Mineral potential tracts for shoreline Ti-Zr placer deposits (phase V, deliverable 85): Chapter P in <i>Second projet de renforcement institutionnel du secteur minier de la République Islamique de Mauritanie (PRISM-II)</i>

Beaudoin, Georges · 2015 · Report

Shoreline placer Ti deposits are composed of ilmenite, rutile, zircon, monazite, and magnetite in well-sorted, fine-to medium-grained sand in coastal dunes

This 2015 document, Mineral potential tracts for shoreline Ti-Zr placer deposits (phase V, deliverable 85): Chapter P in <i>Second projet de renforcement institutionnel du secteur minier de la République Islamique de Mauritanie (PRISM-II)</i>, is preserved in the Mountain Man Mining Library for research and reference. Original source: pubs.usgs.gov.

Prepared in cooperation with the Ministry of Petroleum, Energy and Mines, Islamic Republic of Mauritania Second Projet de Renforcement Institutionnel du Secteur Minier de la République Islamique de Mauritanie (PRISM-II) Mineral Potential Tracts for Shoreline Ti-Zr Placer Deposits: Phase V, Deliverable 85 By Georges Beaudoin Open-File Report 2013-1280 Chapter P U.S. Department of the Interior U.S. Geological Survey

U.S. Department of the Interior SALLY JEWELL, Secretary U.S. Geological Survey Suzette M. Kimball, Acting Director U.S. Geological Survey, Reston, Virginia: 2015 For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment—visit ://www.usgs.gov or call 1-888-ASK-USGS For an overview of USGS information products, including maps, imagery, and publications, visit ://www.usgs.gov/pubprod To order this and other USGS information products, visit ://store.usgs.gov Suggested citation: Beaudoin, Georges, 2015, Mineral potential tracts for shoreline Ti-Zr placer deposits (phase V, deliverable 85), chap. P of Taylor, C.D., ed., Second projet de renforcement institutionnel du secteur minier de la République Islamique de Mauritanie (PRISM-II): U.S. Geological Survey Open-File Report 2013‒1280-P, 10 p., ://dx.doi.org/10.3133/ofr20131280. [In English and French.] Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. Multiple spellings are used in various literatures, and may be reflected in the text. This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or for stratigraphic nomenclature. The report is being released in both English and French. In both versions, we use the French-language names for formal stratigraphic units. ISSN 2331-1258 (online)

Mineral Potential Tracts for Shoreline Ti-Zr Placer Deposits Summary Shoreline Ti-Zr placer deposits in Mauritania are hosted by littoral dune and beach sand on the Atlantic coast. Potential mineral tracts for Shoreline Ti-Zr placer deposits in Mauritania comprise areas along the coast covered by Quaternary sediments. Definition of Shoreline Ti-Zr placer resources in Mauritania is inadequate because their volume is poorly constrained above the water table only, and the TiO2 grade or percentage of ilmenite in the bulk sand is converted to an equivalent tonnage of ilmenite, thereby ignoring more valuable minerals such as rutile, leucoxene and zircon, in the resource inventory. Zircon, in particular is the principal ore mineral in the Grande Côte Zircon project in Senegal. Zircon is reported to be abundant in the Mauritanian deposits, thereby increasing the inferred value of potential deposits. Contents Summary iii Introduction 1 Shoreline Ti Placer Deposits in Mauritania 1 Permissive Mineral Tracts for Shoreline Ti-Zr Placers 7 Conclusion 7 References 7 Appendix A 9

Figures Figure 1. Worldwide distribution of shoreline Ti-Zr placer deposits (modified from Hamilton, 1995) 2 Figure 2. Stratigraphic position of Shoreline placer Ti deposits in Mauritania. Abbreviations: G: gypsum, S: sulfur, Se: salt; T: peat. Modified from Gunn and others.(2004) 3 Figure 3. Location of Shoreline placer Ti deposits as defined by the BRGM (Blanchot, 1975, as modified by Gunn and others, 2004) 5 Figure 4. Top, crescent-shape dunes with dark sand layer on top, the dune at the bottom right of the figure is partly reworked by the active beach. Middle, rippled upper surface of a sand dune where dark-colored heavy minerals concentrate by deflation lag. Bottom, layer of dark-colored heavy minerals in the active beach 6 Table Table 1. Composition chimique des concentrés de minéraux lourds, El Msid, Mauritanie 4

Conversion Factors SI to Inch/Pound Multiply By To obtain Length centimeter (cm) inch (in.) millimeter (mm) inch (in.) decimeter (dm) foot (ft) meter (m) foot (ft) kilometer (km) mile (mi) Area hectare (ha) acre square meter (m2) 0.0002471 acre square kilometer (km2) square mile (mi2) Volume cubic kilometer (km3) cubic mile (mi3) Mass gram (g) ounce, avoirdupois (oz) kilogram (kg) pound avoirdupois (lb) megagram (Mg) ton, short (2,000 lb) megagram (Mg) ton, long (2,240 lb) metric ton per day ton per day (ton/d) megagram per day (Mg/d) ton per day (ton/d) metric ton per year ton per year (ton/yr) Pressure kilopascal (kPa) atmosphere, standard (atm) kilopascal (kPa) bar Energy joule (J) 0.0000002 kilowatt hour (kWh) ppm, parts per million; ppb, parts per billion; Ma, millions of years before present; m.y., millions of years; Ga, billions of years before present; 1 micron or micrometer (µor µm) 1 × 10-6 meters; Tesla (T) the field intensity generating 1 Newton of force per ampere (A) of current per meter of conductor Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows: °F=(1.8×°C)+32 Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows: °C=(°F-32)/1.8 Coordinate information is referenced to the World Geodetic System (WGS 84)

Acronyms AMT

Audio-magnetotelluric ASTER

Advanced Spaceborne Thermal Emission and Reflection Radiometer AVIRIS

Airborne Visible/Infrared Imaging Spectrometer BIF

Banded iron formation BLEG

Bulk leach extractable gold BGS

British Geological Survey BRGM

Bureau de Recherches Géologiques et Minières (Mauritania) BUMIFOM The Bureau Minier de la France d'Outre-Mer CAMP

Central Atlantic Magmatic Province CGIAR-CSI Consultative Group on International Agricultural Research-Consortium for Spatial Information DEM

Digital Elevation Model DMG

Direction des Mines et de la Géologie EC

Electrical conductivity EMPA

Electron Microprobe Analysis EM

Earth Observing System eU

Equivalent uranium GGISA

General Gold International GIF

Granular iron formation GIFOV

Ground instantaneous field of view GIS

Geographic Information System HIF

High grade hematitic iron ores IHS

Intensity/Hue/Saturation IAEA

International Atomic Energy Agency IOCG

Iron oxide copper-gold deposit IP

Islamic Republic of Mauritania JICA

Japan International Cooperation Agency JORC

Large Igneous Province LOR

Lower limit of reporting LREE

Light rare-earth element METI

Ministry of Economy, Trade and Industry (Japan) MICUMA Société des Mines de Cuivre de Mauritanie MORB

Mid-ocean ridge basalt E-MORB Enriched mid-ocean ridge basalt N-MORB Slightly enriched mid-ocean ridge basalt T-MORB Transitional mid-ocean ridge basalt Moz

Million ounces MVT

Mississippi Valley-type deposits NASA

United States National Aeronautics and Space Administration NLAPS

National Landsat Archive Processing System

Omrg

Mauritanian Office for Geological Research ONUDI

(UNIDO) United Nations Industrial Development Organization PRISM

Projet de Renforcement Institutionnel du Secteur Minier PGE

Platinum-group elements RC

Reverse circulation drilling REE

Rare earth element RGB

Red-green-blue color schema RTP

Reduced-to-pole SARL

Société à responsabilité limitée SEDEX

Sedimentary exhalative deposits SIMS

Secondary Ionization Mass Spectrometry SNIM

Société National Industrielle et Minière (Mauritania) SP

Shuttle Radar Topography Mission SWIR

Shortwave infrared TDS

Total dissolved solids TIMS

Thermal Ionization Mass Spectrometry TISZ

Tacarat-Inemmaudene Shear Zone TM

Landsat Thematic Mapper UN

United Nations UNDP

United Nations Development Program US

United States USA

United States of America USGS

United States Geological Survey UTM

Universal Transverse Mercator projection VHMS

Volcanic-hosted massive sulfide VisNIR

Visible near-infrared spectroscopy VLF

Volcanogenic massive sulfide deposit WDS

Wavelength-dispersive spectroscopy WGS

World Geodetic System

1Département de Géologie et de Génie Géologique, 1065 avenue de la Médecine, Québec (Québec) Canada G1V A6. Second Projet de Renforcement Institutionnel du Secteur Minier de la République Islamique de Mauritanie (PRISM-II) Mineral Potential Tracts for Shoreline Ti-Zr Placer Deposits: Phase V, Deliverable 85 By Georges Beaudoin1 Introduction Shoreline placer Ti deposits are composed of ilmenite, rutile, zircon, monazite, and magnetite in well-sorted, fine-to medium-grained sand in coastal dunes, beaches and inlets. In addition to titanium, zirconium, in particular, and rare earth elements (REE) have become a major source of value in shoreline placer deposits. Shoreline placer deposits form mostly on tropical beaches around the world (fig. 1), and consist of dark sand layers rich in heavy minerals that are resistant to mechanical abrasion and chemical weathering. According to Hamilton (1995), shoreline placer deposits supply approximately 80 percent of the world's rutile production, 25 percent of ilmenite, 100 percent of zircon, and 50 percent of both monazite and xenotime. Shoreline Ti Placer Deposits in Mauritania In Mauritania, Quaternary sediments with potential for shoreline placer Ti-Zr deposits are present in the Permian to Recent Senegal-Mauritania sedimentary coastal basin. Quaternary sediments were deposited during the Tafaritian, Aïoujian, and Inchirian 30 Ka) marine transgressions. The Ogolian sequence (10-24 Ka) formed eolian dunes over the coastal basin and continental interior, recording dry conditions during the Wurmian glacial event (Gunn and others, 2004). The Nouakchottian (Tchadian 10-5.2 Ka, Deynoux and others, 2001) is the last transgression that records more humid conditions with clay and shell sands deposits (Gunn and others, 2004). The last, the Tafolian regression 4 Ka), is characterized by a littoral dune system that formed sabkha gypsum and clay deposits. The shoreline Ti-Zr placer deposits are hosted by the Tafolian littoral dunes and by active and ancient beach deposits (fig. 2).

Figure 1. Worldwide distribution of shoreline Ti-Zr placer deposits (modified from Hamilton, 1995). According to Gunn and others (2004) citing Blanchot (1975), the Quaternary formations of Mauritania have been prospected for their content of heavy minerals by the Bureau de Recherche Géologique et Minière (BRGM) between 1959 and 1963. This work identified shoreline placer Ti deposits that were then subjected to further mineralogical and geophysical studies (fig. 3). From north to south, three sectors with shoreline placer Ti have been identified. The first, south of Nouadhibou, from Pointe Minou to Cap el Sass, hosts approximately 2.8 Mm3 (million cubic meters) of sand containing the equivalent of 120,000 t ilmenite (fig. 3). The second, near El Msid north of Nouakchott, hosts approximately 2.6 Mm3 of sand with the equivalent of 242.6 t ilmenite (fig. 3). The third sector, south of Nouakchott and near Legouichichi, contains approximately 0.495 Mm3 of sand with the equivalent of 30,000 t of ilmenite (fig. 3). Blanchot (1975) notes that the auger drill holes used to estimate grade and tonnage did not penetrate beneath the water table so it is possible that additional resources could exist at depth. Gunn and others (2004) citing previous ONUDI studies, indicated that radiometric methods are efficient to locate and estimate the grade of heavy minerals in sand.

Figure 2. Stratigraphic position of shoreline placer Ti deposits in Mauritania. Abbreviations: G, gypsum; S,: sulfur; Se, salt; T, peat. Modified from Gunn and others (2004).

For this study, shoreline Ti-Zr placers were described and sampled near El Msid, north of Nouakchott (figs. 3 and 4). At El Msid, dark sands form layers in crescentshaped dunes that are partly reworked by the action of waves in the active beach (figs. 3 and 4). The top part of the dunes concentrate heavy minerals by the removal of light minerals by the wind, also called deflation lag. The dunes are being slowly reworked by the transgressive, active beach where heavy minerals are redistributed by wave action, which typically yields low-angle cross-bedding within a sand layer (fig. 4). Hand-panned heavy mineral concentrates were prepared on site. Table 1 displays the bulk concentration of important chemical elements from the heavy mineral concentrates. It should be noted that the concentrate composition is affected by the field concentration process. The Fe/Ti ratio is constant at 1.16 to 1.44, similar to slightly above the ilmenite ratio Fe/Ti of 1.17, therefore suggesting most Ti is hosted by ilmenite in the concentrates. The Ti content ranges from 11.6 to 18.2 weight percent which corresponds to 36.8 to 57.7 weight percent of ilmenite, assuming all Ti is in the oxide. The heavy mineral concentrates contain 2.8 to 6.4 weight percent Zr which corresponds to 5.7 to 6.8 weight percent zircon. Th ranges from 356 to 831 ppm whereas U has low variance from 58 to 77 ppm. The low Th and U coupled with low phosphorus content suggest that the abundance of monazite and xenotime is also low. Assuming that all Zr and U are hosted by zircon, the maximum U content of zircon is calculated to be between 10 and 18 ppm. The Zr/Hf ratio ranges from 24 to 38, which is typical for crustal zircons (Clairborne and others, 2006). Several REE have high concentrations in the bulk concentrate, most notably La (≤1,070 ppm), Nd (≤770 ppm), and Y (≤372 ppm).

Table 1. Composition chimique des concentrés de minéraux lourds, El Msid, Mauritanie. No. Lab No. Échan Fe % Ti % P % Dy ppm Ga ppm Gd ppm Ge ppm Hf ppm Ho ppm La ppm Lu ppm Nb ppm C-318115 GB07RIM03B 16.7 11.6 1180 11.8 C-318116 GB07RIM04B 21.6 18.2 1870 12.3 C-318117 GB07RIM05B 20.8 16.6 1470 10.1 1070 C-318118 GB07RIM07C 20.2 17.4 1660 10.1

Nd ppm Pr ppm Sm ppm Tb ppm Th ppm Tl ppm Tm ppm U ppm ppm Y ppm Yb ppm Zr ppm C-318115 GB07RIM03B <0.5 7.53 57.6 482 C-318116 GB07RIM04B <0.5 7.47 77.1 598 C-318117 GB07RIM05B <0.5 5.8 C-318118 GB07RIM07C <0.5 5.81 71.8 548

Mineralogical studies in three areas (Jreida, Bloauokh, and Tanit) indicate that the black sand deposits contain an average composition of 26.5 weight percent rutile, 22.5 weight percent ilmenite, 11.8 weight percent garnet, 10.2 weight percent zircon, 7 weight percent epidote and 22 weight percent other minerals (Zagortchev and others, 1978; Gunn and others, 2004). These results are similar to values estimated from the bulk composition of the concentrates panned on site (table 1). It is instructive to compare the Mauritanian deposits to those being developed in Senegal. Mineral Deposits Ltd (Australia) is planning to mine a mineral resource of 1.03 Gt (Gigatonne 1 x 109 tonnes) of sand with 1.7 weight percent heavy minerals (using a 1.5 weight percent heavy mineral cut-off grade) in the 50-km-long Grande Côte Zircon deposit on the coast of Senegal, between Dakar and St-Louis (www.mineraldeposits.com.au). Heavy minerals are composed of ilmenite (~66-74 percent), leucoxene (~4-7 percent), rutile (~1-3 percent) and zircon (~7-11 percent). The zircon has low levels of impurities such that it can marketed as "high-quality" zircon, thus constituting the most desirable economic mineral in the deposit. Rutile and leucoxene also will produce revenue whereas the abundant ilmenite will probably be stockpiled until its value allows for profitable sale. It is instructive to note that the information at hand so far suggests the shoreline placer Ti-Zr deposits of Mauritania also have a high content of zircon, with low U content, such that it could be of the higher quality which yields higher revenue.

Figure 3. Location of shoreline placer Ti deposits as defined by the BRGM (Blanchot, 1975, as modified by Gunn and others, 2004).

Figure 4. Top, crescent-shape dunes with dark sand layer on top, the dune at the bottom right of the figure is partly reworked by the active beach. Middle, rippled upper surface of a sand dune where dark-colored heavy minerals concentrate by deflation lag. Bottom, layer of dark-colored heavy minerals in the active beach. USGS photos.

Permissive Mineral Tracts for Shoreline Ti-Zr Placers The permissive mineral tracts for Shoreline Ti-Zr placer deposits are defined by location of the littoral dune sand (cordon dunaire fixé: cdf), reworked dune sand (sable dunaire ancien remanié: cdi), active or inactive beach sand (cordon littoral actuel: ccl), eolian sand dunes (dunes: cd), and gulf closure sediments and raised beach sand (sédiments de fermeture du golfe—plages soulevées: csf). Considering the dispersion of shoreline placer Ti deposits along the shore for most of Mauritania's Atlantic coast, the permissive mineral tracts for Shoreline Ti-Zr placer comprises all the Mauritanian coast covered by these sand units (Appendix A). Conclusion The littoral dune sand, reworked dune sand, and recent or inactive beach sand of the coast of Mauritania have demonstrated Shoreline Ti-Zr placer deposits. These beach and dune sands constitute the permissive mineral tract for this deposit type in Mauritania (fig. 5); Reliable resource estimates for the Shoreline Ti-Zr placer deposits do not exist, as the historical figures are not constrained with factors such as a cut-off grade; The Shoreline Ti-Zr placer deposits are currently defined on the basis of their Ti or ilmenite content, whereas the more abundant, and higher value, minerals rutile and leucoxene have been potentially overlooked (either because grade is computed from ilmenite or Ti weight percent is converted into ilmenite grade), and the high zircon content has not been taken into consideration. References Beaudoin, Georges, and Horton, J.D., 2015, Permissive tracts for shoreline placer titanium deposits in Mauritania (phase V, deliverable 84), , chap. P1 of Taylor, C.D., ed., Second projet de renforcement institutionnel du secteur minier de la République Islamique de Mauritanie (PRISM-II): U.S. Geological Survey Open-File Report 2013‒ 1280-P1, 1 pl., scale 1:1,000,000, :/dx.doi.org/10.3133/ofr20131280/. [In English and French.] Blanchot A, 1975, Plan minéral de la Réoblique islamique de Mauritanie: Bureau de Recherches Géologiques et Minières (BRGM), 564 p. [R7500100.PDF]. Claiborne, L.L., Miller, C.F., Walker, B.A., Wooden, J.L., Mazdab, F.K., and Bea, F., 2006, Tracking magmatic processes through Zr/Hf ratios in rocks and Hf and Ti zoning in zircons—An example from the Spirit Mountain batholith, Nevada: Mineralogical Magazine v. 70, p.517‒543. Deynoux, M., Ghienne, J.-F., Kocurek, G., Lancaster, N., Lézine, A.-M., Singhvi, A., Bano, M., Deck, S., Lo, K., and Mahieux, G., 2001, Les systèmes Quaternaires éaliens, lacustre et lagunaire en Mauritanie occidentale (Parc national du Banc d'Arguin). [MU001-14.PDF]. Gunn, A.G., Pitfield, P.E.J., Mckervey, J.A., Key, R.M., Waters, C.N., and Barnes, R.P., 2004, Notice explicative des cartes géologiques et gîtologiques à 1/200 000 et 1/500 000 du Sud de la Mauritanie. Volume 2—Potentiel Minier: Direction des Mines et de la Géologie (DMG), Ministère des Mines et de l'Industrie, Nouakchott.

Hamilton, N.T.M., 1995, Controls on the global distribution of coastal titaniumzirconium placers: International Geology Review, v. 37, p. 755‒779. Zagortchev, I.S., Kralev, G.K., and Katevski, I.G., 1978, Rapport sur les résultats de la reconnaissance des sables lourds du littoral Mauritanien de St. Louis à Cap Timris: Société National Industrielle et Minière (SNIM), 104 p., [R780004.PDF].

Appendix A Régions de la Mauritanie avec un potentiel pour les gites de titane dans les placers cotiers. From: Beaudoin, Georges, and Horton, J.D., 2015, Permissive tracts for shoreline placer titanium deposits in Mauritania (phase V, deliverable 84), , chap. P1 of Taylor, C.D., ed., Second projet de renforcement institutionnel du secteur minier de la République Islamique de Mauritanie (PRISM-II): U.S. Geological Survey Open-File Report 2013‒ 1280-P1, 1 pl., ://dx.doi.org/10.3133/ofr20131280/. [In English and French.]

ISSN 2331-1258 (online) ://dx.doi.org/10.3133/ofr20131280

Plates & figures from the original