Results 41 to 50 of about 33,638 (237)

CHONDRITES-CLADICHNUS ICHNOCOENOSIS FROM THE DEEP-SEA DEPOSITS OF PIERFRANCESCO (CRETACEOUS; ITALY): OXYGEN- OR NUTRIENT-LIMITED?

open access: yesRivista Italiana di Paleontologia e Stratigrafia, 2022
The Italian Northern Apennines are acknowledged as the place where ichnology was born, but there is comparatively little work about their ichnological record. This study bridges this gap by describing two new ichnosites from the locality of Pierfrancesco,
ANDREA BAUCON   +3 more
doaj   +1 more source

The nature and formation of silica minerals in eucrite meteorites: Insight into the protoplanetary magma crystallization

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract Silica polymorphs in meteorites provide critical constraints on crystallization processes associated with thermal activity in the early solar system. A detailed investigation of silica polymorphs in eucrites (the largest group of achondrites) using cathodoluminescence imaging and laser‐Raman spectroscopy revealed significant variations in the ...
Rei Kanemaru   +14 more
wiley   +1 more source

Meteorites and the RNA World: Synthesis of Nucleobases in Carbonaceous Planetesimals and the Role of Initial Volatile Content

open access: yesThe Astrophysical Journal, 2023
Prebiotic molecules, fundamental building blocks for the origin of life, have been found in carbonaceous chondrites. The exogenous delivery of these organic molecules onto the Hadean Earth could have sparked the polymerization of the first RNA molecules ...
Klaus Paschek   +5 more
doaj   +1 more source

Investigation and reclassification of four mesosiderites—Implications for their formation

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract Mesosiderites are rare, differentiated meteorites, so‐called stony‐iron meteorites—they are impact breccias composed of an unusual mix of crustal basalt and pyroxenite, core‐derived metal, but no mantle materials. This odd mixture makes their origin enigmatic and has inspired many different formation theories over the last several decades ...
Gabriel Zachén   +4 more
wiley   +1 more source

Petrography of phosphates in CI and CY carbonaceous chondrites

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract Phosphate minerals are significant carriers of volatiles (e.g., OH) and halogens in chondritic material; however, their origin in most groups of carbonaceous chondrites remains poorly characterized. We have determined the abundance, morphology, texture, and composition of phosphate grains in aqueously altered CI chondrites and in hydrated and ...
C. S. Harrison   +3 more
wiley   +1 more source

Deuterium Isotope Fractionation of Polycyclic Aromatic Hydrocarbons in Meteorites as an Indicator of Interstellar/Protosolar Processing History

open access: yesLife, 2022
The stable isotope composition of soluble and insoluble organic compounds in carbonaceous chondrites can be used to determine the provenance of organic molecules in space.
Heather V. Graham   +4 more
doaj   +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

The Magnesium Isotope Composition of Samples Returned from Asteroid Ryugu

open access: yesThe Astrophysical Journal Letters, 2023
The nucleosynthetic isotope composition of planetary materials provides a record of the heterogeneous distribution of stardust within the early solar system.
Martin Bizzarro   +89 more
doaj   +1 more source

Timing of the formation and migration of giant planets as constrained by CB chondrites

open access: yesScience Advances, 2016
Early dynamical excitement by giant planets leads to the formation of the unique CB chondrite meteorites. The presence, formation, and migration of giant planets fundamentally shape planetary systems. However, the timing of the formation and migration of
Brandon C. Johnson   +4 more
semanticscholar   +1 more source

Cosmic ray exposure and gas retention ages of the shocked angrite Northwest Africa 7203: Implications for a collisional history of angrites' parent body

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract Angrites and eucrites are among the oldest basaltic rocks in the solar system. However, the shock histories of these meteorite groups differ markedly, as most angrites show little to no evidence of shock metamorphism. While some angrites exhibit weak wavy extinction in olivine, indicative of low‐level shock, only two—Northwest Africa (NWA ...
Atsushi Takenouchi   +4 more
wiley   +1 more source

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