Mineral iron

Lunar free iron is great but it’s just not plentiful enough to do everything we need to do. We’re going to have to get most of the iron (and other materials) we need from Lunar rocks. Luckily, much of the resources an expanding homestead needs are readily available right on the Lunar surface. All we have to do is scoop it up and refine it.

Lunar rocks, just like Earth rocks, are made of minerals and glasses. They’re not uniform in their composition or their distribution. The whole issue is a bit of a mess and it really takes a geologist (or selenogist) to get a good grip on it. That’s not me but I’ll do my best to make sense of it.

One thing to keep in mind is that the lack of free water, free oxygen, and biological activity on Luna eliminates the most economically exploitable classes of ore deposits found on Earth (Space Resources: Vol 3 Materials, 19). Those ore types are:

• Placer
• Hydrothermal
• Precipitation (from water)
• Secondary mobilization and enrichment

Lunar ores are typically going to be less concentrated and harder to extract than Earth ores. Many would be considered “low-grade” if found on Earth. We’ll just have to make do with what we’ve got.

There are four distinct groups of Lunar rocks

• Basaltic volcanic rocks (includes lava flows and pyroclastic rocks) – The Lunar mares were formed by lava flows and so most of these rocks are found in the mares.
• Pristine rocks – Lunar highland rocks that haven’t been mixed up due to impacts.
• Polymict breccias – A fancy term for a bunch of different rocks mixed together. There are several different types of breccias but there’s no point in getting into the weeds right now.
• Lunar soil – Earth soil contains organic material but Lunar soil does not. Lunar soil is the small (<1 cm) rocks and dust within the Lunar regolith.

The regolith is the layer of mixed up rocks that cover the Lunar surface. Regolith is 4-5m deep in maria and 10-15m deep in highlands (A Global Lunar Landing Site Study to Provide the Scientific Context for Exploration of the Moon, 413). The regolith can consist of basaltic rocks, highland rocks, and soil. Each of which will have its own chemical composition. It’s composed of mineral fragments, breccias, agglutinates, glasses, free metal, and rock fragments. It ends up being a pretty chaotic mess if you’re trying to figure out how to effectively mine it for iron.

 

Lunar mare basalts

Lunar mare basalts are chiefly composed of:

• Pyroxene
• Plagioclase
• Olivine
• Metal oxides (ilmenite, armalcolite, spinel) – High TiO₂ content in rocks = higher metal oxide content in rocks.

Also present in Lunar mare basalts are free metallic iron and troilite.

In general, the basaltic mare contains the highest concentrations of iron and titanium (Lunar Sourcebook, 186). Regolith with the highest concentrations of iron and titanium are the darkest in color (Geologic History of the Moon, 95). FeTi-rich glasses, Fe and Ti oxides in agglutinates, and metallic Fe are all possible darkening agents (Geologic History of the Moon, 95). Titanium content may be the key determinate as Ti content varies more than Fe content in mare basalts (Geologic History of the Moon, 95).

All nine sampling missions returned mare basalt samples in variable amounts (Geologic History of the Moon, 101). All sampling missions were at mare margins or in the highlands so no central mascon sections were sampled (Geologic History of the Moon, 101). We may find significant differences in the mare regolith as we get further away from the “shores”.

 

Highland pristine rocks

The primary weathering process on Luna is meteoroid impacting. Frequent and severe impacts break up the crust, mix different types of rocks together, and distribute it all over a large area. The heat from the impact also chemically changes the rocks. These types of rocks are described in the next section.  This section is about rocks that broken but unmixed and unchanged.

Fortunately, we’re not too concerned with highland pristine rocks right now as they contain the least amount of iron. They do contain a lot of other useful minerals though, so we’ll eventually get back to them.

 

Polymict breccias

These rocks are mixtures of minerals, glass, and other materials from different locations. Polymict breccias are formed by meteoroid impacts and are also called impact-melt rocks. Almost all of the Lunar samples collected in the highlands are in this category.

You never know what you’re going to get with this type of rock. Chemical compositions can vary widely with a single sample. Highly energetic impacts can throw polymict breccias over a very large area. These rocks can (and have been) hit again, broken up, combined with new materials, and redistributed.

Almost every sample from the highlands is breccia and so are approximately 1/3 of the mare samples (the other 2/3 are basalts)(Handbook of Lunar Materials, 84)

Breccia classification (Handbook of Lunar Materials, 85)

• Vitric-matrix – A conglomeration of minerals, glass, and rock fragments bound together by fused glass and grain-to-grain sintering. Very friable to tough. Usually very porous. Bulk densities between 2.0 and 3.0. May be considered compacted and lithified regolith with no major chemical differences between the local regolith and local vitric-matrix breccias (Handbook of Lunar Materials, 87). Extremely abundant on the surface with 1/3 of all highland samples and all of the mare samples being vitric-matrix breccias (Handbook of Lunar Materials, 87).
  • Mare – High-Ti
  • Mare – Low Ti
  • KREEP
  • Anorthositic gabbro
• Light matrix – Similar to vitric-matrix breccias except they lack glass and are only bonded together by grain-to-grain sintering (Handbook of Lunar Materials, 87). Only found at the Apollo 14 and 16 sites and are hypothesized to make up 10-15% of the highlands.
• Cataclastic anorthosite – Crushed rocks consisting of 50-99% plagioclase feldspar (2/3 of the Apollo samples contained more than 80%) (Handbook of Lunar Materials, 87). Held together by grain-to-grain sintering or very small amounts of glass (Handbook of Lunar Materials, 87). May contain pyroxene, olivine, and other minerals and sizes vary from 1 micrometer to several centimeters (Handbook of Lunar Materials, 87). Might contain sub-micron sized FeS (Handbook of Lunar Materials, 87).  Cataclastic anorthosites make up 5% of the highlands samples (Handbook of Lunar Materials, 88).
• Crystalline matrix – A fine-grain, uniform matrix of interlocking crystals of plagioclase feldspar, pyroxene, olivine, and ilmenite with embedded mineral and rock clasts (Handbook of Lunar Materials, 88). The rock is bound by the interlocking of the crystals. They can range in size from 50 micrometers to tens of meters and are mostly plagioclase (Handbook of Lunar Materials, 89). Crystalline matrix breccias only occur in the highlands and comprise approximately 50% of the samples (Handbook of Lunar Materials, 89).
  • KREEP
  • Anorthositic gabbro
• Granulitic matrix – Metamorphosed rocks bound by an interlocking crystalline matrix. Predominately plagioclase feldspar with some olivine and/or pyroxene (Handbook of Lunar Materials, 90). Granulitic matrix breccias are rare on the surface (only 5 rocks were returned) but are thought to be more common at greater depths (Handbook of Lunar Materials, 90).

 

Lunar soil

The fine-grained powder (4-80 nanometers) that makes up the Lunar soil comes from the mechanical disintegration of all the different types of Lunar rocks. Lunar soil also contains the remains of meteoroid impactors. Subsequently, Lunar soil has a lot of variability.

Glass fragments and droplets are also found in all Lunar soil samples (Lunar Sourcebook, 202). They are produced by volcanic eruptions (pyroclastic deposits) and impact melting. Impact melting produces chemically heterogeneous glass because the glass cools quickly and contains impurities. Volcanic eruptions produce chemically uniform glass and glass that may contain volatile elements. There are 25 distinct types of volcanic glasses.

The amount of iron oxide (FeO) present (by % weight) in Lunar glass samples range from 16.5% to 24.7% (Lunar Sourcebook, 264). That’s enough to make all Lunar glass targets for iron extraction.

Agglutinates are particles composed of mineral grains, glasses, and other agglutinates that are bonded together by melted glass. They are larger than most of the Lunar soil particles. Agglutinates are created by impacts and always contain fine particles of Fe and FeS. How this happens is described on the Lunar Free Iron post. Agglutinates make up a substantial portion of the Lunar soil, from 5% to 65% (Lunar Sourcebook, 298). The average is 25%-30% though (Lunar Sourcebook, 298). Lunar Bases and Space Activities of the 21st Century states that the average is over 50% (Lunar Bases and Space Activities of the 21st Century, 500). That makes agglutinates a prime target for iron extraction.

 

Lunar minerals of interest

By definition minerals must:

• Occur naturally.
• Have a defined chemical composition that varies with in a specific range or not at all.
• Be able to be mechanically separated from other minerals in the same sample. This is critical so we can separate out the minerals we want from the ones we don’t.
• Have a defined atomic arrangement.

Glasses, on the other hand, have a random internal atomic structure (and are not considered minerals).

There are a lot of different minerals and glasses on Luna. Fortunately, we’re only interested in the ones that are plentiful and contain easy (relatively) to extract iron.  That narrows the field down to a handful of minerals.

Silicate minerals are the most abundant of minerals; making up over 90% of the volume of Lunar rocks (Lunar Sourcebook, 122). Silicates are composed primarily of silicon and oxygen, with the other elements present determining which type of silicate the sample is. The silicates we are interested in right now have iron (Fe) in their chemical structure, such as pyroxene and olivine. While plagioclase feldspar is relatively common, I have not included it here because the iron variants are much rarer. It is thought that pyroxene and plagioclase precipitated together and later reacted with each other so that the pyroxene became more iron rich and the plagioclase became less (Lunar Sourcebook, 129).

Oxide minerals are the next abundant, and can make up as much as 20% of the volume of mare basalts (Lunar Sourcebook 122). The most abundant oxide mineral on Luna is ilmenite (Fe,Mg)TiO₃, which can either contain iron or magnesium. We’re interested in the iron. The second most common oxide mineral is spinel, which also has an iron flavor. Finally, armalcolite has a significant presence in titanium-rich basalts and also contains iron. Oxide minerals are very interesting because their oxygen is more weakly bonded than those of silicate minerals (Lunar Sourcebook, 138). This means it takes less energy to extract the iron from the rock.

I’ve also included troilite (FeS), a sulfide mineral, in our list. Although less than 1% (by volume) of Lunar minerals is troilite, it is present in every sample (Lunar Sourcebook, 150). This could make it a very useful source of both iron and sulfur.

 

Pyroxene

Olivine

Ilmenite

Spinel

Armalcolite

Troilite

 

Data

Proportion of minerals and glasses (volume %) from Lunar samples. (90-20μm, not including fused-soil and rock fragments) (Lunar Sourcebook, 123)

• Apollo 11 (Mare)
  • Pyroxene – 44.9%
  • Olivine – 2.1%
  • Ilmenite – 6.5%
  • Mare glass – 16.0%
  • Highland glass – 8.3%

• Apollo 12 (Mare)
  • Pyroxene – 38.2%
  • Olivine – 5.4%
  • Ilmenite – 2.7%
  • Mare glass – 15.1%
  • Highland glass – 14.2%

• Apollo 14 (Large-scale ejecta ridges)
  • Pyroxene – 31.9%
  • Olivine – 6.7%
  • Ilmenite – 1.3%
  • Mare glass – 2.6%
  • Highland glass – 25.0%

• Apollo 15 (Highlands)
  • Pyroxene – 38.0%
  • Olivine – 5.9%
  • Ilmenite – 0.4%
  • Mare glass – 15.9%
  • Highland glass – 4.8%

• Apollo 15 (Mare)
  • Pyroxene – 61.1%
  • Olivine – 5.3%
  • Ilmenite – 0.8%
  • Mare glass – 6.7%
  • Highland glass – 10.9%

• Apollo 16 (Highlands)
  • Pyroxene – 8.5%
  • Olivine – 3.9%
  • Ilmenite – 0.4%
  • Mare glass – 0.9%
  • Highland glass – 17.1%

• Apollo 17 (Highlands)
  • Pyroxene – 27.7%
  • Olivine – 11.6%
  • Ilmenite – 3.7%
  • Mare glass – 9.0%
  • Highland glass – 8.5%

• Apollo 17 (Mare)
  • Pyroxene – 30.1%
  • Olivine – 0.2%
  • Ilmenite – 12.8%
  • Mare glass – 17.2%
  • Highland glass – 4.7%

• Luna 16
  • Pyroxene – 57.3%
  • Olivine – 10.0%
  • Ilmenite – 1.8%
  • Mare glass – 5.5%
  • Highland glass – 11.2%

• Luna 20
  • Pyroxene – 27.0%
  • Olivine – 6.6%
  • Ilmenite – 0.0%
  • Mare glass – 0.9%
  • Highland glass – 12.8%

• Luna 24
  • Pyroxene – 51.6%%
  • Olivine – 17.5%
  • Ilmenite – 1.0%
  • Mare glass – 3.4%
  • Highland glass – 3.8%

 

Statistical data for iron oxide (FeO) concentrations (by percent weight) (Lunar Sourcebook, 449)

• Apollo 11
  • Mare basalts
    • Number of analyses = 11
    • Average = 19.22%
    • dev. = 1.28
    • Minimum = 16.51%
    • Maximum = 21.71%
  • Soils and regolith breccias
    • Number of analyses = 13
    • Average = 16.40%
    • dev. = 0.79
    • Minimum = 15.41%
    • Maximum = 17.74%
• Apollo 12
  • Mare basalts
    • Number of analyses = 20
    • Average = 20.48%
    • dev. = 1.38
    • Minimum = 16.78%
    • Maximum = 22.64%
  • Soils and regolith breccias
    • Number of analyses = 3
    • Average = 17.19%
    • dev. = 1.07
    • Minimum = 16.33%
    • Maximum = 18.39%
• Apollo 14
  • Polymict breccias
    • Number of analyses = 16
    • Average = 9.53%
    • dev. = 2.69
    • Minimum = 0.43%
    • Maximum = 11.50%
• Apollo 15
  • Mare basalts
    • Number of analyses = 14
    • Average = 19.87%
    • dev. = 2.05
    • Minimum = 15.30%
    • Maximum = 22.52%
  • Soils and regolith breccias
    • Number of analyses = 14
    • Average = 14.98%
    • dev. = 3.30
    • Minimum = 11.55%
    • Maximum = 20.70%
  • Polymict breccias
    • Number of analyses = 8
    • Average = 14.04%
    • dev. = 2.77
    • Minimum = 11.10%
    • Maximum = 19.20%
• Apollo 16
  • Mare basalts
    • Number of analyses = 9
    • Average = 18.7%
    • dev. = 0.7
    • Minimum = 17.8%
    • Maximum = 19.9%
  • Soils and regolith breccias
    • Number of analyses = 19
    • Average = 4.98%
    • dev. = 1.08
    • Minimum = 2.91%
    • Maximum = 7.73%
  • Polymict breccias
    • Number of analyses = 41
    • Average = 5.08%
    • dev. = 2.84
    • Minimum = 1.29%
    • Maximum = 13.35%
• Apollo 17
  • Mare basalts
    • Number of analyses = 25
    • Average = 18.82%
    • dev. = 0.73
    • Minimum = 16.60%
    • Maximum = 19.90%
  • Soils and regolith breccias
    • Number of analyses = 16
    • Average = 10.29%
    • dev. = 2.67
    • Minimum = 7.95%
    • Maximum = 15.94%
  • Polymict breccias
    • Number of analyses = 10
    • Average = 9.80%
    • dev. = 3.22
    • Minimum = 7.30%
    • Maximum = 16.50%
• Luna 16
  • Mare basalts
    • Number of analyses = 9
    • Average = 18.7%
    • dev. = 0.7
    • Minimum = 17.8%
    • Maximum = 19.9%
  • Soils and regolith breccias
    • Number of analyses = 3
    • Average = 16.75%
    • dev. = 0.09
    • Minimum = 16.64%
    • Maximum = 16.80%
• Luna 20
  • Soils and regolith breccias
    • Number of analyses = 5
    • Average = 7.46%
    • dev. = 0.47
    • Minimum = 7.02%
    • Maximum = 8.1%
  • Polymict breccias
    • Number of analyses = 27
    • Average = 7.11%
    • dev. = 2.05
    • Minimum = 3.80%
    • Maximum = 13.30%
• Luna 24
  • Mare basalts
    • Number of analyses = 7
    • Average = 21.58%
    • dev. = 0.87
    • Minimum = 20.46%
    • Maximum = 22.40%
  • Soils and regolith breccias
    • Number of analyses = 6
    • Average = 19.55%
    • dev. = 0.62
    • Minimum = 18.70%
    • Maximum = 20.50%
• Highland monomict rocks
  • Anorthosite
    • Number of analyses = 21
    • Average = 1.00%
    • dev. = 1.1
    • Minimum = 0.16%
    • Maximum = 4.0%
  • Norite
    • Number of analyses = 23
    • Average = 8.2%
    • dev. = 2.5
    • Minimum = 3.9%
    • Maximum = 10.7%
  • Troctolite
    • Number of analyses = 12
    • Average = 4.1%
    • dev. = 1.7
    • Minimum = 2.26%
    • Maximum = 8.55%

 

Iron abundance in Lunar soils and soil simulants (by percent) (probably by weight but unspecified)(Lunar Bases and Space Activities of the 21st Century, 498)

• Lunar highlands soils
  • FeO = 5.2%
• Lunar low-Ti mare soils
  • FeO = 15.5%
• Lunar high-Ti mare soils
  • FeO = 15.7%
• Hawaiian basalt
  • FeO = 8.9%
  • Fe₂O₃ = 4.1% (not found on Luna)
• High-Ti mare simulant
  • FeO = 12.8%
  • Fe₂O₃ = 3.7% (not found on Luna)

 

Average composition of soil (<10 to 45 micrometer)(unknown if by weight or volume)(A Global Lunar Landing Site Study to Provide the Scientific Context for Exploration of the Moon, 432)

• Mare (Apollo 11 and Apollo 12)
  • Agglutinates = 47%
  • Total pyroxene = 15%
  • Opx (orthopyroxenes) = 2%
  • Pigeonite = 6%
  • Mg cpx (clinopyroxenes) = 6%
  • Fe cpx (clinopyroxenes) = 1%
  • Plagioclase = 13%
  • Olivine = 2%
  • Ilmenite = 3%
  • Volcanic glass = 2%
  • Other = 3%
• Boundary (Apollo 15 and Apollo 17)
  • Agglutinates = 45%
  • Total pyroxene = 12%
  • Opx (orthopyroxenes) = 2%
  • Pigeonite = 5%
  • Mg cpx (clinopyroxenes) = 5%
  • Fe cpx (clinopyroxenes) = 1%
  • Plagioclase = 15%
  • Olivine = 3%
  • Ilmenite = 4%
  • Volcanic glass = 6%
  • Other = 2%
• Highland (Apollo 14 and Apollo 16)
  • Agglutinates = 47%
  • Total pyroxene = 7%
  • Opx (orthopyroxenes) = 3%
  • Pigeonite = 2%
  • Mg cpx (clinopyroxenes) = 1%
  • Fe cpx (clinopyroxenes) = 0%
  • Plagioclase = 34%
  • Olivine = 2%
  • Ilmenite = 1%
  • Volcanic glass = 2%
  • Other = 1%

 

Lunar basalt FeO range (percent weight) (A Global Lunar Landing Site Study to Provide the Scientific Context for Exploration of the Moon, 298).

• Mare = 15% – 24%
• Highlands (including anorthosite) = 1% – 4%
• Pre-mare KREEP lavas = ~10%

 

Average FeO (percent weight) for soils (Space Resources: Vol 3 Materials,23)

• Mare = 14.1%
• Highland = 5.9%
• Average surface = 7.5%

 

Average Fe atoms for soils (Space Resources: Vol 3 Materials, 23)

• Mare = 4.4% ± 0.7%
• Highland = 1.8% ± 0.3%
• Average surface = 2.3%

 

Modal abundances of major Lunar minerals (percent volume)(Space Resources: Vol 3 Materials, 28)

• High-Ti mare basalts
  • Pyroxene = 42% – 60%
  • Olivine = 0% – 10%
  • Plagioclase = 15% – 33%
  • Opaques (mostly ilmenite) = 10% – 34%
• Low-Ti mare basalts
  • Pyroxene = 42% – 60%
  • Olivine = 0% – 36%
  • Plagioclase = 17% – 33%
  • Opaques (mostly ilmenite) = 1% – 11%
• Highland rocks
  • Pyroxene = 5% – 35%
  • Olivine = 0% – 35%
  • Plagioclase = 45% – 95%
  • Opaques (mostly ilmenite) = 0% – 5%

 

Range of FeO in 79 samples (percent weight (Lunar Sourcebook, 320).

• Range for all samples = 4.2% – 22.0%
• Mean (Sum of values of a data set divided by number of values) = 12.8%
• Median (Middle value separating the greater and lesser halves of a data set) = 13.1%
• Distribution
  • 4.1%-6.0% = 16
  • 6.1%-8.0% = 1
  • 8.1%-10.0% = 7
  • 10.1%-12.0% = 11
  • 12.1%-14.0% = 7
  • 14.1%-16.0% = 12
  • 16.1%-18.0% = 14
  • 18.1%-20.0% = 4
  • 20.1%-22.0% = 7

 

Extraterrestrial Materials Processing and Construction (chapter X,L)

• High-Ti basalts
  • Pyroxene (42-60%) – 8.1-45.8% FeO
  • Olivine (0-10%) – 25.4-28.8% FeO
  • Plagioclase (15-33%) – 0.3-1.4% FeO
  • Opaques (mostly ilmentite) (10-34%) – 14.9-45.7% FeO
• Low-Ti basalts
  • Pyroxene (42-60%) – 13.1-45.5% FeO
  • Olivine (0-36%) – 21.1-47.2% FeO
  • Plagioclase (17-33%) – 0.4-2.6% FeO
  • Opaques (mostly ilmentite) (1-11%) – 44.1-46.8% FeO
• Highland rocks
  • Pyroxene (5-35%) – 8.20-24.0% FeO
  • Olivine (0-35%) – 13.4-27.3% FeO
  • Plagioclase (45-95%) – 0.18-0.34% FeO
  • Opaques (mostly ilmentite) (0-5%) – 11.60-36.0% FeO

 

Lunar Stratigraphy and Sedimentology (pg 237)

• Average Apollo 15 soil and basalt FeO content
  • Soil = 11.62%
  • Olivine basalt = 22.5%
  • Quartz basalt = 18.6%

 

Mare basalts

Abundance of iron in mare basalts (percent weight)(Handbook of Lunar Materials, 72)

• High-Ti basalts = 16.5% – 19.8%
• Low-Ti basalts = 19.3% – 22.5%

 

Range of minerals found in mare basalts (percent volume)(Handbook of Lunar Materials, 75)

• High-Ti basalts
  • Pyroxene = 42% – 60%
  • Olivine = 0% – 10%
  • Opaques (includes metal oxides) = 10% – 34%
• Low-Ti basalts
  • Pyroxene = 42% – 70%
  • Olivine = 0% – 36%
  • Opaques (includes metal oxides) = 1% – 11%

 

Iron oxide (FeO) compositions (percent weight) of major minerals of mare basalts (Handbook of Lunar Materials, 75)

• High-Ti basalts
  • Pyroxene = 8.1% – 45.8%
  • Olivine = 25.4% – 28.8%
  • Opaques (includes metal oxides) = 14.9% – 45.7%
• Low-Ti basalts
  • Pyroxene = 13.1% – 45.5%
  • Olivine = 21.1% – 47.2%
  • Opaques (includes metal oxides) = 44.1% – 46.8%

Mare data (Geologic History of the Moon, 101)

• Clinopyroxene and plagioclase combined compose 75% – 90% of most mare basalt. Pyroxene is more abundant.
• Some samples contained as much as 20% olivine and 24% optically opaque minerals (Fe-Ti oxides – ilmenite is most abundant type).
• Very high in FeO (17-22% by weight). Higher than Earth basalts.
• Essentially contain no Fe³⁺ (extreme reducing environment). Most Fe occurs as Fe²⁺.
• A minor amount of native Fe is present in all samples.
• Gaps between the high-Ti and low-Ti samples could probably be filled by yet-to-be sampled basalt types. About 1/3 of observed spectral types have been sampled.

Statistical summary of database for concentrations (by percent weight) of iron (Fe) in mare basalts (Lunar Sourcebook, 465) (I don’t think they mean free iron. They probably meant FeO).

• Apollo 11
  • Number of analyses = 79
  • Average = 15.2%
  • dev. = 1.0
  • Minimum = 12.8%
  • Maximum = 16.8%
• Apollo 12
  • Number of analyses = 21
  • Average = 15.7%
  • dev. = 1.0
  • Minimum = 13.4%
  • Maximum = 17.2%
• Apollo 14
  • Number of analyses = 3
  • Average = 12.8%
  • dev. = 0.8
  • Minimum = 12.1%
  • Maximum = 13.9%
• Apollo 15
  • Number of analyses = 14
  • Average = 15.9%
  • dev. = 1.7
  • Minimum = 12.9%
  • Maximum = 18.8%
• Apollo 16
  • Number of analyses = 1
  • Average = 15.55%
  • dev. = none
  • Minimum = none
  • Maximum = none
• Apollo 17
  • Number of analyses = 15
  • Average = 14.5%
  • dev. = 0.7
  • Minimum = 12.6%
  • Maximum = 15.5%
• Luna 16
  • Number of analyses = 4
  • Average = 14.7%
  • dev. = 0.6
  • Minimum = 14.0%
  • Maximum = 15.7%
• Luna 24
  • Number of analyses = 12
  • Average = 16.3%
  • dev. = 0.9
  • Minimum = 14.7%
  • Maximum = 17.4%

 

Polymict breccias

• The bulk average (by percent weight) of iron oxide (FeO) in fragmental breccias (a type of polymict breccia) is 3.34% (Lunar Sourcebook, 277).
• Glassy melt breccias do a little better, with a range of 4.7% to 14.7% by weight (Lunar Sourcebook, 278).
• Crystalline melt breccias have a range of 2.9% to 10.1% by weight (Lunar Sourcebook, 280).
• Clast-poor impact melts have a range of 4.1% to 8.4% by weight (Lunar Sourcebook, 282).

 

Iron oxide (FeO) in “granite” glass (percent weight) (Handbook of Lunar Materials, 76) = 3.49%

 

Iron oxide (FeO) in breccia (percent weight)(Handbook of Lunar Materials, 86)

• Mare
  • High-Ti = 17.7%
  • Low-Ti = 12.4%
• Highland
  • Anorthositic gabbro (vitric matrix) = 5.9%
  • KREEP (vitric matrix) = 10.5%
  • Light matrix = 5.8%
  • Cataclastic anorthsite = 5%
  • KREEP (crystalline matrix) = 9.8% – 10.4%
  • Anorthositic gabbro (crystalline matrix) = 4.1%
  • Gran. mix = 4.6%

 

Resources

1. Lunar Sourcebook
2. Handbook of Lunar Materials
3. Lunar Bases and Space Activities of the 21st Century
4. Geologic History of the Moon
5. A Global Lunar Landing Site Study to Provide the Scientific Context for Exploration of the Moon
6. Space Resources: Vol 3 Materials
7. Extraterrestrial Materials Processing and Construction
8. Lunar Stratigraphy and Sedimentology