Results 61 to 70 of about 835 (219)

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

Polymict melt‐bearing breccia dikes in the Morokweng impact structure formed by slip‐induced mechanical mixing of pseudotachylite and cataclasite along large‐displacement impact faults

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract A core drilled through shocked and faulted Archean granitoid gneisses and dolerites in the eroded peak ring of the 70–80 km diameter Morokweng impact structure intersects multiple centimeter‐ to meter‐wide clastic‐matrix breccias containing a polymict clast population of lithic and mineral clasts and altered, millimeter‐ to centimeter ‐size ...
Roger L. Gibson   +3 more
wiley   +1 more source

Geochemical investigation of impactites from the Boltysh impact structure and possible relationship to early Danian sediments from the Umbria–Marche Basin, Italy

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract Within the Danian Scaglia Rossa Formation appears a regionally correlatable horizon cutting across multiple sections and outcrops within the Umbria–Marche Basin of NE Italy, where it is intercalated with uniform pelagic carbonate successions. This horizon is called “ALE layer” and has tentatively been interpreted as a fine‐grained volcanic ash.
Toni Schulz   +5 more
wiley   +1 more source

Visible, near‐, and thermal infrared spectra of asteroid Bennu samples: Relationship to and implications for remote sensing of carbonaceous asteroids

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract Remote spectroscopy is used to characterize the mineralogy and infer the history of planetary bodies. Carbonaceous asteroids, such as B‐type (101955) Bennu, represent the earliest stages of planet formation. B types have a blue (negative) spectral slope and comprise <5% of asteroids.
V. E. Hamilton   +32 more
wiley   +1 more source

Advanced aqueous alteration in primitive meteorites: Micro‐ to nanoscale studies of CR1 iron sulfides

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract This study documents micro‐ to nanoscale observations of primary nebular and secondary parent body iron sulfides in the CR1 GRO 95577. Despite the extensive alteration of the bulk sample, some primary sulfides managed to avoid alteration, having originally formed in the solar nebula during chondrule formation by either fission‐sulfidization or
S. A. Singerling
wiley   +1 more source

The role of composition in the spectral evolution of carbonaceous asteroids as informed by Bennu sample return

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract Near‐Earth rubble‐pile asteroids Bennu and Ryugu are part of the carbonaceous taxonomic complex (C‐complex), and samples returned from both bodies resemble the most aqueously altered carbonaceous chondrites. However, telescopic and spacecraft visible–near infrared (VIS–NIR) reflectance spectra of Ryugu exhibit a red (positive) spectral slope ...
Ralph E. Milliken   +10 more
wiley   +1 more source

Mineralogy, mineral chemistry, and redox equilibria in ten aggregate particles from asteroid Bennu

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract Examination of 10 Bennu aggregate particles has revealed the presence of many phases which taken together can provide constraints on the oxygen fugacity (fO2) of Bennu samples. Phyllosilicates (saponite and serpentine), carbonates, oxides (magnetite, chromite), sulfides (pyrrhotite, pentlandite), phosphate (hydroxyapatite, Na‐Mg‐phosphate ...
K. Righter   +11 more
wiley   +1 more source

A review of the supercritical state of eruption‐fed volcanic density currents in subaerial and subaqueous settings

open access: yesSedimentology, EarlyView.
ABSTRACT Subaerial Pyroclastic Density Currents (PDCs) and Subaqueous Eruption‐Fed Density Currents (SEFDCs) produced during volcanic eruptions can present major hazards to surrounding communities and ecosystems. The bedforms deposited by these volcanic density currents can provide insights into the nature of transport and depositional processes, which
Shannon E. Frey   +2 more
wiley   +1 more source

Formation process of the gravel‐dominated deposit from the 2011 Tohoku‐oki tsunami in Ofunato, northeastern Japan, inferred by integrating sedimentology and tsunami modelling

open access: yesSedimentology, EarlyView.
ABSTRACT Tsunami deposits serve as geological records of past events and are essential for understanding the occurrence and dynamics of tsunamis. However, conventional research has largely focused on sandy and boulder deposits, leaving gravel‐dominated tsunami deposits comparatively underexplored; furthermore, their characteristics and formation ...
Hidetoshi Masuda   +5 more
wiley   +1 more source

Source‐to‐sink sediment transport reversals during glacial sea‐level lowstands sustain soil formation on pericoastal carbonate terrains

open access: yesSedimentology, EarlyView.
ABSTRACT Understanding the processes that drive soil formation is crucial for developing sustainable land‐use strategies, as changing land‐use practices and climate change exacerbate soil erosion. The formation of substantial arable soils on carbonate bedrock requires substantial dust accretion as the underlying bedrock lacks siliciclastic material. In
Daniel Palchan   +3 more
wiley   +1 more source

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