Thermoluminescence sensitivity and thermal history of type 3 ordinary chondrites: Eleven new type 3.0–3.1 chondrites and possible explanations for differences among H, L, and LL chondrites

Benoit, P. H.; Akridge, G.; Ninagawa, K.; Sears, D. W. G.

doi:10.1111/j.1945-5100.2002.tb00856.x

Cited by 16 publications

(20 citation statements)

References 43 publications

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“…The differences between the determined petrographic types are weaker for reduced than for oxidised CV3s. The ITL signal originates from the feldspar formed by the devitrification of mesostasis glass during metamorphism (Sears et al, 1980;Brearley and Jones, 1998;Benoit et al, 2002), and was initially developed on Ordinary Chondrites that suffered weak or negligible aqueous alteration (Grossman et al, 2000). On the other hand, oxidised CV3 chondrites suffered major aqueous alteration that led to dissolution of mesostasis glass and feldspars, explaining why the petrologic subtypes of these objects are systematically underestimated.…”

Section: Attribution Of Petrologic Types To Cv3s By Comparison With Uocsmentioning

confidence: 97%

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Determination of the petrologic type of CV3 chondrites by Raman spectroscopy of included organic matter

Bonal

Quirico

Bourot-Denise

et al. 2006

Geochimica et Cosmochimica Acta

293

387

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Section: Attribution Of Petrologic Types To Cv3s By Comparison With Uocsmentioning

confidence: 97%

“…A first set of measurements was composed of a series of UOCs with well known petrographic types (Sears et al, 1980;Sears et al, 1991b;Benoit et al, 2002) In BSE images, no zoning of olivine phenocrysts is observed for objects of petrographic types ranging between 3.0 and 3.2 (Fig. 7a).…”

Section: Zoning Of Olivine Phenocrystsmentioning

confidence: 99%

Determination of the petrologic type of CV3 chondrites by Raman spectroscopy of included organic matter

Bonal

Quirico

Bourot-Denise

et al. 2006

Geochimica et Cosmochimica Acta

293

387

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“…However, measured thermoluminescence sensitivity of feldspars indicates that this transition occurs at lower temperatures, by petrologic type 3.5 (Sears et al. 1982; Benoit et al. 2001, 2002).…”

Section: Evaluation Of Pyroxene and Plagioclase Geothermometrymentioning

confidence: 99%

Analysis of ordinary chondrites using powder X-ray diffraction: 2. Applications to ordinary chondrite parent-body processes

Dunn

McSween

McCoy

et al. 2010

Meteoritics and Planetary Science

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Abstract-We evaluate the chemical and physical conditions of metamorphism in ordinary chondrite parent bodies using X-ray diffraction (XRD)-measured modal mineral abundances and geochemical analyses of 48 type 4-6 ordinary chondrites. Several observations indicate that oxidation may have occurred during progressive metamorphism of equilibrated chondrites, including systematic changes with petrologic type in XRD-derived olivine and low-Ca pyroxene abundances, increasing ratios of MgO ⁄ (MgO+FeO) in olivine and pyroxene, mean Ni ⁄ Fe and Co ⁄ Fe ratios in bulk metal with increasing metamorphic grade, and linear Fe addition trends in molar Fe ⁄ Mn and Fe ⁄ Mg plots. An aqueous fluid, likely incorporated as hydrous silicates and distributed homogeneously throughout the parent body, was responsible for oxidation. Based on mass balance calculations, a minimum of 0.3-0.4 wt% H 2 O reacted with metal to produce oxidized Fe. Prior to oxidation the parent body underwent a period of reduction, as evidenced by the unequilibrated chondrites. Unlike olivine and pyroxene, average plagioclase abundances do not show any systematic changes with increasing petrologic type. Based on this observation and a comparison of modal and normative plagioclase abundances, we suggest that plagioclase completely crystallized from glass by type 4 temperature conditions in the H and L chondrites and by type 5 in the LL chondrites. Because the validity of using the plagioclase thermometer to determine peak temperatures rests on the assumption that plagioclase continued to crystallize through type 6 conditions, we suggest that temperatures calculated using pyroxene goethermometry provide more accurate estimates of the peak temperatures reached in ordinary chondrite parent bodies.

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“…QUE 97008 was originally classified as L3.4 with a weathering grade of A (Grossman 1999). Benoit et al. (2002) recommended a petrologic type 3.0 for QUE 97008 based on thermoluminescence properties, whereas Grossman and Brearley (2005) suggested a petrologic type of 3.05 based on petrographic characteristics.…”

Section: Samples and Analytical Conditionsmentioning

confidence: 99%

Fe‐Mn systematics of type IIA chondrules in unequilibrated CO, CR, and ordinary chondrites

Berlin¹,

Jones²,

Brearley³

2011

Meteorit & Planetary Scien

115

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Abstract-We have examined Fe ⁄ Mn systematics of 34 type IIA chondrules in eight highly unequilibrated CO, CR, and ordinary chondrites using new data from this study and prior studies from our laboratory. Olivine grains from type IIA chondrules in CO chondrites and unequilibrated ordinary chondrites (UOC) have significantly different Fe ⁄ Mn ratios, with mean molar Fe ⁄ Mn = 99 and 44, respectively. Olivine analyses from both these chondrite groups show well-defined trends in Mn versus Fe (afu) and molar Fe ⁄ Mn versus Fe ⁄ Mg diagrams. In general, type IIA chondrules in CR chondrites have properties intermediate between those in UOC and CO chondrites. In most UOC and CR type IIA chondrules, the Fe ⁄ Mn ratio of olivine decreases during crystallization, whereas in CO chondrites the Fe ⁄ Mn ratio does not appear to change. It is difficult to interpret the observed Fe ⁄ Mn trends in terms of differing moderately volatile element depletions inherited from precursor materials. Instead, we suggest that significant differences in the abundances of silicates and sulfides ± metals in the precursor material, as well as open-system behavior during chondrule formation, were responsible for establishing the different Fe ⁄ Mn trends. Using Fe-Mn-Mg systematics, we are able to identify relict grains in type IIA chondrules, which could be derived from previous generations of chondrules, including chondrules from other chondrite groups, and possibly chondritic reservoirs that have not been sampled previously.

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Thermoluminescence sensitivity and thermal history of type 3 ordinary chondrites: Eleven new type 3.0–3.1 chondrites and possible explanations for differences among H, L, and LL chondrites

Cited by 16 publications

References 43 publications

Determination of the petrologic type of CV3 chondrites by Raman spectroscopy of included organic matter

Determination of the petrologic type of CV3 chondrites by Raman spectroscopy of included organic matter

Analysis of ordinary chondrites using powder X-ray diffraction: 2. Applications to ordinary chondrite parent-body processes

Fe‐Mn systematics of type IIA chondrules in unequilibrated CO, CR, and ordinary chondrites

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