NA NA NA NA >0.17 1.285 0.597 NA

FH-10-KH-01 alvikite 30.47013 63.59568 NA 1.21 NA NA NA NA NA 0.125 0.802 0.506 NA

AC-10-KH-02 alvikite 30.47013 63.59568 NA 0.17 NA NA NA NA NA 0.014 0.95 0.306 NA

AC-10-KH-03 alvikite 30.46870 63.59371 NA 0.09 NA NA NA NA NA 0.008 >2.3 >1.3 NA

RT-10K-10 alvikite tuff 30.47191 63.59710 NA 0.46 NA NA NA NA NA 0.084 0.342 1.239 NA

RT-10K-11 alvikite tuff 30.47358 63.59824 NA 0.47 NA NA NA NA NA 0.119 1.642 >1.3 NA

AC-10-KH-06 alvikite 30.46872 63.59368 NA 0.09 NA NA NA NA NA 0.033 0.367 >1.3 NA

RT-10K-4A alvikite tuff 30.47035 63.59533 NA 1.04 NA NA NA NA NA 0.095 0.099 1.284 NA

RT-10K-1B alvikite tuff 30.47335 63.60572 NA 0.15 NA NA NA NA NA 0.041 1.468 >1.3 NA

RT-10K-2A siltstone 30.47407 63.60501 NA 8.94 NA NA NA NA NA >0.17 0.056 0.227 NA

FH-10-KH-10 alvikite 30.47385 63.60465 NA >9.4 NA NA NA NA NA >0.17 0.283 0.151 NA
14

Unit Description Northing Easting

Trace elements

Sc

ppm

Be

ppm

V

ppm

Co

ppm

Zn

ppm

Ga Ge

ppm ppm

As

ppm

Rb

ppm

Sr

ppm

Y

ppm

Zr

ppm

AC-10-KH-05

RT-10K-03

RT-10K-13

AC-10-KH-01

RT-10K-2B

RT-10K-4B

FH-10-KH-02

FH-10-KH-04

FH-10-KH-05

FH-10-KH-08

AC-10-KH-04

RT-10K-5A

RT-10K-5B

RT-10K-5C

RT-10K-5D

RT-10K-09

RT-10K-12

RT-10K-5E

FH-10-KH-03

FH-10-KH-06

FH-10-KH-07

RT-10K-6A

RT-10K-6B

RT-10K-6C

RT-10K-6D

RT-10K-6E

RT-10K-1A

RT-10K-07

RT-10K-08

FH-10-KH-01

AC-10-KH-02

AC-10-KH-03

RT-10K-10

RT-10K-11

AC-10-KH-06

RT-10K-4A

RT-10K-1B

RT-10K-2A

FH-10-KH-10

alvikite

fluorite-REE dike

alvikite

alvikite

carbonatite dike

carbonatite dike

alvikite

alvikite

alvikite

alvikite

alvikite

sövite 

alvikite 

apatite alvikite

apatite alvikite

sövite

alvikite dike

alvikite

alvikite

alvikite

alvikite

alvikite tuff

alvikite tuff

alvikite tuff

alvikite tuff

alvikite tuff

alvikite agglomerate

alvikite

alvikite agglomerate

alvikite

alvikite

alvikite

alvikite tuff

alvikite tuff

alvikite

alvikite tuff

alvikite tuff

siltstone

alvikite

30.46884

30.47290

30.47363

30.47013

30.47407

30.47035

30.46884

30.47354

30.46816

30.46858

30.46884

30.46884

30.46884

30.46884

30.46884

30.47087

30.47388

30.46884

30.46726

30.46806

30.47056

30.46719

30.46719

30.46719

30.46719

30.46719

30.47335

30.46859

30.46975

30.47013

30.47013

30.46870

30.47191

30.47358

30.46872

30.47035

30.47335

30.47407

30.47385

63.59335

63.59799

63.60064

63.59568

63.60501

63.59533

63.59355

63.59877

63.59297

63.59299

63.59335

63.59361

63.59361

63.59361

63.59361

63.59591

63.59966

63.59361

63.59227

63.59283

63.59573

63.59228

63.59228

63.59228

63.59228

63.59228

63.60572

63.59301

63.59528

63.59568

63.59568

63.59371

63.59710

63.59824

63.59368

63.59533

63.60572

63.60501

63.60465

0.1

0.6

8.2

7.6

11.2

<0.1

<0.1

3.4

1.2

0.6

0.5

4.8

<0,1

<0,1

<0,1

2.3

3.7

<0.1

3.2

7.1

7.9

6.1

3.4

2.9

5.6

1

10.8

0.9

4.9

0.9

0.8

<0,1

2.9

4.6

1.1

3.5

3.4

16.7

22.6

4

4.7

35.8

44.4

16.8

38.4

14.2

5.7

12.4

15.4

19.2

4.7

11.1

4.8

11.6

7.7

4

15.2

4.4

7.1

10.2

10.6

9.5

6.3

11.3

4.6

14.7

19.2

10.3

5.8

2.1

4.9

3.1

4.5

11.5

5.2

66.3

63.4

>100

5,222

47.3

193.9

166.8

122.8

110.5

35.4

80.9

39.1

42.5

154.9

106.2

36.1

32.4

31

116.5

78.9

31.1

250

208.8

107.4

128

89.8

61

241.5

85.7

172.3

55

114

59.9

38.8

31.2

288.8

275

94.5

108.5

84.8

259.1

246.1

8.1

1.9

8

2.1

5.8

6

0.5

2.9

1.8

0.5

6.1

2.6

0.6

0.4

0.4

5

8.4

0.4

16

14.7

3.9

5.4

7.1

1.4

14.9

3.2

6.1

1.3

10.1

4.3

1.1

1.1

5.5

3.9

1.1

3.5

4.2

7.9

12.9

1,847

177

622

952

439

308

951

195

>10,000

2,233

2,155

169

2,811

2,382

1,243

144

75

2,009

507

239

510

220

389

1,041

282

116

364

3,347

268

383

33

793

969

351

1,240

1,815

88

114

116

5.8

49.8

19.5

41.4

14.8

12.7

58.3

10.5

30.5

57.8

15.5

10.1

59.2

52.2

59.2

10.4

6.8

55.6

16.5

11

15.3

10.3

13.3

25.8

10.9

4.1

18

32.4

13.9

14.5

9.8

13.9

22.3

18.1

17.8

25.5

30.9

9.3

13.3

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

58

2,882

208

2,360

379

228

6,498

380

1,012

3,816

118

148

<1.5

>10,000

<1.5

99

159

>10,000

63

<1.5

255

157

107

562

<1.5

106

479

1,107

86

204

104

316

407

323

509

566

907

<1.5

118

5.5

3.1

47.1

9.6

5.3

18.7

2.9

21.3

3.2

2.7

121.2

34.2

4.1

2.2

3.1

31.5

5.5

4.6

66.3

32.7

33

51.4

76.4

7.8

40.1

37.9

49.7

4.4

60.5

42.3

5.6

4.9

37.7

4.2

2.7

26.4

1.8

47.3

40.6

4,538

28,051

13,752

27,885

28,233

11,270

22,926

27,224

14,720

25,693

19,828

15,417

20,171

14,000

18,109

13,851

18,695

17,163

6,491

2,331

15,124

5,441

12,116

22,706

2,761

3,153

18,941

40,469

10,909

16,425

23,451

20,751

26,676

17,623

31,607

20,739

33,723

653

1,145

5

156

223

880

198

172

74

210

37

46

33

43

24

122

75

202

306

28

23

16

286

40

111

127

19

18

255

54

83

61

80

97

174

301

145

416

572

62

111

32.3

44.1

52

84.3

32.3

48.5

256.6

17.4

64.2

58.8

55.8

30.7

100.6

177

52.1

345

17

116.3

70.7

19

68.7

260

209

46

45

41

80.4

34

615

11.1

8.4

69

42

81

29.3

22.7

222.5

145.3

114.5
15

Unit Description Northing Easting

Trace elements—Continued

Nb

ppm

Mo

ppm

Ba

ppm

Bi

ppm

Lu Hf Ta W

ppm ppm ppm ppm

Tl

ppm

Pb

ppm

Th

ppm

U

ppm

AC-10-KH-05

RT-10K-03

RT-10K-13

AC-10-KH-01

RT-10K-2B

RT-10K-4B

FH-10-KH-02

FH-10-KH-04

FH-10-KH-05

FH-10-KH-08

AC-10-KH-04

RT-10K-5A

RT-10K-5B

RT-10K-5C

RT-10K-5D

RT-10K-09

RT-10K-12

RT-10K-5E

FH-10-KH-03

FH-10-KH-06

FH-10-KH-07

RT-10K-6A

RT-10K-6B

RT-10K-6C

RT-10K-6D

RT-10K-6E

RT-10K-1A

RT-10K-07

RT-10K-08

FH-10-KH-01

AC-10-KH-02

AC-10-KH-03

RT-10K-10

RT-10K-11

AC-10-KH-06

RT-10K-4A

RT-10K-1B

RT-10K-2A

FH-10-KH-10

alvikite

fluorite-REE dike

alvikite

alvikite

carbonatite dike

carbonatite dike

alvikite

alvikite

alvikite

alvikite

alvikite

sövite 

alvikite 

apatite alvikite

apatite alvikite

sövite

alvikite dike

alvikite

alvikite

alvikite

alvikite

alvikite tuff

alvikite tuff

alvikite tuff

alvikite tuff

alvikite tuff

alvikite agglomerate

alvikite

alvikite agglomerate

alvikite

alvikite

alvikite

alvikite tuff

alvikite tuff

alvikite

alvikite tuff

alvikite tuff

siltstone

alvikite

30.46884

30.47290

30.47363

30.47013

30.47407

30.47035

30.46884

30.47354

30.46816

30.46858

30.46884

30.46884

30.46884

30.46884

30.46884

30.47087

30.47388

30.46884

30.46726

30.46806

30.47056

30.46719

30.46719

30.46719

30.46719

30.46719

30.47335

30.46859

30.46975

30.47013

30.47013

30.46870

30.47191

30.47358

30.46872

30.47035

30.47335

30.47407

30.47385

63.59335

63.59799

63.60064

63.59568

63.60501

63.59533

63.59355

63.59877

63.59297

63.59299

63.59335

63.59361

63.59361

63.59361

63.59361

63.59591

63.59966

63.59361

63.59227

63.59283

63.59573

63.59228

63.59228

63.59228

63.59228

63.59228

63.60572

63.59301

63.59528

63.59568

63.59568

63.59371

63.59710

63.59824

63.59368

63.59533

63.60572

63.60501

63.60465

429.6

5.5

295

173

162.7

22.9

1.6

21

129.1

15.7

569

21.8

58.3

9.6

218.5

30

80

27.1

86.7

47.5

271

55

57

140

84

31

110

50

84

33.5

6.6

15.7

362

362

44.7

232

56.4

205.1

186.8

3.5

10.4

6.1

17.8

3.8

4.1

1.6

3

17.7

15.8

2.1

2.2

21.8

2.6

6.5

2.9

21.5

4.3

0.3

0.5

6.7

0.6

1.1

4.4

0.5

1.4

2

53.5

0.8

9.6

0.5

6.2

3.3

5.2

9.5

22.2

8.8

0.8

1.3

1,420

4,651

1,124

385

8,824

5,062

748

7,163

2,324

721

998

2,514

674

1,365

1,164

2,840

7,048

576

1,618

7,940

141

2,323

3,244

488

7,428

66

1,553

527

8,751

1,812

1,374

735

6,631

5,314

1,110

7,320

749

684

318

10.6

0.3

10.6

0.4

6.8

2.2

0

4.5

1

0

10.4

0.2

0

0

0

0.2

15.1

0

14.2

3.1

20.9

20

4.4

4.1

1.5

2.2

19.2

0.4

3.4

35.9

8.6

7.4

6.5

21.5

6.9

13.4

17

0.2

0.5

0.1

0.7

2.12

2.2

2

0.8

0.4

1.6

0.4

0.6

0.3

0.4

0.3

0.4

0.3

1.34

1.95

0.3

0.2

0.1

0.9

0.45

0.82

0.67

0.16

0.15

1.3

0.56

0.65

0.5

0.7

0.6

0.73

1.3

0.7

1.1

2.2

0.8

1.4

0.7

1.6

1.68

1.9

0.8

1.5

2.7

0.6

2.6

1.7

1.2

0.8

1.8

2

1.6

2.99

0.85

2.2

1.4

0.8

2.3

4.23

4.22

1.27

1.24

1.21

1.9

1.94

9.38

0.5

0.3

1.2

1.52

3.04

0.8

1.1

2.7

4.2

3.9

10.5

2.1

5.73

2

2

2.3

2.5

1.3

4

3.1

11.5

1.3

2.8

2

2.6

2.16

0.58

2.6

7.1

1.3

18.2

6.71

4.66

0.91

7.96

1.45

4.2

2.22

4.66

1.6

0.5

1

15.07

7.15

2.7

12.2

2.1

0.7

1.2

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

4.6

1.4

2.2

6.6

15.9

1.3

0.9

2.4

2.5

0.5

13.6

3.1

2.2

0.5

1.3

2

4.5

1.9

2 

3.3

3

4.6

4.4

4.2

3.5

1.6

15

3.9

4.7

2.4

0.5

2

7.7

8.2

10.8

39.5

0.5

4.1

6 

1,100

93

848

562

631

229

352

235

6,560

342

827

41

1,483

469

1,476

86

675

1,042

153

133

1,463

630

835

1,020

98

162

1,160

1,230

314

1,210

334

652

1,301

2,174

829

1,848

1,288

36

81

8.1

50.4

279

465.5

340.5

90

52.1

113.6

35.1

52.8

22.1

9.3

54.9

50.3

25.2

82.1

346.5

75.5

10.9

32

126.2

21.5

128

222.5

8.3

10.9

478.9

49.8

62.3

15.1

45.8

69

45.4

233.9

218.7

80.2

364.7

48

77.2

331

29.1

74.7

27.8

20.8

44.4

24.1

17.5

67.8

24.2

412

8.2

60.5

48.8

79.8

12.1

24.5

32.6

12.9

3.6

107.5

12.2

15.1

28.6

4.1

4.5

52.2

32

14.8

3.2

3.5

45.4

54.6

311

21.4

74.3

80.7

1.7

9.5
16

Unit Description Northing Easting

REEs

La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb

ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm

AC-10-KH-05 alvikite 30.46884 63.59335 349 652 73 244 29.7 5.6 20.8 1.2 2.5 0.3 1.5 0.1 0.6

RT-10K-03 fluorite-REE dike 30.47290 63.59799 9,198 10,536 673.9 1,430 119 49.8 198 10.5 25.3 3.6 12.7 1 5

RT-10K-13 alvikite 30.47363 63.60064 1,625 3,183 321 1,148 153 37.95 131.8 11.88 45.18 6.18 17.66 2.07 14.02

AC-10-KH-01 alvikite 30.47013 63.59568 5,816 8,217 708.2 2,079 292 84.9 282 25.5 95.1 13.1 33.7 2.9 16.4

RT-10K-2B carbonatite dike 30.47407 63.60501 1,422 2,262 212.8 624 72.3 19.3 89.2 9.7 40.9 5.9 15.7 1.8 12.8

RT-10K-4B carbonatite dike 30.47035 63.59533 640 1,161 127.1 426 63.3 13.4 51.7 5.1 30.3 5.9 14.7 1.6 7.6

FH-10-KH-02 alvikite 30.46884 63.59355 5,927 11,095 954.2 2,581 240 69.2 236 12.2 18.3 2.2 12.5 0.5 3.1

FH-10-KH-04 alvikite 30.47354 63.59877 956 1,540 155.4 519 91.9 23.6 89.4 11.1 51.4 7.7 18.6 2.1 11.3

FH-10-KH-05 alvikite 30.46816 63.59297 7,556 6,545 366.1 691 43.8 34.1 92.7 3.8 8 1.3 5.3 0.5 2.7

FH-10-KH-08 alvikite 30.46858 63.59299 7,530 11,254 849.2 2,157 189.7 71.5 214 10.2 14.9 1.7 10.4 0.5 3.8

AC-10-KH-04 alvikite 30.46884 63.59335 340 590 59.5 191 25.9 5.8 23.2 2.2 8.3 1.3 3.6 0.4 1.9

RT-10K-5A sövite 30.46884 63.59361 281 549 60.6 208 34.3 7.2 28.2 2.8 11 1.6 4.2 0.5 2.7

RT-10K-5B alvikite 30.46884 63.59361 6,408 11,046 850.3 2,163 180 66.7 204 9.4 13.2 1.5 9.4 0.3 2.2

RT-10K-5C apatite alvikite 30.46884 63.59361 4,783 9,505 860.7 2,543 257 68.7 231 12.9 23.4 2.5 12 0.5 3

RT-10K-5D apatite alvikite 30.46884 63.59361 6,562 11,053 862.2 2,285 207 70.9 227 11 18.1 2 10.7 0.4 2.5

RT-10K-09 sövite 30.47087 63.59591 426 919 108 430 68 17.41 64.67 8.27 43.38 6.58 16.08 1.76 10.1

RT-10K-12 alvikite dike 30.47388 63.59966 458 986 117 473 88 25.33 95.78 14.03 73.82 10.77 24.41 2.68 14.15

RT-10K-5E alvikite 30.46884 63.59361 6,094 10,609 841.4 2,220 179 63.7 207 9.3 12.8 1.4 9.4 0.3 2.3

FH-10-KH-03 alvikite 30.46726 63.59227 117 245 27.9 103 18.4 4.3 16.1 1.8 7.1 1 2.6 0.3 1.4

FH-10-KH-06 alvikite 30.46806 63.59283 117 192 20 68 11.8 4.5 11 1.1 4.6 0.7 1.6 0.2 1.1

FH-10-KH-07 alvikite 30.47056 63.59573 932 1,995 227.5 835 154.2 36.4 139 16.8 73.5 10.1 22.8 1.9 8.5

RT-10K-6A alvikite tuff 30.46719 63.59228 169 335 37 139 20 5.07 18.32 2.02 8.86 1.33 3.61 0.45 3.01

RT-10K-6B alvikite tuff 30.46719 63.59228 831 1,497 150 527 70 16.98 66.86 6.15 25.67 3.55 9.17 0.94 5.97

RT-10K-6C alvikite tuff 30.46719 63.59228 1,784 4,071 458 1,617 151 34.25 127.9 8.23 23.17 3.16 10.92 0.76 5.19

RT-10K-6D alvikite tuff 30.46719 63.59228 85 167 19 71 12 4.28 10.4 1.09 5.16 0.76 2.11 0.21 1.25

RT-10K-6E alvikite tuff 30.46719 63.59228 65 142 17 70 12 2.84 9.62 1.01 4.79 0.71 1.75 0.18 1.15

RT-10K-1A alvikite agglomerate 30.47335 63.60572 1,593 2,659 269.4 874 135 39.6 126 13 54.2 8 19.1 1.9 10.2

RT-10K-07 alvikite 30.46859 63.59301 7,838 7,101 441 1,048 83 6.71 113.1 5.13 12.55 1.7 6.71 0.62 4.37

RT-10K-08 alvikite agglomerate 30.46975 63.59528 554 1,011 110 412 57 14.1 50.29 4.89 20.49 2.94 7.56 0.74 4.5

FH-10-KH-01 alvikite 30.47013 63.59568 495 939 97.6 316 38.9 9 36.1 3.3 13.8 2.4 7 0.8 3.9

AC-10-KH-02 alvikite 30.47013 63.59568 722 1,372 148.3 494 62.6 13.1 54.5 5.1 19.9 2.9 8.7 0.9 5.3

AC-10-KH-03 alvikite 30.46870 63.59371 1,105 1,996 217.7 673 78.8 18.7 70.6 5.9 20.7 3.2 9.6 1 4.9

RT-10K-10 alvikite tuff 30.47191 63.59710 1,554 3,287 371 1,440 190 13.18 151.8 13.12 44.98 5.23 13.18 1.02 5.96

RT-10K-11 alvikite tuff 30.47358 63.59824 1,484 3,215 355 1,396 209 52.8 177.5 16.96 65.4 8.16 19.53 1.76 10.07

AC-10-KH-06 alvikite 30.46872 63.59368 2,245 3,210 298.2 874 111 30.7 112 9.7 31.9 4.2 11.2 1 5.7

RT-10K-4A alvikite tuff 30.47035 63.59533 1,503 2,835 311.6 1,072 150 30.3 128 12.6 53 9.4 26.1 2.3 18.9

RT-10K-1B alvikite tuff 30.47335 63.60572 2,535 5,124 533.4 1,842 268 56.5 234 24.1 92.9 12.7 32.5 3 16.5

RT-10K-2A siltstone 30.47407 63.60501 38 65 7.4 27 8.2 2.6 10.8 1.9 11.7 2 5.5 0.8 5.3

FH-10-KH-10 alvikite 30.47385 63.60465 31 62 7.1 29 10.1 3.6 14.6 3 20.6 4 10.8 1.5 9.5
17

Table 3. Major- and trace- , and rare earth

[wt. %, weight percent; ppm, parts per million]

element (REE) concentration data, traverse 3, Khanneshin carbonatite complex, Afghanistan. 

Unit Description Northing Easting

Major elements

SiO2

wt. %

Al2O3

wt. %

Fe2O3(t)

wt. %

MgO

wt. %

CaO Na2O K2O

wt. % wt. % wt. %

TiO2

wt. %

P2O5

wt. %

MnO

wt. %

LOI

wt. %

RT-11K-1A1

RT-11K-1A2

RT-11K-1B2

RT-11K-2A2

RT-11K-2B1

RT-11K-2B2

RT-11K-3B31

RT-11K-3B32

RT-11K-4AO1

RT-11K-4AO2

RT-11K-4B3

RT-11K-4C1A

RT-11K-4C1B

RT-11K-5A2

RT-11K-5A3

RT-11K-5B1B

RT-11K-5B3B

RT-11K-5B6A

RT-11K-6A2A

RT-11K-6A2B

RT-11K-6B2

RT-11K-6B3

Type-2 fluorine-rich dike

Type-2 fluorine-rich dike

Type-2 fluorine-rich dike

Type-1 concordantly banded REE vein

Type-1 concordantly banded REE vein

Type-1 concordantly banded REE vein

Type-2 patite-rich dike

Type-2 apatite-rich dike

Type-2 fluorine-rich dike

Type-2 fluorine-rich dike

Type-2 fluorine-rich dike

Type-2 fluorine-rich dike

Type-2 fluorine-rich dike

Type-1 concordantly banded REE vein

Type-1 concordantly banded REE vein

Type-1 concordantly banded REE vein

Type-1 concordantly banded REE vein

Type-1 concordantly banded REE vein

Type-2 apatite-rich dike

Type-2 apatite-rich dike

Type-2 apatite-rich dike

Type-2 apatite-rich dike

30.47976

30.47976

30.47976

30.47924

30.47924

30.47924

30.47883

30.47883

30.47844

30.47844

30.47844

30.47844

30.47844

30.47820

30.47820

30.47820

30.47820

30.47820

30.47810

30.47810

30.47810

30.47810

63.59494

63.59494

63.59494

63.59546

63.59546

63.59546

63.59459

63.59459

63.59453

63.59453

63.59453

63.59453

63.59453

63.59450

63.59450

63.59450

63.59450

63.59450

63.59452

63.59452

63.59452

63.59452

0.99

0.82

0.83

0.23

0.22

0.20

1.00

1.20

0.35

0.44

0.34

0.26

15.55

0.35

0.30

0.39

0.34

1.18

16.05

1.01

2.11

6.50

0.07

0.06

0.06

0.02 

0.03

0.02

0.23

0.25

0.06

0.04

0.05

0.04

3.62

0.06

0.05

0.05

0.05

0.21

3.59

0.24

0.49

1.42

1.84

1.70

4.14

3.14

3.14

2.98

3.81

2.49

0.75

0.88

2.11

1.06

8.62

2.51

2.59

2.79

1.81

8.14

11.27

5.12

6.48

7.13

5.25

4.56

5.41

7.10

6.31

6.07

3.30

3.80

5.63

5.18

5.99

6.04

5.80

6.85

6.88

6.63

4.94

10.01

10.01

5.10

6.86

7.00

22.97

21.68

22.66

19.17

16.91

17.19

16.90

10.61

36.17

23.35

27.16

27.18

25.81

16.87

17.97

16.10

20.05

20.85

17.39

19.20

19.23

17.35

0.08

0.07

0.11

0.28

0.23

0.26

0.16

0.66

0.48

0.84

0.73

0.71

0.55

0.12

0.16

0.19

0.13

0.10

1.50

4.62

3.87

3.64

0.17

0.15

0.15

0.02

0.02

0.02

0.23

0.27

3.13

3.60

0.76

2.50

3.90

0.13

0.13

0.13

0.08

0.25

4.07

0.40

0.64

1.73

0.01

0.01

0.00

0.01

0.01

0.00

0.02

0.01

0.00

0.01

0.00

0.00

0.12

0.00

0.00

0.00

0.00

0.01

0.14

0.01

0.02

0.06

0.25

0.25

0.25

2.13

1.76

2.03

1.41

1.06

0.07

0.09

0.09

0.07

4.53

0.20

0.60

1.29

0.54

0.09

6.19

3.75

1.08

3.04

1.16

0.90

1.13

1.90

1.78

1.82

1.97

1.37

0.48

0.36

0.78

0.59

1.22

1.97

2.32

2.28

1.80

3.91

1.81

2.12

2.58

2.06

21.15

20.17

20.39

24.23

23.19

22.71

20.34

18.29

34.98

24.90

31.77

27.62

18.35

17.98

18.72

18.53

16.28

27.76

16.29

27.36

30.17

25.18
18

Unit Description Northing Easting

Trace elements

Sc Be V Co Zn Ga Ge As Rb Sr Y Zr

ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm

RT-11K-1A1 Type-2 fluorine-rich dike 30.47976 63.59494 10 6 20 < 1 1,350 75 7 25 4 30,470 108 42

RT-11K-1A2 Type-2 fluorine-rich dike 30.47976 63.59494 10 6 13 < 1 1,490 82 8 26 4 39,020 112 23

RT-11K-1B2 Type-2 fluorine-rich dike 30.47976 63.59494 10 6 16 < 1 1,370 76 8 27 4 33,570 106 37

RT-11K-2A2 Type-1 concordantly banded REE vein 30.47924 63.59546 11 10 41 2 2,150 50 7 28 <2 22,110 423 147

RT-11K-2B1 Type-1 concordantly banded REE vein 30.47924 63.59546 14 11 43 1 950 65 8 34 <2 38,490 551 148

RT-11K-2B2 Type-1 concordantly banded REE vein 30.47924 63.59546 13 10 39 < 1 860 62 8 32 <2 36,380 552 161

RT-11K-3B31 Type-2 patite-rich dike 30.47883 63.59459 25 12 46 2 1,030 71 8 34 6 44,320 454 28

RT-11K-3B32 Type-2 apatite-rich dike 30.47883 63.59459 24 18 43 < 1 620 92 8 30 8 60,480 321 21

RT-11K-4AO1 Type-2 fluorine-rich dike 30.47844 63.59453 7 16 44 < 1 1,040 45 5 19 <2 47,510 112 33

RT-11K-4AO2 Type-2 fluorine-rich dike 30.47844 63.59453 12 33 74 < 1 810 93 7 26 <2 82,400 103 32

RT-11K-4B3 Type-2 fluorine-rich dike 30.47844 63.59453 11 35 108 < 1 1,200 77 6 31 <2 70,450 108 22

RT-11K-4C1A Type-2 fluorine-rich dike 30.47844 63.59453 10 26 52 < 1 580 74 6 24 <2 71,960 105 26

RT-11K-4C1B Type-2 fluorine-rich dike 30.47844 63.59453 6 58 454 5 520 20 3 11 93 19,120 545 82

RT-11K-5A2 Type-1 concordantly banded REE vein 30.47820 63.59450 15 16 26 1 1,210 79 10 37 <2 25,650 465 20

RT-11K-5A3 Type-1 concordantly banded REE vein 30.47820 63.59450 16 15 25 < 1 1,050 77 10 34 <2 29,090 540 18

RT-11K-5B1B Type-1 concordantly banded REE vein 30.47820 63.59450 14 13 25 2 2,260 75 10 38 <2 37,660 575 18

RT-11K-5B3B Type-1 concordantly banded REE vein 30.47820 63.59450 17 45 39 < 1 270 85 11 39 <2 49,520 594 15

RT-11K-5B6A Type-1 concordantly banded REE vein 30.47820 63.59450 23 40 92 17 2,550 177 18 119 6 49,760 162 21

RT-11K-6A2A Type-2 apatite-rich dike 30.47810 63.59452 17 25 153 7 1,220 61 8 29 131 23,670 1235 93

RT-11K-6A2B Type-2 apatite-rich dike 30.47810 63.59452 27 7 27 4 520 165 19 67 8 68,180 677 22

RT-11K-6B2 Type-2 apatite-rich dike 30.47810 63.59452 23 7 42 10 660 139 16 54 15 56,190 314 16

RT-11K-6B3 Type-2 apatite-rich dike 30.47810 63.59452 22 14 61 11 570 136 15 56 51 56,090 706 38
19

Unit Description Northing Easting

Trace elements—Continued

Nb Mo Ba Bi Lu Hf Ta W Tl Pb Th U

ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm

RT-11K-1A1 Type-2 fluorine-rich dike 30.47976 63.59494 41 5 196,200 < 0.4 0.86 0.7 0.3 3 0.9 962 88 15.4

RT-11K-1A2 Type-2 fluorine-rich dike 30.47976 63.59494 52 4 215,100 < 0.4 0.91 0.7 0.4 4 0.9 951 99 16.7

RT-11K-1B2 Type-2 fluorine-rich dike 30.47976 63.59494 50 6 187,400 < 0.4 0.88 0.8 0.3 3 1.8 885 89 17.5

RT-11K-2A2 Type-1 concordantly banded REE vein 30.47924 63.59546 3 9 190,400 0.6 1.64 1.3 < 0.1 4 0.3 991 306 93.2

RT-11K-2B1 Type-1 concordantly banded REE vein 30.47924 63.59546 2 10 207,000 0.5 2.06 1.6 < 0.1 4 0.4 784 467 89.7

RT-11K-2B2 Type-1 concordantly banded REE vein 30.47924 63.59546 2 9 210,100 0.5 2.11 1.8 < 0.1 4 0.3 748 441 101

RT-11K-3B31 Type-2 patite-rich dike 30.47883 63.59459 83 13 236,300 0.5 1.36 1.2 0.3 3 1.9 390 1,510 29.2

RT-11K-3B32 Type-2 apatite-rich dike 30.47883 63.59459 33 5 285,700 < 0.4 0.81 1.1 0.3 3 2 290 1,230 9.8

RT-11K-4AO1 Type-2 fluorine-rich dike 30.47844 63.59453 14 < 2 49,850 < 0.4 1.34 0.3 0.1 4 0.6 1,210 80 20.7

RT-11K-4AO2 Type-2 fluorine-rich dike 30.47844 63.59453 19 < 2 129,200 < 0.4 1.21 0.4 0.2 4 0.3 716 108 32.3

RT-11K-4B3 Type-2 fluorine-rich dike 30.47844 63.59453 12 4 106,300 0.6 1.3 0.3 0.2 3 0.7 690 170 31.6

RT-11K-4C1A Type-2 fluorine-rich dike 30.47844 63.59453 13 < 2 106,100 0.4 1.43 0.4 0.2 3 0.4 478 116 27.9

RT-11K-4C1B Type-2 fluorine-rich dike 30.47844 63.59453 170 4 39,780 3.8 3.53 1.8 4 8 30.2 983 323 172

RT-11K-5A2 Type-1 concordantly banded REE vein 30.47820 63.59450 28 3 245,900 0.9 1.57 1.3 0.4 8 4.5 660 864 8.5

RT-11K-5A3 Type-1 concordantly banded REE vein 30.47820 63.59450 18 3 224,400 0.9 1.67 1.3 0.2 6 1.9 675 869 8.2

RT-11K-5B1B Type-1 concordantly banded REE vein 30.47820 63.59450 42 3 237,300 1.8 1.8 1.4 0.4 6 2.3 1,420 814 17.6

RT-11K-5B3B Type-1 concordantly banded REE vein 30.47820 63.59450 72 < 2 227,900 < 0.4 1.52 1.5 0.2 4 1.1 622 1,070 28.4

RT-11K-5B6A Type-1 concordantly banded REE vein 30.47820 63.59450 37 11 50,330 1.2 1.36 0.5 2.4 3 2.5 1,950 727 47.6

RT-11K-6A2A Type-2 apatite-rich dike 30.47810 63.59452 58 10 32,450 7 4.33 2.7 6.5 4 3.3 1,590 438 31.5

RT-11K-6A2B Type-2 apatite-rich dike 30.47810 63.59452 22 9 87,040 5.3 2.59 1.1 1.5 3 0.6 973 690 37.3

RT-11K-6B2 Type-2 apatite-rich dike 30.47810 63.59452 16 11 74,900 11.3 1.12 0.7 0.8 3 1 1,630 504 15.5

RT-11K-6B3 Type-2 apatite-rich dike 30.47810 63.59452 24 11 69,980 17.8 2.6 1.4 2 4 1.5 3,070 549 22.7
20

Unit Description Northing Easting

REEs

La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb

ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm

RT-11K-1A1 Type-2 fluorine-rich dike 30.47976 63.59494 10,300 14,600 1,110 2,880 258 40 109 6.9 26.4 3.4 8.3 1.01 5.8

RT-11K-1A2 Type-2 fluorine-rich dike 30.47976 63.59494 11,400 15,800 1,190 3,040 267 41.5 115 7.5 28.4 3.6 8.5 1.06 6.1

RT-11K-1B2 Type-2 fluorine-rich dike 30.47976 63.59494 10,000 14,700 1,160 3,050 278 43.1 109 7.7 28.7 3.5 8.4 1.02 5.7

RT-11K-2A2 Type-1 concordantly banded REE vein 30.47924 63.59546 5,820 8,880 840 2,740 390 74.6 223 27.4 124 15.8 30.5 3.03 14.3

RT-11K-2B1 Type-1 concordantly banded REE vein 30.47924 63.59546 8,620 11,700 1,010 3,090 415 85.1 271 36.5 162 20.8 40.4 3.84 17.1

RT-11K-2B2 Type-1 concordantly banded REE vein 30.47924 63.59546 7,980 11,200 992 3,060 417 84.5 267 36.2 160 20.9 39.8 3.83 16.9

RT-11K-3B31 Type-2 patite-rich dike 30.47883 63.59459 10,400 12,200 945 2,710 445 107 367 47.5 181 18.6 30.9 2.47 11.2

RT-11K-3B32 Type-2 apatite-rich dike 30.47883 63.59459 16,000 16,600 1,180 3,040 328 64.8 221 27 118 13 20.7 1.72 7.1

RT-11K-4AO1 Type-2 fluorine-rich dike 30.47844 63.59453 5,550 7,940 720 2,160 231 37.9 91.7 6.1 22.8 3.1 8.6 1.24 8.4

RT-11K-4AO2 Type-2 fluorine-rich dike 30.47844 63.59453 18,800 17,600 1,170 2,770 217 34.3 108 6.1 23.1 3.3 8.3 1.16 7.4

RT-11K-4B3 Type-2 fluorine-rich dike 30.47844 63.59453 14,500 14,500 1,020 2,540 216 34.3 95.8 5.7 23.1 3.4 9 1.23 7.9

RT-11K-4C1A Type-2 fluorine-rich dike 30.47844 63.59453 14,100 13,900 995 2,470 210 33.1 90.1 5.3 20.2 3.1 8.4 1.25 8.5

RT-11K-4C1B Type-2 fluorine-rich dike 30.47844 63.59453 1,440 2,360 244 838 189 48.7 166 24.4 120 18.6 44.3 5.23 27

RT-11K-5A2 Type-1 concordantly banded REE vein 30.47820 63.59450 5,990 13,000 1,240 3,690 507 110 349 44.1 181 19.9 32.8 2.83 12.6

RT-11K-5A3 Type-1 concordantly banded REE vein 30.47820 63.59450 5,870 12,400 1,190 3,580 512 112 369 47.8 201 22.3 36.7 3.29 14

RT-11K-5B1B Type-1 concordantly banded REE vein 30.47820 63.59450 5,380 11,900 1,180 3,600 508 109 352 46.2 201 23.8 42.3 3.7 15.8

RT-11K-5B3B Type-1 concordantly banded REE vein 30.47820 63.59450 6,400 13,300 1,270 3,990 626 136 431 55.5 236 25.5 38.2 3.01 12.7

RT-11K-5B6A Type-1 concordantly banded REE vein 30.47820 63.59450 21,000 31,500 2,600 7,090 657 102 274 15.8 46.5 5 11 1.36 8.3

RT-11K-6A2A Type-2 apatite-rich dike 30.47810 63.59452 5,790 9,030 870 2,810 397 83.8 279 46.4 266 43.3 98.1 9.48 40.4

RT-11K-6A2B Type-2 apatite-rich dike 30.47810 63.59452 20,900 29,100 2,480 7,300 816 140 376 37.5 175 25.7 54.6 5.32 23.4

RT-11K-6B2 Type-2 apatite-rich dike 30.47810 63.59452 16,600 23,000 1,980 5,800 615 102 279 22.5 90.8 11.4 22 2.16 9.7

RT-11K-6B3 Type-2 apatite-rich dike 30.47810 63.59452 16,700 22,400 1,890 5,680 660 120 358 38.5 180 26.2 56 5.43 23.1
21

3.1 Styles of LREE Mineralization

Our first mission through the southern part of LREE zone (August 2010) confirmed the 

published descriptions of geologic units (Cheremitsyn and Yeremenko, 1976) and identified the 

presence of fluorite-rich dikes containing abundant REE minerals. Our second mission (February 2011), 

to the northwest corner of LREE-enriched zone, confirmed the abundance of REE-enriched rocks that

are mineralized in two different styles (described below). We also established that the ankerite-barite 

alvikites, rich in LREE minerals, were emplaced unconformably above normal alvikites, which were 

already cooled and then intruded by carbonatite dikes before emplacement of LREE-enriched alvikites 

(fig. 4B).

Two styles of REE mineralization occur within ankerite-barite alvikite in the marginal zone of

the central vent (fig. 2, Qesf).

Type-1.— Concordant, symmetrically banded veins and seams (fig. 5). Type-1 REE 

mineralization consists of concordant, symmetrically banded veins and discontinuous seams, as much as 

0.5–0.7 m thick and several tens of meters long. The layers of REE enrichment consist of two outer 

bands of yellow-weathering minerals symmetrically disposed about a dark central band (figs. 5b,c,d). 

The outer bands of yellow-weathering minerals consist of khanneshite-(Ce), barite, strontianite and 

secondary synchysite-(Ce) and parisite-(Ce). The dark, central band consists primarily of ankeriticdolomite, barite, apatite, and strontianite; trace khanneshite-(Ce) is present as well. These banded rocks, 

highly enriched in REE, are interlayered with weakly mineralized ankerite-barite alvikite (that is, the 

host well-rocks) for more than 150 meters of exposed vertical section.

Type-2.—Discordant tabular sheets (fig. 6). Type-2 REE mineralization occurs as discordant 

dikes and tabular sheets composed of primary igneous minerals that crystallized directly from magma or 

a late-stage hydrothermal fluid (fig. 6 A,B,C,H). These REE-enriched igneous dikes are of two types that

are identifiable in the field by their major minerals and phenocryst assemblages: (1) those enriched in 

fluorine and (2) those enriched in phosphorus. The igneous dikes enriched in fluorine contain 

idiomorphic phenocrysts of khanneshite-(Ce) or pseudomorphs of yellow-weathering REE-carbonates 

(fig. 6F), with or without fluorite (fig. 6G); in addition, synchysite-(Ce), bastnäsite-(Ce), and calkinsite-

(Ce), of likely secondary origin (hydrothermal alteration), may also be present. The igneous dikes 

enriched in phosphorus contain idiomorphic phenocrysts of carbocernaite-(Ce) and apatite (fig. 6,D,E); 

in addition, parisite-(Ce) of likely secondary origin, may also be present. Both types of igneous dikes 

occur at many scales throughout the zone of LREE enrichment. Most dikes are 50–60 cm thick and 

traceable for tens of meters; others are 10–50 meters thick and traceable for hundreds of meters 

(Cheremitsyn and Yeremenko, 1976). 

3.2 Whole-Rock Geochemistry

Tables 1–3 present major-, trace-, and rare earth element concentration data for representative

rocks from the Khanneshin carbonatite complex. There is strong geologic evidence for multiple 

generations of igneous rock and at least two or more types of distinctive carbonatite magma. Soviet 

geologists first identified two sequences of volcanic strata (fig. 2, Q1-1 and Q1-3) that are separated by a 

sequence of volcano-sedimentary rocks (Q1-2). These stratified rocks, in turn, are intruded by several 

small hypabyssal intrusions (Qaa) and numerous carbonatite dikes with crude radial geometry (fig. 2). 

Moreover, in the critical zone of LREE enrichment, several outcrops demonstrate that the baritestrontianite alvikites, rich in LREE minerals, were emplaced above an older section of ankerite alvikite 

that had already been cooled and intruded by dikes of carbonatite (ig. 2, Qesf; fig. 4B).
22

Figure 5. Photographs of examples of type-1 rare earth element (REE) mineralization in the marginal zone of the 

intrusive central vent (traverse 3, fig. 2), Khanneshin carbonatite complex, Afghanistan. A, Medium-grained alvikite 
23

in the zone of light rare earth element (LREE) enrichment with characteristic yellow-weathering indicating the 

presence of LREE-carbonate minerals. B, A seam of type-1 mineralization showing the symmetric, banded nature 

of LREE-rich alvikite (sample RT-11K-2A). C, Photograph of a partially rotated type-1 vein, suggesting great fluidity 

of the mineralized rocks (sample RT-11K-2B). D, Dolomite-ankerite (dolo-ankerite) alvikite and type-1 mineral 

bands at station RT-11K-5. The symmetrically banded seams of mineralized alvikite are centimeters thick; they 

consist of two outer bands, enriched in LREE-carbonate minerals, and a dark central band of barite-strontianiteapatite alvikite. These mineral bands alternate, on the scale of centimeters, with typical dolomite-ankerite alvikite, 

over a vertical thickness of approximately 150 m.

These observations are borne out by our geochemical data that indicate major differences in 

chemistry between rocks of the southwestern and northeastern part of the complex (fig. 7). The 

carbonatite dikes and tuffs from the southwest part of the complex (traverse 1A, B) are silicocarbonatites (~21 wt. percent SiO2, table 1), having generally low MgO contents (~2.4 average wt. 

percent, fig. 7a). In contrast, LREE-enriched alvikites from the northeast margin of the central vent are 

mostly ferro- and magnesio-carbonatites (fig. 7B), having relatively low SiO2 contents (~2.3 average wt. 

percent, table 3). The latter group of rocks, particularly the type-2 discordant igneous dikes, grade into 

true calico-carbonatites (fig. 7A).

Other chemical characteristics of the Khanneshin complex include the following: 

1. LREE-enriched alvikites of the central vent contain as much as 10 wt. percent MnO (table 3, fig. 

8A), and they are composed of manganiferous minerals such as manganoan ankerite, ferroan 

rhodochrosite, pyrolusite, and manganosite. 

2. Strontium (Sr) and barium (Ba), commonly present as trace elements in many carbonatite 

massifs, are greatly enriched in LREE-enriched rocks of the Khanneshin complex. In typical 

alvikite and sövite of the volcanic apron and central vent (tables 1 and 2), Sr and Ba average 

10,000 ppm and 3,000 ppm, respectively. In LREE-enriched zone of the central vent (table 3), 

the barite-strontianite alvikites average 4.5 wt. percent Sr (45,000 ppm), and 15.5 wt. percent Ba 

(155,000 ppm). In rare instances, whole-rock concentrations of Sr and Ba in LREE-enriched 

rocks exceed 82,000 and 280,000 ppm, respectively (table 4). Figures 8B and C illustrate the 

high content of Sr and Ba in alvikite of LREE-enriched zone over average ferro-, magnesio-, and 

calico-carbonatite. Also shown in figure 8C are whole-rock analyses of a carbonatite dike and 

mineralized carbonate at Bayan Obo, China. 

3. In addition to Sr and Ba, the LREE zone is extraordinarily enriched in F and S, which is 

indicated by the ubiquitous presence of fluorite, barite, and less commonly, celestine. 

4. In common with carbonatites in general, the igneous rocks from the Khanneshin complex are 

strongly enriched in the LREE over HREE. Within the population of REE-enriched rocks, 

however, there is a positive correlation between the concentration of P and HREE. This 

relationship is particularly apparent for the type-1 mineralized alvikites which contain abundant 

apatite and as much as 40 ppm Yb, a proxy for the HREE (fig. 8D). Type-2 igneous dikes, 

however, are depleted in apatite (having 0.1–0.3 wt. percent P2O5) and contain less than 10 ppm 

Yb. Thus it would appear that apatite, not a REE-carbonate, is the principal carrier of the HREE 

in the type-1 alvikites.

5. Both type-1 and type-2 mineralized rocks have REE concentrations that approach world-class 

levels of enrichment. Figure 9 illustrates the concentration values of REE-enriched rocks from 

Khanneshin together with the ores from Mountain Pass, Calif., and Bayan Obo, China. The most 

REE-enriched samples from Khanneshin, which include both type-1 and type-2 mineralized 
24

rocks, range in ∑ LREE concentration (the sum of La, Ce, Pr, and Nd) between 0.488–6.219 wt. 

percent with an average value of 3.063 wt. percent (table 4). Of these, type-1 mineralized rocks 

have an average ∑ LREE value of 2.775 wt. percent, with a range for eight samples between 

6.219 and 1.826 wt. percent. Type-2 mineralized rocks have an average ∑ LREE value of 3.282 

wt. percent, with a range for 14 samples between 5.978 and 0.488 wt. percent. Although the 

absolute concentrations of the HREE are low relative to LREE, the HREE values of the type-1 

and type-2 mineralized rocks are high relative to the ores from Bayan Obo and Mountain Pass 

ores (fig. 9). 
25
26

Figure 6 (on previous page). Photographs of examples of type-2 mineralized dikes in the zone of light rare

earth element (LREE) enrichment (traverse 3, fig. 2), Khanneshin carbonatite complex, Afghanistan. A, Apatite-rich 

carbonatite dike, with local igneous, pegmatitic texture, at field station RT-11K-6. The carbonatite dike, 

approximately 75 cm thick and steeply dipping, intrudes the concordantly banded type-1 mineralized alvikite (top 

left of the figure). B, Fluorine-rich carbonatite dike (RT-11K-4) that intrudes the banded alvikites of the marginal 

zone, intrusive central vent. C, A thin apatite-rich dike (under the hiker’s foot) intruding yellow-weathering REEenriched alvikite of the marginal zone, intrusive central vent (RT-11K-3B). D, Rock-slab of the apatite-rich 

carbonatite dike, RT-11K-3B, showing the large phenocrysts of carbocernaite in a matrix of dolomitic-ankerite, 

apatite, barite, and strontianite. E, Rock-slab of the apatite-rich carbonatite dike, RT-11K-6, showing the large 

phenocrysts of carbocernaite in a matrix of dolomitic-ankerite, apatite, barite, and strontianite. F, Slab of the 

fluorine-rich carbonatite dike, RT-11K-4, showing the large phenocrysts of LREE-carbonate in a fine-grained matrix 

of dolomite, barite, strontianite, and calcite. Also present, but too small to see at this scale, are phenocrysts of a 

former fluorine-bearing mineral now pseudomorphed by a Sr-rich orthocarbonate and an unidentified compound 

with K, Mg and F. G, Hand-specimen of a fluorite- and khanneshite-bearing carbonatite dike (RT-10K-3, traverse 2) 

that has intruded discordantly across the layering of the host volcanic tuff (alvikite). H, Close-up of the fluorine-rich 

dike (RT-10K-3) and its contact with the layered volcanic tuff.

Table 4. Table of minerals containing rare earth elements (REE), Sr, and Ba as major elements, Khanneshin 

carbonatite complex, Afghanistan. [wt. %, weight percent]

Mineral Formula Theoretical REE2O3 (wt.%)1

Khanneshite-(Ce) (Na,Ca)3 (Ce,Ba,Sr)3(CO3)5 8.03

Carbocernaite-(Ce) (Ca,Na)(Sr,Ce,Ba)(CO3)2 18.64

Ancylite-(Ce) Sr(Ce) (CO3)2 (OH) · H2O 42.87

Calkinsite-(Ce) (Ce,La)2 (CO3)3 . 4H2O 39.53

Synchysite-(Ce) Ca(Ce,La)(CO3)2F 43.89

Parisite-(Ce) Ca(Ce,La)2(CO3)3F2 33.60

Bastnäsite-(Ce) (Ce, La) CO3 F 74.90

Monazite-(Ce) (Ce,La,Th)PO4 51.11

Belovite-(Ce) (Sr,Ce,Na,Ca)5(PO4)3(OH) 32.98

Apatite-(Ce) (Ca,Ce)5PO3F <1.00

Strontianite SrCO3

Barite BaSO4

Celestine SrSO4

1

http://webmineral.com/data/. 
27

Figure 7. Ternary diagrams of major-element concentration data, Khanneshin carbonatite complex, Afghanistan. 

Note the distinctive difference between samples from different parts of the complex. Red circles are volcanic strata 

and minor intrusive rocks from the southwest part of the complex (fig. 2, traverse 1A and B). Filled blue circles are 

type-1 mineralized rocks; open blue circles are type-2 mineralized dikes (fig. 2, traverse 3). A, Type-1 and -2 

mineralized rocks from the zone of LREE enrichment are noticeably depleted in silica, relative to the volcanic rocks 

and dikes from southwest part of the complex. B, Type-1 and -2 mineralized rocks are also noticeably enriched in 

MgO relative to the volcanic rocks and dikes from southwest part of the complex. Field boundaries of silico-, ferro-, 

calico-, and magnesio-carbonatite after Srivastava (1993) and Woolley and Kempe (1989).
28

Figure 8. Variation diagrams illustrating the difference in major- and trace-element concentrations among 

igneous rocks of the, Khanneshin carbonatite complex, Afghanistan. Red circles are volcanic strata and minor 

intrusive rocks from the southwest part of the complex (fig. 2, traverse 1A and B). Filled blue circles are type-1 

mineralized rocks; open blue circles are type-2 mineralized dikes (fig. 2, traverse 3). The orange field delineates the 

intrusive and extrusive igneous rocks from traverses 1 and 2 (fig. 2). Average values of calico-carbonatite (yellow 

star), ferro-carbonatite (red star), and magnesio-carbonatite (blue star) from Woolley and Kempe (1989). A, MnO 

versus Fe2O3 (weight percent). Note the strong enrichment in MnO of light rare earth element (LREE)- enriched 

rocks over common alvikite of the Khanneshin complex. B, CaO (weight percent) versus Ba (parts per million) (1

percent (parts per hundred) equals 10,000 parts per million). Note the very high concentrations of Ba, relative to 

CaO in LREE-enriched rocks of the Khanneshin complex. C, Sr versus Ba (parts per million). Note the very high 

concentrations of Ba relative to Sr in LREE-enriched rocks of the Khanneshin complex. Also shown are 

concentrations in carbonatite dike at Bayan Obo (China) (data from Yang and others, 2009). D, Yb (parts per 

million) versus log P2O5 (weight percent). Note the strong correlation between Yb and P2O5 in LREE-enriched rocks 

of the Khanneshin complex suggesting that apatite controls the abundance of HREE. The type-1 mineralized rocks, 

and those type-2 intrusive dikes having modal apatite and carbocernaite, are enriched in Yb and the heavy rare 

earth elements (HREE). The fluorine-rich type-2 dikes, bearing either fluorite or the unnamed K-Mg-F phase, are 

poor in apatite and HREE.
29
30

Figure 9 (on previous page). Graphs showing the magnitude of rare earth element (REE) enrichment in the 

marginal zone, intrusive central vent, Khanneshin carbonatite complex, Afghanistan. Red circles are volcanic strata 

and minor intrusive rocks from the southwest part of the complex (fig. 2, traverse 1A and B). Filled blue circles are 

type-1 mineralized rocks; open blue circles are type-2 mineralized dikes (fig. 2, traverse 3). Average values of 

calico-carbonatite (yellow star), ferro-carbonatite (red star), and magnesio-carbonatite (blue star) from Woolley and 

Kempe (1989). A, La, representative of light rare earth elements (LREE), versus Sr, in parts per million (ppm). The 

positive correlation of LREE and Sr in REE-enriched rocks indicates the propensity of LREE to substitute for Sr in 

khanneshite-(Ce) (burbankite group) and carbocernaite, the primary carbonate minerals of the Khanneshin 

complex. Also shown are mineralized carbonate and carbonatite dikes from Bayan Obo, China (data from Yang 

and others, 2009), and average ores from Mountain Pass, Calif. (data from Castor, 2008). B, La, representative of 

LREE, versus Yb, representative of the HREE (in ppm). Common alvikites of the Khanneshin complex have LREE 

and HREE (heavy rare earth element) concentrations similar to average ferro-, magnesio-, and calcio-carbonatites 

world-wide. Type-1 and -2 igneous rocks of the Khanneshin complex (filled and open blue circles) are highly 

enriched in REE and comparable in grade to the world-class REE deposits of Bayan Obo (data for average Bayan 

Obo ores from Yuan and others, 1992) and Mountain Pass (data from Castor, 2008). C, Type-1 and type-2 

mineralized rocks from the Khanneshin complex normalized relative to chondrite values (Nakamura, 1974). Also 

shown are REE ores from Mountain Pass (blue stars) and Bayan Obo (data sources as in B).

3.3 Mineralogy

Identification and description of LREE minerals is difficult because of their fine-grained size, 

altered and pseudomorphed appearance, complex chemistry (allowable coupled substitutions and solid 

solutions), and extensive polymorphism. As a result LREE-bearing minerals have variable physical and 

optical properties that make their identification nearly impossible by standard optical petrographic 

means.

The REE-bearing minerals in our samples were examined using energy-dispersive X-ray 

spectroscopy (EDS) and back-scattered electron imaging at the electron microscope and microprobe 

facility, National Center, U.S. Geological Survey, Reston, Virginia. During EDS, a sample is exposed to 

a beam of electrons that collide with electrons within the sample, causing some of the latter to be 

knocked out of their orbits. The vacated positions are filled by higher energy electrons that emit x-rays 

in the process. Our JEOL JXA-8900R scanning electron microprobe is equipped with a Si(Li) EDS 

Noran Instrument detector with a nominal resolution of 138 electron volts (eV). For additional 

confirmation for elements such as F and Ce, appropriate wave-length dispersive X-ray spectrometers 

were peaked-up on standards of known composition. Difficulties that may arise from EDS analysis 

include the inability to determine water and carbon dioxide content, loss of Na and F under the electron 

beam, and subtle interferences of the major and secondary peaks of Ba with REE. 

The key mineralogical features and associations in REE enriched rocks (table 4) are:

1. In the concordantly banded rocks, LREE minerals formed late in the mineral paragenesis; 

they are commonly seen as interstitial crystals, late-forming overgrowths on carbonate 

species, or as spheroidal and anhedral mineral aggregrates perhaps crystallizing as lategeneration immiscible droplets (figs. 10 and 11). 

2. In the discordant dikes, LREE minerals are present as euhedral to subhedral phenocrysts that 

crystallized early in the petrogenetic sequence. Commonly the early phenocrysts are altered 

or pseudomorphed by secondary minerals, including synchysite-(Ce), strontianite, and barite 

(figs. 12, 13, 14). 

3. LREE-enriched rocks contain either fluorite or apatite. In a single instance, an unidentified 

mineral was found, composed of potassium, magnesium, and fluorine (possibly KMgF3, 
31

analogous with neighborite); its crystallographic structure has yet to be determined (fig. 

13F).

4. The principal LREE- minerals in the fluorine-rich rocks are khanneshite-(Ce) or monazite-

(Ce), which may or may not be pseudomorphed by synchysite-(Ce), barite, and strontianite 

(figs. 13C,D). Bastnäsite-(Ce) and calkinsite-(Ce) are also present in these rocks, commonly 

as late alteration minerals growing over khanneshite-(Ce) or calcite. On the basis of our 

limited field work, all rocks rich in fluorine occur as late intrusive dikes and tabular sheets, 

which are meters wide and scores of meters long. Cheremitsyn and Yeremenko (1976), who 

first identified REE-enriched dikes, report them as steeply dipping sheets of variable strike 

that range in thickness and length between 20–60 m and 50-500 m, respectively. 

5. A second suite of igneous dikes contain abundant apatite and lack modal fluoride minerals. 

In this suite, carbocernaite is the primary LREE mineral and forms large (20–100 mm) 

idiomorphic phenocrysts, constituting as much as 20 modal percent of the rock (fig. 14). 

Rocks containing carbocernaite are characterized by moderately high P2O5 contents (1.08–

6.19 wt. percent) and high Na contents (3.64–4.6 wt. percent). Like the fluorine-rich dikes, 

igneous dikes of the second suite form steeply dipping sheets of variable strike that range in 

thickness and length from 0.5–2 m to 10–50 m, respectively. 

6. All of the concordantly banded rocks are rich in apatite and lack fluorite. The concordantly 

banded nature of these rocks is defined by a dark, central layer, centimeters thick, of 

ankeritic dolomite, together with siderite and interstitial barite, strontianite, apatite, and 

calcite (figs. 10A, 11A). Khanneshite-(Ce), barite, and strontianite form the outer lightcolored bands, which are millimeters thick and symmetrically disposed about the dark 

central layer. In thin section, the outer band of khanneshite-(Ce), barite, and strontianite 

displays a brecciated texture against the central band of dolomitic ankerite. This may suggest 

that a hydrothermal fluid, or fluid-rich magma rich in LREE, Ba, Sr, and P, was introduced 

into the ankeritic alvikite late in the petrogenetic history. In many instances, khanneshite-

(Ce) in the outer band forms unusual spherical aggregates, approximately 100 micrometers 

in diameter, suggesting that it crystallized as immiscible LREE-enriched droplets in the latestage liquid.

7. The hypothesis of a late-stage liquid, enriched in LREE, is compatible with other 

observations. Two suites of dikes of different composition intrude the concordantly banded 

LREE-enriched rocks. Type-2 igneous dikes include those enriched in P2O5, and hence 

modal apatite, and those enriched in F, and hence modal fluorite or another F-bearing 

mineral. Thus, there is abundant evidence, both geological and mineralogical, that 

introduction of REE was a late-stage phenomena that also includes enrichment of fluorine, 

phosphorus, Ba, and Sr. In our opinion, it is conceivable that both styles of LREE 

mineralization are penecontemporaneous, having formed in the marginal zone of carbonaterich magma, highly charged with volatile constituents (F, CO2, and P2O5) and strongly 

enriched in Ba, Sr, and LREE. 
32

Figure 10. Mineralogy and crystallization sequence of sample RT-11K-2, type-1 mineralization, Khanneshin 

carbonatite complex, Afghanistan. A, Photograph of the type-1 mineral bands in dolomitic alvikite. B, Slab of the 

symmetrically zoned band, identified in A, showing the location of the false-colored, backscattered electron images 

(C–F). C, False-colored backscattered electron image within the dark band consisting of apatite, dolomite, calcite, 
33

and trace khanneshite-(Ce): apatite (ap), apatite-(Ce) (ap-(Ce)), dolomite (dol), khanneshite-(Ce) (kh), and calcite 

(cc). Calcite and khanneshite-(Ce) appear as late, interstitial minerals enclosing early formed phenocrysts of 

dolomite and apatite. D, False-colored backscattered electron image: dolomitic ankerite (dol-ank), apatite (ap), 

barite (ba), strontianite (str), and khanneshite-(Ce) (kh). Barite, strontianite, and khanneshite appear as an infilling 

of late minerals into brecciated dolomitic ankerite of the host alvikite. E, False-colored backscattered electron 

image, light-colored band: Sr-rich orthocarbonate (Sr >Ca carbonate), barite (ba), dolomitic-ankerite (dol-ank), 

calcite (cc), khanneshite (kh). F, False-colored backscattered electron image, dark-colored band: barite (ba), 

dolomitic-ankerite (dol-ank), apatite (ap), strontianite (str) and khanneshite-(Ce) (kh). Dark bands consist mostly of 

dolomitic ankerite and barite with interstitial strontianite, apatite, and spherical areas (immiscible droplets?) of 

khanneshite-(Ce) and strontianite.
34
35

Figure 11 (on previous page). Mineralogy and crystallization sequence of sample RT-11K-5, type-1 

mineralization, Khanneshin carbonatite complex, Afghanistan. A, Photograph of the type-1 mineral bands in 

dolomitic alvikite. B, Slab of the symmetrically zoned band, identified in A, showing the (approximate) location of 

false-colored, backscattered electron images (C–F). C, Gray-toned backscattered electron image, margin of lightcolored band of ankeritic-dolomite shown in B, consisting of barite, strontianite, calcite, and spherical areas 

(immiscible droplets?) of khanneshite-(Ce): barite (ba), strontianite (str), calcite (cc), ankeritic-dolomite (ank-dol), 

khanneshite-(Ce) (kh). Calcite and khanneshite-(Ce) appear as late, interstitial minerals enclosing early formed 

phenocrysts of barite and strontianite. D, Gray-toned backscattered electron image, light-colored band shown in B: 

dolomite (dol) with ankeritic-siderite core (ank-sid), barite (ba), strontianite (str), calcite (cc), and khanneshite-(Ce) 

(kh). Ankeritic-siderite, dolomite, and barite are early phenocrysts, whereas strontianite and calcite are interstitial 

minerals; khanneshite-(Ce) appears as a late overgrowth (alteration mineral) on calcite. E, Gray-toned 

backscattered electron image, light-colored band shown in B: ankerite (ank), barite (ba), biotite (bio), calcite (cc), 

and khanneshite-(Ce) (kh). Khanneshite-(Ce) appears to have crystallized as an aggregate assemblage, rich in 

silica, within an interstitial zone of calcite. In the center of the khanneshite aggregate is a crystal of biotite. F, Graytoned backscattered electron image, dark-colored band shown in B: ankerite (ank), barite (ba), and apatite (ap). 

The dark bands consist mostly of ankerite and barite with interstitial apatite.
36

Figure 12. Mineralogy and crystallization sequence of fluorite-bearing rocks, Khanneshin carbonatite complex, 

Afghanistan. A, Hand-specimen of a fluorite- and khanneshite-bearing carbonatite dike (RT-10K-3) that has 
37

intruded discordantly across the layering of the volcanic tuff (alvikite). B, Close-up of the fluorine-rich dike, showing 

modal fluorite and abundant yellow-colored prismatic crystals of rare earth element (REE) carbonate. C, Graytoned backscattered electron image of sample RT-10K-3 in B: bastnäsite-(Ce) (bas), calcite (cc), calkinsite-(Ce) 

(cal), celestine (cel), dolomite (dol), khanneshite-(Ce) (kh). Khanneshite-(Ce) appears to have crystallized as an 

idiomorphic phenocryst, surrounded by interstitial dolomite and calcite, and bastnäsite-(Ce) and calkinsite-(Ce) are 

late alteration minerals of khanneshite-(Ce), dolomite, and calcite. D, Slab of a fluorite-bearing rock, Khanneshin 

complex. Note the banded nature of this rock, which is extraordinarily rich in barite and strontianite. Images E and F

are located on the slab. E, False-colored backscattered electron image: barite (ba), dolomite (dol), fluorite (fl), 

siderite (sid), strontianite (str), and synchysite-(Ce) (syn). Igneous phenocrysts of siderite-dolomite and fluorite 

together with interstitial strontianite and barite. Very late crystallization of synchysite-(Ce) as an interstitial phase or 

immiscible droplet. F, False-colored backscattered electron image: barite (ba), biotite (bio), calcite (cc), dolomite 

(dol), fluorite (fl), strontianite (str), synchysite-(Ce) (syn), and a Li-F mica taeniolite (tae) [KLiMg2Si4O10F2]. Early 

crystallization of dolomite, taeniolite, and fluorite, with late interstitial crystallization of barite, strontianite, calcite, 

and synchysite-(Ce).
38

Figure 13. Mineralogy and crystallization sequence of the fluorine-rich intrusive dikes, Khanneshin carbonatite 

complex, Afghanistan. A, Outcrop of intrusive dike RT-11K-4. B, Slab of the fluorine-rich carbonatite dike at RT11K-4 showing the large yellow-weathering phenocrysts of rare earth element (REE) carbonate in a fine-grained 
39

matrix of dolomite, barite, strontianite, and calcite. Approximate location of images C and D are shown by inset 

boxes. C, Gray-toned backscattered electron image showing a isometric phenocryst of fluorite (?) pseudomorphed 

by a Sr-rich orthocarbonate and an unidentified mineral, perhaps isostructural with neighborite (NaMgF3), rich in K, 

Ma, and F. Note location of image F. D, False-colored backscattered electron image, the yellow-colored

“phenocrysts” in the intrusive dike. The yellow-colored “phenocrysts” are actually a complex aggregate of Sr-rich 

orthocarbonate, barite, strontianite, dolomite, and khanneshite. Note location of image E. E, Gray-toned 

backscattered electron image showing the fine-grained intergrowths of dolomite, barite, Sr-rich orthocarbonate, 

strontianite, and khanneshite. F, Gray-toned backscattered electron image showing fluorite pseudomorphed by a 

Sr-rich orthocarbonate, dolomite, and an unknown K-Mg fluoride mineral, perhaps isostructural with neighborite 

(NaMgF3).
40

Figure 14. Mineralogy and crystallization sequence of the apatite-rich intrusive dikes, Khanneshin carbonatite 

complex, Afghanistan. A, Outcrop of intrusive dike RT-11K-6. B, Rock slab of sample RT-11K-6 showing the 

phenocrysts of carbocernaite in a matrix of dolomitic-ankerite, siderite, apatite, and barite. Location of false-colored 

backscattered electron images C, D, and E are shown as inset boxes. C, False-colored backscattered electron 

image showing the textural relationships among carbocernaite (c-cer), dolomite-ankerite (dol-ank), apatite (ap), 

siderite (sid), barite (ba), and parisite-(Ce) (par). Dolomitic ankerite, with siderite rims, and carbocernaite form early 

phenocrysts; apatite and barite form interstitial minerals; and parisite-(Ce) forms a late alteration mineral of 
41

carbocernaite. D, False-colored backscattered electron image showing the textural relationships among 

carbocernaite (c-cer), dolomite-ankerite (dol-ank), siderite (sid), barite (ba), and apatite (ap). Dolomitic ankerite, 

with siderite rims, and carbocernaite form early phenocrysts; apatite and barite form interstitial minerals; and 

parisite-(Ce) forms a late alteration mineral of carbocernaite. E, False-colored backscattered electron image 

showing the textural relationships among carbocernaite (c-cer), dolomite-ankerite (dol-ank), siderite (sid), barite 

(ba), strontianite (str), apatite (ap), and parisite-(Ce) (par). Dolomitic ankerite, with siderite rims, and carbocernaite 

form early phenocrysts; apatite, barite, and strontianite form interstitial minerals; parisite-(Ce) forms a late alteration 

mineral of carbocernaite.

3.4 Structural Control on Alkaline Igneous Magmatism and LREE Mineralization

Regional fault structures played a role in locating the Khanneshin carbonatite complex. The 

Helmand block is bounded by two major wrench faults, the Chaman fault to the east, and the Har-i Rod 

fault to the north (fig. 1A). The north-south-striking Chaman fault has a near-vertical dip with a rightlateral sense of displacement, and it is considered by Auden (1974) to be the transform fault that bounds 

the northwest edge of the Indian Plate. The east-west-striking Har-i Rod fault system is a steeply 

dipping fault with a right lateral sense of displacement, and it is considered by Wheeler and others 

(2005) to form the northern boundary of the Helmand block. Thus, in a regional sense, the Helmand 

block is undergoing displacement to the southwest as the Indian Plate is thrust northward beneath 

southern Asia. Other faults within the Helmand block—for example, the Farah fault (fig. 1A)—are 

subparallel to the Har-i Rod fault, but they do not exhibit displacements as great as the Har-i Rod or 

Chaman faults. It is likely, therefore, that displacement is not uniform throughout the Helmand block 

and that some internal parts of it are in relative transtension or even pure extension. 

Displacement on the Chaman and Har-i Rod faults began in Eocene time, and motion on these 

faults continues to the present. The Chaman fault, for example, is a principal source of earthquakes in 

Afghanistan (Abdullah, 1979), and a major earthquake in 1892 created a surface rupture more than 200 

km long (McMahon, 1897). In addition to earthquakes, the Helmand block has experienced much 

intraplate volcanism. The Chagai Hills, on the southern edge of the Helmand block, contain a large field 

of Late Cretaceous to Eocene volcanic rocks, and other volcanic flows and sills of alkali olivine basalt 

both cover and intrude sedimentary strata of the Sistan basin in southeastern Iran and southwestern 

Afghanistan (Gansser, 1971; Lang, 1971). Perhaps the best example of an intraplate igneous field is the 

Kuh-i-Khwaja alkali basalt (7.3 ±0.2 million-year) (Jux and Kempf, 1983), that caps a mesa of 

lacustrine sediments in eastern Iran (fig. 1A), indicating that the Sistan depression had formed and lakes 

were present by latest Miocene time. This is consistent with the suggestion of Whitney (2006), who 

proposed that Middle to late Tertiary subsidence of basement blocks led to the formation of the 

Helmand basin and that continued subsidence along the Har-i Rod fault formed the Sistan basin in latest 

Tertiary and Quaternary time.

The most recent episode of intraplate volcanism took place in Pliocene and early Quaternary 

time. Three large volcanoes, Koh-i Sultan, Koh-i Taftan, and Koh-i Bazman, are located just south of 

the Helmand basin in neighboring Pakistan and Iran (fig. 1A). These Quaternary volcanic rocks intrude 

folded Eocene mélange and Late Cretaceous volcanic rocks, they have active thermal springs, and the 

present-day emission of hydrogen sulphide and sulphur dioxide gasses infers the existence of hightemperature magma at depth (Amhad and others, 2009). The Khanneshin carbonatite is the fourth 

alkaline igneous complex in this chain of Quaternary volcanoes (fig. 1A). As this trend of southwestnortheast volcanoes does not follow the surface structures of the region, it has been suggested that deep 

crustal fissures are responsible for their alignment (Gansser, 1971). 

Faults with a northeast-southwest trend continue into Khanneshin complex. Indeed, the zone of 

LREE enrichment is located in the northeast margin of the intrusive vent in a section of alvikite that is
42

bounded by north-northeast-trending faults with apparent normal displacement (graben). It is 

conceivable, therefore, that the fluorine- and phosphorus-rich liquids and (or) fluids that produced 

LREE Sr, and Ba enrichment were focused by preexisting structures that helped to channel their flow.

4.0 Estimation of LREE Resources

Mineral resources are materials in such form that economic extraction of one or more 

commodities is currently, or potentially, viable. We present below a preliminary assessment of potential 

LREE resources within the Khanneshin carbonatite complex. Our assessment is an estimation of 

discovered and potential LREE resources within specified volumes of rock in the marginal zone of the 

central vent. Because the rocks with REE enrichment have not been mapped in detail, drilled for 

exploration, or investigated using modern geophysical methods, our estimation is necessarily 

elementary with various assumptions inferred. The elementary calculation to convert rock volume to 

LREE resource involves converting volume to mass, using a density conversion factor, and then mass to 

a theoretically recoverable resource using an average grade of LREE enrichment (tables 5 and 6). 

4.1 Analysis of the Soviet-Defined Zone

Soviet geologists delineated a polygonal zone (fig. 15A, B), approximately 0.64 km2, in which 

ankerite-barite carbonatite is macroscopically enriched in LREE-bearing carbonate minerals. Within this 

zone, the total LREE contents of many rocks rise to several percent, with barite contents as much as 35 

modal percent.
43

Table 5. Summary of barium, strontium, and light rare earth element (LREE) concentrations, barite-ankerite alvikite, Khanneshin carbonatite complex, 

Afghanistan.

[wt. %, weight percent; ppm, parts per million; ∑ LREE, sum of La, Ce, Pr, and Nd; ∆, average value] 

Sample no. Ba Sr La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu La Ce Pr Nd ∑ LREE

wt.% wt.% ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm wt. % wt. % wt. % wt. % wt. %

RT-11K-1A1 19.62 3.05 10,300 14,600 1,110 2,880 258 40 109 6.9 26.4 3.4 8.3 1.01 5.8 0.86 1.030 1.460 0.111 0.288 2.889

RT-11K-1A2 21.51 3.90 11,400 15,800 1,190 3,040 267 42 115 7.5 28.4 3.6 8.5 1.06 6.1 0.91 1.140 1.580 0.119 0.304 3.143

RT-11K-1B2 18.74 3.36 10,000 14,700 1,160 3,050 278 43 109 7.7 28.7 3.5 8.4 1.02 5.7 0.88 1.000 1.470 0.116 0.305 2.891

RT-11K-2A2 19.04 2.21 5,820 8,880 840 2,740 390 75 223 27.4 124 15.8 30.5 3.03 14.3 1.64 0.580 0.888 0.084 0.274 1.826

RT-11K-2B1 20.70 3.85 8,620 11,700 1,010 3,090 415 85 271 36.5 162 20.8 40.4 3.84 17.1 2.06 0.860 1.170 0.101 0.309 2.440

RT-11K-2B2 21.01 3.64 7,980 11,200 992 3,060 417 85 267 36.2 160 20.9 39.8 3.83 16.9 2.11 0.790 1.120 0.099 0.306 2.315

RT-11K-3B31 23.63 4.43 10,400 12,200 945 2,710 445 107 367 47.5 181 18.6 30.9 2.47 11.2 1.36 1.040 1.220 0.095 0.271 2.626

RT-11K-3B32 28.57 6.05 16,000 16,600 1,180 3,040 328 65 221 27 118 13 20.7 1.72 7.1 0.81 1.600 1.660 0.118 0.304 3.682

RT-11K-4AO1 4.99 4.75 5,550 7,940 720 2,160 231 38 91.7 6.1 22.8 3.1 8.6 1.24 8.4 1.34 0.550 0.794 0.072 0.216 1.632

RT-11K-4AO2 12.92 8.24 18,800 17,600 1,170 2,770 217 34 108 6.1 23.1 3.3 8.3 1.16 7.4 1.21 1.880 1.760 0.117 0.277 4.034

RT-11K-4B3 10.63 7.05 14,500 14,500 1,020 2,540 216 34 95.8 5.7 23.1 3.4 9 1.23 7.9 1.3 1.450 1.450 0.102 0.254 3.256

RT-11K-4C1A 10.61 7.20 14,100 13,900 995 2,470 210 33 90.1 5.3 20.2 3.1 8.4 1.25 8.5 1.43 1.410 1.390 0.100 0.247 3.147

RT-11K-4C1B 3.98 1.91 1,440 2,360 244 838 189 49 166 24.4 120 18.6 44.3 5.23 27 3.53 0.144 0.236 0.024 0.084 0.488

RT-11K-5A2 24.59 2.57 5,990 13,000 1,240 3,690 507 110 349 44.1 181 19.9 32.8 2.83 12.6 1.57 0.599 1.300 0.124 0.369 2.392

RT-11K-5A3 22.44 2.91 5,870 12,400 1,190 3,580 512 112 369 47.8 201 22.3 36.7 3.29 14 1.67 0.587 1.240 0.119 0.358 2.304

RT-11K-5B1B 23.73 3.77 5,380 11,900 1,180 3,600 508 109 352 46.2 201 23.8 42.3 3.7 15.8 1.8 0.538 1.190 0.118 0.360 2.206

RT-11K-5B3B 22.79 4.95 6,400 13,300 1,270 3,990 626 136 431 55.5 236 25.5 38.2 3.01 12.7 1.52 0.640 1.330 0.127 0.399 2.496

RT-11K-5B6A 5.03 4.98 21,000 31,500 2,600 7,090 657 102 274 15.8 46.5 5 11 1.36 8.3 1.36 2.100 3.150 0.260 0.709 6.219

RT-11K-6A2A 3.25 2.37 5,790 9,030 870 2,810 397 84 279 46.4 266 43.3 98.1 9.48 40.4 4.33 0.579 0.903 0.087 0.281 1.850

RT-11K-6A2B 8.70 6.82 20,900 29,100 2,480 7,300 816 140 376 37.5 175 25.7 54.6 5.32 23.4 2.59 2.090 2.910 0.248 0.730 5.978

RT-11K-6B2 7.49 5.62 16,600 23,000 1,980 5,800 615 102 279 22.5 90.8 11.4 22 2.16 9.7 1.12 1.660 2.300 0.198 0.580 4.738

RT-11K-6B3 7.00 5.61 16,700 22,400 1,890 5,680 660 120 358 38.5 180 26.2 56 5.43 23.1 2.6 1.670 2.240 0.189 0.568 4.667

Table of summary data

∆ Ba 

wt.%

∆ Sr 

wt.%

∆ La 

wt.%

∆ Ce 

wt.%

∆ Pr 

wt.%

∆ Nd 

wt.%

∆ LREE

15.50 4.51 Total collection 1.091 1.491 0.125 0.357 3.063

19.92 3.61 Type-1 mineralized rock (samples RT-11K-2 and -5) 0.837 1.424 0.129 0.386 2.775

11.07 5.46 Type-2 mineralized rocks (samples RT-11K-3, -4, and -6) 1.279 1.533 0.123 0.347 3.282

19.96 3.44 Fluorine-rich dike rock (RT-11K-1) 1.057 1.503 0.115 0.299 2.974
44

Table 6. Estimated light rare earth element (LREE) resources, Khanneshin 

3 [km, kilometers; g/cm , grams per centimeter cubed; Mt, million metric tons; wt. %, 

carbonatite complex, Afghanistan.

weight percent; ∆, average value; --, no data] 

Length

(km)

Width 

(km) Depth (km) Volume 

(km3) Density (g/cm3) Rock mass

(106 Mt)

∆ LREE 

grade 

(wt. %)

Mt LREE 

(before 10:1 

dilution)1

Mt LREE 

(after 10:1 

dilution)

Zone of LREE enrichment (fig. 15)

Type 1—Concordant veins and seams:

Lower zone 0.750 0.550

Upper zone 0.330 0.250

Type-1 total

Type 2—Discordant veins and seams2:

Dike 1 0.050 0.020

Dike 2 0.500 0.040

Dike 3 0.400 0.035

Type-2 total

Total LREE enrichment3

0.150

0.150

0.150

0.150

0.150

0.061875

0.012375

2.94

2.94

181.913

36.383

2.775

2.775

5.048

1.010

0.505

0.101

0.074250

0.000150

0.003000

0.002100

2.94

2.94

2.94

2.94

218.295

0.441

8.820

6.174

2.775

3.282

3.282

3.282

6.058

--

--

--

0.606

0.014

0.289

0.203

0.005250 2.94 15.435 3.282 -- 0.507

1.113

Remote-sensing polygon (fig. 15)

NW of zone of LREE enrichment

Within zone of LREE enrichment

Total remote-sensing polygon

0.071176

0.073124

2.94

2.94

209.257

214.985

2.775

2.775

5.807

5.966

0.581

0.597

1.178

1

Wall rock is 10 times more abundant than mineralized seams, hence 10:1 dilution 

2

Estimated from mineral content in dikes, not affected by wall-rock dilution. 

3

Sum of type 1 and type 2 tonnage. 

factor. 
45

Figure 15. A, Area of the identified light rare earth element (LREE) prospect in the northeast part of the central 

intrusive vent, Khanneshin carbonatite complex, Afghanistan. The polygonal box outlined in yellow is the area of 
46

LREE mineralization identified by Cheremitsyn and Yeremenko (1976). The polygons outlined in red are areas of 

distinctive rocks identified on LANDSAT images as areas of prospective LREE mineralization. B, Digital elevation 

topography of the northern part of the Khanneshin carbonatite complex. Soviet samples of “LREE ore” are 

indicated by the magenta dots; U.S. Geological Survey samples are indicated in red (February 2011) and green 

(August 2010).

Two brief excursions to the LREE-enriched zone, traverses 2 and 3 (fig. 2), mostly confirmed 

the work of Soviet geologists. During traverse 3 to the northern part of the LREE zone, two types of 

LREE mineralization were observed: (1) a concordant style of mineralization (type-1) and (2) a 

discordant style (type-2) in which LREE mineralization occurs within discordant tabular igneous dikes. 

Concordant Layers of Mineralization.—Concordant mineralization is defined by the yellowweathering LREE carbonates (± fluorine) that form layer-parallel, centimeter-thick bands, which 

alternate with dark, meter-thick layers of ankerite-barite alvikite (wall rock). On the basis of the work of 

Soviet scientists, whose field teams accurately described the geology and mineralogy of the entire 

igneous complex, we assume this style of mineralization is common throughout the area of LREE 

enrichment. This assumption is verified by the many samples of “REE ore” recovered and analyzed by 

Soviet geologists in the area and the fact that our mineralogical descriptions and whole-rock 

concentration data agree very well with the Soviet data. The volume of LREE mineralization, however, 

must be diluted by a factor of 10, which is approximately the ratio of concordantly mineralized rock to 

weakly mineralized wall rock (fig. 5). This dilution factor is probably a conservative value because in 

some sections concordant mineralization is ubiquitous, whereas in other sections the surface exposures 

are sparse or covered by alluvium. The proper way to determine directly this dilution factor is to drill 

and assay recovered rock core throughout the area of LREE enrichment. It was not possible to do this 

for our study because of budgetary, logistical, limited time, and security concerns. 

Because drilling, core analysis, and geophysical exploration were not possible, the depth of 

mineralization throughout the LREE zone is estimated from ground observations. We assert a value of 

150 m based on the vertical dimension of mineralized rock observed over the rugged relief of the region 

(~170 m). In essence, we assume a depth of mineralization that roughly mimics the surface topography 

of the polygonal box. This assumption is justified because the topography is young (<5 Ma), the valley 

walls are steep, and hence the mass of eroded rock is small relative to the unexhumed mass at depth. We 

believe that our estimate is conservative if, as seems likely, the zone of LREE enrichment extends to 

depths well beyond the arbitrary value of the local relief (fig. 15B). Depth of mineralization can be 

determined by drilling and assaying core throughout the region of known LREE enrichment.

Using an average density of mineralized carbonatite (2.94 g/cm3

), an average grade of LREE 

concentration (2.775 wt. percent, table 5), and a dilution factor of 10:1 (wall rock: mineral bands), we 

calculate that approximately 0.505 Mt of LREE is present in the concordantly mineralized rocks of the 

Soviet-defined zone (table 6).

Discordant Tabular Sheets.—Within the LREE-enriched zone, Soviet geologists identified more 

than 50 “ore bodies” of a stockwork type with widths between 60 m and 500 cm and lengths between 

500 m and 20 m. The vertical dimension of the stockwork bodies is not given, but they are likely to be 

hundreds of meters deep because they form near-vertical dikes across the rugged relief of the region.

These bodies correspond to the discordant, steeply dipping tabular sheets of this report. 

Three major stockwork dikes were trenched and sampled by the Soviet teams (Cheremitsyn and 

Yeremenko, 1976): 

1. Stockwork dike 1, located in the northwest part of LREE zone, is 20 m×50 m with a northwest

strike and near vertical dip. Ten small trenches, each 2 m long, were dug across the dike. LREE
47

concentration (La plus Ce) for all of the Soviet samples averages more than 1.5 wt. percent 

(Cheremitsyn and Yeremenko, 1976). 

2. Stockwork dike 2, located in the northern part of LREE zone, is 10 m to 60 m wide and 500 m 

long; it has a north-south strike and near-vertical dip. Three trenches were dug across the dike in 

its northern, central and southern part. The average concentration for La plus Ce for all of the 

trench samples is 1.5 wt. percent (Cheremitsyn and Yeremenko, 1976). 

3. Stockwork dike 3, located in the southeast part of LREE zone, is about 35 m wide and 400 m 

long; it has a northeast strike and near-vertical dip. One trench across its central part wielded an 

average concentration for La and Ce of greater than 1.5 wt. percent (Cheremitsyn and 

Yeremenko, 1976). 

All the Soviet analyses of the stockwork dikes yield LREE concentrations that are compatible 

with the average LREE concentrations of our type-2 dikes (3.282 average wt. percent ∑ LREE, table 5).

Our estimate of LREE resources within the discordant tabular dikes is shown in table 6. This is 

probably a conservative estimate because the calculation is only for the three largest dikes, and more 

than 50 such bodies are recognized. As with the resource calculation for the concordantly mineralized 

rocks, we assume the discordant dikes extend to 150 m depth and that LREE concentrations are uniform 

throughout the mass of rock. 

Assuming an average density for carbonatite (2.94 g/cm3

) and an average grade of LREE 

concentration (3.282 wt. percent, table 5), we estimate approximately 0.507 Mt of LREE are present in 

the three largest dikes (discordant sheets) of the Soviet-defined zone of LREE enrichment (table 6). 

Thus, together with the concordantly mineralized rocks, we estimate a LREE resource of 

approximately 1.1 Mt in the entire Soviet-defined LREE zone.

4.2 Analysis by Remote Sensing

Our complete suite of 23 samples, representing a range of rocks with both concordant and 

discordant REE mineralization, is greatly enriched in LREE. The average total LREE concentration for 

the concordantly banded rocks is 2.8 wt. percent, and the average total LREE concentration for the 

discordant sheets of mineralized rock is 3.3 wt. percent. 

Two of the stockwork dikes, trenched and sampled by the Soviet teams, crop out in the area of 

our February 2011 traverse (traverse 3, fig. 2). We observed many such dikes, but we were unable to 

locate in the field the precise trenches sampled by the Soviet geologists. The zone of LREE enrichment 

is quite distinctive in the field, easily identifiable by the abundance of yellow-weathering LREE

minerals, and we sought to quantify the area of LREE enrichment using remote-sensing techniques. 

QuickBird satellite imagery of the area was obtained. This imagery offers relatively high spatial 

resolution (0.6 m for panchromatic), as well as adequate spectral resolution (red, green, blue, and nearinfrared channels). The imagery of the area was pan sharpened and orthorectified to Transverse 

Mercator projection using ERDAS Imagine version 10 software; this software was also used for image 

enhancement. The imagery was then imported into ArcGIS version 9.3 for GIS analysis. Vector files of 

the sample sites and LREE-enriched area were created, as well as topographic contour files derived 

from ASTER digital terrain elevation data (DTED) for the area. Within LREE-enriched area, a 

polygonal area delineating the region of REE enrichment was drawn, which was based on a subjective 

assessment of surface color and texture. This polygon was then extended north and west beyond the 

Soviet-defined zone of LREE enrichment based on an objective analysis of similar image 

characteristics.

The revised zone of LREE-enrichment is shown in figure 15. This zone is approximately 1,490 

m long, between 70 m and 150 m wide, and covers approximately 157,000 m2

. The eastern half of the 
48

polygon lies within the area of LREE enrichment delineated by Soviet geologists, and it intersects a dry

stream bed where our most REE-enriched samples were collected (fig. 2). The northwestern half of the 

polygon lies outside the area of LREE enrichment delineated by Soviet geologists but, in our view, it 

includes rocks with the same spectral characteristics to those within the earlier defined LREE zone. 

Using a conservative density of mineralized carbonatite (2.94 g/cm3), an average grade of LREE 

concentration (2.775 wt. percent, table 5), and the same dilution factor of 10:1 (wall rock: mineral 

bands), we calculate an estimated LREE resource of approximately 0.581 Mt in the revised area 

northwest of the LREE zone and approximately 0.597 Mt in the revised area within LREE zone. By this 

calculation, a total LREE resource of approximately 1.178 Mt is present within the area designated as 

prospective by remote sensing (table 6). Although clearly preliminary, this estimate agrees well with our 

estimate of LREE resources within the Soviet-defined LREE zone. Both estimates comport well with 

the probabilistic estimate of 1.4 Mt of undiscovered REE resources in all of south Afghanistan (Peters 

and others 2007). In addition to LREE, the Khanneshin carbonatite is also enriched in barium (>10 wt. 

percent), strontium (>6 wt. percent), phosphorus (~ 2 wt. percent), and uranium (>0.05 wt. percent).

5.0 Conclusions

The Khanneshin igneous complex is unusual in many respects, but it shares some interesting 

characteristics in common with other carbonatites worldwide: 

1. Most igneous rocks in the Khanneshin complex are varieties of carbonatite that range in 

composition from silico-carbonatite in the southwest part of the complex to ferro- and calicocarbonatite in the northeast part of the central vent. Only three small plugs of critically 

undersaturated silicate igneous rocks—leucite phonolite—are present in the southeast part of the 

complex.

2. Among the carbonatites at Khanneshin, the alvikites of the northeast central vent are most 

enriched in incompatible elements such as Ba, Sr, and LREE. These alvikites are situated within 

a graben (down-dropped block of rocks) whose bounding faults may have focused the 

emplacement of LREE-enriched magma. These LREE-enriched alvikites were emplaced 

unconformably above an older, and dike intruded, generation of alvikite, and thus LREEenriched magma formed late in the petrogenetic history of the complex.

3. Two distinct styles of mineralization are present in LREE-enriched alvikites. (1) Primary 

igneous LREE-carbonate minerals that crystallized directly from magma (type-2) occur in 

igneous dikes that are as much as 60 m thick and 500 m long. (2) Secondary LREE-carbonate 

minerals (type-1) that were produced by metasomatic or alteration processes, perhaps involving 

fluid-rich immiscible liquids, occur in concordant veins and seams within the alvikite that are 

centimeters thick and meters long. These concordant layers are symmetrically zoned, with an 

inner zone rich in barite, strontianite, and apatite and outer zones rich in khanneshite-(Ce), 

barite, strontianite, and secondary REE minerals. 

4. Type-2 igneous dikes are of two chemical types—one type is enriched in fluorine and another 

type is enriched in phosphorus. The fluorine-rich dikes are characterized by modal fluorite and 

khanneshite-(Ce) and in a single instance, an unnamed mineral, composed of K, Mg, and F, 

perhaps isostructural with neighborite. The phosphorus-rich rocks are characterized by modal 

apatite and carbocernaite, the latter forming large idiomorphic phenocrysts constituting as much 

as 20 modal percent of the rock. The phosphorus-rich intrusive rocks are also characterized by 

high Na contents (1.5 to 4.6 wt. percent Na2O).
49

5. Within the type-2 igneous dikes, rich in fluorite, a proposed general sequence of LREE-Sr-Ba 

mineralization is:

Sr-LREE-Ca-Na rich carbonates [khanneshite-(Ce)] → Ca-REE fluorocarbonates [bastnäsite-

(Ce)] → Ca-LREE hydrated carbonate [calkinsite-(Ce)] 

6. Within the type-2 igneous rocks, rich in apatite, a proposed general sequence for LREE-Sr-Ba 

mineralization is:

Sr-LREE-Ca-Na rich carbonates (carbocernaite) → Ca-LREE fluorocarbonates [parisite-(Ce)] 

→ Sr-LREE hydrated carbonate [ancylite-(Ce)] 

7. All the type-1 concordantly mineralized rocks are rich in apatite and free of fluorite. The 

concordant bands are defined by a dark central layer of ankeritic dolomite and siderite, with 

interstitial barite strontianite, apatite and calcite. Khanneshite-(Ce), barite, and strontianite form 

the outer light colored bands. These minerals commonly display a brecciated texture within the 

ankerite-barite alvikite, which suggests that a LREE, Sr, and Ba-rich fluid (or liquid), perhaps a 

hydrothermal fluid rich in phosphorus, was introduced into the ankerite-barite alvikite late in the 

petrogenetic history. In many instances khanneshite-(Ce) forms spherical aggregates, 

approximately 100 micrometers in diameter, suggesting that it crystallized as immiscible LREEenriched droplets. Synchysite-(Ce) and parisite-(Ce) are the common replacement minerals of 

khanneshite-(Ce).

8. We estimate that at least 1 Mt of light rare-earth elements (LREE) exist within the Khanneshin 

carbonatite, Helmand Province, Afghanistan. This newest evaluation of resources agrees well 

with an earlier USGS estimate of undiscovered resources in south Afghanistan (Peters and 

others, 2007), and it verifies the unpublished work of Soviet scientists in the 1970s (Cheremitsyn 

and Yeremenko, 1976; Chmyrev, 1976; Yeremenko, 1975). 

The REE prospect contains total concentrations of lanthanum, cerium, praseodymium, and 

neodymium, ranging from 0.5 to 6.2 wt. percent, which are present in carbonate and fluorocarbonate 

minerals that formed during the late stages of carbonatite emplacement. The primary area of 

mineralization, first identified by Soviet geologists in the 1970s, covers about 0.74 square kilometers 

and includes both concordantly banded type-1 zones of LREE mineralization (average total LREE of 

2.8 wt. percent), as well as type-2 igneous dikes that are tens of meters wide and hundreds of meters 

long (average total LREE of 3.3 wt. percent). The LREE prospect is comparable in grade to the worldclass deposits of Mountain Pass and Bayan Obo, both LREE deposits. In addition to high concentrations 

of LREE, the carbonatite is greatly enriched in barium (>10 wt. percent), strontium (>6 wt. percent), 

phosphorus (~ 2 wt. percent), and uranium (0.05 wt. percent).

The new REE assessment evaluation is part of a larger report to be released for the TFBSO in 

September 2011 (Peters and others, 2011). That forthcoming report will include an updated evaluation 

of Afghanistan’s principal deposits of gold, silver, iron, copper, lead, zinc, phosphorus, and uranium. 

Mineral and energy resources represent a significant source of Afghanistan’s wealth, and REE are a 

particularly strategic and valuable commodity within their growing list of mineral resources.

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