Michel Maurette

Institut National de Physique Nucléaire et de Physique des Particules · CSNSM - Centre de spectrométrie nucléaire et de spectrométrie de masse

We have studied by combined high voltage and scanning electron microscopies both the latent and etched track distributions in lunar fragmental rocks as well as in solar type gas-rich meteorites. We have used a new experimental approach for studying gas-rich meteorites to avoid problems with the interpretation of the results. Some implications of th...

All noble gases are measured in 100-400 and >400-µm unmelted Antarctic micrometeorites. Significant isotopic and elemental gas variability is observed.

Lunar minerals and impact glasses, convert the polyatomic beam of solar wind (SW) ions into a flux of small molecules (e.g., H2, N2, H2O, CO, CO2, CH4, C2H4, C2H6, HCN, metal carbides and deuterides, etc.). They thus behave as "Solid State Molecular Reactors". Moreover, ~100-200 mum size micrometeoroids (muMs) have also been exposed to the SW in th...

New results on the etchability of lead implanted silicate glasses are presented which are satisfactorily accounted for by a Monte Carlo Model of etching. These results strongly support the radiation damage origin of the ion-induced modification of the chemical reactivity of glass. Major artefacts of ion implantation are then discarded as possible c...

The ion implantation-based simulation of α-recoil aging in radwaste glasses has been applied to several simulated HLW glasses. The results are qualitatively described by a new model of leaching for the implanted glasses although several specific features of irradiated surfaces are not clearly understood. This model suggests that for the most likely...

The accretion of hydrous-carbonaceous meteoroids with sizes of 50-200 µm rightly predicts the total burdens of 20Ne and 132Xe in the terrestrial atmosphere. However, the huge excesses of both 36Ar and 84Kr (15×) required additional "spikes" of cometary gases.

The accretion of hydrous-carbonaceous meteoroids with sizes of 50-200 µm rightly predicts the total burdens of 20Ne and 132Xe in the terrestrial atmosphere. However, the huge excesses of both 36Ar and 84Kr (15×) required additional "spikes" of cometary gases.

Abstract— Depending on their velocity, entry angle and mass, micrometeorites suffer different degrees of heating during their deceleration in the Earth's atmosphere, leading, in most cases, to significant textural, mineralogical and chemical modifications. One of these modifications is the formation of a magnetite shell around most micrometeorites,...

Meteoroids ˜50-200 μm in size represent the dominant mass fraction of extraterrestrial material accreted by the Earth today. About 20% of them survive as unmelted micrometeorites upon atmospheric entry, and they can be recovered from Antarctica ices and snows. Around 99% of them are related to the rare group of the most volatile-rich chondrites (˜2...

Meteoroids that survive upon atmospheric entry can be collected as Antarctic micrometeorites. (AMMs). Their analyses allow predicting the total burdens of sulfur and refractory highly siderophile elements (HSEs) delivered to the Earth by meteoroids, in the early post–lunar eon. They well fit the corresponding measured burdens stored in the primitiv...

Oxygen depth profiles measured in lunar metal grains, and attributed to the implantation of solar ions, could result from the grain "maturation" in the lunar regolith, which covers their external surface with zap-pits and tiny particles.

We present the characterization of Fe-Ni sulfides in Concordia Antarctic micrometeorites. The sulfide population is dominated by troilite which is believed to be the first sulfur containing mineral to have formed in the solar nebula.

The accumulation of short-lived isotopes in refractory minerals irradiated by solar energetic particles near the young T-Tauri Sun was severely disturbed by concomitant ion implantation effects, ranging from ion beam "slicing" to vaporization.

A new conjecture is presented that concerns the synthesis of the billions atoms macromolecules of precellular life from the small molecules of cosmic chemistry. It is rooted in Panthalassa, its winds, waves, tsunamis and recyclable petroleum "skin."

Large unmelted Antarctic micrometeorites with sizes ≥100 μm that survive upon atmospheric entry started to be exploited in planetology and exobiology in the early 1990s. This chapter mostly focuses on micrometeorites that are destroyed upon atmospheric entry, through either volatilization or melting. Their “ashes” behave as powerful “tracers” that...

The contribution of the accretion of “juvenile” micrometeorites to the volatile inventory of the Martian atmosphere had to mostly occur during the period of the late heavy bombardment of the inner solar system, prior to about 3.5 Ga ago, when the flux of micrometeorites was much higher than today. To assess this contribution, a micrometeorite accre...

The constraint of grain sizes. The discussion presented in the last section suggests that Antarctic micrometeorites would dominantly originate from comets. However, they contain refractory inclusions made of refractory oxides (Fig. 46), abbreviated as CAIs (see Sect. 6.2), which can only be formed at the highest temperatures (T ≥ 1800 K) close to t...

This book is an attempt to blend an extended and cross-disciplinary research paper about an initially neglected obscure cosmic dust contamination of the early Earth into a kind of cosmic detective investigation, which should be comprehensible by the space sciences community and undergraduate students in general. The major objectives were to:

Micrometeorites and meteorites. The mass flux (number of tons, per year, for the whole Earth) of meteorites and micrometeorites can be estimated, both before and after atmospheric entry, from the works of Haliday et al. (1989), Zolensky et al. (1992), Love and Brownlee (1993), Bland et al. (1996), Hammer and Maurette (1996), Gounelle et al. (1999)...

It is generally assumed that oxygen appeared much later in the history of the Earth, during the (Great Oxidation Event), GOE which lasted about 150 Myr, about 2 Gyr ago. But the causes of the GOE are still debated. For a long time, it was thought that it resulted from the biogenic activity of photosynthetic early life forms, which decomposed a frac...

Exobiology is a multidisciplinary science that deals with the origin and early evolution of life. For the birth of life to occur, the setting of its cosmic cradle has to be right. The first step is to make early seas and to buildup a benign greenhouse effect that prevents their freezing and/or boiling. Next, an efficient prebiotic chemistry has to...

Planets and small bodies. Besides the Sun, which represents about 99.85% of its mass, the present day solar system include large bodies, i.e., the four terrestrial planets, the four giant planets, and Pluto, which is probably not a planet, but rather an object from the Edgeworth–Kuiper belt of comets captured by Neptune; more than 130 satellites of...

The chemical composition of the Earth’s atmosphere can be defined by the Ne/N 2,H 2O/N 2and CO 2/N 2ratios deduced from the total amounts of these four volatiles in the atmosphere. The same volatiles are released by hydrous–carbonaceous micrometeorites upon frictional heating as to generate a micrometeoritic model atmosphere. Its composition is inf...

In Sect. 5.2, we quoted the excitement about tiny micrometeorites collected in the stratosphere (SMMs) with a collector plate coated with an approximately 100 μm-thick silicone oil layer, which was fixed under the wing of a stratospheric aircraft of NASA. As pointed out by Jessberger et al. (2001), “due to contamination and collection limitations m...

About 80% of the Cap-Prudhomme AMMs collected near the margin of the Antarctic ice sheets showed anomalous low sulfur contents (~0.1%) with regard to the value of ~ 3% measured in CM chondrites, to which about 95% of these AMMs are related. We thought first, like everybody, that sulfur, which is quoted as the most volatile of the moderately volatil...

This section includes a heteroclite set of questions and comments of colleagues, which have still to be fully answered. Progress in science occurs not only with a few spectacular achievements that are generally cleverly advertised by funding agencies and the prestigious journals, but also by incessant questioning. They remain in the shadow for a wh...

Antarctic micrometeorites can be assimilated to a kind of cosmic kerogen-rich "shales" when deposited on the sea floor, and trapped in sediments that get steadily buried. They could thus have formed huge amounts of crude petroleum on the young Earth.

Archeologists only started to trace back successfully the advance of the Roman legions, trade patterns and the evolution of manufacturing techniques in Roman time, once they found an efficient scheme of classification for the fragments of amphora used to transport wine for the soldiers. Similarly, the classification of meteorites and micrometeorite...

In this section micrometeorites are further divided in two distinct families:

On the Earth, an astonishing balance between the absorption and scattering of solar radiation by the early Earth produced the remarkable benign greenhouse effect favourable to the origin and evolution of life. Indeed, the first constraint on any scenario is that the early oceans were not boiling or freezing! It is generally considered that the temp...

A world of “hot” spots. Until the very recent reports of Yada et al. (2004, 2005) individual tiny interstellar dust grains (stardust) were only sought in meteorites and SMMs. This is a diffcult study, which is based on the search for isotopic anomalies in tiny submicron-sized grains with ion analyzers.

The basic time frame of EMMA is the formation time interval of the Earth, Δ(Earth) ~ 100 Myr. This value has been estimated from both the 129I– 129Xe radioactive chronometer (Pepin and Phinney, 1975; Staudacher and Allgre 1982) and modern theories about the formation of the Earth initiated by Wetherill (1994) –for a recent summary see Canup and Agn...

Maurette (1998a and 1998b) gives a more detailed discussion of previous works supporting the role of unmelted micrometeorites in prebiotic chemistry. Krueger and Kissel (1987) quoted thermodynamic computations suggesting that the μm-size C-rich grains that they discovered in the tail of Halley’s comet with their time-of-flight mass spectrometer on...

Micrometeorites played an essential role in the formation of the atmosphere of the Early Earth and also served as a significant source of activation for organic prebiotic chemistry on mineral surfaces. The present book gives a coherent account of this scenario, embedding the more specific results within a broader framework that considers the creati...

A French word, “errance” (the straightforward approximate English translation is wandering) well describes the functioning of the mind when you do not know where you are going. You feel dumb just knowing that you will probably end up somewhere else. Then, you bury this shameful weakness of your neuronal system in the deepest secrecy and start again...

Many observations remind us that the Earth–Moon system has been bombarded by projectiles covering a wide size range between submicrometer particles to the giant Mars-sized body that did form the Moon during its impact with the proto-Earth. They include:

According to the definition of Ozima and Podosek (2002), the Earth’s atmosphere refers to all volatiles in surface reservoirs, including air, water and sedimentary rocks such as carbonates in which early CO2 is now trapped.

Any study of micrometeorites involves a variety of biases, which start right away during their collection, and which have not been suffciently publicized. This section deals with the astonishing folklore of these biases. We shall question whether major differences observed between Antarctic micrometeorites and stratospheric micrometeorites could re...

Jupiter is a gigantic gravitational sling that can alter the orbits of small bodies while triggering their “chaotic” diffusion. This property was used to fly the spacecraft Ulysses around the solar poles. Ulysses was not fired directly to the Sun but to Jupiter, which did sling it back to the Sun, thus saving the spacecraft a lot of energy.

The application of the accretion formula to the Earth–Moon system does not require the identification of the parent bodies of micrometeorites (i.e., asteroids or comets). However, this identification is necessary to better extrapolate this formula to other terrestrial planets, such as Mars. One would also like to understand how the invariant compos...

In accordance with Ozima and Podosek (2002), atmosphere will refer to all volatiles in surface reservoirs of the Earth, including air but also liquid and frozen water and sedimentary rocks, such carbonates, where early CO2 is now trapped. Today, around 90% of the mass of air is found in the first six kilometers of the thick gaseous envelope of the...

The early Earth’s atmosphere was much more massive than today. Before the condensation of water and the subsequent dissolution of CO2 that precipitated into carbonates, the partial pressures of H2O and CO2 were about 270 bars and 60 bars, respectively. Today, planetary exploration has revealed that the atmospheres of 8 planets and 3 of their approx...

In this section, EMMA is first extrapolated to the Moon, to hopefully get new clues about a confusing problem that people have failed to figure out since 1970. It deals with the so-called meteoritic contamination of the lunar crust in siderophile elements such as iridium, which was previously attributed to the crater-forming impactors and not to mi...

Colleagues still have trouble understanding how the dominant relationship between CM-type chondrites and AMMs was established. They also wonder about the meaning of this relationship in terms of solar system history, and they generally expect that it has been markedly altered upon atmospheric entry, except for the smallest particles collected in th...

When they are ejected into the interplanetary medium during interasteroidal collisions, meteorites have a limited lifetime in space, which is scaled by their “cosmic-ray exposure ages” inferred from the concentrations of cosmogenic nuclides such as 3He, 21Ne and 38Ar, produced during the nuclear reactions of galactic cosmic rays with the constituen...

Prediction of iridium content. Iridium is a highly siderophile element. Accordingly to a conventional scenario (c.f., Sect. 3.5), this element was initially stored in both the planetesimals that formed the proto-Earth and the half-dozen planetary embryos (i.e., proto-planets) that subsequently merged into it. Each of these bodies, which were not fu...

About 75% of the incoming micrometeorites are destroyed upon atmospheric entry, being either volatilized or transformed into dry cosmic spherules. In 1998, Cécile Engrand got the first strong hint that the ashes of these "dead" micrometeorites might also have contributed to exobiology. She found that the isotopic composition of the water "ash" that...

When they are ejected into the interplanetary medium during interasteroidal collisions, meteorites have a limited lifetime in space, which is scaled by their “cosmic-ray exposure ages” inferred from the concentrations of cosmogenic nuclides such as 3He, 21Ne and 38Ar, produced during the nuclear reactions of galactic cosmic rays with the constituen...

A French word, “errance” (the straightforward approximate English translation is wandering) well describes the functioning of the mind when you do not know where you are going. You feel dumb just knowing that you will probably end up somewhere else. Then, you bury this shameful weakness of your neuronal system in the deepest secrecy and start again...

Exobiology is a multidisciplinary science that deals with the origin and early evolution of life. For the birth of life to occur, the setting of its cosmic cradle has to be right. The first step is to make early seas and to buildup a benign greenhouse effect that prevents their freezing and/or boiling. Next, an efficient prebiotic chemistry has to...

Maurette (1998a and 1998b) gives a more detailed discussion of previous works supporting the role of unmelted micrometeorites in prebiotic chemistry. Krueger and Kissel (1987) quoted thermodynamic computations suggesting that the μm-size C-rich grains that they discovered in the tail of Halley’s comet with their time-of-flight mass spectrometer on...

Colleagues still have trouble understanding how the dominant relationship between CM-type chondrites and AMMs was established. They also wonder about the meaning of this relationship in terms of solar system history, and they generally expect that it has been markedly altered upon atmospheric entry, except for the smallest particles collected in th...

About 75% of the incoming micrometeorites are destroyed upon atmospheric entry, being either volatilized or transformed into dry cosmic spherules. In 1998, Cécile Engrand got the first strong hint that the ashes of these “dead” micrometeorites might also have contributed to exobiology. She found that the isotopic composition of the water “ash” that...

Ozima and Podosek (2002) clearly state: “In summary, there is still no satisfactory theory on the origin of terrestrial noble gases”. This view is also supported by Porcelli and Pepin (2000), who note: “there still is no consensus on how the terrestrial noble gases originated”. Two of the major problems with the distribution of noble gases on the E...

In Sect. 5.2, we quoted the excitement about tiny micrometeorites collected in the stratosphere (SMMs) with a collector plate coated with an approximately 100 μm-thick silicone oil layer, which was fixed under the wing of a stratospheric aircraft of NASA. As pointed out by Jessberger et al. (2001), “due to contamination and collection limitations m...

Micrometeorites and meteorites. The mass flux (number of tons, per year, for the whole Earth) of meteorites and micrometeorites can be estimated, both before and after atmospheric entry, from the works of Haliday et al. (1989), Zolensky et al. (1992), Love and Brownlee (1993), Bland et al. (1996), Hammer and Maurette (1996), Gounelle et al. (1999)...

In this section, EMMA is first extrapolated to the Moon, to hopefully get new clues about a confusing problem that people have failed to figure out since 1970. It deals with the so-called meteoritic contamination of the lunar crust in siderophile elements such as iridium, which was previously attributed to the crater-forming impactors and not to mi...

On the Earth, an astonishing balance between the absorption and scattering of solar radiation by the early Earth produced the remarkable benign greenhouse effect favourable to the origin and evolution of life. Indeed, the first constraint on any scenario is that the early oceans were not boiling or freezing! It is generally considered that the temp...

In accordance with Ozima and Podosek (2002), atmosphere will refer to all volatiles in surface reservoirs of the Earth, including air but also liquid and frozen water and sedimentary rocks, such carbonates, where early CO2 is now trapped. Today, around 90% of the mass of air is found in the first six kilometers of the thick gaseous envelope of the...

The application of the accretion formula to the Earth–Moon system does not require the identification of the parent bodies of micrometeorites (i.e., asteroids or comets). However, this identification is necessary to better extrapolate this formula to other terrestrial planets, such as Mars. One would also like to understand how the invariant compos...

Prediction of iridium content. Iridium is a highly siderophile element. Accordingly to a conventional scenario (c.f., Sect. 3.5), this element was initially stored in both the planetesimals that formed the proto-Earth and the half-dozen planetary embryos (i.e., proto-planets) that subsequently merged into it. Each of these bodies, which were not fu...

About 80% of the Cap-Prudhomme AMMs collected near the margin of the Antarctic ice sheets showed anomalous low sulfur contents (~0.1%) with regard to the value of ~ 3% measured in CM chondrites, to which about 95% of these AMMs are related. We thought first, like everybody, that sulfur, which is quoted as the most volatile of the moderately volatil...

The basic time frame of EMMA is the formation time interval of the Earth, Δ(Earth) ~ 100 Myr. This value has been estimated from both the 129I– 129Xe radioactive chronometer (Pepin and Phinney, 1975; Staudacher and Allègre 1982) and modern theories about the formation of the Earth initiated by Wetherill (1994) –for a recent summary see Canup and Ag...

This book is an attempt to blend an extended and cross-disciplinary research paper about an initially neglected obscure cosmic dust contamination of the early Earth into a kind of cosmic detective investigation, which should be comprehensible by the space sciences community and undergraduate students in general. The major objectives were to:

In this section micrometeorites are further divided in two distinct families:

Abstract— We have investigated the texture, bulk chemistry, mineralogy, as well as the anhydrous minerals oxygen isotopic composition of 67 small Antarctic micrometeorites (AMMs) collected at Cap Prudhomme, Antarctica, and belonging to the currently poorly studied size fraction 25–50 μm. When compared to larger (50–400 μm) micrometeorites collected...

We recovered micrometeorites trapped in central Antarctica surface snow. The CONCORDIA-Collection is characterized by minimal terrestrial weathering and friable fine-grained micrometeorites. Size distributions are reported.

Micrometeorites with sizes below 1 mm are collected in a diversity of environments such as deep-sea sediments and polar caps. Chemical, mineralogical and isotopic studies indicate that micrometeorites are closely related to primitive carbonaceous chondrites that amount to only approximately 2% of meteorite falls. While thousands of micrometeorites...

We launched a program to recover cosmic dust (micrometeorites) from Dome C surface snow near the French-Italian station CONCORDIA. The Dome C snow is uniquely shielded from both morainic debris and aeolian dust within the micrometeorite size range (>=25 mum). The average temperature at Dome C ranges from -20° C to -75° C throughout the year. Once t...

A highly specific signature of micrometeoric neon (i.e., a ^20Ne/^22Ne ratio of about 11.8 11.9) was found in the upper mantle. Only a small fraction (0.3%) of the available amount of micrometeoritic neon locked in unmelted micrometeorites has to be subducted into the mantle.

We estimate the huge input rates of sulfur, smoke particles and oligoelements on the Earth, which were produced during the early accretion of micrometeorites, after the formation of the Moon. We discuss several of their applications in astrobiology.

A lunar "wind" produced by the volatilization of CM2-type juvenile micrometeorites, during the late heavy bombardment conjectured by W. K. Hartmann, accounts for the contents of Ir measured by J. Wasson and collaborators in lunar samples from the 6 landing sites.

We recovered micrometeorites from surface snow layers near the French-Italian station CONCORDIA. The unique weather and isolation conditions of Dome C allowed us to recover micrometeorites that are much better preserved than those extracted from blue ice fields. We have identified a new population of friable fine-grained micrometeorites; the absenc...

From Ni to CO2. We attempted to get clues about the early history of the Martian atmosphere relying on CO2 and N2 released by micrometeorites upon atmospheric entry, as "tracers" of this history. We did apply the "lunar" model used to predict the Ni contents of the Martian soil (see a companion abstract). An interesting constraint is the CO2/N2 rat...

Model. EMMA is a model describing the effects of the accretion of micrometeorites on the early terrestrial planets during the period of late heavy bombardment (LHBomb), prior to ˜ 3.9 Gyr. On the Earth and Moon there are well preserved remnants of this accretionary phase, including in particular the iridium and Ni content of the lunar crust and the...

The atmosphere includes the air, the ocean and CO2 trapped in carbonates. Its composition was defined by the Ne/N2, H2O/N2 and CO2/N2 ratios inferred from the total quantities of these four volatiles in the atmosphere. This composition, which refers to a total mass of volatiles of about 2 × 1024 g, was found to be unexpectedly similar to that of a...

(1) Processed micrometeorites in Astrobiology. In previous studies, we considered the contribution of unmelted micrometeorites in astrobiology. We now argue that even processed micrometeorites that are destroyed upon atmospheric entry could have participated in the birth of life on Earth. Unweathered micrometeorites from our new "Concordia-collecti...

The discussion of fossil nuclear reactors (the Oklo phenomenon) covers the earth science background, neutron-induced isotopes and reactor operating conditions, radiation-damage studies, and reactor modeling. In conclusion possible future studies are suggested and the significance of the data obtained in past studies is summarized. (JSR)

The evolution of carbonaceous material in sporadic and "shower" micrometeorites under cosmic irradiation (of both galactic and solar energetic particles) is examined. Implications are drawn concerning prebiotic chemistry.

Using a new collection technique, we recovered micrometeorites trapped in central Antarctic surface snow. They are characterized by minimal terrestrial weathering compared to the previous collections in the ice at the coast of the continent.

We point out a possible "Ne fingerprint" to identify, in the 1966 "Leonids" snow layer in central Greenland and Antarctica, micrometeorites coming from recent release of comet Temple-Tuttle. Consequences for the EMMA scenario are discussed.