An igneous-textured clast in the Peace River meteorite: insights into accretion and metamorphism of asteroids in the early solar system

2013 ◽  
Vol 50 (1) ◽  
pp. 14-25 ◽  
Author(s):  
Christopher D.K. Herd ◽  
Jon M. Friedrich ◽  
Richard C. Greenwood ◽  
Ian A. Franchi
Keyword(s):  
Solar System ◽  
Isotope Composition ◽  
Parent Body ◽  
Early Solar System ◽  
Element Abundances ◽  
Fine Grained ◽  
Peace River ◽  
Petrology And Geochemistry ◽  
Mineral Compositions ◽  
The Impact

The mineralogy, petrology, and geochemistry of an igneous-textured clast in the Peace River L6 chondrite meteorite was examined to determine the roles of nebular processes, accretion, and parent-body metamorphism in its origin. The centimetre-scale clast is grey and fine grained and is in sharp contact with the host chondrite. Two sub-millimetre veins cut across both the clast and host, indicating that the clast formed prior to the impact (shock) event(s) that produced the numerous veins present in the Peace River meteorite. The clast and host are indistinguishable in terms of mineral compositions. In contrast, there are differences in modal mineralogy, texture, as well as trace element and oxygen isotope composition between the clast and host. These differences strongly suggest that the clast was formed by impact melting of LL-group chondritic material involving loss of Fe–FeS and phosphate components, followed by relatively rapid cooling and incorporation into the Peace River host meteorite. Subsequent metamorphism on the Peace River parent body caused recrystallization of the clast and homogenization of mineral compositions and thermally labile element abundances between the clast and host. Shock metamorphism, including formation of shock melt veins, occurred post-metamorphism, during fragmentation of the L chondrite parent body. The results suggest that the formation of the Peace River parent asteroid included the incorporation of material from other asteroids and that the pre-metamorphic protolith was a breccia. Accordingly, we propose that the Peace River meteorite be reclassified as a polymict breccia.

scholarly journals Timing and Mechanisms of Silicate Differentiation and Basalt Magma Generation on the Howardite-Eucrite-Diogenite Asteroid Parent Body

2021 ◽  
Author(s):  
◽  
Jessica Anne Dallas
Keyword(s):  
Solar System ◽  
Trace Element ◽  
Isotope Composition ◽  
Parent Body ◽  
Basalt Magma ◽  
Early Solar System ◽  
Magma Body ◽  
Element Concentrations ◽  
Trace Element Chemistry ◽  
Incompatible Elements

<p>Meteorites provide the only direct record of the chronology and nature of the processes that occurred in the early solar system. In this study, meteorites were examined in order to gain insight into the timing and nature of magmatism and silicate differentiation on asteroidal bodies in the first few million years of the solar system. These bodies are considered the precursors to terrestrial planets, and as such they provide information about conditions in the solar system at the time of planet formation. This study focuses on eucrites, which are basaltic meteorites that are believed to represent the crust of the Howardite-Eucrite-Diogenite (HED) parent body. The processes of silicate differentiation and the relationship between eucrites and the diogenitic mafic cumulate of the HED parent body are poorly understood. The major and trace element chemistry of the minerals in the eucrite suite was measured. There is little variability in mineral major element concentrations in eucrites, however considerable variability was observed in mineral trace element concentrations, particularly with respect to incompatible elements in the mineral phases. Magnesium was separated from digested eucrite samples, and the Mg isotope composition of the eucrites was measured to high precision in order to date the samples using the short-lived ²⁶Al–²⁶Mg chronometer and examine magmatic evolution on the HED parent body. Correlations between incompatible elements in pyroxene and ²⁶Mg anomalies, produced by the decay of ²⁶Al, indicate that the eucrite suite was formed from a single, evolving magma body. Large trace element and Mg isotopic differences between eucrites and diogenites indicate that the two meteorite groups did not, as previously suggested, originate from the same magma body. Instead they may have formed from two large magma bodies, which were spatially or temporally separated on the HED parent body. The application of the short-lived ²⁶Al–²⁶Mg chronometer to this suite of eucrites constrains the onset of eucrite formation to ~3 Myr after the formation of the solar system’s first solids, as a result of rapid accretion and melting of planetesimals due to heating from the decay of ²⁶Al.</p>

scholarly journals Timing and Mechanisms of Silicate Differentiation and Basalt Magma Generation on the Howardite-Eucrite-Diogenite Asteroid Parent Body

2021 ◽  
Author(s):  
◽  
Jessica Anne Dallas
Keyword(s):  
Solar System ◽  
Trace Element ◽  
Isotope Composition ◽  
Parent Body ◽  
Basalt Magma ◽  
Early Solar System ◽  
Magma Body ◽  
Element Concentrations ◽  
Trace Element Chemistry ◽  
Incompatible Elements

<p>Meteorites provide the only direct record of the chronology and nature of the processes that occurred in the early solar system. In this study, meteorites were examined in order to gain insight into the timing and nature of magmatism and silicate differentiation on asteroidal bodies in the first few million years of the solar system. These bodies are considered the precursors to terrestrial planets, and as such they provide information about conditions in the solar system at the time of planet formation. This study focuses on eucrites, which are basaltic meteorites that are believed to represent the crust of the Howardite-Eucrite-Diogenite (HED) parent body. The processes of silicate differentiation and the relationship between eucrites and the diogenitic mafic cumulate of the HED parent body are poorly understood. The major and trace element chemistry of the minerals in the eucrite suite was measured. There is little variability in mineral major element concentrations in eucrites, however considerable variability was observed in mineral trace element concentrations, particularly with respect to incompatible elements in the mineral phases. Magnesium was separated from digested eucrite samples, and the Mg isotope composition of the eucrites was measured to high precision in order to date the samples using the short-lived ²⁶Al–²⁶Mg chronometer and examine magmatic evolution on the HED parent body. Correlations between incompatible elements in pyroxene and ²⁶Mg anomalies, produced by the decay of ²⁶Al, indicate that the eucrite suite was formed from a single, evolving magma body. Large trace element and Mg isotopic differences between eucrites and diogenites indicate that the two meteorite groups did not, as previously suggested, originate from the same magma body. Instead they may have formed from two large magma bodies, which were spatially or temporally separated on the HED parent body. The application of the short-lived ²⁶Al–²⁶Mg chronometer to this suite of eucrites constrains the onset of eucrite formation to ~3 Myr after the formation of the solar system’s first solids, as a result of rapid accretion and melting of planetesimals due to heating from the decay of ²⁶Al.</p>

Science and Exploration of the Moon: Overview

2021 ◽  
Author(s):  
Bradley L. Jolliff
Keyword(s):  
Solar System ◽  
Nearest Neighbor ◽  
Space Environment ◽  
Cold Trap ◽  
The Moon ◽  
Early Solar System ◽  
Geologic History ◽  
The Earth ◽  
History Of ◽  
The Impact

Earth’s moon, hereafter referred to as “the Moon,” has been an object of intense study since before the time of the Apollo and Luna missions to the lunar surface and associated sample returns. As a differentiated rocky body and as Earth’s companion in the solar system, much study has been given to aspects such as the Moon’s surface characteristics, composition, interior, geologic history, origin, and what it records about the early history of the Earth-Moon system and the evolution of differentiated rocky bodies in the solar system. Much of the Apollo and post-Apollo knowledge came from surface geologic exploration, remote sensing, and extensive studies of the lunar samples. After a hiatus of nearly two decades following the end of Apollo and Luna missions, a new era of lunar exploration began with a series of orbital missions, including missions designed to prepare the way for longer duration human use and further exploration of the Moon. Participation in these missions has become international. The more recent missions have provided global context and have investigated composition, mineralogy, topography, gravity, tectonics, thermal evolution of the interior, thermal and radiation environments at the surface, exosphere composition and phenomena, and characteristics of the poles with their permanently shaded cold-trap environments. New samples were recognized as a class of achondrite meteorites, shown through geochemical and mineralogical similarities to have originated on the Moon. New sample-based studies with ever-improving analytical techniques and approaches have also led to significant discoveries such as the determination of volatile contents, including intrinsic H contents of lunar minerals and glasses. The Moon preserves a record of the impact history of the solar system, and new developments in timing of events, sample based and model based, are leading to a new reckoning of planetary chronology and the events that occurred in the early solar system. The new data provide the grist to test models of formation of the Moon and its early differentiation, and its thermal and volcanic evolution. Thought to have been born of a giant impact into early Earth, new data are providing key constraints on timing and process. The new data are also being used to test hypotheses and work out details such as for the magma ocean concept, the possible existence of an early magnetic field generated by a core dynamo, the effects of intense asteroidal and cometary bombardment during the first 500 million–600 million years, sequestration of volatile compounds at the poles, volcanism through time, including new information about the youngest volcanism on the Moon, and the formation and degradation processes of impact craters, so well preserved on the Moon. The Moon is a natural laboratory and cornerstone for understanding many processes operating in the space environment of the Earth and Moon, now and in the past, and of the geologic processes that have affected the planets through time. The Moon is a destination for further human exploration and activity, including use of valuable resources in space. It behooves humanity to learn as much about Earth’s nearest neighbor in space as possible.

The thallium isotope composition of carbonaceous chondrites — New evidence for live 205Pb in the early solar system

2010 ◽  
Vol 291 (1-4) ◽  
pp. 39-47 ◽  
Author(s):  
R.G.A. Baker ◽  
M. Schönbächler ◽  
M. Rehkämper ◽  
H.M. Williams ◽  
A.N. Halliday
Keyword(s):  
Solar System ◽  
Isotope Composition ◽  
Carbonaceous Chondrites ◽  
Early Solar System ◽  
New Evidence

Carbonaceous chondrite meteorites experienced fluid flow within the past million years

Science ◽  
2021 ◽  
Vol 371 (6525) ◽  
pp. 164-167
Author(s):  
Simon Turner ◽  
Lucy McGee ◽  
Munir Humayun ◽  
John Creech ◽  
Brigitte Zanda
Keyword(s):  
Fluid Flow ◽  
Solar System ◽  
Cosmic Ray ◽  
Parent Body ◽  
Uranium Isotopes ◽  
The Past ◽  
Uranium Ion ◽  
Impact Heating ◽  
The Impact ◽  
Cosmic Ray Exposure Age

Carbonaceous chondritic meteorites are primordial Solar System materials and a source of water delivery to Earth. Fluid flow on the parent bodies of these meteorites is known to have occurred very early in Solar System history (first <4 million years). We analyze short-lived uranium isotopes in carbonaceous chondrites, finding excesses of 234-uranium over 238-uranium and 238-uranium over 230-thorium. These indicate that the fluid-mobile uranium ion U6+ moved within the past few 100,000 years. In some meteorites, this time scale is less than the cosmic-ray exposure age, which measures when they were ejected from their parent body into space. Fluid flow occurred after melting of ice, potentially by impact heating, solar heating, or atmospheric ablation. We favor the impact heating hypothesis, which implies that the parent bodies still contain ice.

scholarly journals Arrival and magnetization of carbonaceous chondrites in the asteroid belt before 4562 million years ago

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Timothy O’Brien ◽  
John A. Tarduno ◽  
Atma Anand ◽  
Aleksey V. Smirnov ◽  
Eric G. Blackman ◽  
...  
Keyword(s):  
Solar System ◽  
Arrival Time ◽  
Carbonaceous Chondrite ◽  
Parent Body ◽  
Asteroid Belt ◽  
Carbonaceous Chondrites ◽  
Early Solar System ◽  
Outer Disk ◽  
Main Asteroid Belt ◽  
Insight Into

AbstractMeteorite magnetizations can provide rare insight into early Solar System evolution. Such data take on new importance with recognition of the isotopic dichotomy between non-carbonaceous and carbonaceous meteorites, representing distinct inner and outer disk reservoirs, and the likelihood that parent body asteroids were once separated by Jupiter and subsequently mixed. The arrival time of these parent bodies into the main asteroid belt, however, has heretofore been unknown. Herein, we show that weak CV (Vigarano type) and CM (Mighei type) carbonaceous chondrite remanent magnetizations indicate acquisition by the solar wind 4.2 to 4.8 million years after Ca-Al-rich inclusion (CAI) formation at heliocentric distances of ~2–4 AU. These data thus indicate that the CV and CM parent asteroids had arrived near, or within, the orbital range of the present-day asteroid belt from the outer disk isotopic reservoir within the first 5 million years of Solar System history.

Micromagnetic simulation of taenite particles

2021 ◽  
Author(s):  
José Devienne ◽  
Thomas Berndt ◽  
Wyn Williams
Keyword(s):  
Solar System ◽  
Relaxation Times ◽  
Vortex State ◽  
Parent Body ◽  
Early Solar System ◽  
Magnetic Minerals ◽  
Slow Cooling ◽  
Theoretical Evaluation ◽  
Single Vortex ◽  
Micromagnetic Simulations

&lt;p&gt;&lt;/p&gt;&lt;div&gt; &lt;div&gt; &lt;div&gt;The cloudy zone (CZ), an intergrowth structure of Fe-rich and Ni-rich phases that forms during slow cooling of iron meteorites are potential recorders of&amp;#160; their parent body&amp;#8217;s thermal and magnetic history. The ability of the cloudy zone&amp;#8217;s principal magnetic minerals, taenite and tetrataenite, to reliably record ancient magnetic fields from the early solar system has, however, insufficiently been investigated. In this work we performed a series of micromagnetic simulations in order to assess the magnetic stability of taenite grains. Micromagnetic simulations allow to investigate the changes in the magnetic state in taenite as a function of the grain size: in ellipsoidal grains below 68 nm (equivalent sphere volume diameter, ESVD) a single domain state dominates.&amp;#160; At 68 nm (ESVD) a &amp;#8220;flowering&amp;#8221; state starts, and further increase in size (&gt; 75 nm) gives rise to a single vortex state. Contrary to common conception, theoretical evaluation of relaxation times for taenite grains based on micromagnetics leads to values that exceed the age of solar system, which makes taenite, not just its ordered equivalent tetrataenite, a reliable paleomagnetic recorder.&lt;/div&gt; &lt;/div&gt; &lt;/div&gt;

New constraints on the Sulfur isotope signature of the sub-continental lithospheric mantle wedge: in situ δ34S analyses of pentlandite from the exhumed orogenic garnet-bearing peridotite of the Ulten Zone, Eastern Italian Alps

2020 ◽  
Author(s):  
Giulia Consuma ◽  
Roberto Braga ◽  
Marco L. Fiorentini ◽  
Laure Martin ◽  
Peter Tropper ◽  
...  
Keyword(s):  
Lithospheric Mantle ◽  
Mantle Wedge ◽  
Isotope Composition ◽  
Mineral Chemistry ◽  
Isotope Signature ◽  
Fine Grained ◽  
Continental Lithospheric Mantle ◽  
The Impact ◽  
S Isotope

&lt;p&gt;Orogenic peridotites associated with high-grade felsic rocks record mass exchange between crust and mantle reservoirs at convergent plate margins. In this geodynamic framework, fluids released by submerging slabs can mobilize redox-sensitive elements such as carbon (C) and sulfur (S) and percolate the mantle wedge, eventually forming hydrate minerals associated with carbonate and sulfide phases at appropriate T, P and f O&lt;sub&gt;2&lt;/sub&gt;&amp;#160;conditions.&amp;#160;The introduction of sulfur into the sub-continental lithospheric mantle (SCLM) wedge and its mobilization at grain-scale can be investigated by means of in situ &amp;#948;&lt;sup&gt;34&lt;/sup&gt;S analyses of mantle wedge sulfides, which may have inherited the composition of the fluid sources. To date, the impact of the S transfer through the SCLM wedge is poorly known and limited in situ S isotope values of sulfides from mantle wedge peridotite are available in literature. Our study focuses on the Ulten Zone (UZ) orogenic-garnet peridotites, which provide an ideal case to investigate the S mobilization through the SCLM wedge and the effects of crustal fluids on the sulfide &amp;#948;&lt;sup&gt;34&lt;/sup&gt;S signature, especially during the exhumation stage. We therefore integrate a well-constrained paragenesis with mineral chemistry and in situ S isotope signature of sulfides. The UZ peridotites were involved in a collisional setting during the Variscan orogenesis, recording HP-eclogite-facies conditions and exhumation after their incorporation in a m&amp;#233;lange with the associated garnet-kyanite gneisses. A suite of coarse to fine-grained peridotites was investigated in order to cover all the metasomatic stages preserved in these rocks, considering the grade of serpentinization and the occurrence of carbonates. Microstructural observations and major element compositions indicate that pentlandite (&amp;#177;&amp;#160;chalcopyrite &amp;#177;&amp;#160;chalcocite &amp;#177;&amp;#160;sphalerite) is the ubiquitous primary sulfide, which is commonly replaced by secondary heazlewoodite and millerite in medium to highly serpentinized peridotite. Pentlandite occurs in different textural positions related to several metasomatic stages: (i) polycrystalline aggregates (pentlandite + Cl-apatite + phlogopite + ilmenite + calcite-brucite intergrowths) included in spinel (in garnet); (ii) interstitial in matrix; (iii) in carbonate and serpentine veins. Overall, the S isotope signature of pentlandite exhibits a relatively narrow range between -1.62 and +3.76 &amp;#8240;. The relatively low S isotope values require a mantle-like source for the metasomatizing fluids enriched in sulfur, with possible contamination with fluids of other different sources. These new results show that sulfur was introduced into the lithospheric mantle and mobilized by influxes of late metasomatic fluids, in part related to the serpentinization, and provide additional constraints on the S isotope composition of the SCLM wedge.&lt;/p&gt;

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