Results 71 to 80 of about 32,111 (286)

MULTIPLE AND FAST: THE ACCRETION OF ORDINARY CHONDRITE PARENT BODIES [PDF]

open access: yes, 2014
Although petrologic, chemical, and isotopic studies of ordinary chondrites and meteorites in general have largely helped establish a chronology of the earliest events of planetesimal formation and their evolution, there are several questions that cannot ...
P. Vernazza   +11 more
semanticscholar   +1 more source

New knowledge about shock events that affected the L‐chondrite parent body from two heavily shocked L6 meteorite finds

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract We report new results from a study of shock‐related features in the L6 ordinary chondrites Northwest Africa (NWA) 4672 and NWA 12841. Our observations confirm the occurrence of eight high‐pressure (HP) minerals in each meteorite, namely, ringwoodite, majorite, akimotoite, wadsleyite, albitic jadeite, lingunite, tuite, and xieite.
I. Baziotis   +5 more
wiley   +1 more source

Study of the Extraterrestrial Materials at Antarctica, IV. : On the Yamato Meteorites

open access: yesAntarctic Record, 1974
Additional mineralogical and chemical studies of the Yamato meteorites are under way. The mode analysis and the optical properties in thin sections are examined under a microscope.
Makoto SHIMA   +2 more
doaj   +1 more source

Noble gases and nitrogen in material from asteroid Bennu

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract We report the elemental and isotopic abundances of all stable noble gases (helium, neon, argon, krypton, and xenon) in eight particles from asteroid Bennu returned by NASA's OSIRIS‐REx mission. We also report nitrogen abundances and isotopic ratios that were analyzed alongside neon and argon in four additional Bennu particles.
B. Marty   +7 more
wiley   +1 more source

Carbonaceous chondrite NWA 4446

open access: yes, 2022
The authors carried out petrographic, mineralogical, and chemical analyses (bulk chemical composition and microanalyses of mineral chemical composition) of NWA 4446 carbonaceous chondrite. NWA 4446 chondrite is classified as CV3, S2, W2.
Łuszczek, Katarzyna   +7 more
core   +1 more source

Confirmation of the impact origin of the Late Ordovician Tvären impact structure (southeast Sweden) and emplacement of impactites in a marine setting

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract The Tvären structure in southeastern Sweden has been listed as a confirmed marine‐target impact structure for decades. However, to date, no measurements and/or indexed data of planar deformation features in quartz grains from the structure have been published or any other unequivocal evidence of impact.
Katarzyna J. Gajewska   +6 more
wiley   +1 more source

Thermal and impact history of the H chondrite parent asteroid during metamorphism: Constraints from metallic Fe–Ni [PDF]

open access: yes, 2014
We have studied cloudy taenite, metallographic cooling rates, and shock effects in 30 H3–6 chondrites to elucidate the thermal and early impact history of the H chondrite parent body.
E. Scott   +5 more
semanticscholar   +1 more source

Impact‐diagnostic criteria for use in confirming a meteorite impact origin of terrestrial geological structures: Recommendations by the Impact Cratering Committee of the Meteoritical Society

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract The framework of the Impact Cratering Committee (ICC) of the Meteoritical Society was approved in 2020, with the first committee members appointed in 2023. The ICC has a mandate to (1) approve, maintain, and update a database of confirmed terrestrial meteorite impact structures, (2) define and regularly update the criteria used for ...
A. J. Cavosie   +11 more
wiley   +1 more source

Shear-Induced ringwoodite formation in the Martian shergottite Dar al Gani 670

open access: yes, 2013
Shock-produced melt veins in the Martian shergottite Dar al Gani 670 crosscut large olivine crystals. The upper part of one of these crystals appears to be sheared off and displaced along the shock vein.
Fritz, Jörg   +3 more
core   +1 more source

Thermal histories of El Médano 300 (EM 300) and Northwest Africa 8155 (NWA 8155): Implications for the diversity of IAB‐ungrouped iron meteorites and their parent bodies

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract This study provides the first petrographic, crystallographic, and chemical comparison between El Médano 300 (EM 300) and Northwest Africa 8155 (NWA 8155), two particular IAB‐ungrouped iron meteorites. Both contain exceptionally large graphite nodules and “flowers”, providing unique insights into carbon behavior in metallic melts and cooling ...
L. Perez   +8 more
wiley   +1 more source

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