The LaPaz Icefield 04840 meteorite: Mineralogy, metamorphism, and origin of an amphibole- and biotite-bearing R chondrite

McCanta, M. C.; Treiman, Allan H.; Dyar, M. D.; Alexander, Conel M. O'd.; Rumble, Douglas; Essene, Eric J.

doi:10.1016/j.gca.2008.07.034

Cited by 92 publications

(105 citation statements)

References 120 publications

(175 reference statements)

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“…It is true that, as judged from the O isotopic compositions of secondary magnetites, the water in OCs (Choi et al, 1998) and Rs (Greenwood et al, 2000) had higher D 17 O values than water in CCs (Rowe et al, 1994;Choi et al, 1997Choi et al, , 2000Choi et al, , 2008Choi and Wasson, 2003), and it is the OCs and Rs that contain the most D-rich water (Deloule and Robert, 1995;Grossman et al, 2000Grossman et al, , 2002McCanta et al, 2008). However, for the reasons discussed above it is unlikely that the current dD values for water in chondrites are primordial, and the modest range of D 17 O values (À3& to 5&) recorded in the magnetites may simply reflect varying exchange with silicates prior their formation.…”

Section: Why Such Modest D Enrichments In the Water?mentioning

confidence: 99%

“…Isotopically heavy N (d 15 N up to 500-1000&) is also found in brecciated urelites (Grady and Pillinger, 1988), but not in unbrecciated ones, and in some shocked type 3 OCs (Mostefaoui et al, 2005). For H isotopes, there is the intriguing discovery of very D-rich water in mica and amphibole (dD = 3660&) in the R4 LaPaz Ice Field (LAP) 04840 (McCanta et al, 2008). The D enrichment is much higher than in any bulk chondrite or estimates of the water compositions in them, and is comparable to the most enriched IOM.…”

Section: Introductionmentioning

confidence: 99%

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Deuterium enrichments in chondritic macromolecular material—Implications for the origin and evolution of organics, water and asteroids

Alexander

Newsome

Fogel

et al. 2010

Geochimica et Cosmochimica Acta

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Section: Why Such Modest D Enrichments In the Water?mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Deuterium enrichments in chondritic macromolecular material—Implications for the origin and evolution of organics, water and asteroids

Alexander

Newsome

Fogel

et al. 2010

Geochimica et Cosmochimica Acta

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200

227

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“…[62,63]). Direct measurements of water D/H ratios are possible in the R-chondrite LaPaz Icefield (LAP) 04840, because it (uniquely) contains abundant OH-bearing silicate minerals (approx.…”

Section: D/h Ratio Measurementsmentioning

confidence: 99%

D/H ratios of the inner Solar System

Hallis

2017

Phil. Trans. R. Soc. A.

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The original hydrogen isotope (D/H) ratios of different planetary bodies may indicate where each body formed in the Solar System. However, geological and atmospheric processes can alter these ratios through time. Over the past few decades, D/H ratios in meteorites from Vesta and Mars, as well as from S- and C-type asteroids, have been measured. The aim of this article is to bring together all previously published data from these bodies, as well as the Earth, in order to determine the original D/H ratio for each of these inner Solar System planetary bodies. Once all secondary processes have been stripped away, the inner Solar System appears to be relatively homogeneous in terms of water D/H, with the original water D/H ratios of Vesta, Mars, the Earth, and S- and C-type asteroids all falling between δD values of −100‰ and −590‰. This homogeneity is in accord with the ‘Grand tack’ model of Solar System formation, where giant planet migration causes the S- and C-type asteroids to be mixed within 1 AU to eventually form the terrestrial planets.This article is part of the themed issue ‘The origin, history and role of water in the evolution of the inner Solar System’.

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“…Similarly, several years ago, a very unusual hornblende-and biotite-bearing chondrite was discovered from Antarctica, and it remains a one-of-a-kind water-bearing oxidized meteorite that could conceivably be a planetary building block (22). Unusual differentiated bodies have also been documented in the past decade with some reflecting conditions of differentiation not previously known, such as a more reduced version of the metal and silicate mixtures known as pallasites [e.g., the meteorite Itqiy; (23)], a still unknown parent body of the oxidized angrites (24), and an unusual feldspathic crustal meteorite that may represent a previously unknown style of planetesimal differentiation [GRA 06128, GRA 06129; (25)].…”

Section: Compositionmentioning

confidence: 99%

Terrestrial planet formation

Righter

O’Brien

2011

Proc. Natl. Acad. Sci. U.S.A.

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Advances in our understanding of terrestrial planet formation have come from a multidisciplinary approach. Studies of the ages and compositions of primitive meteorites with compositions similar to the Sun have helped to constrain the nature of the building blocks of planets. This information helps to guide numerical models for the three stages of planet formation from dust to planetesimals (∼10 6 y), followed by planetesimals to embryos (lunar to Marssized objects; few × 10 6 y), and finally embryos to planets (10 7 -10 8 y). Defining the role of turbulence in the early nebula is a key to understanding the growth of solids larger than meter size. The initiation of runaway growth of embryos from planetesimals ultimately leads to the growth of large terrestrial planets via large impacts. Dynamical models can produce inner Solar System configurations that closely resemble our Solar System, especially when the orbital effects of large planets (Jupiter and Saturn) and damping mechanisms, such as gas drag, are included. Experimental studies of terrestrial planet interiors provide additional constraints on the conditions of differentiation and, therefore, origin. A more complete understanding of terrestrial planet formation might be possible via a combination of chemical and physical modeling, as well as obtaining samples and new geophysical data from other planets (Venus, Mars, or Mercury) and asteroids.H ow terrestrial planets grew out of the solar nebula has long been a topic of interest, and is still being pursued by a combination of studies involving samples of terrestrial and extraterrestrial materials, as well as computational models. Early nebular models by Descartes, Kant, and Laplace proposed that the planets formed from the solar nebula by various mechanisms such as vortices (analogous to spinning galaxies), or by shedding rings, but all of these general concepts failed to produce fundamental features of our Solar System (e.g., ref. 1). Subsequent models included homogeneous accretion (e.g., refs. 2, 3), in which the planets condensed from the nebula and were composed of homogeneous material that differentiated internally, and heterogeneous accretion (4), in which planets grew like layer cakes as the phases condensing out of the nebula changed with decreasing temperature. The purpose of this review is to elucidate how new samples, experiments, and modeling are contributing to a more thorough and sophisticated understanding of the many factors that helped to shape our inner Solar System ( Fig. 1; see SI Text) and specifically the Earth. We also highlight areas where more extensive work is necessary or more samples are needed to better constrain our models, and where physical and chemical constraints may benefit from combined approaches. CompositionPrimitive chondrites were likely the building blocks for terrestrial planets, with bulk compositions similar to the Sun, but with differing oxygen fugacities (Fig. S1) and other chemical characteristics such as volatile element depletions (5; SI Text, Fig. S2). In a...

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The LaPaz Icefield 04840 meteorite: Mineralogy, metamorphism, and origin of an amphibole- and biotite-bearing R chondrite

Cited by 92 publications

References 120 publications

Deuterium enrichments in chondritic macromolecular material—Implications for the origin and evolution of organics, water and asteroids

Deuterium enrichments in chondritic macromolecular material—Implications for the origin and evolution of organics, water and asteroids

D/H ratios of the inner Solar System

Terrestrial planet formation

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