• Early fracturing and impact residue emplacement: Can modelling help to predict their location in major craters?

      Kearsley, A.; Graham, G.; McDonnell, T.; Bland, P.; Hough, R.; Helps, P. (The Meteoritical Society, 2004-01-01)
      Understanding the nature and composition of larger extraterrestrial bodies that may collide with the Earth is important. One source of information lies in the record of ancient impact craters, some of which have yielded chemical information as to the impacting body. Many deeply eroded craters have no remaining melt sheet or ejecta yet may contain impactor residue within basement fractures. The emplacement mechanism for fractionated siderophile residues is likely to be gaseous, although, melt droplets and some solid materials may survive. For breccia- and melt-filled fractures to contain extraterrestrial material, they must form very early in the impact process. Most current numerical models do not dwell on the formation and location of early major fractures, although, fractures in and around small craters on brittle glass exposed to hypervelocity impact in low Earth orbit have been successfully simulated. Modelling of fracture development associated with larger craters may help locate impact residues and test the models themselves.
    • Early petrologic processes on the ureilite parent body

      Singletary, S. J.; Grove, T. L. (The Meteoritical Society, 2003-01-01)
      We present a petrographic and petrologic analysis of 21 olivine-pigeonite ureilites, along with new experimental results on melt compositions predicted to be in equilibrium with ureilite compositions. We conclude that these ureilites are the residues of a partial melting/smelting event. Textural evidence preserved in olivine and pigeonite record the extent of primary smelting. In pigeonite cores, we observe fine trains of iron metal inclusions that formed by the reduction of olivine to pigeonite and metal during primary smelting. Olivine cores lack metal inclusions but the outer grain boundaries are variably reduced by a late-stage reduction event. The modal proportion of pigeonite and percentage of olivine affected by late stage reduction are inversely related and provide an estimation of the degree of primary smelting during ureilite petrogenesis. In our sample suite, this correlation holds for 16 of the 21 samples examined. Olivine-pigeonite-liquid phase equilibrium constraints are used to obtain temperature estimates for the ureilite samples examined. Inferred smelting temperatures range from ~1150 degrees C to just over 1300 degrees C and span the range of estimates published for ureilites containing two or more pyroxenes. Temperature is also positively correlated with modal percent pigeonite. Smelting temperature is inversely correlated with smelting depth--the hottest olivine-pigeonite ureilites coming from the shallowest depth in the ureilite parent body. The highest temperature samples also have oxygen isotopic signatures that fall toward the refractory inclusion-rich end of the carbonaceous chondrite- anhydrous mineral (CCAM) slope 1 mixing line. These temperature-depth variations in the ureilite parent body could have been created by a heterogeneous distribution of heat producing elements, which would indicate that isotopic heterogeneities existed in the material from which the ureilite parent body was assembled.
    • Earth Impact Effects Program: A Web-based computer program for calculating the regional environmental consequences of a meteoroid impact on Earth

      Collins, G. S.; Melosh, H. J.; Marcus, R. A. (The Meteoritical Society, 2005-01-01)
      We have developed a Web-based program for quickly estimating the regional environmental consequences of a comet or asteroid impact on Earth(www.lpl.arizona.edu/ impacteffects). This paper details the observations, assumptions and equations upon which the program is based. It describes our approach to quantifying the principal impact processes that might affect the people, buildings, and landscape in the vicinity of an impact event and discusses the uncertainty in our predictions. The program requires six inputs: impactor diameter, impactor density, impact velocity before atmospheric entry, impact angle, the distance from the impact at which the environmental effects are to be calculated, and the target type (sedimentary rock, crystalline rock, or a water layer above rock). The program includes novel algorithms for estimating the fate of the impactor during atmospheric traverse, the thermal radiation emitted by the impact-generated vapor plume (fireball), and the intensity of seismic shaking. The program also approximates various dimensions of the impact crater and ejecta deposit, as well as estimating the severity of the air blast in both crater-forming and airburst impacts. We illustrate the utility of our program by examining the predicted environmental consequences across the United States of hypothetical impact scenarios occurring in Los Angeles. We find that the most wide-reaching environmental consequence is seismic shaking: both ejecta deposit thickness and air-blast pressure decay much more rapidly with distance than with seismic ground motion. Close to the impact site the most devastating effect is from thermal radiation; however, the curvature of the Earth implies that distant localities are shielded from direct thermal radiation because the fireball is below the horizon.
    • Editor's Note

      Jull, A. J. Timothy (The Meteoritical Society, 2005-01-01)
    • Editorial

      Rivkin, Andrew; Chabot, Nancy; Dello Russo, Neil (The Meteoritical Society, 2009-01-01)
    • Editorial

      Jull, A. J. T. (The Meteoritical Society, 2005-01-01)
    • Editorial

      Floss, C.; Nittler, L. (The Meteoritical Society, 2007-01-01)
    • Editorial

      Sears, Derek W. G. (The Meteoritical Society, 2004-01-01)
    • Effect of volatiles and target lithology on the generation and emplacement of impact crater fill and ejecta deposits on Mars

      Osinski, Gordon R. (The Meteoritical Society, 2006-01-01)
      Impact cratering is an important geological process on Mars and the nature of Martian impact craters may provide important information as to the volatile content of the Martian crust. Terrestrial impact structures currently provide the only ground-truth data as to the role of volatiles and an atmosphere on the impact-cratering process. Recent advancements, based on studies of several well-preserved terrestrial craters, have been made regarding the role and effect of volatiles on the impact-cratering process. Combined field and laboratory studies reveal that impact melting is much more common in volatile-rich targets than previously thought, so impact-melt rocks, melt-bearing breccias, and glasses should be common on Mars. Consideration of the terrestrial impact-cratering record suggests that it is the presence or absence of subsurface volatiles and not the presence of an atmosphere that largely controls ejecta emplacement on Mars. Furthermore, recent studies at the Haughton and Ries impact structures reveal that there are two discrete episodes of ejecta deposition during the formation of complex impact craters that provide a mechanism for generating multiple layers of ejecta. It is apparent that the relative abundance of volatiles in the near-surface region outside a transient cavity and in the target rocks within the transient cavity play a key role in controlling the amount of fluidization of Martian ejecta deposits. This study shows the value of using terrestrial analogues, in addition to observational data from robotic orbiters and landers, laboratory experiments, and numerical modeling to explore the Martian impact-cratering record.
    • Effects of asteroid and comet impacts on habitats for lithophytic organisms—A synthesis

      Cockell, Charles S.; Lee, Pascal; Broady, Paul; Lim, Darlene S. S.; Osinski, Gordon R.; Parnell, John; Koeberl, Christian; Pesonen, Lauri; Salminen, Johanna (The Meteoritical Society, 2005-01-01)
      Asteroid and comet impacts can have a profound influence on the habitats available for lithophytic microorganisms. Using evidence from the Haughton impact structure, Nunavut, Canadian High Arctic, we describe the role of impacts in influencing the nature of the lithophytic ecological niche. Impact-induced increases in rock porosity and fracturing can result in the formation of cryptoendolithic habitats. In some cases and depending upon the target material, an increase in rock translucence can yield new habitats for photosynthetic cryptoendoliths. Chasmoendolithic habitats are associated with cracks and cavities connected to the surface of the rock and are commonly increased in abundance as a result of impact bulking. Chasmoendolithic habitats require less specific geological conditions than are required for cryptoendolithic habitats, and their formation is likely to be common to most impact events. Impact events are unlikely to have an influence on epilithic and hypolithic habitats except in rare cases, where, for example, the formation of impact glasses might yield new hypolithic habitats. We present a synthetic understanding of the influence of asteroid and comet impacts on the availability and characteristics of rocky habitats for microorganisms.
    • Effects of experimental aqueous alteration on the abundances of argon-rich noble gases in the Ningqiang carbonaceous chondrite

      Yamamoto, Yukio; Okazaki, Ryuji; Nakamura, Tomoki (The Meteoritical Society, 2006-01-01)
      Ar-rich noble gases, the so-called "subsolar" noble gases, are a major component of heavy primordial noble gases in unequilibrated ordinary chondrites and some classes of anhydrous carbonaceous chondrites, whereas they are almost absent in hydrous carbonaceous chondrites that suffered extensive aqueous alteration. To understand the effects of aqueous alteration on the abundance of Ar-rich noble gases, we performed an aqueous alteration experiments on the Ningqiang type 3 carbonaceous chondrite that consists entirely of anhydrous minerals and contains Ar-rich noble gases. Powdered samples and deionized neutral water were kept at 200 degrees C for 10 and 20 days, respectively. Mineralogical analyses show that, during the 10-day alteration, serpentine and hematite formed at the expense of olivine, low-Ca pyroxene, and sulfide. Noble gas analyses show that the 10-day alteration of natural Ningqiang removed 79% of the primordial 36Ar, 68% of the 84Kr, and 60% of the 132Xe, but only 45% of the 4He and 53% of the primordial 20Ne. Calculated elemental ratios of the noble gases removed during the 10-day alteration are in the range of those of Ar-rich noble gases. These results indicate that Ar-rich noble gases are located in materials that are very susceptible to aqueous alteration. In contrast, heavy primordial noble gases remaining in the altered samples are close to Q gas in elemental and isotope compositions. This indicates that phase Q is much more resistant to aqueous alteration than the host phases of Ar-rich noble gases. In the 20-day sample, the mineralogical and noble gas signatures are basically similar to those of the 10-day sample, indicating that the loss of Ar-rich noble gases was completed within the 10-day alteration. Our results suggest that almost all of the Ar-rich noble gases were lost from primitive asteroids during early, low-temperature aqueous alteration.
    • Ejecta formation and crater development of the Mjølnir impact

      Shuvalov, V.; Dypvik, H. (The Meteoritical Society, 2004-01-01)
      Crater-ejecta correlation is an important element in the analysis of crater formation and its influence on the geological evolution. In this study, both the ejecta distribution and the internal crater development of the Jurassic/Cretaceous Mjølnir crater (40 km in diameter; located in the Barents Sea) are investigated through numerical simulations. The simulations show a highly asymmetrical ejecta distribution, and underscore the importance of a layer of surface water in ejecta distribution. As expected, the ejecta asymmetry increases as the angle of impact decreases. The simulation also displays an uneven aerial distribution of ejecta. The generation of the central high is a crucial part of crater formation. In this study, peak generation is shown to have a skewed development, from approximately 50-90 sec after impact, when the peak reaches its maximum height of 1-1.5 km. During this stage, the peak crest is moved about 5 km from an uprange to a downrange position, ending with a final central position which has a symmetrical appearance that contrasts with its asymmetrical development.
    • Ejection ages from krypton-81-krypton-83 dating and pre-atmospheric sizes of martian meteorites

      Eugster, O.; Busemann, H.; Lorenzetti, S.; Terribilini, D. (The Meteoritical Society, 2002-01-01)
      Cosmic-ray exposure (CRE) ages and Mars ejection times were calculated from the radionuclide 81Kr and stable Kr isotopes for seven martian meteorites. The following 81Kr-Kr CRE ages were obtained: Los Angeles = 3.35 +/- 0.70 Ma; Queen Alexandra Range 94201 = 2.22 +/- 0.35 MA; Shergotty = 3.05 +/- 0.50 Ma; Zagami = 2.98 +/- 0.30 Ma; Nakhla = 10.8 +/- 0.8 Ma; Chassigny = 10.6 +/- 2.0 Ma; and Allan Hills 84001 = 15.4 +/- 5.0 Ma. Comparison of these age with previously obtained CRE ages from the stable noble gas nuclei 3He, 21Ne, and 38Ar shows excellent agreement. This indcates that the method for the production rate calculation for the stable nuclei is reliable. in all martian meteorites we observe effects induced by secondary cosmic-ray produced epithermal neutrons. Epithermal neutron fluxes, phi(n) (30-300 cV), are calculated based on the reaction 79Br(n, gamma x Beta)80Kr. We show that the neutron capture effects were induced in free space during Mars-Earth transfer of the meteorids and that they are not due to a pre-exposure on Mars before ejection of the meteoritic material. Neutron fluxes and slowing down densities experienced by the meteoroids are calculated and pre-atmospheric sizes are estimated. We obtain minimum radii in the range of 22-25 cm and minimum masses of 150-220 kg. These results are in good agreement with the mean sizes reported for model calculations using current semiempirical data.
    • Ejection of Martian meteorites

      Fritz, J.; Artemieva, N.; Greshake, A. (The Meteoritical Society, 2005-01-01)
      We investigated the transfer of meteorites from Mars to Earth with a combined mineralogical and numerical approach. We used quantitative shock pressure barometry and thermodynamic calculations of post-shock temperatures to constrain the pressure/temperature conditions for the ejection of Martian meteorites. The results show that shock pressures allowing the ejection of Martian meteorites range from 5 to 55 GPa, with corresponding post-shock temperature elevations of 10 to about 1000 degrees C. With respect to shock pressures and post-shock temperatures, an ejection of potentially viable organisms in Martian surface rocks seems possible. A calculation of the cooling time in space for the most highly shocked Martian meteorite Allan Hills (ALH) 77005 was performed and yielded a best-fit for a post-shock temperature of 1000 degrees C and a meteoroid size of 0.4 to 0.6 m. The final burial depths of the sub-volcanic to volcanic Martian rocks as indicated by textures and mineral compositions of meteorites are in good agreement with the postulated size of the potential source region for Martian meteorites during the impact of a small projectile (200 m), as defined by numerical modeling (Artemieva and Ivanov 2004). A comparison of shock pressures and ejection and terrestrial ages indicates that, on average, highly shocked fragments reach Earth-crossing orbits faster than weakly shocked fragments. If climatic changes on Mars have a significant influence on the atmospheric pressure, they could account for the increase of recorded ejection events of Martian meteorites in the last 5 Ma.
    • El'gygytgyn impact crater, Russia: Structure, tectonics, and morphology

      Gurov, E. P.; Koeberl, C.; Yamnichenko, A. (The Meteoritical Society, 2007-01-01)
      The 3.6 Myr old El'gygytgyn impact crater is located in central Chukotka, northeastern Russia. The crater is a well-preserved impact structure with an inner basin about 15 km in diameter, surrounded by an uplifted rim about 18 km in diameter. The flat floor of the crater is in part occupied by Lake El'gygytgyn, 12 km in diameter, and surrounding terraces. The average profile of the rim is asymmetric, with a steep inner wall and a gentle outer flank. The rim height is about 180 m above the lake level and 140 m above the surrounding area. An outer ring feature, on average 14 m high, occurs at about 1.75 crater radii from the center of the structure. El'gygytgyn crater is surrounded by a complex network of faults. The density of the faults decreases from the bottom of the rim to the rim crest and outside the crater to a distance of about 2.7 crater radii. Lake El'gygytgyn is surrounded by a number of lacustrine terraces. Only minor remnants are preserved of the highest terraces, 80 and 60 m above the present-day lake level. The widest of the terraces is 40 m above the current lake level and surrounds the lake on the west and northwest sides. The only outlet of the lake is the Enmivaam River, which cuts through the crater rim in the southeast. In terms of structure, El'gygytgyn is well preserved and displays some interesting, but not well understood, features (e.g., an outer ring), similar to those observed at a few other impact structures.
    • Elemental and isotope behavior of macromolecular organic matter from CM chondrites during hydrous pyrolysis

      Oba, Y.; Naraoka, H. (The Meteoritical Society, 2009-01-01)
      A new insight into carbon and hydrogen isotope variations of insoluble organic matter (IOM) is provided from seven CM chondrites, including Murchison and six Antarctic meteorites (Y-791198, Y-793321, A-881280, A-881334, A-881458 and B-7904) as well as Murchison IOM residues after hydrous pyrolysis at 270-330 degrees C for 72 h. Isotopic compositions of bulk carbon (delta-13Cbulk) and hydrogen (delta-D) of the seven IOMs vary widely, ranging from 15.1 to 7.6 and +133 to +986 per mil, respectively. Intramolecular carboxyl carbon (delta-13CCOOH) is more enriched in 13C by 7.5 -11 per mil than bulk carbon. After hydrous pyrolysis of Murchison IOM at 330 degrees degrees C, H/C ratio, delta-13Cbulk, delta-13CCOOH, and delta-D values decrease by up to 0.31, 3.5 per mil, 5.5 per mil, and 961 per mil, respectively. The O/C ratio increases from 0.22 to 0.46 at 270 degrees C and to 0.25 at 300 degrees degrees C, and decreases to 0.10 at 330 degrees C. delta-13Cbulk-delta-D cross plot of Murchison IOM and its pyrolysis residues shows an isotopic sequence. Of the six Antarctic IOMs, A-881280, A-881458, Y-791198 and B-7904 lie on or near the isotopic sequence depending on the degree of hydrous and/or thermal alteration, while A-881334 and Y-793321 consist of another distinct isotope group. A delta-13Cbulk-delta-13CCOOH cross-plot of IOMs, including Murchison pyrolysis residues, has a positive correlation between them, implying that the oxidation process to produce carboxyls is similar among all IOMs. These isotope distributions reflect various degree of alteration on the meteorite parent bodies and/or difference in original isotopic compositions before the parent body processes.
    • Empirical and theoretical comparisons of the Chicxlub and Sudbury impact structures

      Pope, K. O.; Kieffer, S. W.; Ames, D. E. (The Meteoritical Society, 2004-01-01)
      Chicxulub and Sudbury are 2 of the largest impact structures on Earth. Research at the buried but well-preserved Chicxulub crater in Mexico has identified 6 concentric structural rings. In an analysis of the preserved structural elements in the eroded and tectonically deformed Sudbury structure in Canada, we identified ring-like structures corresponding in both radius and nature to 5 out of the 6 rings at Chicxulub. At Sudbury, the inner topographic peak ring is missing, which if it existed, has been eroded. Reconstructions of the transient cavities for each crater produce the same range of possible diameters: 80110 km. The close correspondence of structural elements between Chicxulub and Sudbury suggests that these 2 impact structures are approximately the same size, both having a main structural basin diameter of ~150 km and outer ring diameters of ~200 km and ~260 km. This similarity in size and structure allows us to combine information from the 2 structures to assess the production of shock melt (melt produced directly upon decompression from high pressure impact) and impact melt (shock melt and melt derived from the digestion of entrained clasts and erosion of the crater wall) in large impacts. Our empirical comparisons suggest that Sudbury has ~70% more impact melt than does Chicxulub (~31,000 versus ~18,000 km3) and 85% more shock melt (27,000 km3 versus 14,500 km3). To examine possible causes for this difference, we develop an empirical method for estimating the amount of shock melt at each crater and then model the formation of shock melt in both comet and asteroid impacts. We use an analytical model that gives energy scaling of shock melt production in close agreement with more computationally intense numerical models. The results demonstrate that the differences in melt volumes can be readily explained if Chicxulub was an asteroid impact and Sudbury was a comet impact. The estimated 70% difference in melt volumes can be explained by crater size differences only if the extremes in the possible range of melt volumes and crater sizes are invoked. Preheating of the target rocks at Sudbury by the Penokean Orogeny cannot explain the excess melt at Sudbury, the majority of which resides in the suevite. The greater amount of suevite at Sudbury compared to Chicxulub may be due to the dispersal of shock melt by cometary volatiles at Sudbury.
    • Enstatite aggregates with niningerite, heideite, and oldhamite from the Kaidun carbonaceous chondrite: Relatives of aubrites and EH chondrites?

      Kurat, G.; Zinner, E.; Brandstätter, F.; Ivanov, A. V. (The Meteoritical Society, 2004-01-01)
      We studied 2 enstatite aggregates (En >99), with sizes of 0.5 and 1.5 mm, embedded in the carbonaceous matrix of Kaidun. They contain sulfide inclusions up to 650 micrometers in length, which consist mainly of niningerite but contain numerous grains of heideite as well as oldhamite and some secondary phases (complex Fe, Ti, S hydroxides and Ca carbonate). Both niningerite and heideite are enriched in all trace elements relative to the co-existing enstatite except for Be and Sc. The niningerite has the highest Ca content (about 5 wt%) of all niningerites analyzed so far in any meteorite and is the phase richest in trace elements. The REE pattern is fractionated, with the CI-normalized abundance of Lu being higher by 2 orders of magnitude than that of La, and has a strong negative Eu anomaly. Heideite is, on average, poorer in trace elements except for Zr, La, and Li. Its REE pattern is flat at about 0.5 x CI, and it also has a strong negative Eu anomaly. The enstatite is very poor in trace elements. Its Ce content is about 0.01 that of niningerite, but Li, Be, Ti, and Sc have between 0.1 and 1 x CI abundances. The preferential partitioning of typical lithophile elements into sulfides indicates highly O-deficient and S-dominated formation conditions for the aggregates. The minimum temperature of niningerite formation is estimated to be ~850-900 degrees C. The texture and the chemical characteristics of the phases in the aggregates suggest formation by aggregation and subsequent sintering before incorporation into the Kaidun breccia. The trace element data obtained for heideite, the first on record, show that this mineral, in addition to oldhamite and niningerite, is also a significant carrier of trace elements in enstatite meteorites
    • Entry dynamics and acoustics/infrasonic/seismic analysis for the Neuschwantstein meteorite fall

      Revelle, D. O.; Brown, P. G.; Spurný, P. (The Meteoritical Society, 2004-01-01)
      We have analyzed several types of data associated with the well-documented fall of the Neuschwanstein meteorites on April 6, 2002 (a total of three meteorites have been recovered). This includes ground-based photographic and radiometer data as well as infrasound and seismic data from this very significant bolide event (Spurn et al. 2002, 2003). We have also used these data to model the entry of Neuschwanstein, including the expected dynamics, energetics, panchromatic luminosity, and associated fragmentation effects. In addition, we have calculated the differential efficiency of acoustical waves for Neuschwanstein and used these values to compare against the efficiency calculated using available ground-based infrasound data. This new numerical technique has allowed the source height to be determined independent of ray tracing solutions. We have also carried out theoretical ray tracing for a moving point source (not strictly a cylindrical line emission) and for an infinite speed line source. In addition, we have determined the ray turning heights as a function of the source height for both initially upward and downward propagating rays, independent of the explicit ray tracing (detailed propagation path) programs. These results all agree on the origins of the acoustic emission and explicit source heights for Neuschwanstein for the strongest infrasonic signals. Calculated source energies using more than four different independent approaches agree that Neuschwanstein was certainly <500 kg in initial mass, given the initial velocity of 20.95 km/s, resulting in an initial source energy less than or equal to 0.015-0.0276 kt TNT equivalent (4.185 x 10^12 J). Local source energies at the calculated infrasonic/seismic source altitudes are up to two orders of magnitude smaller than this initial source energy.
    • Ernst Florens Friedrich Chaldni (1756-1827) and the origins of modern meteorite research

      Marvin, Ursula B. (The Meteoritical Society, 2007-01-01)
      In 1794, Ernst F. F. Chladni published a 63-page book, Über den Ursprung der von Pallasgefundenen und anderer ihr änlicher Eisenmassen und über einige damit in Verbindung stehendeNaturerscheinungen, in which he proposed that meteor-stones and iron masses enter the atmosphere from cosmic space and form fireballs as they plunge to Earth. These ideas violated two strongly held contemporary beliefs: 1) fragments of rock and metal do not fall from the sky, and 2) no small bodies exist in space beyond the Moon. From the beginning, Chladni was severely criticized for basing his hypotheses on historical eyewitness reports of falls, which others regarded as folk tales, and for taking gross liberties with the laws of physics. Ten years later, the study of fallen stones and irons was established as a valid field of investigation. Today, some scholars credit Chladni with founding meteoritics as a science; others regard his contributions as scarcely worthy of mention. Writings by his contemporaries suggest that Chladnis book alone would not have led to changes of prevailing theories; thus, he narrowly escaped the fate of those scientists who propose valid hypotheses prematurely. However, between 1794 and 1798, four falls of stones were witnessed and widely publicized. There followed a series of epoch-making analyses of fallen stones and native irons by the chemist Edward degrees C. Howard and the mineralogist Jacques-Louis de Bournon. They showed that all the stones were much alike in texture and composition but significantly different from the Earths known crustal rocks. Of primary importance was Howards discovery of nickel in the irons and the metal grains of the stones. This linked the two as belonging to the same natural phenomenon. These chemical results, published in February 1802, persuaded some of the leading scientists in England, France, and Germany that bodies do fall from the sky. Within a few months, chemists in France reported similar results and a new field of study was inaugurated internationally, although opposition lingered on until April 1803, when nearly 3,000 stones fell at LAigle in Normandy and transformed the last skeptics into believers. Chladni immediately received full credit for his hypothesis of falls, but decades passed before his linking of falling bodies with fireballs received general acceptance. His hypothesis of their origin in cosmic space met with strong resistance from those who argued that stones formed within the Earths atmosphere or were ejected by lunar volcanoes. After 1860, when both of these hypotheses were abandoned, there followed a century of debate between proponents of an interstellar versus a planetary origin. Not until the 1950s did conclusive evidence of their elliptical orbits establish meteorite parent bodies as members of the solar system. Thus, nearly 200 years passed before the questions of origin that Chladni raised finally were resolved.