Results 61 to 70 of about 3,762 (245)

The origin of magnetite in carbonaceous chondrites [PDF]

open access: yes, 1982
Typescript (photocopy).The content and distribution of magnetite in carbonaceous chondrites is of particular interest since it is a substantial component in these, the most primitive materials surviving from solar system formation.
Hyman, Marian
core  

FT-IR spectroscopic studies of major organic matter in carbonaceous chondrites using microscopic technique and comparison with terrestrial kerogen [PDF]

open access: yes, 1994
P(論文)Infrared (IR) absorption spectra of major types of carbonaceous matter in four Antarctic carbonaceous chondrites (Y-74662,Y-791198,ALH-77307,Y-791717) and two non-Antarctic carbonaceous chondrites (Murchison, Allende) were taken using a microscopic ...
Murae, Tatsushi
core   +2 more sources

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

Search for carbonaceous chondrites evidence on Vesta through the detection of carbonates [PDF]

open access: yes, 2023
NASA’s Dawn mission was launched in September 2007 and orbited asteroids Vesta (2011 2012) and Ceres (2015–2018). Vesta shows surface dark units that have been suggested to be linked to exogenous materials and are therefore useful to understand the ...
Gisellu, C.   +9 more
core   +1 more source

Unraveling the Cr Isotopes of Ryugu: An Accurate Aqueous Alteration Age and the Least Thermally Processed Solar System Material

open access: yesThe Astrophysical Journal
The analysis of samples returned from the C-type asteroid Ryugu has drastically advanced our knowledge of the evolution of early solar system materials.
Ryoji Tanaka   +25 more
doaj   +1 more source

Protracted Timescales for Nebular Processing of First-formed Solids in the Solar System

open access: yesThe Astrophysical Journal, 2023
The calcium–aluminum-rich inclusions (CAIs) from chondritic meteorites are the first solids formed in the solar system. Rim formation around CAIs marks a time period in early solar system history when CAIs existed as free-floating objects and had not yet
Prajkta Mane   +3 more
doaj   +1 more source

Evaluating maturity of organic matter in hydrated C1 and CM‐like clasts and a dehydrated clast within a polymict eucrite and a howardite

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract Volatile‐rich xenolithic clasts in different types of brecciated meteorites represent unique pristine solar system material. This study investigates the maturity and thermal history of organic matter using Raman spectroscopy and aqueous alteration effects using infrared spectroscopy in the matrix of 15 volatile‐rich clasts (C1 and CM‐like ...
Swarna Prava Das   +7 more
wiley   +1 more source

Raman analysis of organic refractory materials after energetic processing: Evidence for amorphous carbon on TNOs and comets

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract Amorphous carbon (αC) is found in various extraterrestrial particles, including those thought to originate from the outer Solar System. αC can form through two main processes involving C‐rich materials: exposure to energetic charged particles and thermal processing.
M. Germanà   +10 more
wiley   +1 more source

Opaque Assemblages in CK and CV Carbonaceous Chondrites [PDF]

open access: yes, 2006
CK carbonaceous chondrites are the only group of carbonaceous chondrites that exhibit thermal metamorphism. As a result, CKs display features of metamorphism such as silicate darkening, recrystallization and shock veins.
Righter, K., Neff, K. E.
core   +1 more source

The Ames impact structure, Oklahoma: New radioisotopic constraints and implications for North American impact chronology

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract The Ames impact structure (Oklahoma) is thought to have formed during the Ordovician Meteor Event, based on conodont biostratigraphy of its crater fill. Here, U–Pb zircon dates from its impact‐melt portion, conducted using secondary ion mass spectrometry and laser ablation–inductively coupled plasma–mass spectrometry (n = 37 spots), yield a ...
Elizabeth J. Catlos   +9 more
wiley   +1 more source

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