NWA 1152 and Sahara 00182: New primitive carbonaceous chondrites with affinities to the CR and CV groups

Smith, C. L.; Russell, S. S.; Gounelle, M.; Greenwood, R. C.; Franchi, I. A.

doi:10.1111/j.1945-5100.2004.tb00093.x

Cited by 8 publications

(18 citation statements)

References 47 publications

(105 reference statements)

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“…As shown in Fig. 1a, the bulk O‐isotopic composition (Δ 17 O = −3.79‰; Smith et al. 2004) lies nearer the centroids of the fields of CV3 oxA and CV3 oxB than to CV3 R , but consistent with membership in any of these subgroups.…”

supporting

confidence: 53%

“…(2003); 6 = Grossman and Rubin (2006); 7 = Huber et al. (2006a, 2006b); 8 = Grossman (2000); 9 = Grossman (1998); 10 = Grossman (1994); 11 = Smith et al. (2004); 12 = Grossman and Zipfel (2001).…”

Section: Resultsmentioning

confidence: 99%

“…2002) as being of shock‐stage S2 and weathering grade W2/3 (Table 3). Smith et al. (2004) reported that most chondrules are PO and POP types and that chondrule mafic silicates are mainly magnesian (Fa1.2; Fs2.3).…”

mentioning

confidence: 99%

See 2 more Smart Citations

Compositions and taxonomy of 15 unusual carbonaceous chondrites

Choe¹,

Huber²,

Rubin³

et al. 2010

Meteoritics &Amp; Planetary Science

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supporting

confidence: 53%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Compositions and taxonomy of 15 unusual carbonaceous chondrites

Choe¹,

Huber²,

Rubin³

et al. 2010

Meteoritics &Amp; Planetary Science

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“…1c), with highly nonmonotonic depletion patterns. NWA1152 is an anomalous C3 find with affinities to CRs (25). Matrix in NWA has a similar overall level of depletion to CR but departs even further from a monotonic depletion pattern (enrichment in aqueously mobile Sr in NWA matrix is likely a consequence of terrestrial weathering).…”

Section: Resultsmentioning

confidence: 90%

Volatile fractionation in the early solar system and chondrule/matrix complementarity

Bland

Alard

Benedix

et al. 2005

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

154

152

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Bulk chondritic meteorites and terrestrial planets show a monotonic depletion in moderately volatile and volatile elements relative to the Sun's photosphere and CI carbonaceous chondrites. Although volatile depletion was the most fundamental chemical process affecting the inner solar nebula, debate continues as to its cause. Carbonaceous chondrites are the most primitive rocks available to us, and fine-grained, volatile-rich matrix is the most primitive component in these rocks. Several volatile depletion models posit a pristine matrix, with uniform CI-like chemistry across the different chondrite groups. To understand the nature of volatile fractionation, we studied minor and trace element abundances in fine-grained matrices of a variety of carbonaceous chondrites. We find that matrix trace element abundances are characteristic for a given chondrite group; they are depleted relative to CI chondrites, but are enriched relative to bulk compositions of their parent meteorites, particularly in volatile siderophile and chalcophile elements. This enrichment produces a highly nonmonotonic trace element pattern that requires a complementary depletion in chondrule compositions to achieve a monotonic bulk. We infer that carbonaceous chondrite matrices are not pristine: they formed from a material reservoir that was already depleted in volatile and moderately volatile elements. Additional thermal processing occurred during chondrule formation, with exchange of volatile siderophile and chalcophile elements between chondrules and matrix. This chemical complementarity shows that these chondritic components formed in the same nebula region.carbonaceous chondrite ͉ chondrule formation ͉ volatile depletion C arbonaceous chondrites were first recognized as primitive samples of the early solar nebula in the 1960s, when it became apparent that a group of these meteorites contained moderately volatile elements (condensing between Ϸ1,350 K and 650 K) and volatile elements (condensing at Ͻ650 K) in similar abundance to the solar photosphere (1). These elements are severely depleted in the terrestrial planets and in most other meteorite groups. Chondrites are constructed from chondrules, the igneous products of transient heating events, and Ca-Al-rich refractory inclusions (CAIs). These high-temperature components are embedded in a volatile-rich, fine-grained, mineralogically complex matrix, which is a host for presolar grains. In addition to the different compositional groups (e.g., CV, CO, CR, CM, and CI), carbonaceous chondrites are subdivided from types 1 to 6 based on the degree of secondary aqueous and thermal processing that they have experienced, type 3 being the most primitive, with aqueous alteration increasing to type 1, and types 3 to 6 showing increasing thermal alteration. CI1 chondrites, aqueously altered, and composed almost entirely of matrix, have compositions indistinguishable from solar. Other carbonaceous meteorites, containing less matrix (and more chondrules), are depleted in volatiles to varying degrees.The var...

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“…As all CR2s are breccias (Weisberg et al, 1993), some local heating and associated aqueous alteration could also have been induced by impacts. Varying degrees of aqueous alteration occur resulting in different petrologic types (1, 2, and 3) of CR chondrites (Weisberg and Prinz, 2000;Sipiera and Cole, 2004;Smith et al, 2004;Brearley, 2005, 2006a,b;Weisberg and Huber, 2007).…”

Section: Formation and Alteration Of The Cr Parent Bodymentioning

confidence: 99%