TITANIUM AND IRON PROBABLE RESERVES IN THE LUNAR SOIL

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TITANIUM AND IRON PROBABLE RESERVES IN THE LUNAR SOIL. O. I. Turchinskaya1, E. N. Slyuta1,
1Vernadsky Institute of Geochemistry and Analytical Chemistry, Moscow, Kosygina Str. 19, Russia,
olgaturch@yandex.ru
Introduction: Because of meteorite bombardment,
which lasted throughout the entire geological history of
the Moon, a cover of loose material, regolith, was
formed on its surface, which consists of fragments of
underlying rocks, fragments of minerals and secondary
particles: breccias, agglutinates and glass particles. All
the most promising lunar resources are either
concentrated in a loose regolith layer (volatile
components), or are already in the regolith in an
enriched form (minerals Al, Ti, Fe, etc.), which no
longer requires crushing for their further separation and
extraction.
The predominant type of mare rocks on the Moon
are basalts. According to the bulk chemical
composition, mare basalts correspond to the rocks of the
gabbro-basalt group and are usually defined as ilmenite,
olivine, cristobalite basalts (gabbro), etc. The
petrographic specificity of mare basalts consists in the
smaller grain size (hundreds of microns) and the
practical absence of volcanic glass. The main rock-
forming minerals are clinopyroxenes and plagioclase
(An50-95), sometimes olivine (Fo50-75). The main ore
mineral in mare basalts is ilmenite (FeTiO3), which is
also the main ore mineral of titanium and iron on the
Moon. Among the samples delivered to Earth, low-
titanium (TiO2<6 wt%) and high-titanium (TiO2>8
wt%) mare basalts are distinguished, which are further
divided by the content of K and Al. The formation of
mare basalts is associated with the processes of partial
melting of the mantle. Crystallization age of low-
titanium basalts is 3.15-3.45 billion years, high-titanium
basalts - 3.55-3.85 billion years [1].
Ilmenite in lunar soil: Maps of the distribution of
the TiO2 content on the lunar surface, which reflects the
ilmenite content in the regolith, were obtained from the
optical survey of the Moon Near Side. The method is
based on the correlation of the main chromophore
elements content for albedo Fe and Ti with albedo and
color indices in the visible and near IR spectrum ranges
[2-4]. The percentage of TiO2 varies from 0.01 in the
mainland regions to 10% or more in the mare regions
(Fig. 1). The areas of spread of the increased content of
Ti oxides (5-10%) actually reflect the distribution of
high-titanium mare basalts, which are widespread in the
Mare Tranquillitatis, the Mare Imbrium, the Oceanus
Procellarum, as well as in subordinate numbers are
present in the Mare Fecunditatis, the Mare Humorum
and the Mare Nubium (Fig. 1). In some areas of high-
titanium basalt distribution, the ilmenite content can
reach 20 wt%. Low-titanium basalts are widespread in
the Mare Serenitatis, the Mare Crisium, the Mare
Frigoris, the Mare Cognitum and in subordinate
numbers are present on the periphery in the Mare
Imbrium.
Probable reserves estimation: Based on the
distribution of TiO2 content according to the spectral
survey of Clementine spacecraft, four main categories
were identified and contoured - A (> 8.0 wt%), B (5.0-
8.0 wt%), C (3.0-5.0 wt%) and D (1.0-3.0 wt%) (Fig. 1).
The most rich in titanium content is category A, which
is of most practical interest. The total area of category
A is 732477 km2. The two largest deposits with a TiO2
content of more than 8% are distinguished, which are
located in Oceanus Procellarum and in Mare
Tranquillitatis (Fig. 2). The rest of the deposits are much
smaller in terms of their territory and, accordingly, in
terms of predicted reserves. They are located in the
northwestern part of the Mare Imbrium, Mare
Humorum, Mare Nubium, Mare Insularum, Mare
Vaporum and Mare Fecunditatis (Fig. 2).
The regolith thickness in maria areas with the
maximum ilmenite concentration, primarily in the Mare
Tranquillitatis and in the Oceanus Procellarum, was
estimated from instrumental measurements at landing
sites [5], from crater size and morphology [6], and from
the regolith thickness distribution map for various
geomorphological formations and stratigraphic
divisions [7], and was assumed to be 4.4 m. Knowing
the average thickness of regolith and the total area of the
A category deposits and taking the content of the main
ore mineral ilmenite (FeTiO3) equal to 8 wt. %, the
density of regolith equal to 1.9 g cm-3 [8], we can
estimate the probable reserves. Thus, the total probable
reserves of ilmenite in the deposits of A category are
estimated at 4.9×1011 tons. Ilmenite contains 31.6 wt %
titanium and 36.8 wt % iron, the rest is oxygen.
Accordingly, the probable reserves of Ti in the A
category deposits are estimated at 1.5×1011 tons, and Fe
at 1.8×1011 tons.
Conclusion: Because of the analysis of the
distribution of TiO2 content on the surface of the visible
hemisphere of the Moon, according to the optical survey
of Clementine spacecraft, areas with different contents
of the main ore mineral ilmenite were isolated and
contoured. Estimated total area of A category deposits
with maximum titanium content is more than 700,000
km. The main concentration of ilmenite is observed in
Oceanus Procellarum and in Mare Tranquillitatis. The
1667.pdf52nd Lunar and Planetary Science Conference 2021 (LPI Contrib. No. 2548)

probable reserves of titanium in the lunar soil in the A
category deposits are estimated at 1.5×1011 tons, and
iron at 1.8×1011 tons.
Fig. 1 Maps of the TiO2 (wt.%) distribution in the lunar soil on the Moon Near Side according to the Clementine
spacecraft (left) [3] and of outlined categories of metal deposits (right).
Fig. 2. Map of the distribution of the A category deposits
with the content of TiO2 >8 wt.% on the Moon Near
Side.
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in minerology and geochemistry. Eds. Joliff B.L.,
Wieczorek M.A., Shearer C.K., Neal C.R. 2006. M. 60.
721 p. [2] Blewett D.T. et al. (1997) J.G.R. 102(E7),
16319-16326. [3] Lucey P.G. et al. (1998) J.G.R.
103(E2), 3679-3699. [4] Lucey P. G. et al. (2000)
J.G.R. 105(E8), 20377-20387. [5] Nakamura Y. et al.
(1975) Moon, 13(1), 3. [6] Oberbeck V.R., Quaide W.L.
(1968) Icarus 9(3), 446-465. [7] Shkuratov, Y.G.,
Bondarenko, N.V. (2001) Icarus 149, 329-338. [8]
Slyuta E.N. (2014) Sol. Sys. Res. 48(5), 330–353
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