Progressive aqueous alteration of CM carbonaceous chondrites

Rubin, Alan E.; Trigo-Rodríguez, J. M.; Huber, Heinz; Wasson, J. T.

doi:10.1016/j.gca.2007.02.008

Cited by 455 publications

(990 citation statements)

References 61 publications

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“…40). The estimated low permeability of chondritic meteorites 41 and the lack of variations in bulk chemical compositions between meteorites with different degrees of aqueous alteration 1,2,42 imply that the alteration occurred in a chemically closed system, with the fluid flow being restricted to 10-100 mm, which is consistent with rare occurrences of short veins in aqueously altered chondrites (Fig. 1d).…”

Section: Discussionsupporting

confidence: 61%

Early aqueous activity on the ordinary and carbonaceous chondrite parent bodies recorded by fayalite

et al. 2015

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Chronology of aqueous activity on chondrite parent bodies constrains their accretion times and thermal histories. Radiometric 53 Cr dating has been successfully applied to aqueously formed carbonates in CM carbonaceous chondrites. Owing to the absence of carbonates in ordinary (H, L and LL), and CV and CO carbonaceous chondrites, and the lack of proper standards, there are no reliable ages of aqueous activity on their parent bodies. Here we report the first 53 Mn-53 Cr ages of aqueously formed fayalite in the L3 chondrite Elephant Moraine 90161 as 2:4 þ 1:8 À 1:3 Myr after calcium-aluminium-rich inclusions (CAIs), the oldest Solar System solids. In addition, measurements using our synthesized fayalite standard show that fayalite in the CV3 chondrite Asuka 881317 and CO3-like chondrite MacAlpine Hills 88107 formed 4:2 þ 0:8 À 0:7 and 5:1 þ 0:5 À 0:4 Myr after CAIs, respectively. Thermal modelling, combined with the inferred conditions (temperature and water/rock ratio) and 53 Cr ages of aqueous alteration, suggests accretion of the L, CV and CO parent bodies B1.8 À 2.5 Myr after CAIs.

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Section: Discussionsupporting

confidence: 61%

Early aqueous activity on the ordinary and carbonaceous chondrite parent bodies recorded by fayalite

et al. 2015

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“…SCO 06043 contains 88% phyllosilicates). QUE 93005 carbonates have been previously described by de Leuw et al (2006aLeuw et al ( , b, 2007Leuw et al ( , 2009aLeuw et al ( , b, 2010 and Rubin et al (2007). They recorded 2-3 volume % that is distributed randomly throughout the meteorite matrix and comprises grains of Ca-carbonate (50-100 µm) and calcian dolomite (10-30 µm), the latter frequently rimmed by pentlandite.…”

Section: Que 93005mentioning

confidence: 86%

“…Of the three carbonate minerals that have been previously described from the CM2s, calcite occurs in all meteorites, aragonite is found in the relatively unaltered ones, including Murray and Murchison (Barber, 1981;Lee and Ellen, 2008;Sofe et al, 2011), whereas dolomite is limited to the most highly aqueously altered samples (Zolensky et al, 1997;Rubin et al, 2007). This pattern suggests that as alteration progressed Ca-carbonate was followed by dolomite, probably reflecting increasing fluid Mg/Ca accompanying hydration of ferromagnesian silicates.…”

Section: Evolution Of Fluid Compositions During Aqueous Alterationmentioning

confidence: 87%

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Extended chronologies of aqueous alteration in the CM2 carbonaceous chondrites: Evidence from carbonates in Queen Alexandra Range 93005

Lee

Lindgren

Sofe

et al. 2012

Geochimica et Cosmochimica Acta

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The Antarctic CM2 carbonaceous chondrite QUE 93005 contains four compositionally distinct carbonates, namely breunnerite, calcite, dolomite and a Ca-poor dolomite. These carbonates can form monomineralic grains, or may be intergrown as bimineralic grains consisting of dolomite plus breunnerite and dolomite plus calcite, or polymineralic grains containing an intergrowth of breunnerite, Ca-poor dolomite and calcite. Carbonates in all grain types have inclusions of Fe,Ni sulphides and/or Mg-Fe phyllosilicates. In the bimineralic grains dolomite crystallised first to be overgrown by breunnerite or partially replaced by calcite. Polymineralic grains are concentrically layered, with breunnerite crystallising first on pore margins to be later etched, then overgrown and partially replaced by Ca-poor dolomite that was itself partly dissolved prior to being overgrown by calcite. Calcite and dolomite have also cemented fractures that cross-cut the fine-grained rims to aqueously altered chondrules and were formed by expansion of the chondrules during their hydration. Overall, the sequence of mineralisation in QUE 93005 was: (1) dolomite, (2) breunnerite, (3) Ca-poor dolomite then (4) calcite. This secular change in carbonate composition and mineralogy reflects changing solution composition and probably also provenance. Mg-Fe phyllosilicates replaced dolomite, breunnerite and Ca-poor dolomite prior to calcite crystallisation and most or all of the sulphides formed after both the phyllosilicates and calcite. Following sulphide crystallisation the edges of carbonate grains were abraded, either by impact 'gardening' or as a consequence of fluidisation of the matrix during rapid loss of gas or vapour. Determination of the crystallisation age of dolomite via the Mn−Cr system indicates that aqueous alteration of QUE 93005 began on or before 3.93 ± 0.23 Ma after the formation of the solar system. Overall, the water/rock ratio and fO 2 during alteration of QUE 93005 was similar to that of the CM1s and CR1s, but the lower degree of alteration of QUE 93005 overall suggests that alteration timescales were shorter, possibly due to loss of intergranular liquid water during fluidisation.2

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“…We performed Mn-Cr isotope measurements of the standard and carbonates in the CM chondrites with different alteration indexes 14 (calcites in Murchison CM 2.5 and Y791198 CM 2.4 and dolomites in ALH83100 CM 2.1 and Sayama CM 2.1) using a NanoSIMS 50. The Mn/Cr relative sensitivity data are presented in Supplementary Figure S1 and Supplementary Table S1.…”

Section: Initial 53mentioning

confidence: 99%

Evidence for the late formation of hydrous asteroids from young meteoritic carbonates

et al. 2012

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The accretion of small bodies in the solar system is a fundamental process that was followed by planet formation. Chronological information of meteorites can constrain when asteroids formed. secondary carbonates show extremely old 53 mn-53 Cr radiometric ages, indicating that some hydrous asteroids accreted rapidly. However, previous studies have failed to define accurate mn/Cr ratios; hence, these old ages could be artefacts. Here we develop a new method for accurate mn/Cr determination, and report a reliable age of 4,563.4+0.4/-0.5 million years ago for carbonates in carbonaceous chondrites. We find that these carbonates have identical ages, which are younger than those previously estimated. This result suggests the late onset of aqueous activities in the solar system. The young carbonate age cannot be explained if the parent asteroid accreted within 3 million years after the birth of the solar system. Thus, we conclude that hydrous asteroids accreted later than differentiated and metamorphosed asteroids.

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Progressive aqueous alteration of CM carbonaceous chondrites

Cited by 455 publications

References 61 publications

Early aqueous activity on the ordinary and carbonaceous chondrite parent bodies recorded by fayalite

Early aqueous activity on the ordinary and carbonaceous chondrite parent bodies recorded by fayalite

Extended chronologies of aqueous alteration in the CM2 carbonaceous chondrites: Evidence from carbonates in Queen Alexandra Range 93005

Evidence for the late formation of hydrous asteroids from young meteoritic carbonates

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