Geologic Map of the Khanneshin Carbonatite Complex ... · PDF fileBayan Obo, China carbonatite...
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Index map outlining USGS-Afghanistan mineral project areas. Area of this report shown in red. 64°E 62°E 60°E 66°E 68°E 70°E 72°E 35°N 34°N 74°E 76°E 32°N 33°N 30°N 29°N 31°N 36°N 37°N 38°N 39°N 1300 900 1200 1300 900 1300 1100 900 1000 900 900 1000 900 900 1300 1300 900 900 900 900 1200 1300 1300 1300 1000 1300 1100 1100 1100 1000 1000 1000 1000 1000 1000 1000 1000 1100 1200 1100 1100 1100 1100 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1100 1100 1100 1100 1100 1200 1200 1200 900 900 900 900 900 1000 1000 1200 1200 1200 1200 1200 1200 1200 1200 1200 1200 1200 1200 1200 1200 1200 1100 1100 1100 1100 1100 1100 1100 900 900 900 900 900 900 900 900 900 900 900 900 900 900 900 900 900 900 6 5 4 7 6 40 15 20 30 20 20 20 30 40 50 35 70 45 35 45 30 30 50 65 25 12 15 15 10 20 25 30 10 15 20 33 15 20 15 15 15 30 35 30 70 25 10 10 30 6 15 10 20 8 5 7 10 10 10 10 10 15 15 15 20 10 7 7 20 10 35 1 m ap par sid c IMAGE–B 5 cm dol-ank dol- ank dol- ank sid c-cer sid dol- ank ank- dol ank-dol ank-dol ank-dol b RT-11K-6 RT-11K-5 Tuff S C Dike A B C A B 100 1000 10000 100000 1000000 0 10 20 30 40 50 60 Ba (ppm) CC FC MC Khanneshin intrusive and volcanic rocks Type–1 LREE mineralized seams Type–2 LREE mineralized dikes Dikes of the SW complex Bayan Obo, China carbonatite dike Bayan Obo, China mineralized carbonate MC FC CC 100 1000 10000 100000 1000000 1000 10000 100000 Sr (ppm) Ba (ppm) Khanneshin intrusive and volcanic rocks Type–1 LREE mineralized seams Type–2 LREE mineralized dikes Dikes of the SW complex 1000 10000 100000 10 100 1000 10000 100000 Sr (ppm) La (ppm) CaO (wt. percent) La (ppm) Rock/Chondrites FC MC CC Bayan Obo, China carbonatite dike Bayan Obo, China mineralized carbonate Khanneshin intrusive and volcanic rocks Mt. Pass, California REE ores Type–1 LREE mineralized seams Type–2 LREE mineralized dikes Dikes of the SW complex FC MC CC 1 10 100 10 100 1000 10000 100000 Yb (ppm) Bayan Obo, China REE ores Bayan Obo, China carbonatite dike Khanneshin intrusive and volcanic rocks Mt. Pass, California REE ores Type–1 LREE mineralized seams Type–2 LREE mineralized dikes Dikes of the SW complex 1 10 100 1000 10000 100000 1000000 La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Bayan Obo, China REE ores Khanneshin Type–1 concordant seams of LREE mineralization Khanneshin Type–2 LREE mineralized discordant dikes Mt. Pass, California REE ores ap ap str str ap ba c-cer c-cer par 200 um kh kh kh kh ba ba ba ba ba str str cc cc ba kh cc 100 um A B MgO Fe2O3+MnO CaO SiO2 CaO + MgO Fe2O3+MnO Type–1 LREE seams Dikes of the SW complex Type–2 LREE mineralized dikes Calcio-Carbonatites Silico- Carbonatites Magnesio- Carbonatites Ferro- Carbonatites Ferro- Carbonatites Calcio-Carbonatites A B C D F E METERS 1000 1100 METERS 900 800 1200 1300 1400 1000 1100 900 800 1200 1300 1400 METERS 1000 1100 METERS 900 800 1200 1300 1000 1100 900 800 1200 1300 Khanneshin uranium prospect Trench Trench Trench Khanneshin LREE prospect area Traverse no. 2, August 2010 Traverse no. 1B, September 2009 Traverse no. 1A, September 2009 Traverse no. 3, February 2011 A C B D F E CONTOUR INTERVAL 10 METERS SCALE 1:10 000 EXPLANATION OF MAP SYMBOLS Contact—Dashed where inferred Fault or fracture—Inferred Strike and dip of bedding Trench Traverse line—Arrow shows direction Mineralized area containing radioactive elements Carbonatite pipe Seam of rare earth element (REE) enrichment Apatite Strontianite Rare earth carbonate Magnetite Rare earth element (REE) enrichment zone—(Tucker and others, 2011) USGS sample—Taken on Traverse nos. 2 and 3 Russian sample Site of photograph in Traverse nos. 1A and 1B—Tip of arrow at point of observation; number keyed to figure Figure 1.—Parallel northeast-striking carbonatite dikes intruding alvikitic agglomerate (unit Q 1-2c ) along southwestern part of the volcanic sequence. (Traverse no. 1A) Figure 6.—View of volcanic vent margin on southern part of the Khanneshin carbonatite complex, looking southeast. (Traverse no. 1A) Figure 5.—View looking north at sediment-volcanic contact. (Traverse no. 1B) Figure 4.—View looking southwest at volcanic-sediment contact. (Traverse no. 1A) Figure 7.—View of layered agglomerate (unit Q 1-2c ), looking south- west. (Traverse no. 1A) Figure 2.—Alvikitic agglomerate unit Q 1-2c cropping out along the southwestern part of the volcanic sequence. (Traverse no. 1A) Figure 3.—Magnetite-bearing aphanitic alvikitic agglomerate (unit Q 1-3c ) that overlies unit Q 1-2c along the southwestern part of the volcanic sequence. (Traverse no. 1A) Figure 12.—Mineralogy and crystallization sequence of the concordantly REE-mineralized rocks, RT-11K-5, Febru- ary traverse, 2011. (A) Photograph of the concordant symmetric bands of mineralized barite-strontianite alvikite. (B) Gray-toned backscattered electron microscope image of box b, showing margin of light-colored band of ankeritic dolomite, barite, strontianite, calcite, and spherical areas (immiscible droplets?) of khanneshite. Calcite and khanneshite appear as late, interstitial minerals surround- ing early formed phenocrysts of barite and strontianite. Abbreviations: ba, barite; str, strontianite; cc, calcite; ank-dol, ankeritic dolomite; kh, khanneshite. Modified from Tucker and others (2011). Figure 13.—Mineralogy and crystallization sequence of the apatite-rich intrusive dikes, Khanneshin carbonatite complex. (A) Outcrop of intrusive dike RT-11K-6. The rectangle of image B shows the approximate location of the hand specimen pictured in B. (B) Rock slab of sample RT-11K-6 showing the phenocrysts of carbo- cernaite in a matrix of dolomitic ankerite, siderite, apatite, and barite. Location of image C shown as inset box c. (C) False-colored backscattered electron microscope image showing the textural relations 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. Modified from Tucker and others (2011). Figure 22.—View looking southeast over Neogene sedimentary strata (red arkose and green argillite in the foreground) and carbon- atite tuff and ash in the distance. (Traverse no. 2) Figure 17.—Close-up view of another Type-1 mineralized vein with an interior mosaic of fine-grained barite, calcite, celestine and oxides, and a selvage of euhedral crystals of burbankite and bastnaesite. Northeastern margin of the central intrusive vent, Khanneshin carbonatite complex. (Traverse no. 3) Figure 19.—Close-up view of Type-2 mineralization in a coarse- grained carbonatite dike. Note the coarse-grained igneous texture with idiomorphic crystals of fluorite (purplish blue), barite (gray), and calcite (white) and prismatic aggregates of the yellow rare-earth minerals khanneshite (burbankite group) and bastnaesite-(Ce). Width of the sample is ~40 cm. (Traverse no. 2) Figure 18.—Tabular sheet, approximately 1.5 m thick (outlined by dashed line), of typical Type-2 mineralization showing very coarse grained rare earth element (REE)- enriched carbonatite cutting thinly banded alvikite in the northeastern margin of the central intrusive vent, Khanneshin carbon- atite complex. Note the pegmatitic patches, enriched in yellow REE minerals (bounded by dashed circles). (Traverse no. 3) Figure 16.—Type-1 rare earth element (REE) mineralization in fine-grained ankerite-barite alvikite, Khanneshin carbonatite complex. Two Type-1 banded veins are apparent; one approxi- mately 8 cm thick, the other approximately 4 cm thick. Both have an outer selvage of yellow prismatic burbankite and bastnaesite and an inner zone of barite, celestine, calcite, and fine-grained oxide minerals. (Traverse no. 3) Figure 15.—View looking west across the northern margin of the central intrusive vent showing the north-dipping (~25° N) strata of Neogene age deflected by the forceful emplacement of the intrusive vent. (Traverse no. 3) Figure 14.—View looking southeast from the northern margin of the central intrusive vent, Khanneshin carbonatite complex. Note the rugged relief (~200 m) and lack of vegetation on the agglomeratic and brecciated alvikite of the central intrusive vent. (Traverse no. 3) Figure 23.—Alvikite agglomerate intruded by fine-grained carbon- atite dike. Dike is marked by dashed line. (Traverse no. 2) Figure 24.—Close-up view of welded carbonatite tuff cut by thin (10-cm) dike of coarse-grained bastnaesite-khanneshite-pyrochlore carbonatite. (Traverse no. 2) Figure 25.—View looking east at the volcanic strata of the central intrusive vent. Dark stratified rocks (S) in the foreground are alvikite tuffs and lavas; overlying them are light-colored massive carbonatite flows (C) and agglomeratic tuffs. (Traverse no. 2) Figure 30.—Weathered pits in alvikite agglomerate sampled previously by Soviet geologists in the central intrusive vent. (Traverse no. 2) Figure 21.—Hydrothermally altered rare earth element (REE) minerals of the Type-1 veins and disseminated pods in barite- ankerite alvikite, northeastern margin of the central intrusive vent, Khanneshin carbonatite complex. (Traverse no. 3) Figure 20.—Close-up view of bastnaesite and khanneshite (yellow) in pegmatoidal patch of Type-2 mineralized tabular sheet shown in figure 18. Other visible minerals include fluorite, barite, and calcite. (Traverse no. 3) Figure 27.—Massive carbonatite agglomerate enclosing a large block (marked by dashed line) of coarse-grained holocrystalline carbonatite (sövite). (Traverse no. 2) Figure 8A, B.—Ternary diagrams of USGS whole-rock geochemical data, Khanneshin carbonatite complex (modified from Tucker and others (2011). Note the distinctive difference between samples from different parts of the complex. Red circles are volcanic strata and minor intrusive rocks from the southwestern part of the complex (USGS 2009 collection). Filled blue circles are banded alvikite (2011 USGS collection) in the Khanneshin LREE prospect area. Open blue circles are tabular sheets of intrusive carbonatite (2011 USGS collection) also from the Khanneshin LREE prospect area. (A) Rocks from the LREE prospect area are noticeably depleted in silica, relative to the southwestern part of the central intrusive vent, and they are properly classified as calcio- and ferro-carbonatites (fields modified from Srivastava, 1993). Some of the same rocks (B) contain more Mg than Fe and may be classified as magnesio-carbonatite (fields modified from Woolley and Kempe, 1989). DEFINITION OF TERMS used in figures 8–12 REE, LREE, HREE, ppm, Red-filled circles in figures 8–10 are volcanic tuffs and dikes from the southwestern part of the Khanneshin carbonatite complex Blue-filled and unfilled circles in figures 8–10 are LREE-enriched rocks from the Khanneshin LREE prospect area (see Explana- tion of Map Symbols) rare earth elements light rare earth elements heavy rare earth elements parts per million Figure 9A.—Variation diagram of CaO (weight percent) versus Ba (ppm) for rocks of the Khanneshin carbonatite complex illustrating the difference between the LREE-enriched rocks of the marginal zone, central intrusive vent, and normal alvikite and sövite of the Khanneshin carbonatite. Average calcio-carbonatite (yellow star), ferro-carbonatite (red star), and magnesio-carbonatite (green star) from Woolley and Kempe (1989). Note the very high concentrations of Ba, relative to CaO, in the REE-enriched rocks of the Khanneshin carbonatite. One percent (parts per hundred) equals 10,000 ppm (parts per million). Diagram modified from Tucker and others (2011). Figure 10A.—Variation diagram of La (ppm) versus Sr (ppm) illustrating the magnitude and significance of REE enrichment in the marginal zone, central intrusive vent, Khanneshin carbonatite complex (symbols as in fig. 8). Also shown are the fields for ordinary Khanneshin intrusive and volcanic rocks sampled in 2009 and 2010, and average calcio- carbonatite (yellow star), ferro-carbonatite (red star), and magnesio-carbonatite (green star) from Woolley and Kempe (1989). The positive correlation of the LREE and Sr in the REE-enriched rocks indicates the propensity of the LREE to substitute for Sr in khanneshite (burbankite group) and carbo- cernaite, the primary carbonate minerals of the Khanneshin complex. Also shown are mineralized carbonate and carbon- atite dikes from Bayan Obo (data from Yang and others, 2009) and average ores from Mountain Pass (data from Castor, 2008). Diagram modified from Tucker and others (2011). Figure 10B.—Variation diagram of La (ppm) versus Yb (ppm) illustrating the magnitude and significance of REE enrich- ment in the marginal zone, central intrusive vent, Khan- neshin carbonatite complex (symbols as in fig. 8). La (ppm) is representative of the LREE and Yb (ppm) is representative of the HREE. Common alvikites of the Khanneshin complex have LREE and HREE concentrations similar to average ferro-, magnesio-, and calcio-carbonatites worldwide. The highly enriched alvikites of the marginal central vent are enriched in the REE by an order of magnitude, and they are comparable in grade to the world-class deposits of Bayan Obo (data for average Bayan Obo ores from Yuan and others, 1992) and Mountain Pass (data from Castor, 2008). Diagram modified from Tucker and others (2011). Figure 9B.—Variation diagram of Sr (ppm) versus Ba (ppm) for rocks of the Khanneshin carbonatite complex illustrating the difference between the LREE-enriched rocks of the marginal zone, central intrusive vent, and normal alvikite and sövite of the Khanneshin carbonatite. Note the very high concentrations of Ba, relative to Sr, in the REE- enriched rocks of the Khanneshin carbonatite. Also shown are concentrations in carbonatite dikes at Bayan Obo (China) (data from Yang and others, 2009). One percent (parts per hundred) equals 10,000 ppm (parts per million). Diagram modified from Tucker and others (2011). Figure 11.—Rare earth concentrations normalized to chondritic values (Nakamura, 1974). The Khanneshin whole-rock concentrations are from the LREE-enriched zone (filled and open blue circles). All samples are highly enriched in the LREE relative to the HREE, with typical concentra- tions of La, Ce, Pr, and Nd above or near 1 weight percent concentrations. These are comparable in grade to the world-class REE ores from Bayan Obo, China (green crosses) and Mountain Pass, Calif. (blue-filled stars). Note that the Type-1 concordant seams from Khanneshin are more enriched in the HREE than are the Type-2 igneous dikes from Khanneshin. Both types of mineralized rocks from Khanneshin are slightly more enriched in HREE than ores from Mountain Pass. Diagram modified from Tucker and others (2011). Figure 26.—Steeply inclined bedded siltstone and argillite of Neogene age, cut by a thin dike of white carbonatite. (Traverse no. 2) INTRODUCTION This map is a modified version of the Geological map of the Khanneshin carbonatite complex, scale 1:10,000 (Cheremytsin, 1976). The original map and cross sections are contained in Soviet report no. R1142 (Cheremytsin and Yeremenko, 1976), which was prepared in cooperation with the Ministry of Mines and Industries of the Republic of Afghanistan in Kabul in 1976 under contract number 55-184/17500. This modified map illustrates the geological structure of the Khanneshin carbonatite complex and includes cross sections of the same area. The unit colors on the map and cross sections differ from the colors shown on the original version. The units are colored according to the color and pattern scheme of the Commission for the Geological Map of the World (CGMW) (http://www.ccgm.org). This map reproduces the topology (contacts, faults, and so forth) of the original Soviet map and cross sections, and includes modifications based on our examination of these documents and on observations made during brief field visits in September 2009, August 2010, and February 2011. Elevations on the cross sections are derived from the original Soviet topography and may not match the Global Digital Elevation Model (GDEM) topography used on the current map. We have attempted to translate the original Russian terminology and rock classification into modern English geologic usage as literally as possible without changing any genetic or process-oriented implica- tions in the original descriptions. We also use the age designations from the original map. Some field photograph sites are shown on the map by symbols keyed by number to the figures. The photographs were taken by U.S. Geological Survey scientists (Robert Tucker, Stephen Peters, Mike Chornack, Said Mirzad, and Daniel Hayba) and personnel with the Task Force for Business and Stability Operations (TFBSO) during the field visits mentioned above. We acknowledge Forrest Horton, under contract to TFBSO, for field and logistical assistance given during Traverse 2. DESCRIPTION OF MAP UNITS ROCKS OF GEOTHERMAL ORIGIN Travertine (Pleistocene)—White to yellowish-white, fine-grained botryoidal calcite and aragonite limestone VOLCANIC AND SEDIMENTARY STRATIFIED ROCKS OF THE EASTERN AND NORTHEASTERN PART OF THE CARBONATITE COMPLEX Eolian sand (Holocene)—Surrounds the Khanneshin structure; 3 to 5 m thick Proluvial fan (Holocene and Pleistocene?)—Unconsolidated, very coarse grained, poorly sorted and poorly graded conglomerate and breccia; debris flow (lahar?) Carbonatite lava flow (Pleistocene?) (upper bed of upper volcanogenic unit)—Porous, bluish-gray, with porphyritic texture; ranges from 10–20 cm to 4–5 m thick. Contains phenocrysts of rhombohedral calcite crystals (1 mm) Carbonatite tuff (Pleistocene?) (lower bed of upper volcanogenic unit)—Highly abundant, medium-grained, porous, gray and brown, and weakly consolidated. Contains very angular fragments of carbonatite, Neogene sedimentary rock, and magnetite, apatite, and biotite phenocrysts Sandstone and carbonatite conglomerate (Pleistocene?) (upper bed of middle volcanogenic unit)—Coarse-grained, light-gray and brownish-gray sandstone interbedded with siltstone Carbonatite siltstone and sandstone (Pleistocene?) (lower bed of middle volcanogenic unit)—Siltstone, fine-grained, horizontally and thinly layered, light-gray and yellowish-gray. Sandstone, fine-grained, white, yellowish-white, light-gray and yellowish-gray; contains fragments (0.2 mm) of calcite, apatite, quartz, microcline, plagioclase, magnetite, and zircon Carbonatite tuff (Pleistocene?) (lower volcanogenic unit)—Greenish-gray and green, medium-grained carbonatite tuff; contains rocks of geothermal origin, fragments of carbonatite, and Neogene sandstone, siltstone, and argillite VOLCANIC AND SEDIMENTARY STRATIFIED ROCKS OF THE WESTERN AND SOUTHWESTERN PART OF THE CARBONATITE COMPLEX Alvikite tuffs and lava flows (Pleistocene?) (top layer of volcanogenic unit)—Massive, fragmental amygdaloidal flows and tuffs; horizontal flows 10 m thick Sedimentary strata (Pleistocene?) (lower layer of volcanogenic unit)—Thick- bedded, gray to greenish-gray, coarse- to medium-grained sandstone and siltstone, alternating with massive, poorly sorted, very angular fragmental carbonatite tuff; fragments composed of volcanic rocks, Neogene sedimen- tary rocks, and carbonatite intrusives. Interlayered with thin beds (2–20 cm) of siltstone and claystone INTRUSIVE IGNEOUS ROCKS OF THE CENTRAL INTRUSIVE VENT OR STOCK Barite-ankerite-alvikite (Pleistocene?) (exterior stock facies)—Medium- to fine-grained, dark-gray to black; forms an exterior half-ring around the interior stock facies. Transitions gradationally into the interior stock facies Calcite sövite carbonatite (Pleistocene?) (interior stock facies)—Medium- to very coarse grained calcite sövite; gray, thinly laminated and spotted; contains xenoliths of phlogopite fenite (glimmerite); accessory minerals are apatite, magnetite, and pyrochlore. Forms the interior facies of the central intrusive stock; grades into the exterior stock facies Rødberg (Red rock) (Pleistocene?)—Medium- to fine-grained black to red siderite-ankerite-hematite carbonatite; contains siderite (30–35 percent), ankerite (20–25 percent), and hematite (15–20 percent) INTRUSIVE Satellitic (hypabyssal) and volcanic rocks Leucite phonolite (Pleistocene)—Massive, dense, dark-gray to green, porphyritic phonolite with phenocrysts of leucite and sanidine (50 to 70 percent of the rock). Groundmass contains fine- to medium-grained, gray to green clusters (1–1.5 mm in diameter) of aegerine and sanidine Alvikite agglomerate tuff (Pleistocene?)—Calcite carbonatite agglomerate and tuff; contains alvikite fragments, kamaphorites, and xenoliths of alvikite, sövite, and Neogene sedimentary rocks Carbonatite dikes (Pleistocene?)—Massive, generally subvertical dikes, several centimeters to 1–2 m thick; fine- to medium-grained calcite-barite- ankerite carbonatite. Many dikes have radial geometry, cutting through Neogene red beds, intrusive rocks, and lower carbonatite tuffs of unit Q aa PREVOLCANIC SEDIMENTARY ROCKS Sandstone and siltstone (Neogene)—Altered and hornfelsed red sandstone and siltstone in and near the contact within igneous rocks of the subvolca- nic and volcanic-rock facies; brecciated and recrystallized, medium to fine grained Sandstone and siltstone (Neogene)—Unaltered, fine- to medium-grained, orange to brick-red sandstone and siltstone alternating with thin green beds of fine-grained sandstone PROSPECT AREAS Khanneshin uranium prospect—Denotes the area of Neogene sedimentary rocks in the southwestern part of the complex identified by Cheremytsin and Yeremenko (1976) as prospective for uranium and thorium Khanneshin light rare earth element (LREE) prospect area—Red outline denotes the area of intrusive igneous rocks of the subvolcanic facies in the northeastern part of the central intrusive vent, identified by Cheremytsin and Yeremenko (1976) as prospective for LREE Khanneshin phosphorus prospect area—Green outline denotes the area of alvikite tuffs and lava flows identified by Cheremytsin and Yeremenko (1976) as prospective for phosphorus Figure 29.—Red and green clastic sedimentary rocks of Neogene age intruded by a thin, sill-like dike of white carbonatite. Dike is marked by dashed line. (Traverse no. 2) Figure 28.—Contact (dashed line) between coarse-grained alvikite agglomerate above fine-grained carbonatite lava cut by carbonatite dikes. (Traverse no. 2) REFERENCES Abdullah, S., and Chmyriov, V.M., eds., 1977, Map of mineral resources of Afghani- stan: Kabul, Ministry of Mines and Industries of the Democratic Republic of Afghani- stan, Department of Geological and Mineral Survey, scale 1:500,000. [Prepared by V/O Technoexport U.S.S.R.] Abdullah, S., Chmyriov, V.M., Stazhilo-Alekseev, K.F., Dronov, V.I., Gannon, P.J., Lubemov, B.K., Kafarskiy, A.K., and Malyarov, E.P., 1977, Mineral resources of Afghanistan, 2d ed.: Kabul, Ministry of Mines and Industries of the Democratic Republic of Afghanistan, Afghan Geological and Mines Survey, United Nations Development Programme Support Project AFG/74/12, 419 p. Castor, S.B., 2008, The Mountain Pass rare-earth carbonatite and associated ultrapo- tassic rocks, California: The Canadian Mineralogist, v. 46, no. 4, p. 779–806. Cheremytsin, V.G., comp., 1976, Geological map of the Khanneshin carbonatite complex, in Cheremytsin, V.G., and Yeremenko, G.K., Report of the Khanneshin group on the results of prospecting and evaluational activity for 1976 [in Russian]: Kabul, Department of Mines and Geology Survey, report no. R1142, one sheet, scale 1:10,000. [Prepared by V/O Technoexport U.S.S.R. for the Ministry of Mines and Industries of the Republic of Afghanistan, Department of Mines and Geology Survey, under contract no. 55-184/17500.] Cheremytsin, V.G., and Yeremenko, G.K., 1976, Report of the Khanneshin group on the results of prospecting and evaluational activity for 1976 [in Russian]: Kabul, Department of Mines and Geology Survey, report no. R1142, 84 p. and 7 map pls. [Prepared by V/O Technoexport U.S.S.R. for the Ministry of Mines and Industries of the Republic of Afghanistan, Department of Mines and Geology Survey, under contract no. 55-184/17500.] Nakamura, Noboru, 1974, Determination of REE, Ba, Fe, Mg, Na and K in carbona- ceous and ordinary chondrites: Geochimica et Cosmochimica Acta, v. 38, no. 5, p. 757–775. Peters, S.G., Ludington, S.D., Orris, G.J., Sutphin, D.M., Bliss, J.D., and Rytuba, J.J., eds., and the U.S. Geological Survey–Afghanistan Ministry of Mines Joint Mineral Resource Assessment Team, 2007, Preliminary non-fuel mineral resource assessment of Afghanistan: U.S. Geological Survey Open-File Report 2007–1214, 810 p., 1 CD-ROM disk and 1 DVD-ROM disk; also available at http://pubs.usgs.gov/of/2007/1214/. Srivastava, R.K., 1993, Chemical classification of silica-rich carbonatites: Indian Journal of Geochemistry, v. 8, p. 15–24. REFERENCES (continued) 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, 51 p.; also available at http://pubs.usgs.gov/of/2011/1207/. Woolley, A.R., and Kempe, D.R.C., 1989, Carbonatites; nomenclature, average chemical compositions, and element distribution, in Bell, Keith, ed., Carbonatites; genesis and evolution: London, Unwin Hyman, p. 1–14. Yang Xiaoyong, Sun Weidong, Zhang Yuxu, and Zheng Yongfei, 2009, Geochemical constraints on the genesis of the Bayan Obo Fe-Nb-REE deposit in Inner Mongolia, China: Geochimica et Cosmochimica Acta, v. 73, no. 5, p. 1417–1435. Yuan Zhongxin, Bai Ge, Wu Chenyu, Zhang Zhongqin, and Ye Xianjiang, 1992, Geological features and genesis of the Bayan Obo REE ore deposit, Inner Mongolia, China: Applied Geochemistry, v. 7, no. 5, p. 429–442. Q 1-3a Q 1-3a Q 1-3a Q 1-3b Q 1-3b Q 1-3b Q 1-3b Q 1-3b Q 1-3b Q 1-3b N N N N N Q 2-3 Q 1-3a Q 1-3b Q 1-3b Q 1-3b Q 1-3c Q 1-3c Q isf Q esf Q r Q 1-2a Q 1-2b Q 1-1 Q 1-2c Q 1-2c Q 1-2c Q 1-2c Q 4 Q t N N Q 2-3 Q 1-2a Q 1-2b Q 1-2b Q 1-2a Q 1-1 Q 1-1 Q 1-1 Q 1-1 Q 4 Q 4 Q 4 Q 4 Q 4 Q 4 Q 4 Q 4 Q 4 Q 4 Q 4 N N N N N N N N N N N N N N N Q lp Q lp Q lp Q lp Q aa Q aa Q aa Q aa Q aa Q aa Q aa Q aa Q aa Q aa Q aa Q aa Q aa Q aa Q aa Q aa Q aa Q aa Q aa Q aa Q aa Q aa Q aa Q aa Q aa Q aa Q esf Q esf Q isf Q r Q r Q r Q r Q r Q 1-2b Q 1-2b Q 1-2b Q 1-2b Q 1-2b Q 1-2b Q 1-2b Q 1-2b Q 1-2b Q t Q t Q t Q t Q t Q t Q t Q 1-1 Q 1-1 Q 4 Q 1-3a Q 1-3b Q 1-3b Q isf Q isf Q esf Q esf Q esf Q r Q r Q aa Q 1-2a Q 1-2b Q 4 Q 4 Q 4 Q 4 N N N N N N N N N Q 1-3a Q 1-3b Q 1-2b Q lp Q lp Q lp Q aa Q 1-2b Q t Q 1-3c Q 1-3c Q 1-3c Q 1-2c Q 1-2c Q 1-2c Q 1-3c Q 1-3c Q 1-3c Q 1-2c N N 63°39’0”E 63°39’0”E 63°37’1”E 63°37’59”E 63°37’1”E 63°37’59”E 63°36’0”E 63°34’59”E 63°36’0”E 63°34’59”E 63°34’1”E 63°34’1”E 63°33’0”E 63°33’0”E 30°28’1”N 30°28’1”N 30°27’0”N 30°27’0”N 30°28’59”N 30°28’59”N 30°30’0”N 30°30’0”N 30°31’1”N 30°31’1”N Topography and shaded relief derived from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) 30-meter Global Digital Elevation Model (GDEM) data, 2009 Hydrography derived from ASTER GDEM data Projection and grid: Universal Transverse Mercator (UTM), zone 42 north World Geodetic System (WGS) 1984 Datum Modified from original compilation of Cheremytsin, 1976; see References Geologic Map of the Khanneshin Carbonatite Complex, Helmand Province, Afghanistan, Modified From the 1976 Original Map Compilation of V.G. Cheremytsin Compiled by Robert D. Tucker, Stephen G. Peters, Klaus J. Schulz, Karine M. Renaud, Will R. Stettner, Linda M. Masonic, and Patricia H. Packard 2011 Prepared in cooperation with the Afghan Geological Survey Under the auspices of the U.S. Department of Defense U.S. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY OPEN-FILE REPORT 2011–1244 USGS Afghanistan Project Product No. 198 This map is available for sale by U.S. Geological Survey, Information Services, Box 25286, Denver Federal Center, Denver, CO 80225 For product and ordering information: World Wide Web: http://www.usgs.gov; Telephone 1-888-ASK-USGS Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government Printed on recycled paper 1 .5 0 1 KILOMETER 1 1/2 1 MILE 0 NO VERTICAL EXAGGERATION Modified from original compilation of Cheremytsin, 1976 NO VERTICAL EXAGGERATION Modified from original compilation of Cheremytsin, 1976
Transcript of Geologic Map of the Khanneshin Carbonatite Complex ... · PDF fileBayan Obo, China carbonatite...
Index map outlining USGS-Afghanistan mineral project areas. Area of this report shown in red.
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Traverse no. 2, August 2010
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EXPLANATION OF MAP SYMBOLS
Contact—Dashed where inferred
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Mineralized area containing radioactive elements
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Rare earth element (REE) enrichment zone—(Tucker and others, 2011)
USGS sample—Taken on Traverse nos. 2 and 3
Russian sample
Site of photograph in Traverse nos. 1A and 1B—Tip of arrow at point of observation; number keyed to figure
Figure 1.—Parallel northeast-striking carbonatite dikes intruding alvikitic agglomerate (unit Q1-2c ) along southwestern part of the volcanic sequence. (Traverse no. 1A)
Figure 6.—View of volcanic vent margin on southern part of the Khanneshin carbonatite complex, looking southeast. (Traverse no. 1A)
Figure 5.—View looking north at sediment-volcanic contact. (Traverse no. 1B)
Figure 4.—View looking southwest at volcanic-sediment contact. (Traverse no. 1A)
Figure 7.—View of layered agglomerate (unit Q1-2c ), looking south-west. (Traverse no. 1A)
Figure 2.—Alvikitic agglomerate unit Q1-2c cropping out along the southwestern part of the volcanic sequence. (Traverse no. 1A)
Figure 3.—Magnetite-bearing aphanitic alvikitic agglomerate (unit Q1-3c ) that overlies unit Q1-2c along the southwestern part of the volcanic sequence. (Traverse no. 1A)
Figure 12.—Mineralogy and crystallization sequence of the concordantly REE-mineralized rocks, RT-11K-5, Febru-ary traverse, 2011. (A) Photograph of the concordant symmetric bands of mineralized barite-strontianite alvikite. (B) Gray-toned backscattered electron microscope image of box b, showing margin of light-colored band of ankeritic dolomite, barite, strontianite, calcite, and spherical areas (immiscible droplets?) of khanneshite. Calcite and khanneshite appear as late, interstitial minerals surround-ing early formed phenocrysts of barite and strontianite. Abbreviations: ba, barite; str, strontianite; cc, calcite; ank-dol, ankeritic dolomite; kh, khanneshite. Modified from Tucker and others (2011).
Figure 13.—Mineralogy and crystallization sequence of the apatite-rich intrusive dikes, Khanneshin carbonatite complex. (A) Outcrop of intrusive dike RT-11K-6. The rectangle of image B shows the approximate location of the hand specimen pictured in B. (B) Rock slab of sample RT-11K-6 showing the phenocrysts of carbo-cernaite in a matrix of dolomitic ankerite, siderite, apatite, and barite. Location of image C shown as inset box c. (C) False-colored backscattered electron microscope image showing the textural relations 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. Modified from Tucker and others (2011).
Figure 22.—View looking southeast over Neogene sedimentary strata (red arkose and green argillite in the foreground) and carbon-atite tuff and ash in the distance. (Traverse no. 2)
Figure 17.—Close-up view of another Type-1 mineralized vein with an interior mosaic of fine-grained barite, calcite, celestine and oxides, and a selvage of euhedral crystals of burbankite and bastnaesite. Northeastern margin of the central intrusive vent, Khanneshin carbonatite complex. (Traverse no. 3)
Figure 19.—Close-up view of Type-2 mineralization in a coarse-grained carbonatite dike. Note the coarse-grained igneous texture with idiomorphic crystals of fluorite (purplish blue), barite (gray), and calcite (white) and prismatic aggregates of the yellow rare-earth minerals khanneshite (burbankite group) and bastnaesite-(Ce). Width of the sample is ~40 cm. (Traverse no. 2)
Figure 18.—Tabular sheet, approximately 1.5 m thick (outlined by dashed line), of typical Type-2 mineralization showing very coarse grained rare earth element (REE)-enriched carbonatite cutting thinly banded alvikite in the northeastern margin of the central intrusive vent, Khanneshin carbon-atite complex. Note the pegmatitic patches, enriched in yellow REE minerals (bounded by dashed circles). (Traverse no. 3)
Figure 16.—Type-1 rare earth element (REE) mineralization in fine-grained ankerite-barite alvikite, Khanneshin carbonatite complex. Two Type-1 banded veins are apparent; one approxi-mately 8 cm thick, the other approximately 4 cm thick. Both have an outer selvage of yellow prismatic burbankite and bastnaesite and an inner zone of barite, celestine, calcite, and fine-grained oxide minerals. (Traverse no. 3)
Figure 15.—View looking west across the northern margin of the central intrusive vent showing the north-dipping (~25° N) strata of Neogene age deflected by the forceful emplacement of the intrusive vent. (Traverse no. 3)
Figure 14.—View looking southeast from the northern margin of the central intrusive vent, Khanneshin carbonatite complex. Note the rugged relief (~200 m) and lack of vegetation on the agglomeratic and brecciated alvikite of the central intrusive vent. (Traverse no. 3)
Figure 23.—Alvikite agglomerate intruded by fine-grained carbon-atite dike. Dike is marked by dashed line. (Traverse no. 2)
Figure 24.—Close-up view of welded carbonatite tuff cut by thin (10-cm) dike of coarse-grained bastnaesite-khanneshite-pyrochlore carbonatite. (Traverse no. 2)
Figure 25.—View looking east at the volcanic strata of the central intrusive vent. Dark stratified rocks (S) in the foreground are alvikite tuffs and lavas; overlying them are light-colored massive carbonatite flows (C) and agglomeratic tuffs. (Traverse no. 2)
Figure 30.—Weathered pits in alvikite agglomerate sampled previously by Soviet geologists in the central intrusive vent. (Traverse no. 2)
Figure 21.—Hydrothermally altered rare earth element (REE) minerals of the Type-1 veins and disseminated pods in barite-ankerite alvikite, northeastern margin of the central intrusive vent, Khanneshin carbonatite complex. (Traverse no. 3)
Figure 20.—Close-up view of bastnaesite and khanneshite (yellow) in pegmatoidal patch of Type-2 mineralized tabular sheet shown in figure 18. Other visible minerals include fluorite, barite, and calcite. (Traverse no. 3)
Figure 27.—Massive carbonatite agglomerate enclosing a large block (marked by dashed line) of coarse-grained holocrystalline carbonatite (sövite). (Traverse no. 2)
Figure 8A, B.—Ternary diagrams of USGS whole-rock geochemical data, Khanneshin carbonatite complex (modified from Tucker and others (2011). Note the distinctive difference between samples from different parts of the complex. Red circles are volcanic strata and minor intrusive rocks from the southwestern part of the complex (USGS 2009 collection). Filled blue circles are banded alvikite (2011 USGS collection) in the Khanneshin LREE prospect area. Open blue circles are tabular sheets of intrusive carbonatite (2011 USGS collection) also from the Khanneshin LREE prospect area. (A) Rocks from the LREE prospect area are noticeably depleted in silica, relative to the southwestern part of the central intrusive vent, and they are properly classified as calcio- and ferro-carbonatites (fields modified from Srivastava, 1993). Some of the same rocks (B) contain more Mg than Fe and may be classified as magnesio-carbonatite (fields modified from Woolley and Kempe, 1989).
DEFINITION OF TERMSused in figures 8–12
REE,LREE,HREE,ppm,
Red-filled circles in figures 8–10 are volcanic tuffs and dikes from the southwestern part of the Khanneshin carbonatite complex
Blue-filled and unfilled circles in figures 8–10 are LREE-enriched rocks from the Khanneshin LREE prospect area (see Explana-tion of Map Symbols)
rare earth elementslight rare earth elementsheavy rare earth elementsparts per million
Figure 9A.—Variation diagram of CaO (weight percent) versus Ba (ppm) for rocks of the Khanneshin carbonatite complex illustrating the difference between the LREE-enriched rocks of the marginal zone, central intrusive vent, and normal alvikite and sövite of the Khanneshin carbonatite. Average calcio-carbonatite (yellow star), ferro-carbonatite (red star), and magnesio-carbonatite (green star) from Woolley and Kempe (1989). Note the very high concentrations of Ba, relative to CaO, in the REE-enriched rocks of the Khanneshin carbonatite. One percent (parts per hundred) equals 10,000 ppm (parts per million). Diagram modified from Tucker and others (2011).
Figure 10A.—Variation diagram of La (ppm) versus Sr (ppm) illustrating the magnitude and significance of REE enrichment in the marginal zone, central intrusive vent, Khanneshin carbonatite complex (symbols as in fig. 8). Also shown are the fields for ordinary Khanneshin intrusive and volcanic rocks sampled in 2009 and 2010, and average calcio-carbonatite (yellow star), ferro-carbonatite (red star), and magnesio-carbonatite (green star) from Woolley and Kempe (1989). The positive correlation of the LREE and Sr in the REE-enriched rocks indicates the propensity of the LREE to substitute for Sr in khanneshite (burbankite group) and carbo-cernaite, the primary carbonate minerals of the Khanneshin complex. Also shown are mineralized carbonate and carbon-atite dikes from Bayan Obo (data from Yang and others, 2009) and average ores from Mountain Pass (data from Castor, 2008). Diagram modified from Tucker and others (2011).
Figure 10B.—Variation diagram of La (ppm) versus Yb (ppm) illustrating the magnitude and significance of REE enrich-ment in the marginal zone, central intrusive vent, Khan-neshin carbonatite complex (symbols as in fig. 8). La (ppm) is representative of the LREE and Yb (ppm) is representative of the HREE. Common alvikites of the Khanneshin complex have LREE and HREE concentrations similar to average ferro-, magnesio-, and calcio-carbonatites worldwide. The highly enriched alvikites of the marginal central vent are enriched in the REE by an order of magnitude, and they are comparable in grade to the world-class deposits of Bayan Obo (data for average Bayan Obo ores from Yuan and others, 1992) and Mountain Pass (data from Castor, 2008). Diagram modified from Tucker and others (2011).
Figure 9B.—Variation diagram of Sr (ppm) versus Ba (ppm) for rocks of the Khanneshin carbonatite complex illustrating the difference between the LREE-enriched rocks of the marginal zone, central intrusive vent, and normal alvikite and sövite of the Khanneshin carbonatite. Note the very high concentrations of Ba, relative to Sr, in the REE-enriched rocks of the Khanneshin carbonatite. Also shown are concentrations in carbonatite dikes at Bayan Obo (China) (data from Yang and others, 2009). One percent (parts per hundred) equals 10,000 ppm (parts per million). Diagram modified from Tucker and others (2011).
Figure 11.—Rare earth concentrations normalized to chondritic values (Nakamura, 1974). The Khanneshin whole-rock concentrations are from the LREE-enriched zone (filled and open blue circles). All samples are highly enriched in the LREE relative to the HREE, with typical concentra-tions of La, Ce, Pr, and Nd above or near 1 weight percent concentrations. These are comparable in grade to the world-class REE ores from Bayan Obo, China (green crosses) and Mountain Pass, Calif. (blue-filled stars). Note that the Type-1 concordant seams from Khanneshin are more enriched in the HREE than are the Type-2 igneous dikes from Khanneshin. Both types of mineralized rocks from Khanneshin are slightly more enriched in HREE than ores from Mountain Pass. Diagram modified from Tucker and others (2011).
Figure 26.—Steeply inclined bedded siltstone and argillite of Neogene age, cut by a thin dike of white carbonatite. (Traverse no. 2)
INTRODUCTIONThis map is a modified version of the Geological map of the Khanneshin
carbonatite complex, scale 1:10,000 (Cheremytsin, 1976). The original map and cross sections are contained in Soviet report no. R1142 (Cheremytsin and Yeremenko, 1976), which was prepared in cooperation with the Ministry of Mines and Industries of the Republic of Afghanistan in Kabul in 1976 under contract number 55-184/17500. This modified map illustrates the geological structure of the Khanneshin carbonatite complex and includes cross sections of the same area.
The unit colors on the map and cross sections differ from the colors shown on the original version. The units are colored according to the color and pattern scheme of the Commission for the Geological Map of the World (CGMW) (http://www.ccgm.org).
This map reproduces the topology (contacts, faults, and so forth) of the original Soviet map and cross sections, and includes modifications based on our examination of these documents and on observations made during brief field visits in September 2009, August 2010, and February 2011. Elevations on the cross sections are derived from the original Soviet topography and may not match the Global Digital Elevation Model (GDEM) topography used on the current map. We have attempted to translate the original Russian terminology and rock classification into modern English geologic usage as literally as possible without changing any genetic or process-oriented implica-tions in the original descriptions. We also use the age designations from the original map.
Some field photograph sites are shown on the map by symbols keyed by number to the figures. The photographs were taken by U.S. Geological Survey scientists (Robert Tucker, Stephen Peters, Mike Chornack, Said Mirzad, and Daniel Hayba) and personnel with the Task Force for Business and Stability Operations (TFBSO) during the field visits mentioned above.
We acknowledge Forrest Horton, under contract to TFBSO, for field and logistical assistance given during Traverse 2.
DESCRIPTION OF MAP UNITSROCKS OF GEOTHERMAL ORIGIN
Travertine (Pleistocene)—White to yellowish-white, fine-grained botryoidal calcite and aragonite limestone
VOLCANIC AND SEDIMENTARY STRATIFIED ROCKS OF THE EASTERN AND NORTHEASTERN PART OF THE
CARBONATITE COMPLEX
Eolian sand (Holocene)—Surrounds the Khanneshin structure; 3 to 5 m thick
Proluvial fan (Holocene and Pleistocene?)—Unconsolidated, very coarse grained, poorly sorted and poorly graded conglomerate and breccia; debris flow (lahar?)
Carbonatite lava flow (Pleistocene?) (upper bed of upper volcanogenic unit)—Porous, bluish-gray, with porphyritic texture; ranges from 10–20 cm to 4–5 m thick. Contains phenocrysts of rhombohedral calcite crystals (1 mm)
Carbonatite tuff (Pleistocene?) (lower bed of upper volcanogenic unit)—Highly abundant, medium-grained, porous, gray and brown, and weakly consolidated. Contains very angular fragments of carbonatite, Neogene sedimentary rock, and magnetite, apatite, and biotite phenocrysts
Sandstone and carbonatite conglomerate (Pleistocene?) (upper bed of middle volcanogenic unit)—Coarse-grained, light-gray and brownish-gray sandstone interbedded with siltstone
Carbonatite siltstone and sandstone (Pleistocene?) (lower bed of middle volcanogenic unit)—Siltstone, fine-grained, horizontally and thinly layered, light-gray and yellowish-gray. Sandstone, fine-grained, white, yellowish-white, light-gray and yellowish-gray; contains fragments (0.2 mm) of calcite, apatite, quartz, microcline, plagioclase, magnetite, and zircon
Carbonatite tuff (Pleistocene?) (lower volcanogenic unit)—Greenish-gray and green, medium-grained carbonatite tuff; contains rocks of geothermal origin, fragments of carbonatite, and Neogene sandstone, siltstone, and argillite
VOLCANIC AND SEDIMENTARY STRATIFIED ROCKS OF THE WESTERN AND SOUTHWESTERN PART OF THE
CARBONATITE COMPLEX
Alvikite tuffs and lava flows (Pleistocene?) (top layer of volcanogenic unit)—Massive, fragmental amygdaloidal flows and tuffs; horizontal flows 10 m thick
Sedimentary strata (Pleistocene?) (lower layer of volcanogenic unit)—Thick- bedded, gray to greenish-gray, coarse- to medium-grained sandstone and siltstone, alternating with massive, poorly sorted, very angular fragmental carbonatite tuff; fragments composed of volcanic rocks, Neogene sedimen-tary rocks, and carbonatite intrusives. Interlayered with thin beds (2–20 cm) of siltstone and claystone
INTRUSIVE IGNEOUS ROCKS OF THE CENTRALINTRUSIVE VENT OR STOCK
Barite-ankerite-alvikite (Pleistocene?) (exterior stock facies)—Medium- to fine-grained, dark-gray to black; forms an exterior half-ring around the interior stock facies. Transitions gradationally into the interior stock facies
Calcite sövite carbonatite (Pleistocene?) (interior stock facies)—Medium- to very coarse grained calcite sövite; gray, thinly laminated and spotted; contains xenoliths of phlogopite fenite (glimmerite); accessory minerals are apatite, magnetite, and pyrochlore. Forms the interior facies of the central intrusive stock; grades into the exterior stock facies
Rødberg (Red rock) (Pleistocene?)—Medium- to fine-grained black to red siderite-ankerite-hematite carbonatite; contains siderite (30–35 percent), ankerite (20–25 percent), and hematite (15–20 percent)
INTRUSIVESatellitic (hypabyssal) and volcanic rocks
Leucite phonolite (Pleistocene)—Massive, dense, dark-gray to green, porphyritic phonolite with phenocrysts of leucite and sanidine (50 to 70 percent of the rock). Groundmass contains fine- to medium-grained, gray to green clusters (1–1.5 mm in diameter) of aegerine and sanidine
Alvikite agglomerate tuff (Pleistocene?)—Calcite carbonatite agglomerate and tuff; contains alvikite fragments, kamaphorites, and xenoliths of alvikite, sövite, and Neogene sedimentary rocks
Carbonatite dikes (Pleistocene?)—Massive, generally subvertical dikes, several centimeters to 1–2 m thick; fine- to medium-grained calcite-barite-ankerite carbonatite. Many dikes have radial geometry, cutting through Neogene red beds, intrusive rocks, and lower carbonatite tuffs of unit Qaa
PREVOLCANIC SEDIMENTARY ROCKS
Sandstone and siltstone (Neogene)—Altered and hornfelsed red sandstone and siltstone in and near the contact within igneous rocks of the subvolca-nic and volcanic-rock facies; brecciated and recrystallized, medium to fine grained
Sandstone and siltstone (Neogene)—Unaltered, fine- to medium-grained, orange to brick-red sandstone and siltstone alternating with thin green beds of fine-grained sandstone
PROSPECT AREAS
Khanneshin uranium prospect—Denotes the area of Neogene sedimentary rocks in the southwestern part of the complex identified by Cheremytsin and Yeremenko (1976) as prospective for uranium and thorium
Khanneshin light rare earth element (LREE) prospect area—Red outline denotes the area of intrusive igneous rocks of the subvolcanic facies in the northeastern part of the central intrusive vent, identified by Cheremytsin and Yeremenko (1976) as prospective for LREE
Khanneshin phosphorus prospect area—Green outline denotes the area of alvikite tuffs and lava flows identified by Cheremytsin and Yeremenko (1976) as prospective for phosphorus
Figure 29.—Red and green clastic sedimentary rocks of Neogene age intruded by a thin, sill-like dike of white carbonatite. Dike is marked by dashed line. (Traverse no. 2)
Figure 28.—Contact (dashed line) between coarse-grained alvikite agglomerate above fine-grained carbonatite lava cut by carbonatite dikes. (Traverse no. 2)
REFERENCESAbdullah, S., and Chmyriov, V.M., eds., 1977, Map of mineral resources of Afghani-
stan: Kabul, Ministry of Mines and Industries of the Democratic Republic of Afghani-stan, Department of Geological and Mineral Survey, scale 1:500,000. [Prepared by V/O Technoexport U.S.S.R.]
Abdullah, S., Chmyriov, V.M., Stazhilo-Alekseev, K.F., Dronov, V.I., Gannon, P.J., Lubemov, B.K., Kafarskiy, A.K., and Malyarov, E.P., 1977, Mineral resources of Afghanistan, 2d ed.: Kabul, Ministry of Mines and Industries of the Democratic Republic of Afghanistan, Afghan Geological and Mines Survey, United Nations Development Programme Support Project AFG/74/12, 419 p.
Castor, S.B., 2008, The Mountain Pass rare-earth carbonatite and associated ultrapo-tassic rocks, California: The Canadian Mineralogist, v. 46, no. 4, p. 779–806.
Cheremytsin, V.G., comp., 1976, Geological map of the Khanneshin carbonatite complex, in Cheremytsin, V.G., and Yeremenko, G.K., Report of the Khanneshin group on the results of prospecting and evaluational activity for 1976 [in Russian]: Kabul, Department of Mines and Geology Survey, report no. R1142, one sheet, scale 1:10,000. [Prepared by V/O Technoexport U.S.S.R. for the Ministry of Mines and Industries of the Republic of Afghanistan, Department of Mines and Geology Survey, under contract no. 55-184/17500.]
Cheremytsin, V.G., and Yeremenko, G.K., 1976, Report of the Khanneshin group on the results of prospecting and evaluational activity for 1976 [in Russian]: Kabul, Department of Mines and Geology Survey, report no. R1142, 84 p. and 7 map pls. [Prepared by V/O Technoexport U.S.S.R. for the Ministry of Mines and Industries of the Republic of Afghanistan, Department of Mines and Geology Survey, under contract no. 55-184/17500.]
Nakamura, Noboru, 1974, Determination of REE, Ba, Fe, Mg, Na and K in carbona-ceous and ordinary chondrites: Geochimica et Cosmochimica Acta, v. 38, no. 5, p. 757–775.
Peters, S.G., Ludington, S.D., Orris, G.J., Sutphin, D.M., Bliss, J.D., and Rytuba, J.J., eds., and the U.S. Geological Survey–Afghanistan Ministry of Mines Joint Mineral Resource Assessment Team, 2007, Preliminary non-fuel mineral resource assessment of Afghanistan: U.S. Geological Survey Open-File Report 2007–1214, 810 p., 1 CD-ROM disk and 1 DVD-ROM disk; also available at http://pubs.usgs.gov/of/2007/1214/.
Srivastava, R.K., 1993, Chemical classification of silica-rich carbonatites: Indian Journal of Geochemistry, v. 8, p. 15–24.
REFERENCES (continued)
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, 51 p.; also available at http://pubs.usgs.gov/of/2011/1207/.
Woolley, A.R., and Kempe, D.R.C., 1989, Carbonatites; nomenclature, average chemical compositions, and element distribution, in Bell, Keith, ed., Carbonatites; genesis and evolution: London, Unwin Hyman, p. 1–14.
Yang Xiaoyong, Sun Weidong, Zhang Yuxu, and Zheng Yongfei, 2009, Geochemical constraints on the genesis of the Bayan Obo Fe-Nb-REE deposit in Inner Mongolia, China: Geochimica et Cosmochimica Acta, v. 73, no. 5, p. 1417–1435.
Yuan Zhongxin, Bai Ge, Wu Chenyu, Zhang Zhongqin, and Ye Xianjiang, 1992, Geological features and genesis of the Bayan Obo REE ore deposit, Inner Mongolia, China: Applied Geochemistry, v. 7, no. 5, p. 429–442.
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63°39’0”E
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63°37’1”E 63°37’59”E
63°37’1”E 63°37’59”E
63°36’0”E63°34’59”E
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30°31’1”N30°31’1”N
Topography and shaded relief derived from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) 30-meter Global Digital Elevation Model (GDEM) data, 2009Hydrography derived from ASTER GDEM data Projection and grid: Universal Transverse Mercator (UTM), zone 42 northWorld Geodetic System (WGS) 1984 Datum
Modified from original compilation of Cheremytsin, 1976; see References
Geologic Map of the Khanneshin Carbonatite Complex, Helmand Province, Afghanistan, Modified From the 1976 Original Map Compilation of V.G. CheremytsinCompiled by
Robert D. Tucker, Stephen G. Peters, Klaus J. Schulz, Karine M. Renaud, Will R. Stettner, Linda M. Masonic, and Patricia H. Packard2011
Prepared in cooperation with the Afghan Geological Survey
Under the auspices of the U.S. Department of Defense
U.S. DEPARTMENT OF THE INTERIORU.S. GEOLOGICAL SURVEY
OPEN-FILE REPORT 2011–1244USGS Afghanistan Project Product No. 198
This map is available for sale by U.S. Geological Survey, Information Services, Box 25286, Denver Federal Center, Denver, CO 80225
For product and ordering information:World Wide Web: http://www.usgs.gov; Telephone 1-888-ASK-USGS
Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government
Printed on recycled paper
1 .5 0 1 KILOMETER
1 1/2 1 MILE0
NO VERTICAL EXAGGERATION Modified from original compilationof Cheremytsin, 1976
NO VERTICAL EXAGGERATION Modified from original compilationof Cheremytsin, 1976
