Shock metamorphism
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Shock metamorphism of planetary silicate rocks and sediments: Proposal for an updated classification system Open
We reevaluate the systematics and geologic setting of terrestrial, lunar, Martian, and asteroidal “impactites” resulting from single or multiple impacts. For impactites derived from silicate rocks and sediments, we propose a unified and up…
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High‐pressure minerals in shocked meteorites Open
Heavily shocked meteorites contain various types of high‐pressure polymorphs of major minerals (olivine, pyroxene, feldspar, and quartz) and accessory minerals (chromite and Ca phosphate). These high‐pressure minerals are micron to submicr…
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Impacts into quartz sand: Crater formation, shock metamorphism, and ejecta distribution in laboratory experiments and numerical models Open
We investigated the ejection mechanics by a complementary approach of cratering experiments, including the microscopic analysis of material sampled from these experiments, and 2‐D numerical modeling of vertical impacts. The study is based …
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High-pressure minerals in eucrite suggest a small source crater on Vesta Open
High-pressure minerals in meteorites are important records of shock events that have affected the surfaces of planets and asteroids. A widespread distribution of impact craters has been observed on the Vestan surface. However, very few hig…
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Petrological Traverse of the Olivine Cumulate Séítah Formation at Jezero Crater, Mars: A Perspective From SuperCam Onboard Perseverance Open
Séítah is the stratigraphically lowest formation visited by Perseverance in the Jezero crater floor. We present the data obtained by SuperCam: texture by imagery, chemistry by Laser‐Induced Breakdown Spectroscopy, and mineralogy by Superca…
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Poirierite, a dense metastable polymorph of magnesium iron silicate in shocked meteorites Open
A dense magnesium iron silicate polymorph with a structure intermediate between olivine, ringwoodite, and wadsleyite was theoretically predicted about four decades ago. As this group of minerals constitute the major component of shocked me…
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Donwilhelmsite, [CaAl4Si2O11], a new lunar high-pressure Ca-Al-silicate with relevance for subducted terrestrial sediments Open
We report on the occurrence of a new high-pressure Ca-Al-silicate in localized shock melt pockets found in the feldspatic lunar meteorite Oued Awlitis 001 and discuss the implications of our discovery. The new mineral crystallized as tiny,…
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Shock stage distribution of 2280 ordinary chondrites—Can bulk chondrites with a shock stage of S6 exist as individual rocks? Open
The brecciation and shock classification of 2280 ordinary chondrites of the meteorite thin section collection at the Institut für Planetologie (Münster) has been determined. The shock degree of S3 is the most abundant shock stage for the H…
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Shock‐induced microtextures in lunar apatite and merrillite Open
Apatite and merrillite are the most common phosphate minerals in a wide range of planetary materials and are key accessory phases for in situ age dating, as well as for determination of the volatile abundances and their isotopic compositio…
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Microspectroscopic and Petrographic Comparison of Experimentally Shocked Albite, Andesine, and Bytownite Open
Plagioclase feldspars are common on the surfaces of planetary objects in the solar system such as the Moon and Mars, and in meteorites. Understanding their response to shock deformation is important for interpretations of data from remote …
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Shock‐induced thermal history of an <span>EH</span>3 chondrite, Asuka 10164 Open
Shock‐induced features are abundantly observed in meteorites. Especially, shock veins, including high‐pressure minerals, characterize many kinds of heavily shocked meteorite. On the other hand, no high‐pressure phases have been yet reporte…
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Riesite, a New High Pressure Polymorph of TiO2 from the Ries Impact Structure Open
This paper describes riesite, a new high-pressure polymorph of TiO2 from the Ries impact structure, Germany. Riesite occurs in shock-induced melt veins within xenoliths of bedrock in suevite. It is structurally closely related to srilankit…
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Primordial, thermal, and shock features of ordinary chondrites: Emulating bulk X‐ray diffraction using in‐plane rotation of polished thin sections Open
Using an X‐ray diffractometer, powder‐like diffraction patterns were acquired from in‐plane rotation of polished thin sections (PTSs) of 60 ordinary chondrites (23 H, 21 L, and 16 LL), in order to explore the thermal and shock metamorphism…
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Impact melting of the largest known enstatite meteorite: Al Haggounia 001, a fossil <span>EL</span> chondrite Open
Al Haggounia 001 and paired specimens (including Northwest Africa [ NWA ] 2828 and 7401) are part of a vesicular, incompletely melted, EL chondrite impact melt rock with a mass of ~3 metric tons. The meteorite exhibits numerous shock effec…
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Linking shock textures revealed by BSE, CL, and EBSD with U‐Pb data (LA‐ICP‐MS and SIMS) from zircon from the Araguainha impact structure, Brazil Open
A silicious impact melt rock from polymict impact breccia of the northern part of the alkali granite core of the Araguainha impact structure, central Brazil, has been investigated. The melt rock is thought to represent a large mass of impa…
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Natural diamond formation by self-redox of ferromagnesian carbonate Open
Significance The presence of extra reducer was thought to be essential for producing natural diamonds from reduction of carbonates. The present study of the Xiuyan meteoritic crater, however, finds natural diamond formation via a subsolidu…
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Chondrules in <span>CK</span> carbonaceous chondrites and thermal history of the <span>CV</span>–<span>CK</span> parent body Open
CK chondrites are the only group of carbonaceous chondrites with petrologic types ranging from 3 to 6. It is commonly reported than ~15 vol% of CK 4–6 samples are composed of chondrules. The modal abundance of chondrules estimated here for…
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The Chelyabinsk meteorite: New insights from a comprehensive electron microscopy and Raman spectroscopy study with evidence for graphite in olivine of ordinary chondrites Open
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 impa…
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A history of mild shocks experienced by the regolith particles on hydrated asteroid Ryugu Open
Micrometeorites, a possible major source of Earth’s water, are thought to form from explosive dispersal of hydrated chondritic materials during impact events on their parental asteroids. However, this provenance and formation mechanism hav…
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A Spectral Investigation of Aqueously and Thermally Altered CM, CM‐An, and CY Chondrites Under Simulated Asteroid Conditions for Comparison With OSIRIS‐REx and Hayabusa2 Observations Open
Volatile‐rich asteroids are crucial to understanding the transport of water and organics to the terrestrial planet forming region in the early Solar System. Observations of two such asteroids by Hayabusa2 and Origins, Spectral Interpretati…
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Shock metamorphic history of >4 Ga Apollo 14 and 15 zircons Open
During impact events, zircons develop a wide range of shock metamorphic features that depend on the pressure and temperature conditions experienced by the zircon. These conditions vary with original distance from impact center and whether …
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Boom boom pow: Shock-facilitated aqueous alteration and evidence for two shock events in the Martian nakhlite meteorites Open
Evidence for impact-generated water on Mars ~633 Ma ago predicts two craters at the nakhlite meteorite’s ejection site.
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Mineralogy and petrogenesis of lunar magnesian granulitic meteorite Northwest Africa 5744 Open
Lunar meteorite Northwest Africa ( NWA ) 5744 is a granulitic breccia with an anorthositic troctolite composition that may represent a distinct crustal lithology not previously described. This meteorite is the namesake and first‐discovered…
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Characterization of Mason Gully (H5): The second recovered fall from the Desert Fireball Network Open
Mason Gully, the second meteorite recovered using the Desert Fireball Network ( DFN ), is characterized using petrography, mineralogy, oxygen isotopes, bulk chemistry, and physical properties. Geochemical data are consistent with its class…
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Complex crater formation: Insights from combining observations of shock pressure distribution with numerical models at the West Clearwater Lake impact structure Open
Large impact structures have complex morphologies, with zones of structural uplift that can be expressed topographically as central peaks and/or peak rings internal to the crater rim. The formation of these structures requires transient st…
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The Chelyabinsk meteorite: Thermal history and variable shock effects recorded by the <sup>40</sup>Ar‐<sup>39</sup>Ar system Open
We studied three lithologies (light and dark chondritic and impact melt rock) differing in shock stage from the LL 5 chondrite Chelyabinsk. Using the 40 Ar‐ 39 Ar dating technique, we identified low‐ and high‐temperature reservoirs within …
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Characterization of shocked quartz grains from Chicxulub peak ring granites and shock pressure estimates Open
Planar deformation features (PDFs) in quartz are a commonly used and well‐documented indicator of shock metamorphism in terrestrial rocks. The measurement of PDF orientations provides constraints on the shock pressure experienced by a rock…
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The Kaidun Breccia Material Variety: New Clasts and Updated Hypothesis on a Space Trawl Origin Open
The Kaidun meteorite is a breccia containing a wide variety of different material types [1-5]. It contains lithologies of CI, CM1 and CM2, CR chondrites [6], CAIs of Types A and B [7, 8], enstatite chondrite materials (EH and EL) [3, 4], i…
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High‐pressure phases in shock‐induced melt of the unique highly shocked <span>LL</span>6 chondrite Northwest Africa 757 Open
Northwest Africa 757 is unique in the LL chondrite group because of its abundant shock‐induced melt and high‐pressure minerals. Olivine fragments entrained in the melt transform partially and completely into ringwoodite. Plagioclase and Ca…
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Petrography, classification, oxygen isotopes, noble gases, and cosmogenic records of Kamargaon (L6) meteorite: The latest fall in India Open
A single piece of meteorite fell on Kamargaon village in the state of Assam in India on November 13, 2015. Based on mineralogical, chemical, and oxygen isotope data, Kamargaon is classified as an L‐chondrite. Homogeneous olivine (Fa: 25 ± …