Results 31 to 40 of about 1,707 (189)

Timing of Metamorphism and Deformation in the Neoarchean Quetico Metasedimentary Belt, Superior Craton, Constrained by Garnet Trace‐Element Mapping and Lu–Hf Geochronology

Journal of Metamorphic Geology, EarlyView.
ABSTRACT The Quetico subprovince of the Superior Province is among the largest metasedimentary belts globally and provides evidence of tectonic processes at play during the final stages of Archean cratonization. Although previous studies have shown that deformation and metamorphism of the 2.7‐Ga turbiditic protolith resulted in regional subvertical ...
Adrian G. Rehm, Antoine Godet, Doug Tinkham, Carl Guilmette, Matthijs A. Smit   +4 more
wiley   +1 more source

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

Antarctic 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, Akihiko OKADA, Masako SHIMA   +2 more
doaj   +1 more source

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

Meteoritics &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, L. Ferrière, C. Ma, J. Hu, D. Palles, P. D. Asimow   +5 more
wiley   +1 more source

Noble gases and nitrogen in material from asteroid Bennu

Meteoritics &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, L. Zimmermann, E. Füri, D. V. Bekaert, J. J. Barnes, A. N. Nguyen, H. C. Connolly, D. S. Lauretta   +7 more
wiley   +1 more source

The effect of early diagenetic processes on the quantification of fossil micrometeorite abundance and flux in the geological record

Meteoritics &Planetary Science, EarlyView.
Abstract Fossil micrometeorites (MMs) recovered from lithified sedimentary rocks, particularly iron‐rich (I‐type) cosmic spherules (CSs) provide valuable insights into past dust‐forming events. Their abundances, when combined with estimates of local sedimentation rates can be used to reconstruct the flux of extraterrestrial dust.
Isabelle S. Mattia, Matthew J. Genge, Martin D. Suttle   +2 more
wiley   +1 more source

Small‐scale elemental abundance variations in Ryugu particles from touchdown 1

Meteoritics &Planetary Science, EarlyView.
Abstract Ryugu materials closely resemble CI chondrites' mineralogical, chemical, and isotopic compositions; yet minor but resolvable differences in certain elemental abundances are evident. In this study, the bulk chemical compositions of eight individual Ryugu particles (1.5–4.3 mg) from the first touchdown site (TD1) were determined using triple ...
Karina López García, Tetsuya Yokoyama, Ikshu Gautam, Makiko K. Haba, Tsuyoshi Iizuka, Nao Nakanishi, Ryota Fukai   +6 more
wiley   +1 more source

Young asteroidal fluid activity revealed by absolute age from apatite in carbonaceous chondrite

Nature Communications, 2016
Chondritic meteorites formed in the early solar system and may tell us about primary processes at that time. Here, Zhang et al. report an absolute 207Pb/206Pb isochron age (4,450±50 Ma) of apatite from a carbonaceous chondrite constraining timing of ...
Ai-Cheng Zhang, Qiu-Li Li, Hisayoshi Yurimoto, Naoya Sakamoto, Xian-Hua Li, Sen Hu, Yang-Ting Lin, Ru-Cheng Wang   +7 more
doaj   +1 more source

Uncertainties in physical properties of Itokawa-like asteroids widen constraints on their formation time

Earth, Planets and Space, 2023
One of the outstanding questions in planetary science is to determine how the fundamental mechanical and physical properties of materials determine the thermal evolution of asteroids, and which properties have the greatest influence.
Jonas Hallstrom, Maitrayee Bose
doaj   +1 more source

Initial study of regolith exposure ages and burial conditions on Ryugu: Cosmogenic nuclides score in two touchdowns

Meteoritics &Planetary Science, EarlyView.
Abstract Surface processes on the asteroid Ryugu have been investigated using cosmic‐ray‐produced radionuclides, 10Be, 26Al, and 36Cl, and stable noble gases, on eight samples returned by the Hayabusa2 spacecraft. The 10Be and 26Al along with 21Ne measurements indicate that the two Chamber A samples A0105 collected during the first touchdown (TD) were ...
Kunihiko Nishiizumi, Keisuke Nagao, Marc W. Caffee, Ryuji Okazaki, Jozef Masarik, Hisayoshi Yurimoto, Tomoki Nakamura, Takaaki Noguchi, Hiroshi Naraoka, Hikaru Yabuta, Kanako Sakamoto, Kasumi Yogata, Toru Yada, Shogo Tachibana, Sei‐ichiro Watanabe, Yuichi Tsuda, Masanao Abe, Kazuya Kumagai, Akiko Miyazaki, Aiko Nakato, Satoru Nakazawa, Masahiro Nishimura, Tatsuaki Okada, Takanao Saiki, Hirotaka Sawada, Satoshi Tanaka, Tomohiro Usui, Koji Wada, Hajime Yano, Makoto Yoshikawa, Hayabusa2 Initial Analysis Volatile Team   +30 more
wiley   +1 more source

An asteroidal origin for water in the Moon

Nature Communications, 2016
Recent samples have shown that the Moon's interior, previously thought to be anhydrous, contains water, yet how this water was delivered is unclear. Here, using isotopic analyses and modelling, Barnes et al.
Jessica J. Barnes, David A. Kring, Romain Tartèse, Ian A. Franchi, Mahesh Anand, Sara S. Russell   +5 more
doaj   +1 more source