Next Article in Journal
Origin and Evolution of Ore-Forming Fluid and Metallogenic Mechanism of the Baoshan Cu-Pb-Zn Deposit, South China: Constraints of Fluid Inclusion and C-H-O Isotopes
Previous Article in Journal
Test Method for Mineral Spatial Distribution of BIF Ore by Imaging Spectrometer
Previous Article in Special Issue
Derivation of Predictive Layers Using Regional Till Geochemistry Data for Mineral Potential Mapping of the REE Line of Bergslagen, Central Sweden
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Minerals
Volume 14
Issue 10
10.3390/min14100960
minerals-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Characteristics of Lithium Deposits in Mongolia

by
Jaroslav Dostal
1,* and
Ochir Gerel
2
1
Department of Geology, Saint Mary’s University, Halifax, NS B3H 3C3, Canada
2
Geoscience Centre, Mongolian University of Science and Technology, Baga Toiruu 34, Ulaanbaatar 14139, Mongolia
*
Author to whom correspondence should be addressed.
Minerals 2024, 14(10), 960; https://doi.org/10.3390/min14100960
Submission received: 29 July 2024 / Revised: 11 September 2024 / Accepted: 18 September 2024 / Published: 24 September 2024
(This article belongs to the Special Issue Editorial Board Members’ Collection Series: "Critical and Strategic Minerals", 2nd Edition)
Browse Figures
Versions Notes

Abstract

:
Lithium is a strategic metal due to its use in green technologies, particularly battery manufacturing. It is on the US List of Critical Minerals and the European Union’s List of Critical Raw Materials. In Mongolia, there are three major types of potentially economic Li deposits: (1) Deposits related to granites, granitic pegmatites and associated rocks; (2) Li-rich clay deposits; (3) Salar (Li brine) deposits. The first type of mineralization is associated with the lithium–fluorine-rich peraluminous A-type granites and related rocks (greisens, pegmatites, ongonites, ongorhyolites). The mineralization includes Li and also Sn, W, Ta and Nb. Lithium is hosted in Li-rich micas, unlike the world-class Li-bearing pegmatite deposits where the bulk of Li is in spodumene. In Mongolia, particularly promising are Li brines of endorheic basins in the Gobi Desert with an arid environment, high evaporation rates and low precipitation.

1. Introduction

Lithium (Li), the lightest metal on Earth, has been used in a wide range of applications from psychiatric medicine to lubricating grease to the glass and ceramics industry. It has excellent electric and heat conductivity and low density, thus making it a strategic compound for battery manufacturing. Interest in this element in the global market has exploded in recent years because of its use in rechargeable batteries for electric and hybrid cars, which are seen as key to reducing climate-changing carbon emissions produced by gas-powered cars. However, Li is also used in the batteries of laptops, cell phones, power tools, lawnmowers and many others. This has led to a significant increase in the demand for Li and a worldwide “lithium rush”. In fact, the strategic importance of Li has been reflected in its inclusion in the US Government’s List of Critical Minerals and the European Union’s List of Critical Raw Materials. Identification and assessment of mineral resources of Li are critical steps for the discovery of new mineral deposits. The purpose of this paper is to report on the mineral resources of Li in Mongolia, particularly on their geological and mineralogical characteristics, and to provide new whole-rock chemical analyses of some of the sites. The review will be useful for future prospecting, particularly as its neighbors, China and Russia, have significant Li resources in nearby areas.

2. Lithium Deposit Types

Lithium does not occur in native (elemental) form in nature. However, more than 100 minerals contain Li as an essential constituent [1,2], but only a few of these species are of economic interest (Table 1). Most of the Li-bearing minerals are silicates (~73%) and phosphates (19%). The rest are either carbonates, fluorides, oxides, hydroxides, borates or arsenites [1]. Among these minerals, spodumene is the most economically important Li-bearing mineral, which occurs in granites and pegmatites. Other economically important Li-bearing minerals that occur in pegmatite and granite deposits are micas—lepidolite and zinnwaldite (Table 1). A mineral that is not currently extracted for Li but has the potential to be a significant source in the future is hectorite [3]. This mineral is a clay mineral produced during the alteration of volcaniclastic rocks by hydrothermal or hot spring activity. Another mineral that could be an important Li source is jadarite [4]. Four other minerals from which Li was formerly extracted but are now of lesser economic importance are eucryptite, amblygonite, montebrasite and petalite (Table 1). These four minerals occur in Li-bearing pegmatites. In addition, Li is also extracted from brines.
There are three main types of Li deposits [3]: (1) Granite–pegmatite deposits (“hard rock deposits”), which include pegmatites, hydrothermally altered and metasomatized granites, lithium–fluorine granites, ongonites and similar silica-rich igneous rocks; (2) Clay deposits where Li is hosted in hectorite and other clay minerals; (3) Brine deposits where Li occurs in continental salt-rich lakes. Li can also be extracted from geothermal and oil field brines. According to the US Geological Survey [6], the hard rock Li deposits account for about 60% of the world’s Li production but they represent only about a quarter of the global Li reserves.

2.1. Granite–Pegmatite-Related Lithium Deposits

Granites and particularly pegmatites are important sources of rare metals, including Li. Although granitic pegmatites are common, rare-metal pegmatites represent only about 0.1% of the pegmatite total, and Li-rich pegmatites are only a fraction of those [7]. In addition to pegmatites, this group of deposits also includes rare-metal Li-F granites, their subvolcanic (ongonites) and volcanic (ongorhyolites) equivalents, and greisens.
Granitic pegmatites have been the predominant source of Li for many decades. Only in recent years, their share has been reduced by production from continental brines. Compositionally, Li-rich pegmatites are similar to peraluminous rare-metal granites. These pegmatites are enriched in incompatible trace elements, including Li, Cs, Ta, Sn, Rb, Be and Nb (e.g., [8,9]). They are composed of quartz, plagioclase, potassium feldspar and micas with various amounts of garnet, tourmaline, apatite and Li-bearing minerals such as spodumene, petalite, amblygonite, lepidolite and eucryptite. Mongolian Li-rich pegmatites belong to this category. Their Li2O content ranges mostly from 0.5% to 1.5% [10].
Rare-metal granites (RMG; [11]) are felsic, peraluminous to peralkaline rocks that contain magmatic disseminated mineralization (e.g., [12]). Among these rocks, Li mineralization is typically confined to two major types of granites [5,11]. The first are metaluminous to peraluminous low-phosphorus RMG with high contents of Nb, Ta, Sn and Li, which occur in both anorogenic and post-orogenic tectonic environments. Elevated Li concentrations are hosted by Li-F micas including lepidolite and zinnwaldite. An example is the Cínovec (Zinnwald) deposit in the Czech Republic. The second type refers to the peraluminous high-phosphorus RMG which are enriched in Ta, Sn, Li and F and were typically emplaced in a continental collision setting. These granitic rocks have high concentrations of Li (~0.5% to 1% Li2O), which is hosted by lepidolite and Li-rich muscovite. Examples of such granitic bodies are Beauvoir (France) and Argemela (Portugal) [5,11].
Greisens are highly fractionated granitic rocks that underwent a high-temperature transformation which led in the extreme to the generation of a porous Li–mica–quartz assemblage. In these rocks, Li is hosted in micas, in particular Li-rich muscovite, lepidolite and zinnwaldite. Greisens typically form veins or haloes around the granitic bodies, both peraluminous and metaluminous RMG. In addition to quartz and mica, they may contain subordinate feldspars, topaz, tourmaline, cassiterite and wolframite. The greisen deposits can be related to both magmatic and hydrothermal processes. In addition to Li, important co-products in these rocks are Sn and W [5].

2.2. Lithium Clay Deposits (Sedimentary Rocks Hosted Lithium Deposits)

Lithium clay deposits contain an anomalous accumulation of Li-bearing clay minerals, in particular hectorite. These clays have the potential to be a significant source of Li. Bowell et al. [3] recognized three types of these deposits. The first type includes those in which Li is within the clay mineral (hectorite or similar mixed layered clays). The second type is the case where Li is an absorbed ion into clay minerals (ion–clay deposits). These clay deposits were found in the western USA (Nevada, Oregon). Lithium-bearing clay deposits typically have a genetic and/or spatial relationship to rhyolitic rocks [3,13]. The last type of these deposits refers to the jadarite clay deposit. This world-class Li deposit, which contains 118 Mt of ore with a grade of 1.8 wt.% Li2O and 13.1 wt.% B2O3, is hosted in an intermontane lacustrine evaporite basin in Serbia [4,14]. The ore is composed of jadarite-bearing Miocene siltstone and mudstone.

2.3. Lithium Brine Deposits

A brine is a watery solution with concentrations of dissolved salts higher than that of seawater (>3.5%) [3,15]. The lithium content in most brines typically ranges between 200 and 700 ppm, with some reaching more than 1000 ppm [16]. The total salinity of Li brines typically ranges from 1.7 to 24 times that of seawater. There are three categories of brines: continental Li-rich salt lakes, oilfield brines and geothermal brines. The continental brine deposits are by far the largest source. The amount of Li in the high-altitude continental brine deposits around the world is about 40 million tons. Most of this Li resource is in the “lithium triangle” of the central Andes, an area of about 400,000 km2 that includes northern Chile, western Bolivia and northwestern Argentina. The continental brines/deposits are hosted in young (mostly Quaternary) enclosed, tectonically active basins that contain lacustrine evaporites. The basins occur in an arid climate, where inflowing surface and sub-surface water contains Li which has been released from surrounding felsic volcanic rocks by weathering or leaching. Lithium-rich continental brine deposits have been identified in many places [17], including Mongolia [10]. Groundwater brines are also associated with oil fields in the USA (North Dakota, Texas, Oklahoma, Arkansas, Utah) and can contain up to 700 mg/L (ppm) of lithium [17]. Geothermal brines from Reykjanes in Iceland have up to 130 mg/L of Li and Salton Sea geothermal brines of California hold up to 286 mg/L of Li [18]. Lithium-containing geothermal brines are also known from Wairakei in New Zealand. All these Li-bearing brines are concentrated by natural evaporation before extracting lithium.

3. Lithium Mineralization in Mongolia

Although all three types of Li deposits are known from Mongolia, the focus of the paper is on deposits hosted by felsic igneous rocks as there are only limited amounts of data on the Li mineralization generated by exogenic processes.
In Mongolia and an adjoining part of Russia (Transbaikalia), Li mineralization is linked to rare-metal Li-F granites and related rocks (Figure 1). These Late Paleozoic and Mesozoic granites are associated with Sn, W, Li and Ta-Nb mineralization (e.g., [19,20]) and were the subject of discussion among Russian geologists. Initially, they were defined as “apogranites” generated by post-magmatic metasomatic processes [21] but later, after the discovery of ongonites, their subvolcanic equivalents, they were considered to be of magmatic origin [22,23]. These granites are shallow-seated, highly fractionated, peraluminous A-type granites enriched in fluorine and rare metals but low in P. They resemble the first (post-orogenic) type of granite of Gourcerol et al. [5].

3.1. Granite–Pegmatite-Related Lithium Deposits

Rare-metal granitic rocks that contain Li mineralization in Mongolia occur within the Mongol–Okhotsk orogenic belt (MOOB). The belt is linked to the closure of the Mongol–Okhotsk Ocean, which lasted from the Permian to the Late Jurassic. MOOB, which extends from the Khangai region in central Mongolia to the Okhotsk Sea, hosts a belt of granitoid rocks of Permian to Mesozoic ages that runs parallel to the suture zone. Some of these rocks were emplaced in post-collisional settings [10]. A significant part of the MOOB in central Mongolia is made up of the Khentei batholith of a Late Triassic to Early Jurassic age (230–180 Ma). The batholith consists of rocks ranging from granodiorites to leucogranites accompanied by minor gabbros and diorites. The last stages of magmatic activity in the batholith featured the emplacement of rare-metal granites, which constitute about 10% of granitoids in the belt. These late-stage granitoids include lithium–fluorine granites and related rocks (Li pegmatites, ongonites, ongorhyolites and greisens) emplaced mainly along the margin of the batholith [10]. The Li-F granites are relatively rare, post-orogenic and represent either the latest, highly fractionated portions of multiphase plutons or late one- or two-phase stocks/plutons occurring along the margins of the Khentei batholith.
Gerel [10] recognized three different sub-types of granite–pegmatite-related Li deposits in Mongolia. These deposits comprise (1) Li pegmatites, (2) Li-F granites and greisens, and (3) subvolcanic (ongonites) and volcanic (ongorhyolites) equivalents of Li-F granites (Figure 1).

3.1.1. Lithium Pegmatite

In Mongolia, rare-metal pegmatites, particularly Li-bearing ones, belong to the LCT pegmatites of Černý and Ercit [9]. The Mongolian pegmatites are typically peraluminous, ferroan and alkali–calcic. Among them, the most prominent are pegmatites of Khukh Del Uul (site No. 1 in Figure 1 and Table 2) in the Middle Gobi belt (Figure 2) located about 250 km southeast of Ulaanbaatar [24]. The Late Paleozoic pegmatite swarm includes about 25 dikes which spread over an area of about 6 km2 where they intruded Precambrian metamorphic rocks and Paleozoic syenites and granites [24]. The pegmatite dikes are steeply dipping, 50 to 300 m long and 1 to 10 m wide. The dominant mineral assemblage of this pegmatite swarm is quartz (25–35 vol.%), coarse-grained platy albite (cleavelandite; 20–35 vol.%), sugary albite (5–10 vol.%), lepidolite (10–30 vol.%), topaz (5–10 vol.%) and microcline (1–5 vol.%).
Some dikes show zoning and replacement textures where the quartz–albite–topaz–lepidolite core can be substituted by sugary metasomatic albite. Mineral assemblages are locally replaced by greisens composed of quartz and lepidolite or zinnwaldite, which in turn can be invaded by sugary albite with traces of columbite–tantalite or fluorite–quartz veinlets. According to Vladykin et al. [24], the fine-grained sugary albite is nearly pure albite (Ab>0.90 Or~0.01–0.03), while coarse plagioclase (cleavelandite; grain size ~1–6 cm) contains Ab~0.75–0.90 Or~0.01–0.05. Microcline’s composition is Or~0.50–0.70 Ab~0.18–0.50 [24]. The dominant mica in the pegmatites is lepidolite, which occurs as flakes up to about 5 cm in size, but it also forms crystals ~5 mm in diameter or patches of fine-grained crystals (0.5–1 mm). Lepidolite typically contains ~3.84–5.45 wt.% Li2O and 5.75 to 8.51 wt.% F. Fluorite is a late mineral that commonly occurs in veinlets intersecting pegmatites (Figure 3). The averages of the chemical compositions of pegmatites reported by Vladykin et al. [24] are moderately high in silica (~70 wt.%) and alkalis (Na2O + K2O ~8.5 wt.%) but with Na2O > K2O.
Topaz–lepidolite–albite pegmatites such as those of the Khukh Del Uul deposit differ from typical spodumene pegmatites from elsewhere by having lower silica but higher contents of Fe, Na and especially F. Pegmatites have on average about 2 wt.% F, although in many samples it reaches up to 4 wt.% [24]. The high F content is also reflected by the presence of F-rich minerals such as micas, topaz, fluorite and F-rich greisens. The typical pegmatite of the swarm contains about 1.75 wt.% Li2O [24]. In general, topaz–lepidolite–albite pegmatites of the Khukh Del Uul have high contents of F, Li, Rb, Cs, Nb, Ta and Be but are depleted in Sr, Ba and Zr. These characteristics show distinct similarities to rare-metal Li-F leucogranites and ongonites [22,23]. Compared to typical calc–alkaline granites and pegmatites, all these rocks have low abundances of B and tourmaline [24].
Munkhtiin Tsagaan Durvuljin (Figure 1; site No. 2) is another Li-rich pegmatite site in Central Mongolia [25]. Pegmatite dikes occur in an area of about 0.5 km × 0.5 km. The pegmatite swarm (Late Paleozoic to Early Mesozoic age) includes fifteen dikes which are ~200–400 m long and 1–5 m wide. The pegmatite dikes are composed of fine-grained lepidolite–quartz–feldspar leucogranitic rocks which are hosted in biotite granites. The host biotite granites are porphyritic composed of quartz (30–40%), plagioclase (oligoclase 20–25%), K–feldspar (25–35%) and biotite (9–12%). Along the contact with the pegmatite dikes, the granites are greisenized and show signs of shearing. Greisenization involves replacing biotite and feldspars by zinnwaldite. Pegmatites have a highly variable composition, in part, due to strong greisenization. Greisens are composed mainly of quartz and lepidolite/zinnwaldite, where the mica content can reach up to 40 vol.%. Accessory minerals of pegmatites are fluorite, cassiterite, columbite–tantalite and topaz. The biotite granites are peraluminous A-type granites with silica ranging from 66 to 70 wt.% while total alkalis (Na2O + K2O) vary from ~6.6 to 8 wt.%. The pegmatites are also peraluminous and contain 65–73 wt.% SiO2 and 6.5–9 wt.% (Na2O + K2O). Compared to biotite granites, pegmatites have significantly lower contents of Fe, Mg and Ca but high concentrations of Li, Sn, W, Ta, Nb and F, typical of rare-metal Li-F granites. The pegmatites contain 0.1 to 2.4 wt.% Li2O, whereas greisens have 1.5 to 2.4 wt.% Li2O. In total, the Munkhtiin Tsagaan Durvuljin pegmatite hosts 2.28 Mt of ore with a grade of 0.65 wt.% Li2O [26].
Bayan Teeg pegmatite of Central Mongolia (site No. 5, Figure 1, Table 2) is another Li-rich pegmatite [27]. Its body, which is about 140 m long and up to 1.3 m thick, intruded Neoproterozoic metasedimentary rocks. In addition to quartz, plagioclase and K–feldspar, the pegmatite also contains lepidolite, muscovite, secondary albite and accessory amblygonite, cassiterite, topaz, columbite–tantalite, monazite, zircon and fluorite. The pegmatite carries 1.48–2.15 wt.% Li2O, 0.1 wt.% BeO, ~200 ppm Ta2O5 and ~100 ppm Nb2O5. Bolorchimegh et al. [27] obtained the U-Pb cassiterite age of ~135 Ma and Ar/Ar lepidolite plateau age of ~131 Ma and argued that the pegmatite was formed by melting of crustal basement during the post-collisional extension after the Mongol–Okhotsk Ocean closure. Dashtseren et al. [28] also reported Li-bearing pegmatites dated at ~500 Ma from this part of Central Mongolia.

3.1.2. Lithium–Fluorine Granites

Li-F granites [10,19,20] are highly fractionated alkali-rich peraluminous RMG granites associated with Sn, W, Li, Ta and Nb mineralization. In Mongolia and the neighboring part of Russia (Transbaikalia), these post-orogenic subalkaline rocks occur either as a part of large differentiated multistage granitic complexes or as small single-stage intrusions. Typical Li-F granites are composed of albite, quartz, K–feldspar, mica and minor topaz but their modal composition is variable. They are mostly porphyritic with phenocrysts of quartz set in fine-grained groundmass dominated by albite. Li mineralization is mainly associated with lepidolite–albite assemblage, which forms minor bodies in apical or marginal parts of the granitic intrusions. These lepidolite–albite granites are made up of quartz, albite (55–60 vol.%), K–feldspar (~15 vol.%), lepidolite (~4 vol.%) and topaz (2–2.5 vol.%), although they may contain up to 10 vol.% topaz and up to 20 vol.% lepidolite [10,29]. Locally, the granites were affected by post-magmatic processes and converted to greisens composed mainly of quartz and Li-rich mica (zinnwaldite, lepidolite). One of the prominent occurrences of Li-F granites is the Janchivlan pluton (Figure 4), located about 90 km southeast of Ulaanbaatar (Site No. 7 in Figure 1; Table 2). The pluton occurs in the outer part of the Early Mesozoic Khentei batholith, which is composed of numerous intermediate to felsic granitoid complexes.
The Janchivlan pluton dated at ~190+/−2.1 Ma [31,32,33] is composed of four distinct phases of peraluminous granites. The first phase includes porphyritic coarse-grained biotite granites with miarolitic pegmatites, while the second phase is made up of medium-grained two mica granites that locally host Sn-bearing greisens. The third phase is minor, composed of K–feldspar granite. These three phases constitute the bulk of the pluton. In the southern part, the pluton includes the minor fourth phase, Li-F leucogranite. This rock type (Table 3; [31]) is compositionally similar to two adjoining but separate minor bodies—Urt Gozgor and Buural Khangai stocks. Each of these bodies includes three distinct phases: microcline–albite, amazonite–albite and lepidolite–albite. Li contents of amazonite–albite and microcline–albite vary from ~290 to 430 ppm while the lepidolite–albite granite contains on average 878 ppm Li [10]. Accessory minerals of lepidolite–albite granites are fluorite, zircon, monazite, columbite–tantalite, microlite and cassiterite. The greisenized part of these rocks contains up to 1315 ppm Li [10].
Another composite pluton containing Li-F granites is the Baga–Gazar in Central Mongolia, located about 220 km SSW of Ulaanbaatar (Figure 5). The pluton spreads over an area of about 120 km2 and is dome-shaped. This ~200 Ma old [32] ovoidal zoned body is composed of the dominant core made up of coarse- to medium-grained biotite granite surrounded by fine-grained Li-F leucogranite of a younger second phase containing Li-biotite and topaz. Both phases are crosscut by greisens (zwitters) and microcline–albite–fluorite dikes which could be over 1 km long, up to 50 m thick and occur mainly around the periphery of the pluton. Zwitters are dark Li–mica-bearing greisens containing topaz.
Both main phases of the pluton have similar chemical compositions. They are peraluminous highly fractionated high silica (~75–77 wt.%) and alkali (~8–9 wt.%) rocks that are enriched in Li, Rb, Na, Ta, Th and U but depleted in Ba, Sr and Eu (Table 3; Supplementary Text S1). They are compositionally like those of the Janchivlan pluton (Figure 6). The granites have elevated contents of F (0.3–0.4 wt.% [30]) and Li (~160 ppm [33,34]), which are mainly hosted in fluorite and Li-bearing biotite, respectively. The rocks were modified by post-magmatic processes which produced both greisens and microcline–albite–fluorite dikes. Greisens have typically 0.8–1.7 wt.% F and 550–1520 ppm Li whereas the microcline–albite–fluorite dikes contain ~1600–4300 ppm Li. Greisenization led to a decrease in Al, Na and K and an increase in Fe, Li and Cs. The average of pegmatite dikes in the Baga–Gazar pluton has 1,4400 ppm F and 630 ppm Li [33,34].
The Avdar pluton is characteristic of the small Li-F granitic intrusions in Central Mongolia. The pluton occurs about 150 km southwest of Ulaanbaatar (Figure 1; site No. 10), where it intrudes Devonian clastic metasedimentary rocks. This elliptical-shaped body is about 6 km long and spreads over an area of about 10 km2 [33]. Several age determinations range from about 202 to 212 Ma [33,35]. The intrusion is composed of a dominant core made up of medium-grained biotite leucogranite surrounded by a rim of amazonite–albite leucogranite. The contact between these two units is gradational (Figure 7). The biotite leucogranite contains plagioclase (An4–18), quartz, microcline and minor Li–biotite (2–3 vol.%) whereas the amazonite–albite leucogranites contain albite (An2–7) (~30 vol.%), quartz (~45 vol.%), microcline (amazonite ~20 vol.%) and Li-rich mica. Accessory minerals of both phases include Fe-Ti oxides, zircon, fluorite, cassiterite and columbite–tantalite. Both granitic rock types are rich in silica (72–77 wt.%) and alkalis (8–10 wt.%) but are low in Ca, Mg, and Fe. Their trace element composition is typical of Li-F granites (Table 3). The average content of F and Li in the biotite leucogranites is F ~1300 ppm and Li ~38 ppm, whereas amazonite–albite leucogranite has F ~ 2600 ppm and Li ~ 507 ppm Li [35].
Minerals 14 00960 g006
Figure 6. Primitive mantle-normalized incompatible element abundances of RMG granites and related rocks. (A) Janchivlan, phase 1 granite: JA-1 (o); phase 3: leucogranite (+). (B) Janchivlan, Li-F granite, lepidolite–albite: JA-7 (o), amazonite–albite: JA-9 (+). (C) Baga–Gazar: average of phase 1 (o), average of greisens (+). Normalizing values after McDonough and Sun [36]. Data are from Table 3; data of Baga–Gazar are from Antipin et al. [33].
Figure 6. Primitive mantle-normalized incompatible element abundances of RMG granites and related rocks. (A) Janchivlan, phase 1 granite: JA-1 (o); phase 3: leucogranite (+). (B) Janchivlan, Li-F granite, lepidolite–albite: JA-7 (o), amazonite–albite: JA-9 (+). (C) Baga–Gazar: average of phase 1 (o), average of greisens (+). Normalizing values after McDonough and Sun [36]. Data are from Table 3; data of Baga–Gazar are from Antipin et al. [33].
Minerals 14 00960 g006
Minerals 14 00960 g007
Figure 7. Generalized geological map of Avdar pluton modified after Antipin et al. [30] and Dostal and Gerel [31]. Location: Site No. 10 in Figure 1; Table 2. 1—Biotite leucogranite; 2—Amazonite–albite leucogranite; 3—Country rock; 4—Faults.
Figure 7. Generalized geological map of Avdar pluton modified after Antipin et al. [30] and Dostal and Gerel [31]. Location: Site No. 10 in Figure 1; Table 2. 1—Biotite leucogranite; 2—Amazonite–albite leucogranite; 3—Country rock; 4—Faults.
Minerals 14 00960 g007

3.1.3. Li-F Subvolcanic and Volcanic Felsic Rocks (Ongonites and Ongorhyolites)

Ongonites were discovered and defined by Kovalenko et al. [22] and Kovalenko and Kovalenko [23] in the Ongon Khairkhan Mountains, Central Mongolia, as topaz-bearing albite–quartz keratophyres, containing phenocrysts of albite, K–feldspar, quartz, mica and topaz hosted in a groundmass composed of the same minerals. It was named after the Ongon Khairhan pluton and associated tungsten deposit. These rocks are strongly enriched in several incompatible elements, particularly Li, Rb, Cs and Ta but depleted in Mg, Ba, Sr and Eu (Table 3) and are frequently associated with Sn-W-Ta-Nb mineralization. Compositionally, they resemble glassy volcanic rocks—macusonites from Peru (e.g., [37,38,39]).
In Mongolia, there are two types of ongonites: subvolcanic, which typically occur as dikes, and the volcanic variety. As the subvolcanic ongonites are better known in Mongolia, the emphasis here is on this type. In Central Mongolia, the Cretaceous ongonite dikes crop out in the Mesozoic Kharkhorin rift zone, in a string of the SW–NE-trending grabens. The ongonite dikes (~120 Ma old; [40]) at the type locality—the Ongon Khairkhan—are shallow-seated [41] and hosted by the Devono–Carboniferous clastic sedimentary rocks (Figure 8).
The ongonites form a dike swarm about 2 km long with the thickness of individual dikes ranging from several cm to about 5 m. The dikes have chilled margins. The content of Li2O is variable, ranging typically from about 0.1 wt % in porphyritic ongonites to 0.56 wt.% in aphyric types [41]. Kovalenko and Kovalenko [23] reported the average Li contents of the main ongonite dike as 1950 ppm. The dominant Li mineral is Li-rich mica, which occurs both as microphenocrysts and in the groundmass. The mica microphenocrysts are rare (<0.1 to 2 vol.%) whereas the groundmass contains up to 7 vol.% mica [40]. The mica is zinnwaldite. The primary mica usually contains about 2.5 wt.% Li2O although it can reach up to ~8 wt.%. The secondary mica has slightly lower concentrations of Li2O (~2 wt.%; [40]).
The ongonites are rich in SiO2 (70–74 wt.%), Al2O3 (16–18 wt.%) and alkalis (Na2O + K2O; 8.5–10 wt.%) but have low contents of MgO, TiO2, CaO (<0.4 wt.%) and P2O5 (< 0.06 wt.%) (Table 3). These leucocratic granitic rocks are strongly peraluminous and have high contents of F (~2 wt.%; [23]). The primitive mantle-normalized incompatible element patterns for the ongonites feature large negative anomalies for Ba, Sr, Eu and Ti (Figure 9) and are in general similar to those of RMG [11] and Li-F granites [30]. The ongonites have unusually low ratios of several incompatible elements including K/Rb (<20), Zr/Hf (2–5) and Nb/Ta (0.6–2.2) versus typical crustal values of K/Rb~250, Zr/Hf~35–40 and Nb/Ta~11. The low values of these ratios are indicative of the role of hydrothermal fluids [42,43,44] and suggest the involvement of both crystal and fluid fractionation in the evolving ongonitic melt. Li-F granites and related rocks were generated through prolonged fractional crystallization which involved fluids, including F. However, recent experimental data [45] suggest that the distinctive geochemical features of these rocks require not only such a fractionation process but also mica dehydration melting and probably a distinct source.
The ongonites are the product of protracted fractional crystallization mainly due to high contents of fluorine which allows the melts to crystallize over a range from a liquidus temperature that exceeded 800 °C to an anomalously low solidus temperature of around 600 °C. This is also supported by the saturation temperatures for apatite (814 ± 27 °C), monazite (747 ± 13 °C) and zircon (615 ± 15 °C) (Supplementary Text S2). The ongonites probably represent melt from the apical part of an underlying granitic pluton and correspond to the last stage of fractionation of a highly evolved F-rich granitic magma.
Similar occurrences of subvolcanic ongonites (dikes) occur, for example, at Baga–Gazar and Janchivlan (Figure 1; sites No. 7 and No. 9) in Central Mongolia. Their average Li content was reported to be about 2780 ppm while the average of Rb was 2380 ppm and Ta was 88 ppm [10]. Volcanic analogs of ongonites occur in southern Mongolia and are called ongorhyolites [10,22]. They form volcanic necks and sheets. Compared to subvolcanic types, the volcanic ongonites have lower contents of Li and rare metals such as Ta, Nb and Be but are much more voluminous. Some of these mineralized units expand over > 1 km2 and are 10–20 m thick. The main occurrence of volcanic ongonites (ongorhyolite) is Teeg Uul (Figure 1; site No. 15).

3.2. Sedimentary Rocks Hosted Lithium Deposits

The Mongol–Okhotsk orogenic belt that runs across Mongolia was affected during the Jurassic and Cretaceous by extension probably accompanied by gravitational collapse leading to the formation of a series of extensional basins in eastern and central Mongolia [46]. Sedimentary successions of the basins are typically 3–4 km thick. The bounding faults are mostly shallow dipping. Individual basins are composed internally of various-scale sub-basins. The extensional basins are frequently elongated, roughly parallel to the Mongol–Okhotsk suture zone and spread over the China–Mongolia border region [46]. Some of these basins host uranium and lithium mineralization [10].
The most prominent Mongolian deposit of this type is the Khukh Del deposit (Figure 1, site No. 16) situated in the middle of the Gobi Desert, about 550 km southwest of Ulaanbaatar [47]. The deposit is hosted in a basin (Tugrug Valley) filled by middle–upper Jurassic clastic sediments including siltstones and clays. The deposit is 6 km long and 5 km wide. The ore horizon, which is ~1.1 m thick, is clay-bearing siltstone containing reserves of 37.7 thousand tons of ore with 0.153 wt.% Li [10,26].

3.3. Lithium-Bearing Brines

The Gobi Desert is dry with very low rainfall and high evaporation rates, resulting in the development of saline lakes. The host basins are endorheic, closed drainage basins that do not have an outlet and retain water. Such watersheds are needed for the formation of saline lakes that have elevated Li from inflow during weathering, leaching and erosion of surrounding rocks and the subsequent concentrations of Li through evaporation.
Mongolia hosts several promising sites of Li-bearing salt lake brines [10], but the information is rather limited. Ariunbileg et al. [48] reported elevated concentrations of Li in lake waters from Eastern Mongolia, particularly at Dund Bayan nuur and Baruun Davst nuur (Figure 1; Table 2). They concluded that the closed saline lakes in the Gobi Desert have significant Li potential. Another promising site, the Baavhai Uul solar in southeastern Mongolia (Figure 1; Table 2), is close to the border with China. The site is in the Gobi Desert, within the subsiding basin filled, in part, with Cretaceous volcanic and sedimentary rocks and Quaternary sediments that form a favorable aquifer for Li brine (the average content of Li in brines is 426 ppm with the maximum of 811 ppm Li [49]). Another similar site is the Urgakh Naaran Li brine [49] located in the South Gobi Desert, about 450 km southeast of Ulaanbaatar (Figure 1; Table 2). Some of these lakes in the Gobi of Eastern Mongolia have also high concentrations of U [50]. Similar salt lakes with elevated concentrations of Li in water are present in Western Mongolia. Isupov et al. [51] reported Li concentrations up to 600 ppm in lakes of the West Mongolian Great Lake Valley (Uvs nuur, Khyargas nuur and Dergen; Figure 1). Ariunbileg et al. [52] also noted that the Valley of Lakes in the Gobi Desert in Southern Mongolia hosts promising sites such as a Cretaceous Zunbayan basin.

4. Conclusions

Mongolia hosts several promising sites of Li mineralization, which can be of economic importance. However, there is insufficient knowledge of most of these occurrences, in part, due to a relative lack of interest in this commodity in the past. The prospective deposits include both endogenic (Mesozoic hard rocks: Li-rich pegmatites, rare-metal Li-F granites, ongonites, ongorhyolites and greisens) and exogenous (Li-bearing clays and Li salt lake brines) mineralization.
The lithium in hard rocks is contained mainly in Li-bearing micas, particularly lepidolite and zinnwaldite, unlike the world-class Li-bearing pegmatite deposits such as those in Australia (Greenbushes) and Canada (Whabouchi) where the bulk of Li is in spodumene. This is likely due to the high contents of F in the Mongolian rocks, indicating different fluxing fluids (F vs. B and P). Compared to pegmatites, the rare-metal Li-F granites and volcanic equivalents form large kilometer-scale bodies.
A favorable geodynamic environment for Mongolian Li accumulation in hard (igneous) and sedimentary rocks is a post-orogenic extensional setting. Li-F granites and related rocks from an area around the margin of the Khentei batholith are particularly prospective for Li mineralization. Likewise noteworthy are Li salt lake brines in the Gobi Desert with an arid environment, high evaporation rates and low precipitation. They occur in evaporite-bearing endorheic basins without outflow to an external water reservoir and with shallow aquifers occurring in vicinities of felsic igneous rocks including Cretaceous felsic volcanic rocks.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/min14100960/s1, Text S1. Analytical methods; Text S2. Saturation temperatures [42,53,54,55,56].

Author Contributions

Both authors contributed equally. All authors have read and agreed to the published version of the manuscript.

Funding

This research was supported by funding provided by NSERC Canada to J.D. and by the Science and Technology Foundation of Mongolia to O.G.

Data Availability Statement

The authors declare that all analytical data supporting the findings of this study are available within the paper or cited in peer-reviewed references.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Grew, E.S. The minerals of lithium. Elements 2020, 16, 235–240. [Google Scholar] [CrossRef]
  2. Brooks, K. Lithium minerals. Geol. Today 2020, 36, 192–197. [Google Scholar] [CrossRef]
  3. Bowell, R.J.; Lagos, L.; de los Hoyos, C.; Declercq, J. Classification and characteristics of natural lithium resources. Elements 2020, 16, 259–264. [Google Scholar] [CrossRef]
  4. Stanley, C.; Jones, G.C.; Rumsey, M.S.; Blake, C.; Roberts, A.C.; Stirling, J.A.R.; Carpenter, G.J.C.; Whitfield, P.S.; Grice, J.D.; Lepage, Y. Jadarite, LiNaSiB3O7(OH), a new mineral species from the Jadar Basin, Serbia. Eur. J. Mineral. 2007, 19, 575–580. [Google Scholar] [CrossRef]
  5. Gourcerol, B.; Gloaguen, E.; Melleton, J.; Tuduri, J.; Galiegue, X. Re-assessing the European lithium resource potential—A review of hard-rock resources and metallogeny. Ore Geol. Rev. 2019, 109, 494–519. [Google Scholar] [CrossRef]
  6. U.S. Geological Survey. Mineral Commodity Summaries 2019; U.S. Geological Survey: Reston, VA, USA, 2019; pp. 98–99. [Google Scholar]
  7. Láznička, P. Giant Metallic Deposits; Springer: Berlin, Germany, 2006; 732p. [Google Scholar]
  8. London, D. Ore-forming processes within granitic pegmatites. Ore Geol. Rev. 2018, 101, 349–383. [Google Scholar] [CrossRef]
  9. Černý, P.; Ercit, T.S. The classification of granitic pegmatites revisited. Can. Mineral. 2005, 43, 2005–2026. [Google Scholar] [CrossRef]
  10. Gerel, O. Rare Metals: Tin, Tungsten, Molybdenum, Lithium, Tantalum and Niobium Deposits. In Mineral Resources of Mongolia; Gerel, O., Pirajno, F., Batkhishig, B., Dostal, J., Eds.; Modern Approaches in Solid Earth Sciences; Springer: Singapore, 2021; pp. 129–184. [Google Scholar]
  11. Černy, P.; Blevin, P.L.; Cuney, M.; London, D. Granite-related ore deposits. Econ. Geol. 2005, 100, 337–370. [Google Scholar]
  12. Dostal, J. Rare Earth Element Deposits of Alkaline Igneous Rocks. Resources 2017, 6, 34. [Google Scholar] [CrossRef]
  13. Evans, K. Lithium. In Critical Metals Handbook; Gunn, G., Ed.; American Geophysical Union: Washington, DC, USA, 2014; pp. 230–260. [Google Scholar]
  14. U.S. Geological Survey. Minerals Yearbook 2015; Mineral Industry of Serbia: Boulder, CO, USA, 2015; 36p. [Google Scholar]
  15. Kharaka, Y.K.; Hanor, J.S. Deep fluids in the continents: I. Sedimentary basins. In Surface and Ground Water, Weathering, and Soils. Treatise on Geochemistry 5; Drever, J.I., Ed.; Elsevier: Amsterdam, The Netherlands, 2003; pp. 1–48. [Google Scholar]
  16. Kesler, S.E.; Gruber, P.W.; Medina, P.A.; Keoleian, G.A.; Everson, M.P.; Wallington, T.J. Global lithium resources: Relative importance of pegmatite, brine and other deposits. Ore Geol. Rev. 2012, 48, 55–69. [Google Scholar] [CrossRef]
  17. Collins, A.G. Lithium abundances in oilfield waters. In Lithium Resources and Requirements by the Year 2000; Vine, J.D., Ed.; US Geological Survey Professional Paper; Boulder, CO, USA, 1976; Volume 1005, pp. 116–123. Available online: https://pubs.usgs.gov/pp/1005/report.pdf (accessed on 18 June 2020).
  18. Thompson, J.M.; Fournier, R.O. Chemistry and geothermometry of brine produced from the Salton Sea scientific drill hole, Imperial Valley, California. J. Geophys. Res. Solid Earth 1988, 93, 13165–13173. [Google Scholar] [CrossRef]
  19. Kovalenko, V.I.; Kuzmin, M.I.; Zonenshain, L.P.; Nagibina, M.S.; Pavlenko, A.S.; Vladykin, N.V.; Tseden, T.; Gundsambuu, T.; Goreglyad, A.V. Rare-Metal Granitoids in Mongolia: Petrology, Distribution of Rare Elements and Origin; Nauka: Moscow, Russia, 1971; 225p. (In Russian) [Google Scholar]
  20. Tauson, L.V. The Geochemical Types of Granitoids and Their Potential Ore Capacity; Nauka: Moscow, Russia, 1977; 280p. (In Russian) [Google Scholar]
  21. Beus, A.A.; Severov, V.A.; Citnin, A.A.; Cubbotin, K.D. Albitizated and Greisenizated Granites (Apogranites); Academy of Sciences of USSR: Moscow, Russia, 1962; 196p. (In Russian) [Google Scholar]
  22. Kovalenko, V.I.; Kuzmin, M.I.; Antipin, V.S.; Petrov, I.I. Topaz-bearing quartz keratophyre (ongonite): A new variety of subvolcanic igneous dike rocks. Dokl. Akad. Nauk SSSR Earth Sci. Sect. 1971, 199, 132–135. [Google Scholar]
  23. Kovalenko, V.I.; Kovalenko, N.I. Ongonites-subvolcanic analogues of rare metal lithium-fluorine granites. In Joint Soviet-Mongolian Scientific-Research Geological Expedition. Transaction 15; Nauka: Moscow, Russia, 1976; 128p. (In Russian) [Google Scholar]
  24. Vladykin, N.V.; Dorfman, M.D.; Kovalenko, V.I. Mineralogy, geochemistry and origin of rare metal topaz-lepidolite-albite pegmatites in Mongolian People’s Republic. Proc. Fersman Mineral. Mus. 1974, 23, 6–49. (In Russian) [Google Scholar]
  25. Kuznetsova, L.G.; Spiridonov, A.M.; Dril, S.I.; Kulikova, Z.I. Geochemistry of lepidolitic granitoids from the Mungutiyn Tsagaan Durulj occurrence (central Mongolia). Russ. Geol. Geophys. 2012, 53, 1077–1089. [Google Scholar] [CrossRef]
  26. Mineral Resources and Petroleum Authority of Mongolia. The Annual Report 2016. Ulaanbaatar. Available online: https://www.mrpam.gov.mn/public/pages/66/MPRAMreport2016EN.pdf (accessed on 18 June 2020).
  27. Tunnell, B.N.; Dashtseren, K.; Boldbaatar, E.; Locmelis, M.; Yang, Y.; Nakano, N.; Adachi, T.; Hames, W.; Arribas, A. Genesis and geochronology of the Bayanteeg LCT pegmatite in the Idermeg terrane, Central Mongolia. In Proceedings of the Goldschmidt Conference, Chicago, IL, USA, 18–23 August 2024. Paper 23849. [Google Scholar]
  28. Dashtseren, K.; Tunnell, B.N.; Boldbaatar, E.; Locmelis, M.; Yang, Y.; Nakano, N.; Adachi, T.; Hames, W.; Arribas, A. Geochronology of the LCT pegmatites in Central Mongolia. In Proceedings of the Goldschmidt Conference, Chicago, IL, USA, 18–23 August 2024; Paper 23340, poster#168. [Google Scholar]
  29. Gerel, O.; Kanisawa, S.; Ishikawa, K. Petrological characteristics of granites from the Avdrant and Janchivlan plutons, Khentei Range, Central Mongolia. Probl. Geodyn. Metallog. Mongolia. Trans. 1999, 13, 34–39. [Google Scholar]
  30. Antipin, V.S.; Gerel, O.; Perepelov, A.; Odgerel, D.; Zolboo, T. Late Paleozoic and Early Mesozoic rare-metal granites in Central Mongolia and Baikal region: Review of geochemistry, possible magma sources and related mineralization. J. Geosci. 2016, 61, 105–125. [Google Scholar] [CrossRef]
  31. Dostal, J.; Gerel, O. Occurrences of Niobium and Tantalum Mineralization in Mongolia. Minerals 2022, 12, 1529. [Google Scholar] [CrossRef]
  32. Machowiak, K.; Stawikowski, W.; Achramowicz, S. Late Triassic 40Ar–39Ar ages of the Baga–Gazryn Chuluu granites (Central Mongolia). J. Geosci. 2012, 57, 173–188. [Google Scholar] [CrossRef]
  33. Antipin, V.S.; Kuzmin, M.I.; Odgerel, D.; Kushch, L.V.; Sheptyakova, N.V. Rare-metal Li-F granites in the Late Paleozoic, Early Mesozoic, and Late Mesozoic magmatic areas of Central Asia. Russ. Geol. Geophys. 2022, 63, 772–788. [Google Scholar] [CrossRef]
  34. Antipin, V.S.; Kushch, L.V.; Odgerel, D.; Belozerova, O.Y. Early Mesozoic rare-metal granites and metasomatites of Mongolia: Mineral and geochemical features and hosted ore mineralization (Baga Gazriin Chuluu pluton). Russ. Geol. Geophys. 2021, 62, 1061–1073. [Google Scholar] [CrossRef]
  35. Antipin, V.S.; Odgerel, D. Abdar-Khoshutula intrusive-dike series: Evolution and origin of granitoids in Early Mesozoic magmatic area (Central Mongolia). Petrology 2016, 24, 497–511. [Google Scholar] [CrossRef]
  36. McDonough, W.F.; Sun, S.-S. The composition of the Earth. Chem. Geol. 1995, 120, 229–253. [Google Scholar] [CrossRef]
  37. London, D.; Morgan, C.B.; Hervig, R.I. Vapour-undersaturated experiments with Macusani glass + H2O at 200 MPa, and their internal differentiation of granitic pegmatites. Contrib. Mineral. Petrol. 1989, 102, 1–17. [Google Scholar] [CrossRef]
  38. Pichavant, M.; Kontak, D.J.; Herrera, J.V.; Clarke, A.H. The Miocene–Pliocene Macusani volcanics, SE Peru, I. Mineralogy and magmatic evolution of two-mica aluminosilicate-bearing ignimbrite suite. Contrib. Mineral. Petrol. 1988, 100, 300–324. [Google Scholar] [CrossRef]
  39. Pichavant, M.; Kontak, D.J.; Herrera, J.V.; Clarke, A.H. The Miocene–Pliocene Macusani volcanics, SE Peru, II. Geochemistry and origin of a felsic peraluminous magma. Contrib. Mineral. Petrol. 1988, 100, 325–338. [Google Scholar] [CrossRef]
  40. Dostal, J.; Kontak, D.J.; Gerel, O.; Shellnutt, J.G.; Fayek, M. Cretaceous ongonites (topaz-bearing albite-rich microleucogranites) from Ongon Khairkhan, Central Mongolia: Products of extreme magmatic fractionation and pervasive metasomatic fluid: Rock interaction. Lithos 2015, 236, 173–189. [Google Scholar] [CrossRef]
  41. Štemprok, M. Ongonite from Ongon Khairkhan, Mongolia. Mineral. Petrol. 1991, 43, 253–273. [Google Scholar] [CrossRef]
  42. Dostal, J.; Chatterjee, A.K. Origin of topaz-bearing and related peraluminous granite of the Late Devonian Davis Lake Pluton, Nova Scotia, Canada: Crystal versus fluid fractionation. Chem. Geol. 1995, 123, 67–88. [Google Scholar] [CrossRef]
  43. Dostal, J.; Chatterjee, A.K. Contrasting behaviour of Nb/Ta and Zr/Hf ratios in a peraluminous granitic pluton (Nova Scotia, Canada). Chem. Geol. 2000, 163, 207–218. [Google Scholar] [CrossRef]
  44. Ballouard, C.; Poujol, M.; Boulvais, P.; Branquet, Y.; Tarese, R.; Vineresse, J.L. Nb-Ta fractionation in peraluminous granites: A marker of the magmatic-hydrothermal transition. Geology 2016, 44, 231–234. [Google Scholar] [CrossRef]
  45. Michaud, J.A.; Pichavant, M.; Villaros, A. Rare elements enrichment in crustal peraluminous magmas: Insights from partial melting experiments. Contrib. Mineral. Petrol. 2021, 176, 96. [Google Scholar] [CrossRef]
  46. Meng, Q.-R.; Hu, J.-M.; Jin, J.-Q.; Zhang, Y.; Xu, D.-F. Tectonics of the late Mesozoic wide extensional basin system in the China-Mongolia border region. Basin Res. 2003, 15, 397–415. [Google Scholar] [CrossRef]
  47. Chuluun, O.; Odontuya, O. Geology, structure and ore mineralization of the Khukh Del sedimentary lithium deposit. In Geology, Mineralogy and Metallogeny of Mongolia’ore Deposits; MUST Printing House: Ulaanbaatar, Mongolia, 2017; 62p. [Google Scholar]
  48. Ariunbileg, S.; Isupov, V.P.; Vladimirov, A.G.; Krivonogov, S.K.; Shatskaya, S.S. Trace element contents of mineralize lakes in Eastern Mongolia. Mong. Geosci. 2009, 35, 115–116. [Google Scholar]
  49. Ion Energy TSX-V. Exploring and Developing Mongolia’s Lithium Salars. Available online: https://www.ionenergy.ca (accessed on 17 July 2024).
  50. Linhoff, B.S.; Bennett, P.C.; Tamir, P.; Gerel, O. Geochemical evolution of uraniferous soda lakes in Eastern Mongolia. Environ. Earth Sci. 2010, 62, 171–183. [Google Scholar] [CrossRef]
  51. Isupov, V.P.; Vladimirov, A.; Ariunbileg, S.; Kolpakova, M.; Shvartsev, S.; Volkova, N. Hydromineral resources of saline lakes of Mongolia and Russian Altai. Adv. Miner. Res. 2015, 1085, 166–170. [Google Scholar] [CrossRef]
  52. Ariunbileg, S.; Isupov, V.P.; Vladimirov, A.G.; Orkhonselenge, A.; Shatskaya, S.S. Impact of climate change on hydrogeochemical characteristics of lakes in the Valley of Lakes, southern Mongolia. In Proceedings of the Goldschmidt Conference, Paris, France, 13–18 August 2017; Presentation #2169. [Google Scholar]
  53. Boehnke, P.; Watson, E.B.; Trail, D.; Harrison, T.M.; Schmitt, A.K. Zircon saturation revisited. Chem. Geol. 2013, 351, 324–334. [Google Scholar] [CrossRef]
  54. Watson, E.B.; Harrison, T.M. Zircon saturation revisited: Temperature and composition effects in a variety of crustal magma types. Earth Planet. Sci. Lett. 1983, 64, 295–304. [Google Scholar] [CrossRef]
  55. Harrison, T.M.; Watson, E.B. The behavior of apatite during crustal anatexis: Equilibrium and kinetic considerations. Geochim. Et Cosmochim. Acta 1984, 48, 1467–1477. [Google Scholar] [CrossRef]
  56. Montel, J.M. A model for monazite/melt equilibrium and application to the generation of granitic magmas. Chem. Geol. 1993, 110, 127–146. [Google Scholar] [CrossRef]
Minerals 14 00960 g001
Figure 1. Map of Mongolia showing the locations of the significant Li mineralization. Locations of significant Li mineralization sites hosted by granitic pegmatite (No. 1–6), Li-F granites (No. 7–13), ongonites and ongorhyolites (No. 14–15), sedimentary rocks (No. 16) and Li salt lakes (No. 17–23) (Table 2). Inset map shows a geological sketch of northeastern Asia and the location of Mongolia. DPRK: Democratic People’s Republic of Korea (North Korea).
Figure 1. Map of Mongolia showing the locations of the significant Li mineralization. Locations of significant Li mineralization sites hosted by granitic pegmatite (No. 1–6), Li-F granites (No. 7–13), ongonites and ongorhyolites (No. 14–15), sedimentary rocks (No. 16) and Li salt lakes (No. 17–23) (Table 2). Inset map shows a geological sketch of northeastern Asia and the location of Mongolia. DPRK: Democratic People’s Republic of Korea (North Korea).
Minerals 14 00960 g001
Minerals 14 00960 g002
Figure 2. Generalized geological sketch map of topaz–lepidolite–albite pegmatite swarm of Khukh Del Uul (after Vladykin et al. [24]). Location: Site No. 1 in Figure 1, Table 2; coordinates N46°00′ E108°49′. 1—Quaternary cover; 2—Middle Paleozoic quartz porphyry; 3—Late Paleozoic granite; 4—post-Devonian syenite porphyry; 5—Proterozoic metamorphic rocks; 6—Pegmatite; 7—Syenite dike.
Figure 2. Generalized geological sketch map of topaz–lepidolite–albite pegmatite swarm of Khukh Del Uul (after Vladykin et al. [24]). Location: Site No. 1 in Figure 1, Table 2; coordinates N46°00′ E108°49′. 1—Quaternary cover; 2—Middle Paleozoic quartz porphyry; 3—Late Paleozoic granite; 4—post-Devonian syenite porphyry; 5—Proterozoic metamorphic rocks; 6—Pegmatite; 7—Syenite dike.
Minerals 14 00960 g002
Minerals 14 00960 g003
Figure 3. Generalized cross-section through a typical Khukh Del Uul pegmatite dike (modified after Vladykin et al. [24]. 1—Country rock (gneiss); 2—Pegmatite: composed of coarse-grained plagioclase (cleavelandite)–quartz–lepidolite with minor topaz; 3—Greisens: composed of quartz and lepidolite; 4—Albite veins: veins of fine-grained (sugary) albite; 5—Quartz–plagioclase: pegmatite (plagioclase + quartz) with large quartz crystals. Location: Site No. 1 in Figure 1.
Figure 3. Generalized cross-section through a typical Khukh Del Uul pegmatite dike (modified after Vladykin et al. [24]. 1—Country rock (gneiss); 2—Pegmatite: composed of coarse-grained plagioclase (cleavelandite)–quartz–lepidolite with minor topaz; 3—Greisens: composed of quartz and lepidolite; 4—Albite veins: veins of fine-grained (sugary) albite; 5—Quartz–plagioclase: pegmatite (plagioclase + quartz) with large quartz crystals. Location: Site No. 1 in Figure 1.
Minerals 14 00960 g003
Minerals 14 00960 g004
Figure 4. Generalized geological map of the Janchivlan complex modified after Kovalenko et al. [19], Antipin et al. [30] and Dostal and Gerel [31]. Location: Site No. 7 in Figure 1; Table 2. 1—Quaternary sediments; 2—Li-F leucogranite; 3—Phase III leucogranite; 4—Phase II granite; 5—Phase I granite; 6—Precambrian basement; 7—Paleozoic clastic sediments; 8—Faults.
Figure 4. Generalized geological map of the Janchivlan complex modified after Kovalenko et al. [19], Antipin et al. [30] and Dostal and Gerel [31]. Location: Site No. 7 in Figure 1; Table 2. 1—Quaternary sediments; 2—Li-F leucogranite; 3—Phase III leucogranite; 4—Phase II granite; 5—Phase I granite; 6—Precambrian basement; 7—Paleozoic clastic sediments; 8—Faults.
Minerals 14 00960 g004
Minerals 14 00960 g005
Figure 5. Generalized geological map of Baga–Gazar intrusive complex (after Antipin et al. [34]). 1—Country rock: metasedimentary rocks intercalated with Permian volcanic rocks; 2—Fine-grained leucogranites: the late–second phase; 3—Coarse- to medium-grained biotite granite: the early–first phase; 4—Zones of greisenization and veins of greisens (zwitters); 5—Faults. Location: Site No. 9 in Figure 1; Table 2.
Figure 5. Generalized geological map of Baga–Gazar intrusive complex (after Antipin et al. [34]). 1—Country rock: metasedimentary rocks intercalated with Permian volcanic rocks; 2—Fine-grained leucogranites: the late–second phase; 3—Coarse- to medium-grained biotite granite: the early–first phase; 4—Zones of greisenization and veins of greisens (zwitters); 5—Faults. Location: Site No. 9 in Figure 1; Table 2.
Minerals 14 00960 g005
Minerals 14 00960 g008
Figure 8. Generalized geological map of ongonite dike from Ongon Khairhan; modified after Dostal et al. [40]. Location: Site No. 14 in Figure 1; Table 2. 1—Sedimentary rocks; 2—Ongonite; 3—Ongonite regolith; 4—Stockwork; 5—Strike/Dip; 6—Faults.
Figure 8. Generalized geological map of ongonite dike from Ongon Khairhan; modified after Dostal et al. [40]. Location: Site No. 14 in Figure 1; Table 2. 1—Sedimentary rocks; 2—Ongonite; 3—Ongonite regolith; 4—Stockwork; 5—Strike/Dip; 6—Faults.
Minerals 14 00960 g008
Minerals 14 00960 g009
Figure 9. Primitive mantle-normalized abundances of incompatible elements of granitic rocks from the Avdar intrusion and ongonites. Avdar: biotite leucogranite (o) and amazonite–albite leucogranite (+); ongonite from Ongon Khairkhan (x). Normalizing values after McDonough and Sun [36]. Data are from Table 3.
Figure 9. Primitive mantle-normalized abundances of incompatible elements of granitic rocks from the Avdar intrusion and ongonites. Avdar: biotite leucogranite (o) and amazonite–albite leucogranite (+); ongonite from Ongon Khairkhan (x). Normalizing values after McDonough and Sun [36]. Data are from Table 3.
Minerals 14 00960 g009
Table 1. Main lithium minerals, their chemical formula and Li2O content.
Table 1. Main lithium minerals, their chemical formula and Li2O content.
NameFormulaLi2O (wt.%) *
EucryptiteLiAlSiO411.86
SpodumeneLiAl (Si2O6)8.03
PetaliteLiAl (Si4O10)4.88
Lepidolite K(Li,Al)3(Si,Al)4O10(OH,F)27.70
ZinnwalditeKLiFeAl(Al,Si3)O10(OH,F)24.12
TriphyliteLi(Fe,Mn)PO49.47
Amblygonite LiAl(PO4)F10.10
MontebrasiteLiAl(PO4)OH10.10
JadariteLiNaSiB3O7(OH)7.30
HectoriteNa0.3(Mg,Li)3(Si4O10)(F,OH)2x nH2O
* Theoretical value [5].
Table 2. Coordinates of Li mineralization sites.
Table 2. Coordinates of Li mineralization sites.
Pegmatite 1–6
1Khukh Del UulN 46°00′E 108°49′
2Munkhiin Tsagaan DurvuljinN 45°53′E 108°22′
3BerkhN 47°46′E 111°11′
4UnjuulN 47°19′E 105°03′
5Bayan TeegN 45°16′E 107°07′
6Baga, Ikh YamaatN 49°46′E 97°06′
Granite 7–13
7JanchivlanN47°35′E 107°34′
8Urt GozgorN 47°34′E 107°32′
9Baga GazarN 46°15′E 105°56′
10AvdarN 47°37′E 105°27′
11ArbaynN 46°03′E 115°47′
12UizenN 46°03′E 110°38′
13Bor KhujirN 46°33′E 109°14′
Ongonite 14–15
Ongonite; Ongorhyolite
14Ongon KhairkhanN 47°04′E 105°10′
15Teeg UulN 44°19′E 105°10′
Li sediments 16
16Khukh DelN 45° 07′E 106°52′
Li brines 17–23
Eastern Mongolia
17Dund Bayan nuurN 46°26′E 114°07′
18Baruun Davst nuurN 48°20′E 114°35′
19Baavhai UulN 45°17′E 113°49′
20Urgakh NaaranN 45°50′E 112°20′
Western Mongolia
21Uvs nuurN 50°23′E 92°41′
22Khyargas nuurN 49°11′E 93°16′
23Dergen nuurN 46°13′E 93°27′
Table 3. Major and trace element composition of the Li-F granitic rocks from Mongolia.
Table 3. Major and trace element composition of the Li-F granitic rocks from Mongolia.
wt.%JA-1JA-4JA-7JA-9ONGAvdar-1Avdar-2Baga-1Baga-2Baga-Gr
SiO273.0476.175.870.970.8472.3375.8476.0377.0280.23
TiO20.2150.0610.0140.0040.020.220.020.120.100.11
Al2O3 13.5212.2212.7817.6516.6513.4812.7612.589.759.58
Fe2O3(t)1.611.030.790.120.242.821.731.421.854.66
MnO0.0440.0330.0240.0340.170.040.040.030.030.10
MgO0.270.030.010.010.030.640.130.040.300.05
CaO0.970.440.260.120.171.280.320.550.400.88
Na2O3.233.494.295.855.904.214.463.393.280.10
K2O4.904.604.033.223.144.974.144.814.632.03
P2O50.100.010.010.010.030.070.050.030.040.04
LOI0.770.520.490.861.400.460.430.650.641.57
Total98.66998.53498.49898.77898.59100.5299.9299.6598.0499.34
ppm
Li1653528593891950338396156158856
Cs12.724.515.210.11041220151536
Rb26562775112502404730753429525556
Ba384611515.532.5782753.4
Sr115152612.717.913.6312324.7
Ta2.976.175.9322.671.12.017.15.46.88.9
Nb8.835.62256.883.81578404793.5
Hf3.27.18.96.49.08.322897.6
Zr111143831833.0230140163165160
Y18.494.7164115.421.867.48213087.3
Th15.14930.520.815.038.436.4405638
U6.954.944.414.135.482.75.19.74.88.36
La23.657.322.62.436.5910.310.331.273336.84
Ce49.210668.27.6125.4727.725.573.977986.59
Pr5.6811.69.771.133.517.82.99.391010.85
Nd21.138.039.02.6716.728.59.035.183740.29
Sm4.308.6414.40.734.865.93.19.2710.710.14
Eu0.520.2070.0070.0250.030.460.010.170.100.20
Gd3.557.9514.90.322.935.43.69.9112.110.4
Tb0.581.723.550.100.570.860.751.932.512.02
Dy3.4212.926.50.773.166.56.713.7418.714.36
Ho0.622.885.740.160.451.211.433.034.273.15
Er1.99.7319.30.591.324.46.010.2614.810.54
Tm0.2761.643.430.1730.260.821.21.662.521.72
Yb1.8611.924.41.641.7313.813.711.5818.011.9
Lu0.2871.813.690.2880.231.081.621.732.691.80
F 8400280031003900430024,739
Baga-1 and Baga-2: averages of the biotite granite (core) and leucogranite of the Baga Gazar intrusion [33]; Avdar-1 and Avdar-2: averages of the core and rim of the Avdar intrusion [33]; Baga-Gr: average of greisens, zwitters and metasomatized granite of the Baga Gazar intrusion [34]; JA: Janchivlan intrusion; JA-1: phase 1 biotite granite; JA-4: phase 3 leucogranite; JA-7: Li-F granite, lepidolite–albite; JA-9: Li-F granite, amazonite–albite; ONG: average of 21 ongonites from the type locality.
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Dostal, J.; Gerel, O. Characteristics of Lithium Deposits in Mongolia. Minerals 2024, 14, 960. https://doi.org/10.3390/min14100960

AMA Style

Dostal J, Gerel O. Characteristics of Lithium Deposits in Mongolia. Minerals. 2024; 14(10):960. https://doi.org/10.3390/min14100960

Chicago/Turabian Style

Dostal, Jaroslav, and Ochir Gerel. 2024. "Characteristics of Lithium Deposits in Mongolia" Minerals 14, no. 10: 960. https://doi.org/10.3390/min14100960

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop