Article

Enigmatic Glass‐Like Carbon from the Alpine Foreland, Southeast Germany: A Natural Carbonization Process

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Unusual carbonaceous matter, termed here chiemite, composed of more than 90% C from the Alpine Foreland at Lake Chiemsee in Bavaria, southeastern Germany has been investigated using optical and atomic force microscopy, X‐ray fluorescence spectroscopy, scanning and transmission electron microscopy, high‐resolution Raman spectroscopy, X‐ray diffraction and differential thermal analysis, as well as by δ13C and 14C radiocarbon isotopic data analysis. In the pumice‐like fragments, poorly ordered carbon matter co‐exists with high‐ordering monocrystalline α‐carbyne, and contains submicrometer‐sized inclusions of complex composition. Diamond and carbyne add to the peculiar mix of matter. The required very high temperatures and pressures for carbyne formation point to a shock event probably from the recently proposed Holocene Chiemgau meteorite impact. The carbon material is suggested to have largely formed from heavily shocked coal, vegetation like wood, and peat from the impact target area. The carbonization/coalification high PT process may be attributed to a strong shock that instantaneously caused the complete evaporation and loss of volatile matter and water, which nevertheless preserved the original cellular structure seen fossilized in many fragments. Relatively fresh wood encapsulated in the purported strongly shocked matter point to quenched carbon melt components possibly important for the discussion of survival of organic matter in meteorite impacts, implying an astrobiological relationship.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... The following are some proposed examples of low-altitude Type 2 airbursts that caused extensive damage to Earth's surface: (i) Chrudim/Pardubice in the Czech Republic [12,13], (ii) Nalbach/Saarlouis in Germany [14][15][16]. (iii) Chiemgau in Germany [17][18][19][20][21][22][23][24][25][26][27], (iv) Niederrhein in Germany [28], (v) Franconia in Germany [29], (vi) Sachsendorf Bay in Germany [30], (vii) seven possibly related strewn fields across about half of the Czech Republic [13], (viii) a 6400-year-old strewn field in Finland [31], (ix) the Luzice melt rock and megabreccia outcrops, proposed as evidence of a low-altitude airburst [32], (x) the 20-km-diameter Kolesovice airburst crater in the Czech Republic [33], (xi) a 2600-year old strewn field in Kansas [34], (xii) a human settlement whose destruction by a cosmic airburst led possible eyewitnesses to construct an oral history that was written down centuries later [1]. For further discussions of this evidence, see Bunch et al. [1] and references [2][3][4][68][69][70][71][72][73][74][75][76][77][78][79][80][81][82]. ...
... In the Chiemgau district of southeast Germany, extensive evidence exists of a significant Holocene-age airburst event [17][18][19][20][21][22][23][24][25][26][27]. The Chiemgau field is roughly elliptical, covering an area of about 60 km by 30 km (1,800 km 2 ) and containing more than 100 impact craters ranging from a few m to 1,300 m. ...
Article
Full-text available
A previous study presented evidence supporting the hypothesis that a low-altitude airburst approximately 3600 years ago destroyed Tall el-Hammam, a Middle-Bronze-Age city northeast of the Dead Sea in modern-day Jordan. The evidence supporting this hypothesis includes a widespread charcoal-and-ash-rich terminal destruction layer containing shock-fractured quartz, shattered and melted pottery, melted mudbricks and building plaster, microspherules, charcoal and soot, and melted grains of platinum, iridium, nickel, zircon, chromite, and quartz. Here, we report further evidence supporting a cosmic airburst event at Tall el-Hammam. Fifteen years of excavations across the city revealed a consistent directionality among scattered potsherds from individually decorated vessels, including one potsherd group distributed laterally approximately southwest to northeast across ∼22 m, spanning six palace walls. Similar trails of charred grains, charcoal, and bone fragments were also found distributed across multi-meter distances inside the destroyed city. Although an earlier report of the directionality of this debris was challenged, further evidence presented here strengthens that interpretation. We also report Middle-Bronze-Age partially melted breccia that likely formed at >2230 °C, consistent with a cosmic event. We investigated additional glass-filled fractured quartz grains using ten analytical techniques, including transmission electron microscopy (TEM), scanning electron microscopy (SEM), cathodoluminescence (CL), and electron backscatter diffraction (EBSD). These grains are inferred to have formed by high-pressure shock metamorphism, consistent with an earlier report that has been challenged. To test that the mode of destruction could have been an airburst, we produced a hydrocode computer model of a Type 2 or touch-down airburst, in which a high-temperature, high-pressure, high-velocity jet intersects Earth’s surface, producing meltglass, microspherules, and shock metamorphism. The modeling shows that the explosive energy released can propel high-velocity airburst fragments to strike the Earth’s surface, producing shock metamorphism and creating superficial craters potentially susceptible to geologically rapid erosion. Although the probability of such airbursts is low, the potential for substantial damage is high, especially in cities.
... The Chiemgau strewn field discovered and established in the early new millennium (Schryvers and Raeymaekers, 2004;Rösler et al. 2005, Rappenglück, M. et al., 2005, 2006Yang et al 2008), extensively investigated in the following decade until today , 2017, 2020, 2023, 2024, Hiltl et al. 2011, Isaenko et al. 2012, 2020a, b, c, 2021, Rappenglück M.A, et al. 2013, 2020, Shumilova et al. 2018, 2020a, b, 2024, Ernstson and Shumilova 2020, Poßekel and Ernstson 2019, 2020, and dated to 900-600 BC in the Bronze Age/Iron Age (Rappenglück, B. et al. 2023) comprises far more than 100 mostly rimmed craters scattered in a region of about 60 km length and ca. 30 km width in the very South-East of Germany. ...
Preprint
Full-text available
The article is the first part of a treatise on the large impact crater strewn field of the Holocene Chiemgau impact with a focus on the now huge number of craters, and a model description of typical examples, for which the craters #004 Emmerting, Kaltenbach and Mauerkirchen were selected here in the first part of addressing the small craters. The selection is justified by the fact that they were already at the beginning of research into the remarkable impact event with geological, geophysical, geochemical, and mineralogical-petrographic investigations and today, some 20 years later, demonstrate how the application of extremely high-resolution digital terrain models down to the decimeter and centimeter range has changed impact research almost in a paradigm shift. This is also a key aspect of this article, which will be followed by two more for the medium-sized and larger craters. Keywords: Chiemgau impact, impact crater strewn field, Digital Terrain Model, impact rocks, shock metamorphism,
... The Chiemgau impact in Bavaria is another more-convincing case ( Ernstson et al., 2010Ernstson et al., , 2011Ernstson et al., , 2012Liritzis et al., 2010;Rappengluck et al., 2010;Shumilova et al., 2018) over the arguments of some opponents (Doppler et al., 2011;Rappen- gluck et al., 2011). ...
Article
Full-text available
Liritzis, I.; Westra, A., and Miao, C., 2019. Disaster geoarchaeology and natural cataclysms in world cultural evolution: An overview. Journal of Coastal Research, 35(6), 1307–1330. Coconut Creek (Florida), ISSN 0749-0208. Human records of short-term, catastrophic, geological processes, mainly in coastal or fluvial environments, and related phenomena in historic and prehistoric times have to be considered as functions of event intensities and impacts (and damages) caused on ancient human settlements and lives. Catastrophic events, such as, floods, earthquakes, volcanic eruptions, tsunamis, and the collapse of ancient cultures, in particular, those allied to the birth of myths and legends, are the subject of long-lasting, vivid debate. Longer-term, more-or-less consecutive, geological processes and climatic fluctuations have a more pronounced effect on human history. Historical accounts provide many descriptions about cultural evolution in a recurrent manner. The geoarchives (geology, sedimentology, and geomorphology) and the human record (archaeology and history) are considered documentary evidence of these past events. Astronomical causes have introduced severe phenomena (warming, heavy precipitation, monsoons, droughts) imposed on ancient societies, including catastrophic meteor impact. Terrestrial upheavals and astronomical impacts have introduced a nonlinear character of a quasiperiodic nature in transforming human cultural evolution and reshaping the earth's surface. The transient nature of geological, geophysical, and proxy climatic indices, as well as, astronomical phenomena within the solar system, exhibit a wide spectrum of quasiperiodic frequencies as variable and effective environmental factors, which, in addition to anthropogenic factors, reshape the human context. Several conspicuous examples have been reported on mythological deluges and their relation to natural catastrophes. The Anthropocene sea level rise and climatic episodes have had a decisive and prominent role on coastlines and human settlements. Alluvial sediments, sedimentary deposits, and land modifications have drastic effects on settlements. These effects were memorized as floods, deluges, and fallen sky. World examples of disasters derived from the coastal Mediterranean, the Great Flood of Gun-Yu in China, and those from South America, Mesopotamia, and the Middle East and others, were critically assessed with scientific methods.
Article
Full-text available
We use Schmieder and Kring's article to show how science still works within the so-called "impact community" and how scienti c data are manipulated and "rubber-stamped" by reviewers (here, e.g., C. Koeberl and G. Osinski). We accuse the authors of continuing to list the Azuara and Rubielos de la Cérida impact structures and one of the world's most prominent ejecta occurrences of the Pelarda Fm. in Spain 1 2 as non-existent in the compilation. The same applies to the spectacular Chiemgau impact in Germany, which has been proven by all impact criteria for several years. For the authors' dating list, we propose that the multiple impact of Azuara is included together with the crater chain of the Rubielos de la Cérida impact basin as a dated candidate for the third, so far undated impact markers in the Massignano outcrop in Italy.
Article
Full-text available
This review systematically presents all finds of geogenic, impact-induced, and extraterrestrial iron silicide minerals known at the end of 2021. The respective morphological characteristics, composition, proven or reasonably suspected genesis, and possible correlations of different geneses are listed and supported by the available literature (2021). Artificially produced iron silicides are only dealt with insofar as the question of differentiation from natural minerals is concerned, especially regarding dating to pre-industrial and pretechnogenic times.
Article
Full-text available
Terrestrially occurring iron silicide spherules, described in the geological literature for 160 years as cosmogenic and approved as “extraterrestrial” minerals by IMA CNMMN in 1984, so far have escaped any serious examination by meteoriticists. Our isotopic and REE data, obtained for silicide spherules for the first time, disagree with the meteoritic origin of gupeiite (Fe3Si) and xifengite (Fe5Si3) spherules from two continents. Despite departures from terrestrial norms (87Rb/86Sr—0.0174; 87Sr/86Sr—0.700181; 3He/4He—7.57 × 10−6; 40Ar/36Ar—325.9), the compositions of 143Nd/144Nd (0.512034) and 147Sm/144Nd (0.06357), as well as REE abundances, clarify provenance from upper crust sediments for samples with U/Pb age of 121–314 ka from the Ala‐Tau range in the Urals. However, the morphology of flanged button shapes, ring waves, and eccentro‐radiating ridges reliably constrains the origin of silicide spherules to distal meteoritic impact ejecta. Arc jet ablation experiments have previously demonstrated that similar morphologies, observed on australite tektites, reflect aerodynamic ablation rates corresponding to flight velocities well into orbital range. These features are generally accepted as conclusive evidence for hypervelocity atmospheric entry from space. Internal structure, consistent with accretion through the coalescence of 3–5 µm droplets, and composition, closely corresponding to 1893–1154 K span of C‐type condensation sequences, indicate a high probability of processing through recondensation of ejecta vapor.
Conference Paper
Full-text available
The Digital Terrain Model (DTM) of craters in the Chiemgau meteorite impact strewn field with extreme topographic resolution excludes anthropogenic and glacial origin in principle and provides insight into unusual formation processes.
Article
Full-text available
We report on a fragment of the quasicrystal-bearing CV3 carbonaceous chondrite Khatyrka recovered from fine-grained, clay-rich sediments in the Koryak Mountains, Chukotka (Russia). We show higher melting-point silicate glass cross-cutting lower melting-point Al-Cu-Fe alloys, as well as unambiguous evidence of a reduction-oxidation reaction history between Al-Cu-Fe alloys and silicate melt. The redox reactions involve reduction of FeO and SiO_2 to Fe and Fe-Si metal, and oxidation of metallic Al to Al_2O_3, occurring where silicate melt was in contact with Al-Cu-Fe alloys. In the reaction zone, there are metallic Fe and Fe-Si beads, aluminous spinel rinds on the Al-Cu-Fe alloys, and Al_2O_3 enrichment in the silicate melt surrounding the alloys. From this and other evidence, we demonstrate that Khatyrka must have experienced at least two distinct events: first, an event as early as 4.564 Ga in which the first Al-Cu-Fe alloys formed; and, second, a more recent impact-induced shock in space that led to transformations of and reactions between the alloys and the meteorite matrix. The new evidence firmly establishes that the Al-Cu-Fe alloys (including quasicrystals) formed in outer space in a complex, multi-stage process.
Article
Full-text available
FIT2D is one of the principal area detector data reduction, analysis and visualization programs used at the European Synchrotron Radiation Facility and is also used by more than 400 research groups worldwide, including many other synchrotron radiation facilities. It has been developed for X-ray science, but is applicable to other structural techniques and is used in analysing electron diffraction data and microscopy, and neutron diffraction and scattering data. FIT2D works for both interactive and ‘batch’-style data processing. Calibration and correction of detector distortions, integration of two-dimensional data to a variety of one-dimensional scans, and one- and two-dimensional model fitting are the main uses. Many other general-purpose image processing and image visualization operations are available. Commands are available through a ‘graphical user interface’ and operations common to certain types of analysis are grouped within ‘interfaces’. Executable versions for most workstation and personal computer systems, and web page documentation, are available at http://www.esrf.eu/computing/scientific/FIT2D.
Article
Full-text available
We report the discovery of a new phase of carbon (referred to as Q-carbon) and address fundamental issues related to direct conversion of carbon into diamond at ambient temperatures and pressures in air without any need for catalyst and presence of hydrogen. The Q-carbon is formed as result of quenching from super undercooled state by using high-power nanosecond laser pulses. We discuss the equilibrium phase diagram (P vs. T) of carbon and show that by rapid quenching kinetics can shift thermodynamic graphite/diamond/liquid carbon triple point from 5000 K/12 GPa to super undercooled carbon at atmospheric pressure in air. It is shown that nanosecond laser heating of diamond-like amorphous carbon on sapphire, glass, and polymer substrates can be confined to melt carbon in a super undercooled state. By quenching the carbon from the super undercooled state, we have created a new state of carbon (Q-carbon) from which nanodiamond, microdiamond, microneedles, and single-crystal thin films are formed depending upon the nucleation and growth times allowed for diamond formation. The Q-carbon quenched from liquid is a new state of solid carbon with a higher mass density than amorphous carbon and a mixture of mostly fourfold sp3 (75%-85%) with the rest being threefold sp2 bonded carbon (with distinct entropy). It is expected to have new and improved mechanical hardness, electrical conductivity, chemical, and physical properties, including room-temperature ferromagnetism (RTFM) and enhanced field emission. Here we present interesting results on RTFM, enhanced electrical conductivity and surface potential of Q-carbon to emphasize its unique properties. The Q-carbon exhibits robust bulk ferromagnetism with estimated Curie temperature of about 500 K and saturation magnetization value of 20 emu g-1. From the Q-carbon, diamond phase is nucleated and a variety of micro- and nanostructures and large-area single-crystal diamond sheets are grown by allowing growth times as needed. Subsequent laser pulses can be used to grow nanodiamond into microdiamond and nucleate other nanostructures of diamond on the top of existing microdiamond and create novel nanostructured materials. The microstructural details provide insights into the mechanism of formation of nanodiamond, microdiamond, nanoneedles, microneedles, and single-crystal thin films. This process allows carbon-to-diamond conversion and formation of useful nanostructures and microstructures at ambient temperatures in air at atmospheric pressure on practical and heat-sensitive substrates in a controlled way without need for any catalysts and hydrogen to stabilize sp3 bonding for diamond formation.
Article
Full-text available
Biochar is widely recognized as an efficient tool for carbon sequestration and soil fertility. The understanding of its chemical and physical properties, which are strongly related to the type of the initial material used and pyrolysis conditions, is crucial to identify the most suitable application of biochar in soil. A selection of organic wastes with different characteristics (e.g., rice husk (RH), rice straw (RS), wood chips of apple tree (Malus pumila) (AB), and oak tree (Quercus serrata) (OB)) were pyrolyzed at different temperatures (400, 500, 600, 700, and 800 °C) in order to optimize the physicochemical properties of biochar as a soil amendment. Low-temperature pyrolysis produced high biochar yields; in contrast, high-temperature pyrolysis led to biochars with a high C content, large surface area, and high adsorption characteristics. Biochar obtained at 600 °C leads to a high recalcitrant character, whereas that obtained at 400 °C retains volatile and easily labile compounds. The biochar obtained from rice materials (RH and RS) showed a high yield and unique chemical properties because of the incorporation of silica elements into its chemical structure. The biochar obtained from wood materials (AB and OB) showed high carbon content and a high absorption character.
Article
Full-text available
Impact cratering can destroy life from local to global scales and result in sudden turnovers of dominant genera and/or species. Here we report that it can also preserve components of the local biology present at the time of impact. We have investigated floral matter encapsulated within Cenozoic Era impact glasses produced by separate bolide impacts into the loessoid sediments of Argentina that occurred between 9.2 Ma (Miocene) and 6 ka (Holocene). The encapsulation preserved not only macro-scale morphological biosignatures such as vascular bundles, veins, phytoliths, and papillae, but also structures down to the cellular level. In the best-preserved samples we also found evidence for organic matter. While fossilization typically occurs over an extended time period as minerals slowly replace organic matter and the host rock lithifies under pressure, the process documented here is instantaneous. Preservation of morphological and chemical biosignatures in impact events can provide snapshots of the ecology in environments that do not otherwise promote a diverse fossil record. We suggest that this would provide a new strategy for identifying signs of possible early life on ancient Mars, where similar target conditions once existed.
Book
Full-text available
The book opens the main low connections between the processes of formation and distribution of native carbon in the nature. The modern classification of carbon forms, mechanisms and thermodynamic conditions of formation of carbon mineralization are described. The typomorphic features of carbon mineralization of different genetic types including new natural carbon forms and new localization of rare carbon forms have been written. Tight genetic connection between carbon forms in the nature is proved the one defines joint presence of diamond, graphite, carbyne and hybrid types of carbon. On the basis of carbon paragenesis new criterion of prospecting of origin diamond deposits is offered. The book is intended for scientists and students of geological specialization and material science the one may be useful for specialists working on the problems of prospecting, synthesis and modifying of diamond, graphite and other forms of carbon materials.
Article
Full-text available
After several ad hoc proposals of new 2-dimensional carbon structures, interest in their actual synthesis has begun to increase. One needs a clear orientation or criteria to describe those carbon structures in an appropriate way. In the present paper, we propose a systematic method for discovering new stable structures of carbon crystals with sp2sp2-bonding using advanced mathematical methods. There are two key ideas: geometric descriptions based on curvatures, symmetries, etc. and the standard realization of crystal lattices via harmonic theory to identify stable coordinates. We apply this new method to study negatively curved carbon crystals with octahedral symmetry after Mackay–Terrones [1], and identify several new structures. The stability and electronic states of the proposed structures are investigated using first principles calculations.
Conference Paper
Full-text available
Introduction: The Holocene Chiemgau impact event is considered to have produced a large meteorite crater strewn field in southeast Germany in the Bronze Age/Celtic era ([1], and ref. therein). The impact is documented by impact melt rocks and various glasses, strong shock metamorphism, geophysical anomalies and ejecta deposits, and substantiated by the abundant occurrence of metallic, glass and carbon spherules. Enigmatic carbon matter containing carbynes and diamond-like/carbyne-like carbon allotropes also testify extreme temperatures and pressures [2, 3]. From the beginning of the discovery and investigation of the strewn field, extended finds of iron silicide particles in the subsoil mainly composed of xifengite and gupeiite and obviously associated with the craters played a significant role as possible meteoritic matter. New analytical SEM, TEM and EBSD have shown that the iron silicides when going down to micrometer scales are hosting a real «zoo» of more than 30 chemical elements, extremely rare minerals and peculiar textural features. Observations: Iron silicides (Fig. 1, A). — So far the minerals xifengite, gupeiite, fersilicite, ferdisilicite and hapkeite have been established to occur as a matrix of intimate intergrowth. Different from the cubic hapkeite found for the first time in the Dhofar 280 lunar meteorite [4], the Chiemgau hapkeite could be shown to be the trigonal polymorph. Carbides (Fig. 1, A). — The iron silicide matrix contains abundant extremely pure crystals of SiC, cubic moissanite, TiC, and (Ti, V, Fe) C, khamrabaevite. Calcium-aluminum inclusions, CAIs (Fig. 1, B). — The Chiemgau iron silicides contain the monoclinic high-temperature (>1.500 °C), low-pressure dimorph of CaAl 2 O 4 , mineral krotite, and the orthorhombic Ca 2 Al 2 O 5 dicalcium dialuminate high pressure phase with the brownmillerite-type structure. Zirconium and uranium (Fig. 1, C, D). — Zirconium (zircon or/and baddeleyite) shows as possible exsolution lamellae in iron silicide. Clusters of tiny (< 10 m) zircon crystals coated by uranium are interspersing the iron silicide matrix. EDX spectra show the uranium to be free of any decay products Fig. 1. A: Titanium carbide (dark gray) and silicon carbide (moissanite, black) crystals in a matrix of intergrowth of various iron silicides. B: Light edging CAIs (arrow) around black C (graphite, diamond?) film in iron silicide matrix. C: Zircon crystals in iron silicide matrix. The white tips on the crystals have been shown to be uranium. D: Zirconium (zircon or/and baddeleyite) possible exsolution lamellae in iron silicide. E: Rimmed micro-craters on the surface of an iron silicide particle. F: Strongly fractured titanium carbide crystal in iron silicide matrix. Note the open, tensile fractures pointing to dynamic (shock?) spallation
Article
Full-text available
Meteorites can have played a role in the delivery of the building blocks of life to Earth only if organic compounds are able to survive the high pressures and temperatures of an impact event. Although experimental impact studies have reported the survival of organic compounds, there are uncertainties in scaling experimental conditions to those of a meteorite impact on Earth and organic matter has not been found in highly shocked impact materials in a natural setting. Impact glass linked to the 1.2-km-diameter Darwin crater in western Tasmania is strewn over an area exceeding 400km2 and is thought to have been ejected by a meteorite impact about 800kyr ago into terrain consisting of rainforest and swamp. Here we use pyrolysis-gas chromatography-mass spectrometry to show that biomarkers representative of plant species in the local ecosystem--including cellulose, lignin, aliphatic biopolymer and protein remnants--survived the Darwin impact. We find that inside the impact glass the organic components are trapped in porous carbon spheres. We propose that the organic material was captured within impact melt and preserved when the melt quenched to glass, preventing organic decomposition since the impact. We suggest that organic material can survive capture and transport in products of extreme impact processing, at least for a Darwin-sized impact event.
Article
Full-text available
This study aimed to investigate the influence of raw material moisture content on the properties of charcoal from fast-growing Eucalyptus benthamii wood. For that, three treatments were performed with 0, 30, and 50% in relation to the wet basis moisture of the wood samples. The carbonization process used an electric kiln with a heating rate of 1.60 degrees C min(-1), initial temperature of 25 to 600 degrees C at the end, kept constant at that temperature for two hours. Variables were statistically analyzed for charcoal yield, non-condensable gases, liquor, and fixed carbon and properties: fixed carbon content, volatile, ash, bulk density, and moisture content of charcoal. According to the results, the charcoal produced from dry wood presented the highest properties, yet the charcoal produced from wood with 30% moisture content showed similar properties.
Article
Full-text available
Arguing from a critical reading of the text, and scientific evidence on the ground, the authors show that the myth of Phaethon – the delinquent celestial charioteer – remembers the impact of a massive meteorite that hit the Chiemgau region in Bavaria between 2000 and 428 BC.
Article
Full-text available
Carbynes and DLC in naturally occurring carbon matter from the Alpine Foreland, South-East Germany: Evidence of a probable new impactite S. Isaenko (1), T. Shumilova (1), K. Ernstson (2), S. Shevchuk (1), A. Neumair (3), and M. Rappenglück (3) (1) Institute of Geology Komi SC UB RAS, Syktyvkar, Russian Federation (shumilova@geo.komisc.ru), (2) Faculty of Philosophy, University of Würzburg, Würzburg, Germany (kernstson@ernstson.de), (3) Institute for Interdisciplinary Studies, Gilching, Germany (mr@infis.org) Unusual carbonaceous matter (UCM) in the form of mostly centimeter-sized lumps and cobbles has been sampled in the southeast Bavarian Alpine Foreland. It is a highly porous blackish material with a glassy luster on freshly crushed surfaces. In some cases aerodynamically shaped cobbles like volcanic bombs were sampled. The material is unknown from any industrial or other anthropogenic processes and thus appears to have a natural origin, which is underlined by findings on a small island in the large Lake Chiemsee and at some altitude in the pre-Alps mountains. Here we report a detailed analysis of this strange matter by a complex of high resolu-tion Raman spectroscopy, X-Ray diffraction, electron scanning and atomic force microscopy, transmission electron microscopy and differential thermal analysis. We have found that the carbon matter is presented by the association of different carbon phases. The matrix is consisting of fully amorphous black glass-like carbon with a porous struc-ture and almost pure carbon content with traces of O, S, Si, Al. Inside of the matter monocrystal-line carbyne and amorphous diamond-like carbon (DLC) inclusions are found. The first is pre-sented by flattened particles of a-carbyne (predominantly) and in a single case by cooriented in-tergrowths of a- and b-carbyne modifications (Shumilova et al., 2012). The DLC is characterized by optically transparent particles of generally flattened irregular shape and rare bulk particles sometimes of trigonal form and octahedrons. The typical DLC Raman spectrum is decomposed into three general wide bands – around 1400-1500, 1325-1370 and 1580-1600 cm-1 and two bands at down-shoulder side – around 1070-1090 and 1200-1250 cm-1. Among known carbon substances there are no exactly equal spectra. However, the listed Raman features could be interpreted as sp2-3 glass-like carbon containing some quantity of DLC, while the wide bands 1325-1370 and 1580-1600 cm-1 are rather expected to correspond to D and G Raman bands of carbon materials. The other features should be attributed to the presence of amorphous carbon with high content of tetrahedral carbon bonds (Ferrari & Robertson, 2004; Wei & Sankar, 2000; Robertson, 2002; Osswald et al., 2009). Following Xu-Li et al. (2009), the analyzed optically transparent amorphous inclusions are pre-sented by DLC formed under high temperature. The observed carbon phases association and carbon state diagram are pointing to a process of very high pressures and temperatures to produce the UCM. We suggest the material to be a new impactite that was probably formed in the shock event of the proposed Chiemgau impact (Ernstson et al., 2010) with the formation of a large crater strewn field only a few thousand years ago.
Article
Full-text available
CAIs Ca_2Al_2O_5 and CaAl_2O_4 add to SiC and (Ti,V,Fe)C pure crystal inclusions in an iron silicide (xifengite, gupeiite, hapkeite) matrix constituting metallic particles from the subsoil in the Alpine Foreland. A cosmic origin is suggested.
Article
Full-text available
The Chiemgau strewn field in the Alpine Foreland discovered in the early new millennium comprises more than 80 mostly rimmed craters in a roughly elliptically shaped area with axes of about 60 km and 30 km. The crater diameters range between a few meters and a few hundred meters. Geologically, the craters occur in Pleistocene moraine and fluvio-glacial sediments. The craters and surrounding areas so far investigated in more detail are featuring heavy deformations of the Quaternary cobbles and boulders, abundant fused rock material (impact melt rocks and various glasses), shock-metamorphic effects, and geophysical anomalies. The impact is substantiated by the abundant occurrence of metallic, glass and carbon spherules, accretionary lapilli, and of strange matter in the form of iron silicides like gupeiite and xifengite, and various carbides like, e.g., moissanite SiC. The hitherto established largest crater of the strewn field is Lake Tüttensee exhibiting an 8 m-height rim wall, a rim-to-rim diameter of about 600 m, a depth of roughly 30 m and an extensive ejecta blanket. Physical and archeological dating confine the impact event to have happened most probably between 1300 and 300 B.C. The impactor is suggested to have been a low-density disintegrated, loosely bound asteroid or a disintegrated comet in order to account for the extensive strewn field.
Article
Full-text available
We investigated the atomic structure, electrical, and infrared range optical properties of diamondlike carbon (DLC) films containing alloy atoms (Cu, Ti, or Si) prepared by pulsed laser deposition. Radial distribution function (RDF) analysis of these films showed that they are largely sp3 bonded. Both pure DLC and DLC + Cu films form a Schottky barrier with the measuring probe, whereas DLC + Ti films behave like a linear resistor. Pure DLC films and those containing Cu exhibit p-type conduction, and those containing Ti and Si have n-type conduction. Photon-induced conduction is observed for pure DLC, and the mechanism is discussed in terms of low-density gap states of highly tetrahedral DLC. Our results are consistent with relative absence of gap states in pure DLC, in accordance with theoretical prediction by Drabold et al.37 Temperature dependence of conductivity of DLC + Cu shows a behavior σ ∞ exp(−B/T1/2), instead of the T−1/4 law (Mott–Davis law). Contributions from band-to-band transitions, free carriers, and phonons to the emissivity spectrum are clearly identified in pure DLC films. The amorphous state introduces a large contribution from localized states. Incorporation of a small amount of Si in the DLC does not change the general feature of emissivity spectrum but enhances the contribution from the localized states. Cu and Ti both enhance the free carrier and the localized state contributions and make the films a black body.
Article
Full-text available
Archaeological excavation at Chieming-Stöttham in the Chiemgau region of Southeast Germany revealed a diamictic (breccia) layer sandwiched between a Neolithic and a Roman occupation layer. This exotic layer bears evidence of its deposition in a catastrophic event that is attributed to the Chiemgau meteorite impact. In the extended crater strewn field produced by the impact, geological excavations have uncovered comparable horizons with an anomalous geological inventory intermixed with archaeological material. Evidences of extreme destruction, temperatures and pressures including impact shock effects suggest that the current views on its being an undisturbed colluvial depositional sequence as postulated by archaeologists and pedologists/geomorphologists is untenable
Article
Full-text available
Soil or rock liquefaction is a well-known process initiated by seismic shaking during strong earthquakes and exemplarily revealed by, e.g., the 1811/1812 devastating New Madrid, Missouri, earthquake series. In the Bavarian Alpine Foreland, typical soil liquefaction surface features have been investigated by complex 4-frequency resistivity measurements in the form of 2D electrical imaging. We used a pole-dipole configuration and a 1 m station spacing resulting in apparent resistivity and apparent induced polarization (IP) pseudosections. The profiles crossed a recently collapsed 1 m-diameter sink hole (a so-called thunderhole) and a 4.5 m-diameter active soil subsidence. Both resistivity and IP (selected phase shift at 8,33 Hz) pseudosections reveal that sink hole collapse and active depression are only small-scale snapshots in time of a much larger geologic scenario going off in the subsurface. Over at least 20 m in the first case and 40 m in the latter, the underground structures, normally well bedded Quaternary fluvio-glacial sands and gravels, loamy moraine material and loess deposits, show a drastically disturbed resistivity pattern. Conspicuously, the IP pattern is significantly more affected by small-scale structures and obviously much more sensitive to even minor changes of rock facies. Thus, in the investigation under discussion the IP pattern points to distinct multiple intrusion and extrusion features typical of soil liquefaction, while in this respect the resistivity expression is comparatively poor. A deep excavation of the thunderhole on a larger scale following the geophysical measurements confirmed the prediction of the complex resistivity survey in very detail. Moreover, it gave insight into a geological underground liquefaction process that must have released enormous energies leading to the assumption that the liquefaction, because of absent earthquake activity in the region, has been induced by the recently proposed Holocene so-called Chiemgau meteorite impact event. Since the liquefaction features including the widespread sink hole activity, known in the region within living memory, have engineering-geology implications we suggest the application of complex resistivity measurements as an important tool for the investigation of subsoil properties in construction works. Because of the frequently thick loamy and clayey low-resistivity cap rocks in the liquefaction-affected region, complex resistivity surveys may be superior to ground penetration radar (GPR) measurements otherwise useful in subgrade geophysics.
Article
Full-text available
A more exact dating of the Chiemgau meteorite impact in Bavaria, southeast Germany, that produced a large strewn field of more than 80 craters sized between a few meters and several hundred meters, may provide the indispensable fundament for evaluating its cultural implications and thus enable an extraordinary case study. A straightforward answer has not yet been provided due to e.g. scarce existence of diagnostic material, lack of specialised micromorphologists, absence of absolute dating data etc. Here we report on a first OSL dating applied to a catastrophic impact layer that features both impact ejecta and tsunami characteristics attributed to proposed falls of projectiles into Lake Chiemsee in the impact event. The OSL dating was conducted on a quartzite cobble and four sediment samples collected from an excavated archaeological stratigraphy at Lake Chiemsee that comprised also the impact layer. In a first approach the analyses were based on the assumption of zero luminescence resetting clock from the induced impact shock for the quartzite cobble, and a solar bleaching of tsunamigenerated sediments. Optically Stimulated Luminescence (OSL) was applied using the Single Aliquot Regeneration (SAR) protocol and relevant reliability criteria. For sediments the beta-TL method was also applied. Reported ages fall around the beginning of 2nd millennium BC. Special attention is given to the peculiar situation of OSL dating of material that may have been exposed to impact shock of strongly varying intensity, to excavation, ejection and ejecta emplacement, the latter overprinted by and mixed with tsunami transport processes resulting in possibly very complex bleaching scenarios largely differing from the original assumptions.
Article
Full-text available
Sudden collapse of the Quaternary soil to form sinkholes on the order of meters and tens of meters has been a geologic phenomenon within living memory in a localized area north of Lake Chiemsee in Southeast Germany. Failing a satisfying explanation, a relation with an undefined glaciation process has always been proposed. Excavations and geophysical measurements at three newly affected sites show underground features such as prominent sandy-gravelly intrusions and extrusions typical of rock liquefaction processes well known to occur during strong earthquakes. Since strong earthquakes can reasonably be excluded to have affected the area under discussion, it has been suggested that the observed widespread liquefaction is related with the recently proposed Holocene Chiemgau meteorite impact event. Except for one earlier proposed but unassertive relation between impact and liquefaction, the obviously direct association of both processes in the Chiemgau area emphasizes that observed paleoliquefaction features need not necessarily have originated solely from paleoseismicity but can provide a recognizable regional impact signature.
Conference Paper
The largest meteorite impact of the Holocene known to date occurred during the Bronze/Iron Age in southeastern Bavaria, between Altötting and the edge of the Alps. The event is known as the "Chiemgau Impact". More than 100 craters with diameters from 5 m up to several hundred meters are distributed over an area of about 60 km length and 30 km width. Finds of meteoric material confirm the event as well as the widespread evidence of so-called shock metamorphosis in the rock. The article focuses on new investigations of "slags" from an archaeological excavation in Chieming-Stöttham, on the eastern shore of Lake Chieming. Six objects analysed with polarisation microscope and SEM-EDS turned out to be complex combinations of rock and metal particles. While the rock components show the shock metamorphosis typical for a meteorite impact, the metallic components proved to be remnants of artefacts made of bronze or iron with a high lead content. Together they form an impact rock. To our knowledge, these are the first examples worldwide in which artefacts have become components of an impact rock. In addition, the special nature of the metallic components and the consideration of the archaeological context allow the more precise dating of the Chiemgau Impact to approximately 900-600 BC.
Article
Rapidly formed eutectic textures are observed in Fe silicides in a fulgurite from Michigan. The 14 cm-diameter fulgurite was formed in sandy glacial till in 2014 near Houghton Lake, Michigan. Spherical droplets of iron silicides up to ∼200 μm in diameter were found in the natural glass. Back-scattered electron images of some droplets show a eutectic intergrowth texture of two iron silicides with individual crystals up to ∼1 μm in maximum dimension. X-ray diffraction study showed the specimens to be an intergrowth of naquite (FeSi) and linzhiite (FeSi2) or naquite and xifengite (Fe5Si3). Droplets also contain minor native silicon, Fe-Ti silicides, and/or other Ti- rich phases which were discovered during TEM observations. It is important to note that the lower-temperature phase luobusaite (Fe3Si7) was not observed in any droplets, indicating rapid quenching of the fulgurite, consistent with a natural origin during a lightning strike as opposed to an artificial origin, e.g., resulting from a downed power line.
Article
Unusual carbonaceous matter, termed here chiemite, composed of more than 90% C from the Alpine Foreland at Lake Chiemsee in Bavaria, southeastern Germany has been investigated using optical and atomic force microscopy, X‐ray fluorescence spectroscopy, scanning and transmission electron microscopy, high‐resolution Raman spectroscopy, X‐ray diffraction and differential thermal analysis, as well as by δ13C and 14C radiocarbon isotopic data analysis. In the pumice‐like fragments, poorly ordered carbon matter co‐exists with high‐ordering monocrystalline α‐carbyne, and contains submicrometer‐sized inclusions of complex composition. Diamond and carbyne add to the peculiar mix of matter. The required very high temperatures and pressures for carbyne formation point to a shock event probably from the recently proposed Holocene Chiemgau meteorite impact. The carbon material is suggested to have largely formed from heavily shocked coal, vegetation like wood, and peat from the impact target area. The carbonization/coalification high PT process may be attributed to a strong shock that instantaneously caused the complete evaporation and loss of volatile matter and water, which nevertheless preserved the original cellular structure seen fossilized in many fragments. Relatively fresh wood encapsulated in the purported strongly shocked matter point to quenched carbon melt components possibly important for the discussion of survival of organic matter in meteorite impacts, implying an astrobiological relationship.
Article
To understand the influence of the diagenetic water medium on the isotopic compositions of thermogenic coalbed gas, both hydrous and anhydrous closed‐system pyrolyses were performed at temperatures of 250°C to 650°C on an herbaceous marsh peat. Compared to the results of anhydrous pyrolysis, the hydrocarbon gases generated from hydrous pyrolyses have very different hydrogen isotopic compositions. However, the carbon isotopic compositions of the hydrocarbon gases became only slightly heavier in hydrous pyrolysis, compared to that from anhydrous pyrolysis. With the progress of thermal evolution from peat to a more advanced thermal maturity of vitrinite reflectance values (Ro) of 5.5% during the pyrolysis, the difference in the average δD value increased from 52‰ to 64‰ between the hydrous pyrolysis with saltwater and anhydrous pyrolysis and increased from 18‰ to 29‰ between the hydrous pyrolysis with freshwater and anhydrous pyrolysis, respectively. The difference in the average δ¹³C value was only 1‰–2‰ between the hydrous and anhydrous pyrolysis. The relationships between the δD values of the generated hydrocarbon gases and Ro values as well as among δD values of the hydrocarbon gas species are established. The close relationships among these parameters suggest that the water medium had a significant effect on the hydrogen isotopic composition and a minimal effect on the carbon isotopic composition of the hydrocarbon gases. The results of these pyrolyses may provide information for the understanding of the genesis of coalbed gas from herbaceous marsh material with the participation of different diagenetic water media.
Article
Constraining the timing and intensity of Solar System bombardment is critical to understanding planetary formation, evolution and habitability. However, the identification and dating of shockmetamorphic events in the mafic igneous lithologies that dominate planetary materials remains highly challenging, particularly at relatively modest shock pressures. The accessory mineral baddeleyite (monoclinic-ZrO2) is common in these mafic crustal rocks, though the microstructural response of this mineral to shock loading is currently unconstrained. Here we show that baddeleyite yields a predictable sequence of microstructures in the shock pressure range of 5 to ~20 GPa, based on analysis of mafic rocks collected along a well-constrained shock-pressure gradient in the crystalline bedrock of the Sudbury impact structure, Canada. High-resolution electron backscatter diffraction mapping of baddeleyite grains exposed to < 20 GPa of shock loading reveals a range of microstructures, including complex orthogonally related crystalline subgrains, amorphous domains, and crystal plastic deformation. Evidence that the observed microstructures are principally controlled by the transition to, and subsequent reversion from, the high-pressure (experimentally constrained to > 5 GPa) orthorhombic-ZrO2 polymorph is provided by phase-heritage reconstruction using relationships between reverted monoclinic orientations. Baddeleyite is a sensitive shock barometer and chronometer over low pressure ranges that can augment ongoing studies into the intensity of Solar System bombardment.
Article
Impact diamonds were discovered in the 70s and are usually accepted as being paramorphs after graphite, resulting in grains of extremely high mechanical quality. A diffusion-less mechanism for the graphite-to-diamond transition under huge pressure has been experimentally realized and theoretically explained. Besides, another type of impact product has received much less attention, namely diamonds formed after coal as a result of the impact. Here we describe after-coal impact diamonds from the giant Kara astrobleme (Pay-Khoy, Russia), which resulted from a large asteroid impact about 70 Ma ago. The impact created a large number of unusual impact diamonds, which are described here for the first time using high-resolution techniques including visible and UV Raman spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM) and transmission electron microscopy (TEM). Two main varieties of after-coal diamonds occur: micrograined (sugar-like, subdivided into coherent and friable) and, as a new type, paramorphs after organic relics. After-coal diamonds differ from after-graphite impact diamonds by the texture, the absence of lonsdaleite, a micro- and nanoporous structure. The sugar-like variety consists of tightly aggregated, well-shaped single nanocrystals. The after-organic diamond paramorphs are characterized by a well-preserved relict organic morphology, sub- nanocrystalline–amorphous sp3-carbon (ta-C) nanocomposites and other specific properties (optical transparence, brown color, very high luminescence, spectral features). Based on the description of after-coal diamonds, we propose a new, polystage formation mechanism: high-velocity coal pyrolysis with hetero-elements removal followed by diffusion-limited crystallization of pure carbon. The similarity of the after-coal diamonds features with carbonado is a strong piece of evidence in support of the impact hypothesis for the origin of carbonado.
Article
Time-resolved x-ray diffraction (XRD) of compressed liquid water shows transformation to ice VII in 6 nsec, revealing crystallization rather than amorphous solidification during compression freezing. Application of classical nucleation theory indicates heterogeneous nucleation and one-dimensional (e.g., needlelike) growth. These first XRD data demonstrate rapid growth kinetics of ice VII with implications for fundamental physics of diffusion-mediated crystallization and thermodynamic modeling of collision or impact events on ice-rich planetary bodies.
Chapter
A review with 218 refs. of prepn. methods and electronic structure and crystal structure of carbyne.
Article
Because of the unique geographical location and important ecological effect of the Qinling Mountains, reconstruction of its vegetation and climate needs comprehensive research. We need to consider a multiple-proxy approach to gain more information on recovering the paleovegetation and climate in the Qinling Mountains. Black carbon (BC) is produced by the incomplete combustion of vegetation and fossil fuels, and is a good proxy, recording paleoenvironmental information. However, in the Qinling Mountains, what are the characteristics of the BC, and whether BC stable carbon isotope (δ13CBC) can be used as a new proxy to study ancient vegetation, still need further study. In order to establish a sound basis for studying paleoenvironmental by BC proxy in the Qinling Mountains, we carried out systematic and detailed study on modern process of BC on the northern slope of the mountains. We analyzed stable carbon isotopes and carbon concentration of organic carbon (%SOC, δ13CSOC) and BC (%BC, δ13CBC), and identified the pollen assemblages from systematically sampled surface soil. The results show that the calculated ratio of C4 plants in the vegetation (%C4) based on the δ13CSOC data reflects a similar distribution of C4 plants in the surface vegetation and the pollen assemblage. The δ13Cbc values have a strong positive correlation with δ13Csoc values, and their difference (Δ13CSOc-bc) is in the low range. These data indicate that δ13Cbc and δ13Csoc have very similar characteristics. Surface soil δ13Cbc values can indicate surface vegetation as effectively as δ13CSOC values, and the δ13Cbc proxy can be used effectively in paleovegetational research in the northern slope of Qinling Mountains.
Article
Late Quaternary geyserite and travertine in Ol’khon Area and Ol’khon Island contain a recently discovered high�temperature association of hydrocarbon and carbonaceous phases, including highly crystal� line graphite, α�carbyne, and bitumen, which were produced at temperatures no lower than 400°C. A carbon modification α�carbyne, which was previously found only among experimental products, was first identified in geyserite from the Ol’khon area. Nanometer�sized morphostructures and crystallites were detected on the surface of highly crystalline graphite from the geyserite and travertine. No such structures and crystallites have ever been found on graphite of magmatic, metamorphic, metasomatic, or pneumatolytic origin. The newly formed nanometer�sized morphostructures and crystallites should be regarded as typomorphic features of carbonaceous phases in high�temperature hydrothermal rocks. Graphite was likely produced in the geyserite and travertine by low�pressure polycondenssation of hydrocarbons, at free growth in open space from over� saturated solutions and/or a gas phase.
Article
The authors comment on the date of the formation of the Tüttensee, holding that it was not created by a meteorite in the first millennium BC as claimed in the Antiquity article, but formed at the end of the Ice Age and can have nothing to do with Phaethon and his chariot. In reply, Rappenglück et al . offer a brief defence of their thesis.
Article
aBstRaCt Krotite, CaAl 2 O 4 , occurs as the dominant phase in an unusual Ca-,Al-rich refractory inclusion from the NWA 1934 CV3 carbonaceous chondrite. Krotite occupies the central and mantle portions of the inclusion along with minor perovskite, gehlenite, hercynite, and Cl-bearing mayenite, and trace hexamolybdenum. A layered rim surrounds the krotite-bearing regions, consisting from inside to outside of grossite, mixed hibonite, and spinel, then gehlenite with an outermost layer composed of Al-rich diopside. Krotite was identified by XRD, SEM-EBSD, micro-Raman, and electron microprobe. The mean chemical composition determined by electron microprobe analysis of krotite is (wt%) Al 2 O 3 63.50, CaO 35.73, sum 99.23, with an empirical formula calculated on the basis of 4 O atoms of Ca 1.02 Al 1.99 O 4. Single-crystal XRD reveals that krotite is monoclinic, P2 1 /n; a = 8.6996(3), b = 8.0994(3), c = 15.217(1) Å, β = 90.188(6), and Z = 12. It has a stuffed tridymite structure, which was refined from single-crystal data to R 1 = 0.0161 for 1014 F o > 4σF reflections. Krotite is colorless and transparent with a vitreous luster and white streak. Mohs hardness is ~6½. The mineral is brittle, with a conchoidal fracture. The calculated density is 2.94 g/cm 3. Krotite is biaxial (–), α = 1.608(2), β = 1.629(2), γ = 1.635(2) (white light), 2V meas = 54.4(5)°, and 2V calc = 55.6°. No dispersion was observed. The optical orientation is X = b; Y ≈ a; Z ≈ c. Pleochroism is colorless to very pale gray, X > Y = Z. Krotite is a low-pressure CaAl 2 O 4 mineral, likely formed by condensation or crystallization from a melt in the solar nebula. This is the first reported occurrence of krotite in nature and it is one of the earliest minerals formed in the solar system.
Article
Impact glasses from meteorite craters often contain high pressure polymorphic modifications derived from quartz, graphite, and other minerals. The transformation of carbonaceous material under these conditions remained unknown until recently. This lends interest to impactites from the melting of low-grade metamorphic rocks (polymict sandstones, shales, and so on) containing coals of various rank. Such impactites (suevites and tagamites) consist mainly of altered impact glasses but contain fragments of shock-metamorphosed and other rocks, among which are sediments containing fragments of coals of ranks T-A. The overall chemical compositions of the impactites are close to those of the corresponding target rocks: SiO/sub 2/ 57-59%, Al/sub 2/O/sub 3/ 13-17%, FeO + Fe/sub 2/O/sub 3/ 5.6-7.2%, MgO 3.8-4.5%, CaO 3.7-5.8%, Na/sub 2/O + K/sub 2/O 3.8-5.6%, and other components. This paper describes a series of shock-transformed coals from an unnamed impact structure (presumably Popigay), which includes types very similar to carbonado. The origin of carbonado diamond has never been clear, and Yezerskiy suggests it may be an impact product. 26 references.
Conference Paper
Did in the Holocene meteorite impacts of a size capable to affect human cultures happen at all and – if the answer is “yes” – which cultural implications did they have? Since a few years this question is fiercely and controversially discussed. The Chiemgau meteorite impact event may provide an important contribution to the discussion. This event stroke south-east Germany very probably in the 1st millenium BC and left a field of about 80 craters. In comparison to other Holocene impacts it provides extraordinary data by the extension of its crater field, the size of the biggest crater, the variety of secondary effects, the direct embedding of the impact layer in an archaeological stratigraphy, and the comparably good dating. The recently known data are introduced and discussed with regard to the question of cultural effects of Holocene impacts.
Article
We report an extensive study of the properties of carbyne using first-principles calculations. We investigate carbyne's mechanical response to tension, bending, and torsion deformations. Under tension, carbyne is about twice as stiff as the stiffest known materials and has an unrivaled specific strength of up to 7.5×10^7 N∙m/kg, requiring a force of ~10 nN to break a single atomic chain. Carbyne has a fairly large room-temperature persistence length of about 14 nm. Surprisingly, the torsional stiffness of carbyne can be zero but can be 'switched on' by appropriate functional groups at the ends. Further, under appropriate termination, carbyne can be switched into a magnetic-semiconductor state by mechanical twisting. We reconstruct the equivalent continuum-elasticity representation, providing the full set of elastic moduli for carbyne, showing its extreme mechanical performance (e.g. a nominal Young's modulus of 32.7 TPa with an effective mechanical thickness of 0.772 Å). We also find an interesting coupling between strain and band gap of carbyne, which is strongly increased under tension, from 3.2 to 4.4 eV under a 10% strain. Finally, we study the performance of carbyne as a nanoscale electrical cable, and estimate its chemical stability against self-aggregation, finding an activation barrier of 0.6 eV for the carbyne-carbyne cross-linking reaction and an equilibrium cross-link density for two parallel carbyne chains of 1 cross-link per 17 C atoms (2.2 nm).
Conference Paper
We report a supernova graphite that contains internal subgrains of TiC, SiC, Fe and Ni silicides, and iron metal. These phases comprise a complete list of the phases predicted by equilibrium calculations to condense from C-rich supernova zones.
Article
Multiple impacts (i.e. progressive impacts) with reduction state produce characteristic compositions originated from target rock. Pure carbon can be obtained from limestone target rocks by multi-impact reaction with reduction state which can be found in natural and artificial impact craters. Pure Fe spherules in lunar agglutinates can be obtained from FeO-rich basaltic rock by multiple impacts including multi-impact reaction on the airless Moon.