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Meteorites and Their Parent Planets
Abstract
This book explores the origins of meteorites by tracing them back to
their parent bodies, which are the sites of various geological
processes. Recent discoveries are reviewed which reveal that the
chemical and physical properties of meteorites contain a record of the
processes that formed the solar system. How meteorites escape their
parent bodies and find their way to earth is explained.
... Ernst Chladni published a book in 1794 (Chladni, 1794) proposing the possibility that meteorites were derived from larger bodies in the solar system, rather than condensing as small chunks that periodically fell from space or clouds. At the time of publication, Chladni's explanations were largely ignored and occasionally ridiculed because no object capable of producing meteorites had been observed (McSween, 2006). In 1801, astronomer Giuseppe Piazza accidentally discovered asteroid (1) Ceres (Serio et al., 2002). ...
... The formula suggests that, extending outward, each planet should be approximately twice as far from the Sun as the proceeding planet. (McSween, 2006). ...
... Due to these discoveries, Olbers agreed with Chladni that meteorites were fragments of the same exploded planet (Cunningham, 2017). The hypothesis that the asteroid belt is a remnant of a destroyed planet proved to be popular and was the consensus amongst astronomers and geologists throughout the 19 th and the first half of the 20 th century (Cunningham, 2017;McSween, 2006). The idea of a cataclysmic event destroying an entire planet also aligned well with catastrophism, which was a prevalent geologic doctrine in the 18 th and 19 th centuries (Lutgens et al., 2012). ...
This study investigates the visible and near-infrared (VNIR) spectral properties (0.4-2.5-µm) of five Tholen G-class asteroids. Spectral features relating to hydrated Fe- or Mg-rich minerals have been identified at 0.7-µm, 0.95-µm, 1.4-µm, 1.9-µm, and 2.3-µm, while spectral features that may be related to CH or NH compounds were identified at 1.14-µm and 1.25-µm. (1) Ceres lacks features related to hydrated minerals and is spectrally disparate from the other four investigated asteroids. (13) Egeria, (19) Fortuna, (84) Klio, and (130) Elektra all exhibit at least two measurable features that may be related to hydrated minerals. (19) Fortuna, (84) Klio, and (130) Elektra each exhibit similar spectral slope and feature intensity, while (13) Egeria has a bluer slope and more intense features. These differences may be related to (13) Egeria’s higher density, surface particle size, or the effects of space weathering
... Historically, the classification of asteroids has been carried out by optical albedo observations, measuring the scintillation spectrum of light that they give off [3]. However, because the bulk and surface composition can differ greatly, albedo measurements are not always the most accurate way of determining composition of the bulk of the asteroid. ...
... 30 kg, 32 W for Mars Odyssey and 10 kg, 15 W for GRaND [5,8]. While 3 He gas tubes are highly efficient neutron detectors due to a high cross-section for neutron detection, they are heavy, require high voltage, and are bulky. Similarly, most scintillator-based detectors require pairing with photomultiplier tube (PMT) systems, which are sensitive to magnetic fields and add weight to payload and increase power consumption. ...
We present a preliminary design for a novel neutron detection system that is compact, lightweight, and low power consuming, utilizing the CubeSat platform making it suitable for space-based applications. This is made possible using the scintillating crystal lithium indium diselenide (LiInSe), the first crystal to include Li in the crystalline structure, and a silicon avalanche photodiode (Si-APD). The schematics of this instrument are presented as well as the response of the instrument to initial testing under alpha radiation. A principal aim of this work is to demonstrate the feasibility of such a neutron detection system within a CubeSat platform. The entire end-to-end system presented here is 10 cm x 10 cm x 15 cm, weighs 670 grams and requires 5 Volts direct current at 3 Watts.
... Meteorites are fragments of naturally occurring space material that have fallen to any planetary surface through natural processes. Collisions between asteroids and between asteroids and larger bodies such as the Moon and planets, can send fragments into Earth-crossing orbits, some of these can fall as meteorites (McSween et al. 1987). They can be linked spectroscopically. ...
... A probable terrestrial rock has been found on the Moon in one of the samples returned by the Apollo 14 mission (Bellucci et al. 2019). Most meteorites are, however from the asteroid belt (McSween et al. 1987). Figure 4 shows a number of asteroids visited or about to be visited by space missions that represent the most common asteroid classes. ...
... Both bulk and mantle compositions are poorly constrained compared with the Earth. Mantle compositions are inferred from studies of SNC meteorites for Mars, the eucritic meteorites for Vesta, and samples collected from the Moon's surface (McSween, 1999;Warren, 1993). In all cases, the samples (e.g., lavas and cumulates) are the products of crustal differentiation processes, and therefore, mantle compositions have to be inferred by taking the effects of differentiation into account. ...
... Compared to the Earth's mantle, current assessments indicate that the Martian mantle is relatively depleted in Ni and Co, whereas concentrations of HSEs are similar. As in the Earth's mantle, the HSEs appear to be present in chondritic relative abundances ( Jones et al., 2003;Kong et al., 1999;McSween, 1999;Warren et al., 1999). The mantles of both the Moon and Vesta show relatively large depletions in most siderophile elements (Righter and Drake, 1996;Walter et al., 2000). ...
The formation of the Earth's core is intimately linked to the manner in which the planet accreted. Small bodies (i.e., planetesimals), if they accreted sufficiently early, may have melted and differentiated due to the decay of short-lived radioisotopes such as ²⁶Al. For Earth-sized bodies, the final stages of accretion involved impacts between comparably sized objects, many of which were probably already differentiated. These impacts were sufficiently energetic to melt large portions of the planet, although the lateral extent of the melting and the lifetime of the resulting magma oceans are both currently poorly understood. Metal-silicate segregation, as required for core formation, can occur by several mechanisms depending on the degree of melting. The percolation of molten iron through solid silicates, which depends on the wetting properties of the melt (dihedral angle), melt fraction and shear stress, is unlikely to be an efficient mechanism in an Earth-sized planet. In a magma ocean, on the other hand, the separation of molten iron from molten silicates is very rapid and efficient. Core formation itself releases gravitational energy and thus generates further heating. Thus, once the Earth grew sufficiently large, melting and core formation were inevitable. Because of the stochastic nature of late-stage impacts, large bodies of iron (the cores of planetesimals) were delivered to the Earth at discrete intervals. The extent to which these iron bodies emulsified during impacts is currently uncertain but has important implications for the chemical evolution of the core and mantle.The hafnium-tungsten (Hf-W) chronometer has been used to constrain the core formation time of the Earth to 30-50 Myr after solar system formation. This timescale, though it cannot fully capture the growth of the core by multiple, discrete impacts, is in good agreement with numerical accretion models. The Hf-W results show that the cores of impactors at least partly reequilibrated with the silicate mantle, suggesting that emulsification during impacts is a relatively efficient process.Mantle siderophile element concentrations are higher than would be expected based on low-pressure partition coefficients. Metal-silicate partition coefficients determined at high P-. T conditions (20-40. GPa and 2500-4000. K) can explain the abundances of moderately siderophile elements. These partition coefficients are again consistent with metal-silicate equilibration occurring near the base of a magma ocean, though the true picture is likely to involve multiple magma oceans with different (and evolving) conditions of pressure, temperature, and oxygen fugacity. The highly siderophile element (HSE) concentrations require the addition of chondritic material to the mantle (the 'late veneer') after core formation ended.The identity of the light element(s) in the core is currently uncertain, due mainly to the paucity of experiments at the required P-. T conditions. As for the siderophile elements, the light element content was likely set during core formation through metal-silicate partitioning. Based on cosmochemical arguments and a range of recent studies, the major light element in the core is most likely silicon, with a lesser amount of O and ~2. wt%S.
... John Anfinogenov proposed a hypothesis for the existence of sedimentary-origin meteorites (hereinafter referred to as "sedimentary meteorites") after he found a fresh impact site in the epicenter of the 1908 Tunguska explosion containing the exotic sedimentary boulder (John's stone or John's rock) whose splinters had glassy surface reminiscent of freshly applied enamel or fusion crust. His reports on discovery of John's rock and hypothesis of sedimentary meteorites from Mars or from hypothetical planet called Phaeton [McSween 1999] were published by local mass media in 1973 [Anfinogenov 1973]. Findings were further discussed in more detail [Anfinogenov et al. 1998b] and presented to international audience [Anfinogenov et al. 1998a]. ...
... In early 1970s, after discovering sedimentary boulder associated with high-speed impact in the epicenter of the 1908 Tunguska catastrophe, John Anfinogenov [1973] hypothesized that sedimentary meteorites may come to the Earth from hypothetical planet called Phaeton [McSween 1999]. Findings of so-called Martian meteorites and some pseudo-meteorites belonging to upper-crust rocks (volcanic and highly-metamorphic igneous and sedimentary rocks) from Mars-like planets provide rationale for reconsideration of the hypothesis on past existence of a planet between the orbits of Mars and Jupiter as a parent body of the asteroid belt. ...
This concept article discusses the possibilities for identifying sedimentary-origin meteorites. The paper concerns (i) the macroscopic candidate for sedimentary meteorite in the epicenter of the 1908 Tunguska catastrophe; (ii) potential parent bodies for sedimentary meteorites; (iii) isotopic heterogeneity of unmixed silicate reservoirs on Mars; (iv) possible terrestrial loss or contamination in the noble gas signatures in new type meteorites that spent time in extreme weather conditions; (v) cosmogenic isotopes and shielding; and (vi) pseudo meteorites. We conclude that the list of candidate parent bodies for sedimentary meteorites includes, but is not limited by the Earth, Mars, Enceladus, Ganymede, Europa, and hypothetical planets that could exist between orbits of Mars and Jupiter in the past. A parent body for extraterrestrial sedimentary rocks on the Earth should be identified based on the entire body of evidence which is not limited solely by tests of oxygen and noble gas isotopes whose signatures may undergo terrestrial contamination and may exhibit significant heterogeneity within the parent bodies. Observed fall of cosmic body, evidence of hypervelocity impact complying with the criteria of impact structures, and the presence of fusion crust on the fragments should be considered as priority signs of meteoritic origin.
... After discovery of the sedimentary boulder associated with hypervelocity disruption of the ground in the epicenter of the 1908 Tunguska catastrophe, it was hypothesized [Anfinogenov 1973, Anfinogenov and Budaeva 1998] that sedimentary meteorites may come to the Earth from a hypothetical planet called Phaeton [McSween 1999]. Findings of the so-called Martian meteorites and some pseudo-meteorites belonging to upper-crust rocks (volcanic and highlymetamorphic igneous and sedimentary rocks) from Mars-like planets provide rationale for reconsideration of the hypothesis on past existence of a planet between the orbits of Mars and Jupiter as a parent body of the asteroid belt. ...
This concept article discusses the challenges of identifying planetary-origin meteorites of non-igneous composition, primarily of sedimentary origin, distinct from SNC meteorites. The paper reviews evidence on putative sedimentary-origin meteorites and potential parent bodies for sedimentary meteorites. Authors conclude that the list of candidate parent bodies for sedimentary meteorites includes, but is not limited by the Earth, Mars, Enceladus, Ganymede, Europa, and hypothetical planets that could exist between orbits of Mars and Jupiter in the past. Authors argue that extraterrestrial origin and a parent body for meteoritic sedimentary rocks may be identified based on the entire body of evidence which is not limited solely by tests of oxygen and noble gas isotopes whose signatures may undergo terrestrial contamination and may exhibit significant heterogeneity within the Solar system and within the parent cosmic bodies. Observed fall of a cosmic body, evidence of hypervelocity fall, signs of impact in target, and the presence of fusion crust, melting, and/or shock deformation features in the fragments should be considered as priority signs of meteoritic origin.
... However, the rapid formation of relatively large planetesimals also implies that they are likely to have acquired similar quantities of radioactive 26 Al isotopes, as those found in the most primitive Calcium-Aluminium-rich inclusions (CAIs). Under such conditions, the heat released from nuclear fission would be adequate to melt and differentiate planetesimals with sizes larger than a few tens of kilometers (McSween 1999). Under the rapid formation scenario, first-generation large planetesimals are likely to be differentiated. ...
The distribution of heavy elements is anomalously low in the asteroid main belt region compared with elsewhere in the solar system. Observational surveys also indicate a deficit in the number of small (~km size) asteroids that is two orders of magnitude lower than what is expected from the single power-law distribution that results from a collisional coagulation and fragmentation equilibrium. Here, we consider the possibility that a major fraction of the original asteroid population may have been cleared out by Jupiter's secular resonance, as it swept through the main asteroid belt during the depletion of the solar nebula. This effect leads to the excitation of the asteroids' orbital eccentricities. Concurrently, hydrodynamic drag and planet-disk tidal interaction effectively damp the eccentricities of sub-100 km-size and of super-lunar-size planetesimals, respectively. These combined effects lead to the asteroids' orbital decay and clearing from the present-day main belt region (~AU). The intermediate-size (50 to several hundreds of kilometers) planetesimals therefore preferentially remain as main belt asteroids near their birthplaces, with modest asymptotic eccentricities. The smaller asteroids are the fragments of subsequent disruptive collisions at later times as suggested by the present-day asteroid families. This scenario provides a natural explanation for both the observed low surface density and the size distribution of asteroids in the main belt. It also offers an explanation for the confined spatial extent of the terrestrial planet building blocks without the requirement of extensive migration of Jupiter.
... Not to mention the fact that they are made up of the most disparate materials: some are made entirely of metal, others, the majority with about 75% of the total, of carbonaceous rocks and another 15% of silicates [15]. In any case, all rocks and metals that must necessarily have formed inside some massive body at very high pressure and temperature [16]. ...
All astronomical bodies originate inside clouds of gas and dust, therefore there should be a common process that leads to their condensation. In a galactic cloud there is always a gradient of speeds from point to point. Thanks to it, vortices originate that rake the material of the surrounding cloud gradually forming large gaseous disks, inside which vortices of second order develop that concentrate the matter of their orbits forming smaller and much denser disks, within which third order vortices further concentrate the matter. The dense cores of these vortices finally condense in massive bodies: sun, planets and satellites. The result should be a well ordered planetary system with no “debris” around and where both planets and satellites obey to a precise rule of the distances from their central body. The solar system complies with these conditions with three main exceptions. First, in an orbit where a large planet should be there is only a huge number of scattered asteroids. Second, Earth and its moon with all evidence were not formed in the same vortex, which means that Moon originated somewhere else. Third, Neptune’s satellite system has been shattered by the intrusion of a foreign body, Triton, and its largest satellites are missing. These exceptions seem to be strictly connected to each other and all due to a unique event, that is: Triton has diverted the largest Neptune satellite towards the Sun. This satellite impacted at high speed against the missing planet, scattering myriads of fragments from its mantle and pushing it towards the sun, where it eventually fell. The planet had at least 4 satellites some of which remained in their previous orbit, but two of them were dragged towards the sun and were captured by Earth. The largest became its lonely moon while the second fell on its surface giving origin to the continents. This event happened about 3,96 billion of years ago, as it is proven by the ages of the numerous samples brought from the moon.
... The siderophile element budget of iron meteorites have provided liquidus temperature estimates as well the mass fraction of cores of IMPBs (Hilton et al., 2022;Tornabene et al., 2023). In addition, thermal modeling combined with cooling experiments has constrained the possible sizes of IMPBs (Kaminski et al., 2020;Yang et al., 2008Yang et al., , 2010Yang and Goldstein, 2006;McSween, 1999). We explored how the N budget in the IMPBs could be affected by the styles of magmatic differentiation in these small protobodies. ...
... Dalgety Downs presenta una composición mineralógica muy homogénea entre los cóndrulos y su matriz, que junto a otros rasgos texturales característicos de un metamorfismo térmico avanzado como son la recristalización de la matriz, la pérdida de nitidez en bordes de cóndrulos y la desvitrificación de sus mesostasias, en la se forman microcristales de plagioclasa (Muñoz-Espadas, 2003), permiten confirmar el tipo petrológico 4 asignado a esta condrita (Van Schmus y Wood, 1967) en un contexto de temperaturas intermedias compren-didas entre los 600 y 700 ºC (McSween, 1999). ...
El meteorito de Dalgety Downs, hallado en el Desierto de Australia Occidental, es una condrita ordinaria muy poco estudiada, que sin embargo contiene una valiosa información acerca de la evolución de la materia primitiva del Sistema Solar y los procesos que le afectan. Este ejemplar presenta unas características texturales, mineralógicas y geoquímicas en la matriz y cóndrulos que revelan procesos metamórficos de temperaturas intermedias y eventos de impacto moderados, además de una intensa alteración desarrollada durante su entrada en la atmósfera terrestre y su posterior exposición al clima, en lo que se define como la costra de fusión. Entre los métodos empleados en este estudio destaca la espectroscopía Raman como herramienta de identificación mineralógica, técnica que ha demostrado una gran precisión en materiales geológicos y que será empleada en próximas misiones espaciales.
... While these changes were taken into account, the IAU also considered that the definition of meteorite did not need to be modified under the definition of meteoroid proposed by Beech and Stell (1995), since by then the definition for a meteorite had gone through a long process of modifications (Craig 1849;Rubin & Grossman 2010;Cohen 1894;Farrington 1915;Nininger 1933;Millman 1961;Mason 1962;Gomes & Keil 1980;McSween 1987;Krot et al. 2003). Therefore, by 2003 the definition of a meteorite was established as: a solid body of extraterrestrial material that penetrates the atmosphere and reaches the Earth's surface (Krot et al. 2003). ...
In this document we briefly review the evolution of the term meteoroid and we make several proposals for a definition, emphasizing the importance of the criteria used for it. Finally, we propose a definition based on observations rather than on the instrument of observation.
... Se conocen muy pocos y, como es de esperarse, son muy apetecidos por museos y coleccionistas privados que no reparan en adquirirlos por centenares de miles de dólares. Casi todos ellos se conocen con el nombre de meteoritos Shergottita-Nakhlita-Chassignita (SNC), denominación que responde de los nombres de los lugares donde fueron encontrados (McSween, 1999). ...
... Meteorites are an important source of extraterrestrial matter; their chemical and physical characteristics, texture and internal structure contribute to the understanding of the birth and early history of the solar system (McSween 1999). In many meteorites shock-induced transformations are found which provide important clues on the geological history of the meteorite and its parent body (Lange et al. 1985;Keil et al. 1992;Rubin and Bottke 2009;Hemley et al. 2009;Friedrich et al. 2014;Krzesiñska and Jörg 2014;Nagy et al. 2012;Pang et al. 2016;Gyollai et al. 2017Gyollai et al. , 2019Miyahara et al. 2020). ...
For the first time, the presence of olivine-ringwoodite and plagioclase-maskelynite transformations is reported in Natun Balijan L4 chondrite determined by micro-Raman and infrared spectroscopic techniques with mineral phases characterised by electron microprobe analysis. Micro-Raman spectra reveal trace of ringwoodite, which is independently confirmed with the powder X-ray diffraction analysis. Full width at half maximum data of Raman spectrum reveals structural disordered olivine and pyroxene. The nature of infrared peaks at 639 and 724 cm-1 depicts the presence of maskelynite. Observed maskelynite Raman band at 509 and 581 cm-1 are used to estimate the shock stage of Natun Balijan L4 chondrite as at least S5. The impact metamorphism with a shock pressure of at least 40 GPa is estimated. INTRODUCTION Meteorites are an important source of extraterrestrial matter; their chemical and physical characteristics, texture and internal structure contribute to the understanding of the birth and early history of the solar system (McSween 1999). In many meteorites shock-induced transformations are found which provide important clues on the geological history of the meteorite and its parent body (Lange et al. Miyahara et al. 2020). The shocked meteorites contain many different, at times unique, high pressure minerals e.g. plagioclase transforms into maskelynite (a diaplectic glass) through compression at high shock pressures, and ringwoodite (a high-pressure polymorphous phase of olivine with a spinel structure), which formed in the vicinity of silicate melt veins in many highly shocked ordinary chondrites (Rubin and Ma 2017; Ma 2018; Chandra et al.
... Meteorites are an important source of extraterrestrial matter; their chemical and physical characteristics, texture and internal structure contribute to the understanding of the birth and early history of the solar system (McSween 1999). In many meteorites shock-induced transformations are found which provide important clues on the geological history of the meteorite and its parent body (Lange et al. 1985;Keil et al. 1992;Rubin and Bottke 2009;Hemley et al. 2009;Friedrich et al. 2014;Krzesiñska and Jörg 2014;Nagy et al. 2012;Pang et al. 2016;Gyollai et al. 2017Gyollai et al. , 2019Miyahara et al. 2020). ...
For the first time, the presence of olivine-ringwoodite and plagioclase-maskelynite transformations is reported in Natun Balijan L4 chondrite determined by micro-Raman and infrared spectroscopic techniques with mineral phases characterised by electron microprobe analysis. Micro-Raman spectra reveal trace of ringwoodite, which is independently confirmed with the powder X-ray diffraction analysis. Full width at half maximum data of Raman spectrum reveals structural disordered olivine and pyroxene. The nature of infrared peaks at 639 and 724 cm−1 depicts the presence of maskelynite. Observed maskelynite Raman band at 509 and 581 cm−1 are used to estimate the shock stage of Natun Balijan L4 chondrite as at least S5. The impact metamorphism with a shock pressure of at least 40 GPa is estimated.
... Most meteorites originated from different solar system bodies formed during the accretion processes that took place in the first few Myr, thus they vary in elemental and isotopic composition. Consequently, meteorites are an important source of extraterrestrial matter and their chemical and physical characteristics, texture and internal structure contribute to our understanding of the birth and early history of our solar system (McSween, 1999). The most common type of meteorites is chondrites and they originate from debris of the solar nebula (e.g., Brearley, 2003;Hutchison, 2004). ...
We present here the evidence for the presence of organic matters in Dergaon, Mahadevpur and Natun Balijan ordinary chondrites using Fourier transforminfrared and micro-Raman spectroscopic technique. The Fourier transforminfrared spectrum of these ordinary chondrites in the range 2700 3000 cm-1 indicates the presence of CH3 asymmetric stretching, and CH2symmetric and asymmetric stretching modes due to aliphatic hydrocarbons. The micro-Raman spectrum exhibits the diamond and graphite peaks correspondingly at 1331 cm-1 , 1349 cm-1 and 1588 1618 cm-1. The full wave at half maximum value correspondingly 120 cm-1 , 70 cm-1 and 17.5 cm-1 for Dergaon, Mahadevpur and Natun Balijan, indicate the nature of disordered phase involved shock metamorphism in the meteorites. The diamond and graphite peaks intensity ratios of ~1.121, ~1.075 and ~0.532, correspondingly for Dergaon, Mahadevpur and Natun Balijan, indicates the disordered nature of graphite. This study has strong implications in understanding of the origin of organic matters in extra-terrestrial materials and origin of extraterrestrial life.
... Compositional and mineralogical studies on meteorites are found to be the most useful tools in understanding the planetary processes and oAer great insight in getting the shock pressure and temperature conditions of the planetary bodies (McSween 1999). The study of chemical composition and mineralogical characterization of meteorites are very important in understanding the origin and dynamics of solar system (Dhingra et al. 2004;Parthasarathy et al. 2004;Bhandari et al. 2005Bhandari et al. , 2008Bhandari et al. , 2009Saikia et al. 2009a;Chandra et al. 2013;Agarwal et al. 2014;Saikia et al. 2017a, b, c;Chandra et al. 2018). ...
We present here the composition and spectroscopic studies on the Kamargaon (L6) chondrite using laser micro-Raman spectroscopic and powder X-ray diffraction techniques. Both powder XRD and micro-Raman studies reveal the unambiguous presence of high-pressure polymorphs of silica (stishovite), traces of ringwoodite and wadsleyite (high-pressure phase of olivine) in Kamargaon (L6) ordinary chondrite. The presence of wadsleyite along with ringwoodite and stishovite suggests a minimum post-shock pressure and temperature conditions of this meteorite should be 14–15 GPa and 1400–1500°C as the ringwoodite is known to coexist with wadsleyite at ~18 GPa and ~1800 K at the boundary of wadsleyite-ringwoodite transition.
... These meteorites display trace element distributions that are unambiguously the consequence of fractional crystallization. Additional evidence for an origin in asteroidal cores comes from the relatively large sizes (perhaps to >10 m maximum dimension) of some iron meteorites, a feature not consistent with dispersed masses of Fe-Ni alloy, as well as the occurrence of individual kamacite crystals several meters in length-a sign of slow cooling (i.e., on the order of ~1 to 10 degrees per million years) in the differentiated interior of an asteroid at least tens of kilometers in diameter (Haack et al. 1990;McSween 1999;Goldstein et al. 2009). ...
The fourth installment of the evolutionary system of mineralogy considers two stages of planetesimal mineralogy that occurred early in the history of the solar nebula, commencing by 4.566 Ga and lasting for at least 5 million years: (1) primary igneous minerals derived from planetesimal melting and differentiation into core, mantle, and basaltic components and (2) impact mineralization resulting in shock-induced deformation, brecciation, melting, and high-pressure phase transformations.
We tabulate 90 igneous differentiated asteroidal minerals, including the earliest known occurrences of minerals with Ba, Cl, Cu, F, and V as essential elements, as well as the first appearances of numerous phosphates, quartz, zircon, and amphibole group minerals. We also record 40 minerals formed through high-pressure impact alteration, commencing with the period of asteroid accretion and differentiation. These stages of mineral evolution thus mark the first time that high pressures, both static and dynamic, played a significant role in mineral paragenesis.
... Enfin, la classe des chondrites carbonées est divisée en 8 groupes : les types CI, CM, CO (ces deux derniers forment un clan), CV, CK (ces deux derniers forment un clan), CR, CH et CB (ces trois derniers forment un clan). Le groupe CH est présent dans Hutchison [2004] mais n'est pas présent dans McSween [1999]. Le groupe CB n'est pas présent dans ces deux livres. ...
L’analyse chimique des chondrites montre qu’il y a différents groupes de chondrites avec des différences (faibles) de composition. L’objectif de ce court article est de présenter l’abondance élémentaire des différents types de chondrites en insistant notamment sur certains des critères chimiques qui permettent de les différencier.
... Les glaciers à fleur de la roche continentale sont constamment abrasés par les vents catabatiques, ce qui concentre les météorites qui étaient piégées dans la glace. Tiré deMcSween and McSween (1999), page 22. ...
La ceinture principale d’astéroïdes abrite une grande variété d’objets, des corps rocheux auxcorps glacés, dont la taille varie du mètre au millier de kilomètres. Depuis sa formation, cetteceinture a été façonnée par son évolution dynamique, notamment à travers les processus decollisions. Les surfaces d’astéroïdes, recouvertes de cratères, témoignent de la violence de ces impacts.Le matériel excavé au moment du choc peut retomber en un lit d’éjectas ou bien échapperà l’attraction gravitationnelle de l’astéroïde. Sous l’effet de forces non gravitationnelles coupléesà des instabilités dynamiques, les fragments libérés voyagent ensuite dans l’espace interplanétaire,pour parfois atteindre la Terre sous la forme de météorites. Les plus abondantes d’entreelles sont les chondrites ordinaires, originaires des astéroïdes de type S à la composition rocheuse.L’objectif de cette thèse est d’apporter de nouvelles contraintes sur l’évolution des corpsparentsdes chondrites ordinaires en conjuguant l’étude du flux de météorites et celle descratères d’impact. Les résultats présentés s’articulent autour des différents stades de la viedes météorites, de leurs corps-parents jusqu’à leur chute sur Terre en passant par l’entréeatmosphérique. En particulier, la datation de chondrites ordinaires retrouvées dans le désertd’Atacama au Chili montre que cette ancienne surface a enregistré continûment le flux météoritiquesur plusieurs millions d’années. Cette échelle de temps, ainsi que la grande densité demétéorites de la région, font de ce désert une surface privilégiée pour contraindre de l’histoirecollisionnelle des corps parents des chondrites ordinaires. Par ailleurs, l’étude de spectres hauterésolutionde météorites fondues en laboratoire réévalue les apports de la spectroscopie pourla caractérisation de la composition du flux actuel par les réseaux d’observations de météores.La spectroscopie de météores ne s’avère pas en mesure de distinguer différents sous-groupesde météorites, mais seulement les grandes classes (chondrites, achondrites, métalliques). Enfin,concernant les gros astéroïdes, le système d’optique adaptative dans le visible monté surl’instrument SPHERE du Very Large Telescope (VLT) rend désormais possible l’identificationdes cratères d’impact à leur surface. La détermination des diamètres de cratères et du tauxde cratérisation sont utilisées pour expliquer les propriétés de surface d’astéroïdes et commecontrainte observationnelle sur l’origine de quelques familles.
... Toujours utilisé, ce système définit une série de types pétrographiques allant de 1 à 7. Les météorites de type pétrographique 3 sont considérées comme n'ayant pas subi de processus secondaires. Les Page 22 Clayton and Mayeda (1984, 1999 0-20 °C Zolensky et al. (1989,1997) 1-450 °C Ikeda and Prinz (1993) 25 to 225° Zolensky et al. (1993) <50° Grimm and McSween (1989) 25 °C Zolensky (1984) <170° Hayatsu and Anders (1981) 105-125° Bunch and Chang (1980) <125° DuFresne and Anders (1962) 20 °C ...
Les serpentines riches en fer sont des composants majeurs des chondrites CM. Formées au cours d'épisodes d'altération hydrothermale sur leur corps parent astéroïdal, à une étape précoce de la formation du Système Solaire, elles peuvent constituer un proxy des conditions d'altération de ces roches et permettre de mieux comprendre l'évolution à long terme des colis de stockage des déchets nucléaires, car ces processus sont considérés comme un bon analogue des interactions fer-argiles-eau. Pendant cette thèse, nous nous sommes intéressés aux conditions de formation et d'équilibre des ces minéraux, en prêtant une attention particulière à l'évolution de la valence du fer pendant l'altération. Trois approches sont présentées : la synthèse de Fe-serpentines, l'altération expérimentale d'assemblages chondritiques à basse température, en milieu anoxique, et l'affinement d'un modèle thermodynamique incluant des serpentines de composition Fe2+-Fe3+-Mg-Al-Si-O-H. Le modèle thermodynamique, basé sur des données expérimentales, devrait permettre de mieux prédire les assemblages à l'équilibre dans les chondrites altérées. Nos expériences de synthèses suggèrent que la précipitation de phases de composition proche du pôle pur cronstedtite est contrôlée cinétiquement. Aux premiers stades de l'altération expérimentale de minéraux primaires anhydres, nous avons observé la formation de phases peu cristallines avec une proportion relativement faible de fer ferrique. Nos résultats suggèrent que le rapport Fe/Si et la teneur en Fe3+ favorisent la précipitation des serpentines. Ils apportent un éclairage intéressant aux premiers stades d'altération dans les chondrites carbonées.
... Shocked samples are not common in the rock record on earth as many have been subsequently altered through additional geologic processing (Grieve, 1991;French, 1998). Meteorite samples have many unknowns related to body of origin and target material (McSween, 2000). Therefore, to better constrain the effects of shock conditions and target material properties on the resulting melt redox state, alternate materials must be considered. ...
Understanding the geochemical effects of shock metamorphism that occur on planetary surfaces is critical when using potentially shocked planetary samples. Fulgurites, formed by lightning strikes on Earth’s surface, could provide an analog for understanding shock metamorphism, because the intense heat and pressure of impact events are similar to those experienced during lightning strikes. The oxidation state generated during impact is the result of temperature (above 2000 K) and pressure (above 10 GPa) conditions, though the composition and physical nature of the country rock are also important. Atomic explosions such as the Trinity nuclear test and the resulting melted surface material Trinitite can also serve as proxies of shock metamorphism. This study compares samples of fulgurite and Trinitite glasses with the associated country rock using petrography, backscattered electron images, and Mössbauer spectroscopy, with a focus on evaluating redox changes associated with lightning-induced and atomic explosion metamorphism as a function of target material. Two fulgurite melts were also subjected to additional analysis using X-ray absorption spectroscopy to assess potential spatial variations in redox state via in-situ microscale measurements. Results indicate lightning-induced redox variations are heterogeneous at micron scales, although the net effect is overall target reduction with an average reduction of Fe³⁺ by 66%. Moreover, the data show that the physical state of the country rock (i.e., particulate vs. solid rock) has an effect on the magnitude of how the lightning-induced metamorphism effects are observed.
... Meteorites are an important source of extraterrestrial matter, their chemical and physical characteristics, texture and internal structure contribute to our understanding of the birth and early history of our solar system [1]. The primitive meteorites contain abundant amounts (up to 1500 ppm) of nanodiamonds [2,3]. ...
We report here for the first time the possible presence of organic compounds in Sadiya (LL5) ordinary chondrite using micro-Raman and infrared spectroscopic technique. The micro-Raman spectrum exhibits the diamond and graphite peaks correspondingly at 1331 cm-1 , 1349 cm-1 and 1588-1618 cm-1. The full wave at half maximum value of about 18 cm-1 for Sadiya indicating the nature of disordered phase involved shock metamorphism in the meteorite samples. The diamond and graphite peaks intensity ratio (~0.53) indicates the disordered nature of graphite. The infrared spectrum in the range 2700-3000 cm-1 indicates the presence of CH 3 asymmetric stretching, and CH 2 symmetric and asymmetric stretching modes due to aliphatic hydrocarbons. This study has strong implications in understanding of the organic compounds in extra-terrestrial materials.
... Direct evidence for catastrophic disruption of planetary progenitors is found in suites of meteorites (McSween 1999;Keil et al. 1994) including thousands of irons that are thought to sample exhumed cores of ~50-100 differentiated planetesimals (Wood 1964, Wasson 1990). Astronomical evidence for disrupted minor planets is less straightforward to interpret, because spectroscopy detects only surface characteristics, and asteroid densities are seldom measured. ...
Terrestrial planets grew in a series of similar-sized collisions that swept up most of the next-largest bodies. Theia was accreted by the Earth to form the Moon according to the theory. Planetesimals likewise may have finished their accretion in a sequence of 'junior giant impacts', scaled down in size and velocity. This chapter considers the complicated physics of pairwise accretion, as planetesimals grow to planetary scales, and considers how the inefficiency of that process influences the origin of planetesimals and the diversity of meteorites and primary asteroids.
... Asteroidal achondrites are enhanced in lithophiles and depleted in siderophiles, whereas iron meteorites are enhanced in siderophiles and depleted in lithophiles (Wiik 1956;Scott & Wasson 1975). These meteorite suites are understood to be the fragments of larger differentiated bodies, which were produced when differentiated bodies in the asteroid belt catastrophically collided (McSween 1987). Collisional grinding of differentiated bodies has been shown to lead to fragments with a similar range of compositions as those observed in non-primitive meteorites (Marcus et al. 2009;Carter et al. 2015). ...
White dwarfs that have accreted rocky planetary bodies provide unique insights regarding the bulk composition of exoplanetary material. The analysis presented here uses observed pollutant abundances to constrain both where in the planetary system the pollutant bodies originated, and the geological and collisional history of the pollutant bodies. At least 1, but possibly up to 9, of the 17 systems analysed have accreted a body dominated by either corelike or mantle-like material. The approximately even spread in the core mass fraction of the pollutants and the lack of crust-rich pollutants in the 17 systems studied here suggest that the pollutants are often the fragments produced by the collision of larger differentiated bodies. The compositions of many pollutants exhibit trends related to elemental volatility, which we link to the temperatures and, thus, the locations at which these bodies formed. Our analysis found that the abundances observed in 11 of the 17 systems considered are consistent with the compositions of nearby stars in combination with a trend related to elemental volatility. The even spread and large range in the predicted formation location of the pollutants suggests that pollutants arrive in white dwarf atmospheres with a roughly equal efficiency from a wide range of radial locations. Ratios of elements with different condensation temperatures such as Ca/Mg, Na/Mg, and O/Mg distinguish between different formation temperatures, whilst pairs of ratios of siderophilic and lithophilic elements such as Fe/Mg, Ni/Mg and Al/Mg, Ca/Mg distinguish between temperature-dependent trends and geological trends. © 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society.
... Meteorites act as important and complimentary objects for understanding planetesimal formation (e.g., McSween 1999). This is because they literally contain the fossil record of how the solar system formed. ...
Chondrites are one of the most primitive objects in the solar system, and keep the record of the degree of thermal metamorphism experienced in their parent bodies. This thermal history can be classified by the petrologic type. We investigate the thermal evolution of planetesimals to account for the current abundances (known as the fall statistics) of petrologic types 3 - 6 ordinary chondrites. We carry out a number of numerical calculations in which formation times and sizes of planetesimals are taken as parameters. We find that planetesimals that form within 2.0 Myr after the formation of Ca-Al-rich inclusions (CAIs) can contain all petrologic types of ordinary chondrites. Our results also indicate that plausible scenarios of planetesimal formation, which are consistent with the fall statistics, are that planetesimals with radii larger than 60 km start to form around 2.0 Myr after CAIs and/or that ones with radii less than 50 km should be formed within 1.5 Myr after CAIs. Thus, thermal modelling of planetesimals is important for revealing the occurrence and amount of metamorphosed chondrites, and for providing invaluable insights into planetesimal formation.
... Asteroidal achondrites are enhanced in lithophiles and depleted in siderophiles, whereas iron meteorites are enhanced in siderophiles and depleted in lithophiles (Wiik 1956;Scott & Wasson 1975). These mete- orite suites are understood to be the fragments of larger dif- ferentiated bodies, which were produced when differentiated bodies in the asteroid belt catastrophically collided (McSween 1987). Collisional grinding of differentiated bodies has been shown to lead to fragments with a similar range of compositions as those observed in non-primitive meteorites ( Marcus et al. 2009;Carter et al. 2015). ...
White dwarfs that have accreted rocky planetary bodies provide unique insights regarding the bulk composition of exoplanetary material. The analysis presented here uses observed pollutant abundances to constrain both where in the planetary system the pollutant bodies originated, and the geological and collisional history of the pollutant bodies. At least 1, but possibly up to 9, of the 17 systems analysed have accreted a body dominated by either core-like or mantle-like material. The approximately even spread in the core mass fraction of the pollutants and the lack of crust-rich pollutants in the 17 systems studied here suggest that the pollutants are often the fragments produced by the collision of larger differentiated bodies. The compositions of many pollutants exhibit trends related to elemental volatility, which we link to the temperatures and, thus, the locations at which these bodies formed. Our analysis found that the abundances observed in 11 of the 17 systems considered are consistent with the compositions of nearby stars in combination with a trend related to elemental volatility. The even spread and large range in the predicted formation location of the pollutants suggests that pollutants arrive in white dwarf atmospheres with a roughly equal efficiency from a wide range of radial locations. Ratios of elements with different condensation temperatures such as Ca/Mg, Na/Mg, and O/Mg distinguish between different formation temperatures, whilst pairs of ratios of siderophilic and lithophilic elements such as Fe/Mg, Ni/Mg and Al/Mg, Ca/Mg distinguish between temperature dependent trends and geological trends.
... After the discovery of the sedimentary boulder associated with hypervelocity disruption of the ground in the epicenter of the 1908 Tunguska catastrophe, it was hypothesized (Anfinogenov, 1973;Anfinogenov and Budaeva, 1998a,b;Anfinogenov et al., 2014Anfinogenov et al., , 2017a that sed-type meteorites on Earth may originate from a hypothetical planet called Phaeton (McSween, 1999). Finding of socalled Martian meteorites and some pseudo-meteorites belonging to upper-crust rocks (volcanic and metamorphosed igneous and sedimentary rocks) from Mars-like planets provided the rationale for reconsidering a hypothesis suggesting that a previously existing planet between the orbits of Mars and Jupiter is the parent body of the asteroid belt. ...
This concept article discusses the challenges of identifying planetary-origin meteorites of non-igneous composition, primarily of sedimentary origin, distinct from SNC meteorites. The paper reviews evidence on putative sedimentary-origin meteorites and potential parent bodies for sedimentary meteorites. Authors conclude that the list of candidate parent bodies for sedimentary meteorites includes, but is not limited by the Earth, Mars, Enceladus, Ganymede, Europa, and hypothetical planets that could exist between orbits of Mars and Jupiter in the past. Authors argue that extraterrestrial origin and a parent body for meteoritic sedimentary rocks may be identified based on the entire body of evidence which is not limited solely by tests of oxygen and noble gas isotopes whose signatures may undergo terrestrial contamination and may exhibit significant heterogeneity within the Solar system and within the parent cosmic bodies. Observed fall of a cosmic body, evidence of hypervelocity fall, signs of impact in target, and the presence of fusion crust, melting, and/or shock deformation features in the fragments should be considered as priority signs of meteoritic origin.
... Therefore, minerals can be safely analyzed if they are far enough away from the fusion crust (i.e., >200 lm). The affected volume seems quite small, regarding the high temperatures needed to produce a mafic whole-rock melt, but as rocks are poor heat conductors and their inner temperatures are near interplanetary temperatures, the frictional heating only affects the surface and they cool down again shortly after the fall (McSween 1999). ...
We present results of petrographic, mineralogical, and chemical investigations of three Chelyabinsk meteorite fragments. Three distinct lithologies were identified: light S3 LL5, dark S4–S5 LL5 material, and opaque fine-grained former impact melt. Olivine–spinel thermometry revealed an equilibration temperature of 703 ± 23 °C for the light lithology. All plagioclase seems to be secondary, showing neither shock-induced fractures nor sulfide-metal veinlets. Feldspathic glass can be observed showing features of extensive melting and, in the dark lithology, as maskelynite, lacking melt features and retaining grain boundaries of former plagioclase. Olivine of the dark lithology shows planar deformation features. Impact melt is dominated by Mg-rich olivine and resembles whole-rock melt. Melt veins (<2 mm) are connected to narrower veinlets. Melt vein textures are similar to pegmatite textures showing chilled margins, a zone of inward-grown elongated crystals and central vugs, suggesting crystallization from supercooled melt. Sulfide-metal droplets indicate liquid immiscibility of both silicate and sulfide as well as sulfide and metal melts. Impact melting may have been an important factor for differentiation of primitive planetary bodies. Graphite associated with micrometer-sized melt inclusions in primary olivine was detected by Raman mapping. Carbon isotopic studies of graphite could be applied to test a possible presolar origin.
... Interestingly, PGEs content of terrestrial rocks and meteorites is usually compared to that of CI carbonaceous chondrites, because their chemical composition has some similarities with that of the solar photosphere and this is the reason why they viewed in many cases as standards representing composition of solar nebula during its earliest evolution [23] [58] [59]. CI (Ivuna type) group represents the smallest group of carbonaceous chondrites, which in turn making a small fraction (~5%) of all chondrites [60]. CI chondrites are very poor in content of chondrules (<1 vol%), CAIs (<1 vol%), and contain no metal [61]. ...
Numerous unique geological processes [1] occurred during the early Earth evolution; several of them, especially those occurring in the Hadean—Early Archean and later, are reflected in the modern geological (geophysical, geochemical, etc.) pattern. One such significant enigmatic feature is the preservation of extremely dense and heavy platinum group elements (PGEs): Pt, Pd, Rh, Ru, Ir, Os. The concentration of PGEs during this period could have taken place in two ways: 1) presence of particular matter capable of preserving PGEs near the earth's surface, 2) transportation of PGEs by magma flows from deep lithospheric (asthenospheric) layers (slabs) to the subsurface. Clearly, much of the dense and heavy PGEs did not sink through to the Earth’s mantle (core) at the time of the magma-ocean and occur near Earth’s surface in abundances for the formation of ore deposits with PGE concentrations found to be 2-3 orders of magnitude greater than those in their host media. Their enrichments are associated in numerous cases with such enigmatic phenomena as the formation of anorthosites and anorthosite-bearing layered magmatic intrusions. PGE deposits and mineralization zones are also associated with chromitites, dunites, and serpentinites. In this review, problems related to the initial concentration and preservation of PGEs, their association with anorthosites, and the formation of layered intrusions are discussed in detail. The main aim of this article is an analysis of the requirements—initial concentration and preservation of PGE and PGM (Platinum Group Minerals) during the early Earth evolution, as well as an examination of the distribution behavior of some PGEs in different ore deposits and meteorites. It is supposed that the meteoritic bombardment of Earth has played a significant role in the formation of PGEs deposits. Some conclusions made in this article may be useful for developing and enhancing strategies of prospecting for PGEs deposits.
The ever-expanding universe is infinite in space and time and is believed to have come into existence, sometimes around 13.787 ± 0.020 billion years ago. The Sun, which is one of the billions of stars in our Milky Way, is orbited by groups of celestial objects, such as eight numbers of planets, nine numbers of dwarf planets, countless asteroids, planetoids or minor planets, comets, and centaurs, is the main source of energy. The Milky Way is a part of several galaxies in the universe. The planets, the dwarf planets, and the smaller solar system bodies (SSSBs) are orbited by natural satellites, referred to as moons. Combined, they form a solar system, a part of billions of galaxies in the universe. The Earth, located at about 150 million kilometres (i.e., 1 AU) from the Sun, is one of eight planets, including Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune. The Pluto, Eris, Haumea, Makemake, Gonggong, Quaoar, Sedna, Ceres, and Orcus are the recognized dwarf planets. The comets, asteroids, planetoids or minor planets, and centaurs are considered small solar system bodies. Each planet, except Venus, has its own natural satellites called the Moon. The interplanetary medium of the universe consists of the interplanetary dust, the solar magnetic field, cosmic rays, and solar wind. The outer space of the solar system, beyond the radius of 30 AU from the Sun, is known as the Trans-Neptunian region (TNR), where mainly dwarf planets and asteroids are located. According to the distance from the Sun, this region can be categorized into three larger groups: the Kuiper belt region (KBR), the Scattered Disc Zone, and the Oort Cloud. Mostly unexplored, the region beyond 150–250 AU, orbiting the Sun, is called an extremely scattered disc, referred to as the “third zone of the Solar System”, and objects such as sednoids are located in this area. There exist different hypotheses and theories about the origin and evolution of planetary systems; the nebular theory is the most accepted so far. The universe and planetary system evolved from the very early universe to the Dark Ages when large-scale structures emerged, and gradually, the present-day universe appeared. Our planet Earth is also evolved along with the solar system sometimes around 4.6 billion years ago. It rotates around the Sun, has one natural satellite—the Moon, and is the only planet having a biosphere with conditions suitable for the survival of life. It comprises three layers, the outer crust, middle mantle, and central core, and has its atmosphere, magnetic and gravitational field.
Interplanetary space is populated with large numbers of small bodies known as meteorites, which are in orbits that can intersect those of planets and moons. Therefore, individual impacts appear on the surfaces of planetary bodies which are called impact craters. While impacting meteorites are useful to determine the early solar system processes, resultant impact craters are useful to determine the ages of the surfaces and related erosional effects on the body. At Canakkale Onsekiz Mart University (COMU) we aim to create a Meteorite Impact Craters Data Base for Turkey in a computer environment. The data base will be reachable through internet for wider use. Preparations and actions for this exercise are described. For the initial phase, we have collected related information through literature including papers and thesis on the topic. We classify our present efforts for acquisition of information along the following lines on: 1) Meteorites which have fallen down to Turkey recently, i.e. Antalya meteorite in 2001, Afyon meteorite in 2002 and others; 2) Meteorites and impact craters, mentioned in historical records, i.e., Gallipoli meteorite (467 BC); Birgi meteorite (1335 AD) etc.; 3) Candidate impact craters in Turkey which were studied earlier; 4) Other events that can be recognized through satellite images and maps; 5) New events during our preparations. Present candidates and established structures will be investigated and relevant data will be used for the aimed data base.
The collision of large extraterrestrial bodies with Earth is rare, which is fortunate because the damage they could cause increases proportionally with their size. This chapter argues that Earth encounters an object of the size of the one that generated the Chelyabinsk meteorite about every 100 years, and an object the size of Tunguska about every 1,000 years. There are a few objects dating from the Bronze Age made of metallic iron: a dagger found in the tomb of Tutankhamen, the blades of Chinese weapons. Original hypotheses are far from being proven, and the question of the origin of isotopic variations of oxygen between groups of meteorites remains one of the fundamental problems of cosmochemistry. Differentiated meteorites come from planetary bodies that underwent sufficiently intense fusion for their materials to have separated into distinct layers. Howardites, eucrites, diogenites meteorites are vestiges of ancient magmatic activity that occurred in the crust of a planetary body.
The taxonomic classification of asteroids has been mostly based on spectroscopic observations with wavelengths spanning from the visible (VIS) to the near-infrared (NIR). VIS-NIR spectra of ~2500 asteroids have been obtained since the 1970s; the Sloan Digital Sky Survey (SDSS) Moving Object Catalog 4 (MOC 4) was released with ~4 × 10 ⁵ measurements of asteroid positions and colors in the early 2000s. A number of works then devised methods to classify these data within the framework of existing taxonomic systems. Some of these works, however, used 2D parameter space (e.g., gri slope vs. z-i color) that displayed a continuous distribution of clouds of data points resulting in boundaries that were artificially defined. We introduce here a more advanced method to classify asteroids based on existing systems. This approach is simply represented by a triplet of SDSS colors. The distributions and memberships of each taxonomic type are determined by machine learning methods in the form of both unsupervised and semi-supervised learning. We apply our scheme to MOC 4 calibrated with VIS-NIR reflectance spectra. We successfully separate seven different taxonomy classifications (C, D, K, L, S, V, and X) with which we have a sufficient number of spectroscopic datasets. We found the overlapping regions of taxonomic types in a 2D plane were separated with relatively clear boundaries in the 3D space newly defined in this work. Our scheme explicitly discriminates between different taxonomic types (e.g., K and X types), which is an improvement over existing systems. This new method for taxonomic classification has a great deal of scalability for asteroid research, such as space weathering in the S-complex, and the origin and evolution of asteroid families. We present the structure of the asteroid belt, and describe the orbital distribution based on our newly assigned taxonomic classifications. It is also possible to extend the methods presented here to other photometric systems, such as the Johnson-Cousins and LSST filter systems.
The Atlas of Meteorites in Thin Section is an on-line educational resource of the Dipartimento di Scienze della Terra of the Università di Pisa, Italy. It is a collection of optical microscopic images of 45 polished thin sections from 45 meteorites representative of a variety of different types of stony meteorites, belonging to the Museo Nazionale dell’Antartide di Siena. The micrographs in the catalogue include whole section images taken with the petrographic microscope under both transmitted and reflected light.The catalogue is an educational tool for students interested in the petrography and petrology of planetary materials, particularly those attending the courses of Planetary Geology and Cosmochemistry. Furthermore, all the images can be downloaded in high resolution through the links present above each section.
Work continues in this collection to better document the variety of petrographic features of meteorites.
The Museo Nazionale dell'Antartide di Siena (Sezione di Scienze della Terra), is acknowledged for the loan of the polished thin sections.
https://repositories.dst.unipi.it/index.php/meteoriti-in-sezione-sottile
In this chapter we explore the consequences of capturing a 0.1 moon-mass (~0.01 mars-mass) planetoid from a mars-like heliocentric orbit into a stable prograde orbit of large major axis and high eccentricity. One of the major paradoxes of the gravitational capture process is that most of the energy for capture must be stored and subsequently dissipated in the body of the encountering planetoid. This statement seems counterintuitive and has been a major conceptual “hurdle” for capture proponents. Once a planetoid is captured into a planetocentric orbit (marocentric in this case), it then undergoes a lengthy period of marocentric orbit evolution. During this marocentric orbit evolution the primordial rotation rate of the mars-like body decreases systematically from 24.6 to ~88 hr/day as angular momentum is transferred from the rotating planet to the orbit of the satellite. A calculated estimate of the time scale for orbit circularization to 10% eccentricity is about 4.0 billion years. If the satellite mass is increased to 0.2 moon-mass, then the time-scale for orbit circularization decreases considerably to about 1.5 billion years. Equilibrium rock tidal amplitudes on Mars for a 0.1 moon-mass planetoid are about 10 km for the initial (capture) encounter and for a 0.2 moon-mass planetoid the tidal amplitudes are about 20 km. During a prograde capture and orbit circularization sequence of events much of the primitive crust of the mars-like body, especially in the equatorial zone, would be subducted by rock tidal activity over a short period of marologic time and would be replaced by a basaltic-gabbroic crustal complex. Assuming an ample supply of surface water, habitable conditions would prevail for a few eons following the prograde capture episode.
Here, we discuss the merits of non‐destructive UV laser‐induced fluorescence spectroscopy (LIF) as a flight or laboratory instrument to analyze organic and mineral material in samples on or returned from carbon‐rich asteroids such as (101955) Bennu by NASA’s OSIRIS‐REx mission. LIF is a unique instrument that is non‐destructive while acquiring data, and allows for no sample preparation, crushing, or cutting. This method provides spectral data indicative of specific minerals and organics in less time than Raman spectroscopy, and can be set up to produce 2‐D raster images of areas of interest. Furthermore, if an LIF system is set up with a gated CCD camera, time‐resolved fluorescence spectroscopy can be performed, providing a unique identification tool for organic and mineral contents using fluorescence decay over several nanoseconds. This technique was used to analyze millimeter‐sized chondrules and calcium‐aluminum‐rich inclusions on four carbonaceous chondrite samples provided by the Royal Ontario Museum: Murchison (CM2), Allende (CV3), NWA 11554 (CV3), and NWA 12796 (CK3). The LIF 2‐D maps, point spectra, and time‐resolved fluorescence data and mineral identifications using LIF were compared to that of well‐known techniques such as Raman spectroscopy and SEM/EDS.
Ordinary chondrites record shock metamorphism resulting from hypervelocity collisions on small bodies, and underpin the petrographic assessment of shock stage, a scale of progressive stages of shock metamorphism from S1 (unshocked) to S7 (shock melted). In this work, olivine grains in 11 L and LL chondrites (S1–S5) were investigated in thin section and hand sample using in situ two‐dimensional X‐ray diffraction (2‐D XRD). Olivine grains were measured under a 300 µm X‐ray beam for multiple lattice reflections, by measuring diffracted streak length along the chi (χ) dimension (Debye ring dimension), to examine their strain‐related mosaicity. Olivine strain‐related mosaicity was observed to increase with greater shock deformation, with more complex multi‐peak streaks apparent at higher shock levels. The full width at half maximum (FWHMχ) of the simple peak shapes along χ was measured to quantify petrographic shock stage for comparison with that described optically. The average FWHMχ values for simple peaks in olivine show an increase with increasing shock stage: S1 (0.44°± 0.06°), S2 (0.58°± 0.11°), S3 (0.67°± 0.15°), S4 (0.76°± 0.13°), and S5 (0.86°± 0.12°). This method complements optical petrographic methods and offers a ±1 shock stage accuracy in determining shock stage. In particular, 2‐D XRD analysis of strain‐related mosaicity allows quantitative analysis of shock stage in shock‐darkened samples that are difficult to work with petrographically, and for hand samples without need for thin section preparation.
The timing of formation of 100-300 km size planetesimals in the protoplanetary disk remains largely unconstrained. Recent models show that gravitational collapse of boulders in overdense regions of a dusty accretion disk can overcome the meter-sized barrier and lead to rapid formation of planetesimals with size of several km that further grow by pebble accretion. Hf/W ages indicate that the first large planetesimals to form could be the parent bodies of magmatic iron meteorites. These ages have been so far used to constrain timing of accretion considering (i) instantaneous accretion, and (ii) purely conductive heat transfer in the planetesimal. To relax these hypotheses we model the thermal evolution of a planetesimal in course of accretion and we take into account the possibility of convection onset. Our model is further based on considering the possibility of a common thermal evolution for all the parent bodies of iron meteorites. Within that framework we show that the planetesimals could have grown following a universal accretion law starting at the very beginning of the history of the disk by a nearly instantaneous formation of 60 ± 30 km size nuclei, followed by a growth via pebble accretion at a much slower pace to reach final sizes of 150–300 km in about 3 Myr. In this universal scenario, complete melting and total differentiation are not bound to happen in the parent body due to the continuous accretion of cold pebbles. The model, though calibrated here on iron meteorites, is general and can in principle be applied to other types of planetesimals such as for instance the parent bodies of CV chondrites.
Impaktprozesse sind grundlegend die Entstehung und Entwicklung planetarer Körper in unserem Sonnensystem. Die Bildung von Meteoritenkratern zu erforschen, heißt einen Einblick in die frühe Erdgeschichte zu bekommen und einen Prozess zu verstehen, der aktiv die meisten festen planetaren Oberflächen bestimmt. Meteoriteneinschläge erzeugen eine Reihe von charakteristischen Eigenschaften im Gestein, die sogenannte Stoßwellenmetamorphose, im Zuge des hoch dynamischen Prozesses. Diese Effekte, helfen Meteoritenkrater zu erkennen und ein besseres Prozessverständnis zu entwickeln. Von diesen charakteristischen Merkmalen sind Strahlenkegel (shatter cones) der einzig makroskopische Effekt der Stoßwellenmetamorphose. Strahlenkegel sind als diagnostisches Mittel Meteoritenkrateridentifizierung anerkannt und können durch ihre sehr markanten Strukturen gut bereits im Gelände erkannt werden.
Unter kontrollierten Laborbedingungen haben Hochgeschwindigkeitseinschlagsexperimente und Stoß-wellenrückgewinnungsexperimente in den letzten Jahrzenten das Verständnis von Krater-bildungsmechanismen grundlegend Verbessert. Entstehungsregime von Mikroskopischen Stoßwellen-Effekten wurden kalibriert, oder zum Bespiel der Einfluss von Porosität oder Lagenbau auf die Kraterbildung untersucht. Strahlenkegel hingegen, sind in Experimenten – auch auf Grund ihrer Häufigkeit - kaum untersucht worden. So kommt es, dass viele Aspekte der Entstehung von Strahlenkegeln immer noch unklar sind. Physikalische Rahmenbedingungen, wie Verformungsraten, Bildungsdrücke oder -temperaturen sind unklar, ebenso ist der Zeitpunkt zur Ausbildung der Strahlenkegel strittig.
Die MEMIN (Multidisciplinary Experimental and Modeling Impact Research Network) Experimente gaben die Möglichkeit die Entstehung von Strahlenkegeln systematisch zu erforschen. Ziel dieser experimentellen Arbeit ist es, physikalische Rahmenparameter einzugrenzen und ein Modell zur Stahlenkegelbildung auf dieser Grundlage zu entwickeln. Hierfür sind eine Reihe Makro- und Mikrostrukturelle Analysen an den MEMIN Experimenten durchgeführt und mit natürlich gebildeten Strahlenkegeln verglichen worden.
Aus dem Untersuchten Ejecta-Material von 37 MEMIN Experimenten wurden 24 Strahlenkegel-Fragmente geborgen. Darüber hinaus wurden Krateruntergründe mehrerer MEMIN Kampagnen untersucht und am Kraterboden Strahlenkegel-typische Striationen (striae) gefunden. Die Strahlenkegel wurden in fast allen Lithologien dokumentiert und es zeigte sich, dass Impakt-Geschwindigkeit der wichtigste Faktor ist um die Strahlenkegelnildung zu begünstigen. Auf Grundlage der Mikrostrukturellen Untersuchungen und iSale Modellierungen konnten die Bildungsbedingungen der gefundenen Fragmente auf 2-5 GPa und hohe Prozesstemperaturen von >2000° C abgegrenzt werden. Zudem wurden Scher- und Extensionsprozesse an den Bruchflächen dokumentiert. Oberflächeneigenschaften (Apizes, Bifurkation, Kurvatur, Rauigkeit der Bruchoberfläche) wurden mit Hilfe gewonnener 3D Daten analysiert und zeigen zum einen die Übereinstimmung der experimentellen und natürlichen Strahlenkegel, und halfen des Weiteren ein phänomenologisches Modell zu entwickeln. Aus der vorliegenden Arbeit geht hervor, dass Strahlenkegel bereit früh im Kraterbildungsprozess angelegt werden und die Bruchbildung durch Risswachstum unter Mixed-mode-Beanspruchung und extrem hohe Verformungsraten bestimmt wird.
La meteorita como una ciencia, en la América Latina del siglo XIX, se desarrolló en focos geográficos aislados de estudio. Mostró notables avances, comparada con el conocimiento de la época, sobre todo realizados en Chile y México. Se produjeron mapas mostrando los sitios de hallazgoo caída meteorítica (algunos conocidos desde el siglo
XVI), y se realizaron estudios mineralógicos y químicos, de manera petrológica y geográfica comparativa. Dos factores fundamentales incidieron en los estudios de la meteorítica:
1) El hecho obvio de que se encontraban meteoritos antiguos (principalmente masas férreas) o fueran avistados en su caída, y 2) el que existiera un buen grado de desarrollo en las ciencias geológicas en esos países donde cayeron, ya fuera por Escuelas de Minas o
instituciones de investigacion minera y geológica.
Le principal objectif de ce travail de recherche a été la mise au point d'une nouvelleméthode expérimentale visant à établir et contrôler des pressions partielles de potassium gazeux (PK) à haute température et sous fugacité d'oxygène imposée (PO2) . Cette approche thermochimique a permis d'acquérir des données sur le partage du potassium entre silicates fondus et gaz.Le protocole expérimental développé est basé sur l'utilisation d'une source de potassium gazeux : un mélange de K2CO3, et de graphite. La décomposition de cette source, placée à environ 1000°C dans le gradient thermique d'un four vertical à atmosphère contrôlée, fixe la PK selon la réaction: K2CO3 + 2C = 2K(g) + 3CO(g). La mesure thermogravimétrique de la source permet de déterminer la PK in situ dans le four. La PO2 est ajustée en soufflant un mélange gazeux (CO-CO2). Les échantillons de liquides silicatés sont placés dans la zone chaude du four (à 1410°C)et sont trempés dans l'atmosphère du four. Un système de trempe multiple permet de tremper les échantillons indépendamment les uns des autres. Ce système permet soit de tremper des échantillons de même composition à des temps différents au cours de la même expérience et ainsi, de suivre la cinétique de condensation et de volatilisation du potassium, soit de tremperdes échantillons de compositions différentes simultanément et ainsi tester la dépendance de la solubilité du potassium à la composition de liquide sous les mêmes conditions de T. PO2 et PK. Les résultats de cette étude montrent que les processus de condensation et de volatilisation du potassium dans les liquides silicatés peuvent être décrits par l'équation suivante :KO 1/2 (liquide) = K (g) + 1/4 O2 (g). Ces deux processus sont fortement liés à la PK, la PO2 ainsi qu'à la composition du liquide silicaté. Dans un liquide appartenant au système CaO-MgO-Al2O3-SiO2, la condensation du potassium est rapide et l'é moins d'une heure. La vitesse de condensation et la teneur en K2O dans les échantillons observée à l'équilibre sont fonction de la Po2et la PK imposées dans le four. La condensation suit une loi de type : (K2O)1 =(K2O)éq . (1-exp(-K'1))où (K2O), et (K2O)éqI sont les teneurs en K2O du liquide silicaté à l'instant t et à l'équilibre respectivement. K' est la constante de condensation (min-1) .D'autre part, les données obtenues à l'équilibre sur des liquides de compositions différentes ont permis de dériver un modèle permettant de prédire la solubilité du potassium dans un liquide silicate, à 1410°C et sous une PO2 de 10-13.9 atm, en fonction de la composition de ce dernier (degré de polymérisation, teneur en SiO2 ,Al2O3 et MgO). Cette étude a permis, en outre, d'apporter des contraintes nouvelles sur la formation des chondres des météorites primitives (pressions partielles d'alcalins de la nébuleuse prorosolaire) et d'apporter des réponses relatives au problème de l'extraction des alcalins des hauts fourneaux sidérurgiques par les laitiers (aluminosilicates calciques).
Das Modell der Erdentstehung basiert auf astrophysikalischen Beobachtungen unseres Sonnensystems sowie auf isotopenchemischen Daten von Gesteinen der Erde, des Mondes und der Meteorite. Die Sonne und die Planeten entstanden vermutlich vor ca. 4,6 Ga aus einer rotierenden Scheibe aus Gas und Staub. Im Zentrum dieses Solarnebels bildete sich die Sonne durch Zusammenballung von Materie (gravitative Akkretion). Als hierbei eine kritische Masse überschritten wurde, setzte im Innern der Sonne die Wasserstoff-Fusion ein. Ihre Strahlung blies einen großen Teil der leichtflüchtigen Materie (i. W. H, C, N, O) in das äußere Sonnensystem. Im inneren Sonnensystem kondensierte vorwiegend schwerflüchtige Materie zu kleinen Körpern (Planetesimale, Planetoide) und anschließend zu den erdähnlichen (terrestrischen) Planeten (Merkur, Venus, Erde, Mars).
Hypothetical planets as parent bodies of some asteroids and meteorites
Meteorites are rocks from other worlds. To reach Earth intact, all meteoroids must pass a rigorous test before they can become meteorites. They must survive passage through Earth’s dense atmosphere. Earth’s atmosphere provides an effective shield against most incoming meteoroids. With this protective shield in place, they stand little chance of reaching Earth’s surface without considerable damage. Particles from dust-sized to two or three millimeters diameter normally don’t make it. They are totally consumed, ablated away by frictional heating in the atmosphere. Larger bodies fortunately can survive their passage relatively unscathed, though reduced in mass and size but still intact. Every year, worldwide, about 40,000 tons of meteoritic debris make it through the atmosphere. Among them are the meteorites we see preserved in museums and in private collections. They are the ones that have passed the fiery test.
One should not confuse the occasional bright meteor with the most spectacular of meteors called fireballs or bolides. They are produced by relatively large meteoroids ranging from walnutsized to several feet across. By long established convention, a fireball is any meteoroid that has attained an apparent magnitude of −5 or brighter with no real upper limit (the Sun is −26.5). The brightest fireballs often have magnitudes exceeding the brightness of the full moon (−12.5). These chunks of rock are often large enough to survive atmospheric passage. They are pieces of asteroids that have been involved in impacts with other asteroids in space numerous times in their history. Often the most energetic impacts result in fractures that structurally weaken them. If they happen to encounter Earth’s atmosphere in their weakened condition they stand a good chance of fragmenting into several pieces.
Hinweise für den Benutzer:1.
Literaturhinweise finden sich auch am Ende eines jeden Kapitels in diesem Handbuch. Dort sind Buchtitel und Zeitschriftenaufsätze angegeben.
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Bewußt sind im nachfolgenden Literaturverzeichnis ältere Titel belassen worden, die bereits in den letzten Auflagen dieses Handbuchs aufgeführt waren. Wenn nicht antiquarisch, so bekommt man leihweise ältere Bücher bestimmt in großen Bibliotheken (z. B. in den Staatsbibliotheken auf dem Weg der Fernleihe). Zum besseren Verständnis manchen astronomischen Problems ist es unerläßlich, auch die ältere Literatur zu Rate zu ziehen.
4.
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Mit Blick auf die 1987 in der Zeitschrift für Astronomie „Sterne und Weltraum“ begonnene Rubrik „Literaturquellen, die nicht jeder kennt“ sei auch an dieser Stelle der Leser auf Veröffentlichungen aufmerksam gemacht, die staatliche Stellen (z.B. US-Regierung), Forschungsinstitute (z. B. Deutsche Forschungs- und Versuchsanstalt für Luft- und Raumfahrt) und astronomische Organisationen (z. B. Astronomische Gesellschaft) herausgeben und die für die praktische astronomische Arbeit hilfreich sein können.
Natural objects evolve from initial chaotic motions to order through a fascinating internal self-organization, which is embedded in their structure. The dynamics of this process is the focus of this work. They can be subjected to temporal and spatial variations or retain their stability for a long time. Ordered structures surround us ubiquitously on Earth; numerous examples of self-organization are observed in space. Turbulent flows characterized by a great variety of dynamical processes are widespread in the surrounding world. We mainly focus on the problems of macroscopic modeling these natural flows.
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