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dc.contributor.authorSmith, C. L.
dc.contributor.authorRussell, S. S.
dc.contributor.authorGounelle, M.
dc.contributor.authorGreenwood, R. C.
dc.contributor.authorFranchi, I. A.
dc.date.accessioned2021-02-12T21:17:04Z
dc.date.available2021-02-12T21:17:04Z
dc.date.issued2004-01-01
dc.identifier.citationSmith, C. L., Russell, S. S., Gounelle, M., Greenwood, R. C., & Franchi, I. A. (2004). NWA 1152 and Sahara 00182: New primitive carbonaceous chondrites with affinities to the CR and CV groups. Meteoritics & Planetary Science, 39(12), 2009-2032.
dc.identifier.issn1945-5100
dc.identifier.doi10.1111/j.1945-5100.2004.tb00093.x
dc.identifier.urihttp://hdl.handle.net/10150/655939
dc.description.abstractWe have investigated the mineralogy, petrography, bulk chemistry, and light element isotope composition of the ungrouped chondrites North West Africa (NWA) 1152 and Sahara 00182. NWA 1152 contains predominantly type 1 porphyritic olivine (PO) and porphyritic olivinepyroxene (POP) chondrules. Chondrule silicates are magnesium-rich (Fo98.8 +/- 1.2, n = 36; Fs2.3 +/- 2.1 Wo1.2 +/- 0.3, n = 23). Matrix comprises ~40 vol% of the sample and is composed of a micron sized silicate groundmass with larger silicate, sulfide, magnetite, and Fe-Ni metal (Ni ~50 wt%) grains. Phyllosilicates were not observed in the matrix. Refractory inclusions are rare (0.3 vol%) and are spinel pyroxene aggregates or amoeboid olivine aggregates; melilite is absent from the refractory inclusions. Sahara 00182 contains predominantly type 1 PO chondrules, POP chondrules are less common. Most chondrules contain blebs of, and are often rimmed with, Fe-Ni metal and sulfide. Chondrule phenocrysts are magnesium-rich (Fo92.2 +/- 0.6, n = 129; Fs4.4 +/- 1.8 Wo1.3 +/- 1.1, n = 16). Matrix comprises ~30 vol% of the meteorite and is predominantly sub-micron silicates, with rare larger silicate gains. Matrix Fe-Ni metal (mean Ni = 5.8 wt%) and sulfide grains are up to mm scale. No phyllosilicates were observed in the matrix. Refractory inclusions are rare (1.1 vol%) and melilite is absent. The oxygen isotope composition of NWA 1152 falls within the range of the CV chondrites with delta-17O = -3.43 ppm delta-18O = 0.70 ppm and is similar to Sahara 00182, delta-17O = -3.89 ppm, delta-18O = -0.19 ppm (Grossman and Zipfel 2001). Based on mineralogical and petrographic characteristics, we suggest NWA 1152 and Sahara 00182 show many similarities with the CR chondrites, however, oxygen isotopes suggest affinity with the CVs. Thus, neither sample can be assigned to any of the currently known carbonaceous chondrite groups based on traditionally recognized characteristics. Both samples demonstrate the complexity of inter- and intra-group relationships of the carbonaceous chondrites. Whatever their classification, NWA 1152 and Sahara 00182 represent a source of relatively pristine solar system material.
dc.language.isoen
dc.publisherThe Meteoritical Society
dc.relation.urlhttps://meteoritical.org/
dc.rightsCopyright © The Meteoritical Society
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/
dc.subjectNorthwest Africa (NWA) 1152
dc.subjectSahara 00182
dc.subjectCV chondrites
dc.subjectCR chondrites
dc.subjectcarbonaceous chondrites
dc.titleNWA 1152 and Sahara 00182: New primitive carbonaceous chondrites with affinities to the CR and CV groups
dc.typeArticle
dc.typetext
dc.identifier.journalMeteoritics & Planetary Science
dc.description.collectioninformationThe Meteoritics & Planetary Science archives are made available by the Meteoritical Society and the University of Arizona Libraries. Contact lbry-journals@email.arizona.edu for further information.
dc.eprint.versionFinal published version
dc.description.admin-noteMigrated from OJS platform February 2021
dc.source.volume39
dc.source.issue12
dc.source.beginpage2009
dc.source.endpage2032
refterms.dateFOA2021-02-12T21:17:04Z


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