I. Franchi | University of Siena / Università di Siena (original) (raw)
Papers by I. Franchi
TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN, 2010
We are entering in a new era of space exploration defined by sample return missions. The study of... more We are entering in a new era of space exploration defined by sample return missions. The study of extraterrestrial samples in the laboratory has given us many insights to Solar System formation and evolution, but is hampered by having to rely on the arrival of meteorites -fairly random samples from asteroids, the Moon and Mars. There is now increased interest
Science, 1992
One hypothesis for the origin of the nanometer-size diamonds found at the Cretaceous-Tertiary (K-... more One hypothesis for the origin of the nanometer-size diamonds found at the Cretaceous-Tertiary (K-T) boundary is that they are relict interstellar diamond grains carried by a postulated asteroid. The I3C/l2C and I5N/l4N ratios of the diamondsfrom two sites in North America, however, show that the diamonds are two component mixtures differing in carbon and nitrogen isotopic composition and nitrogen abundance. Samples from a site from Italy show no evidence for either diamond component. All the isotopic signatures obtained from the K-T boundary are material well distinguished from known meteoritic diamonds, particularly the fine-grain interstellar diamonds that are abundant in primitive chondrites. The K-T diamonds were most likely produced during the impact of the asteroid with Earth or in a plasma resulting from the associated fireball.
Rapid Communications in Mass Spectrometry, 1999
ABSTRACT
Meteoritics & Planetary Science, 2002
Sayh al Uhaymir (SaU) 094 is a 223.3 g, partially crusted, strongly to very strongly shocked mela... more Sayh al Uhaymir (SaU) 094 is a 223.3 g, partially crusted, strongly to very strongly shocked melanocratic olivine-porphyric rock of the shergottite group showing a microgabbroic texture. The rock consists of pyroxene (52.0-58.2 vol%)-dominantly prismatic pigeonite (En 60-68 Fs 20-27 Wo 7-9 ) associated with minor augite (En 46-49 Fs 15-16 Wo 28-31 )-brown (shock-oxidized) olivine (Fo 65-69 ; 22.1-31%), completely isotropic interstitial plagioclase glass (maskelynite; An 50-64 Or 0.3-0.9 ; 8.6-13.0%), chromite and titanian magnesian chromite (0.9-1.0%), traces of ilmenite (Ilm 80-86 ), pyrrhotite (Fe 92-100 ; 0.1-0.2%), merrillite (<<0.1%), and pockets (4.8-6.7%) consisting of green basaltic to basaltic andesitic shock glass that is partially devitrified into a brown to black product along boundaries with the primary minerals. The average maximum dimensions of minerals are: olivine (1.5 mm), pyroxene (0.3 mm) and maskelynite (0.3 mm). Primary melt inclusions in olivine and chromite are common and account for 0.1-0.6% of the rock. X-ray tomography revealed that the specimen contains ∼0.4 vol% of shock-melt associated vesicles, up to 3 mm in size, which show a preferred orientation. Fluidization of the maskelynite, melting and recrystallization of pyroxene, olivine and pyrrhotite indicate shock stage S6. Minor terrestrial weathering resulted in calciteveining and minor oxidation of sulfides. The meteorite is interpreted as paired with SaU 005/008/051. The modal composition is similar to Dar al Gani 476/489/670/735/876, with the exception that neither mesostasis nor titanomagnetite nor apatite are present and that all phases show little zonation. The restricted mineral composition, predominance of chromite among the oxides, and abundance of olivine indicate affinities to the lherzolitic shergottites.
Meteoritics & Planetary Science, 2002
Fines, microbreccias and agglutinates from the Luna 16 mature regolith 1635 and fines from the im... more Fines, microbreccias and agglutinates from the Luna 16 mature regolith 1635 and fines from the immature/submature Luna-24 regolith have been analysed for N and argon isotopes in order to understand the origin of isotopically distinct N released at different temperatures. All high-resolution runs reveal a similarity in the release of 36Ar, 40Ar and N over a wide temperature interval. The
Meteoritics & Planetary Science, 1998
... S., PALME, H., PILLINGER, CT, SCHULTZ, L., SEXTON, AS, SPETTEL, B., VERCHOVSKY, AB, WEBER, HW... more ... S., PALME, H., PILLINGER, CT, SCHULTZ, L., SEXTON, AS, SPETTEL, B., VERCHOVSKY, AB, WEBER, HW, WECKWERTH, G. and WOLF, D. (1998 ... Abstract Lunar meteorite Dar al Gani 262 (DG 262)found in the Libyan part of the Saharais a mature, anorthositic regolith ...
Meteoritics & Planetary Science, 2002
... Chang, 1993). A major component of the organics is thought to be derived directly from inters... more ... Chang, 1993). A major component of the organics is thought to be derived directly from interstellar organic molecules (eg, Alexander et al., 1993); parent-body processes (mainly aqueous) have altered the remainder. Up until ...
Thin layer growths of silicon on sapphire are proposed as a collector for carbon on the Genesis s... more Thin layer growths of silicon on sapphire are proposed as a collector for carbon on the Genesis solar wind sample return mission. An evaluation of the collectors and a laser extraction technique for the sample analysis is given.
Experimental Astronomy, 2009
How to cite: Barucci, M. A.; Yoshikawa, M.; Michel, P.; Kawaguchi, J.; Yano, H.; Brucato, J. R.; ... more How to cite: Barucci, M. A.; Yoshikawa, M.; Michel, P.; Kawaguchi, J.; Yano, H.; Brucato, J. R.; Franchi, I. A.; Dotto, E.; Fulchignoni, M.; Ulamec, S.; Boehnhardt, H.; Coradini, M.; Green, S. F.; Josset, J.-L.; Koschny, D.; Muinonen, K.; Oberst, J. and Marco Polo, Science Team (2008). Marco Polo: A near Earth object sample return mission.
Until now, light-element isotopic anomalies have been confined to primitive chondritic meteorites... more Until now, light-element isotopic anomalies have been confined to primitive chondritic meteorites. Bencubbin, an unusual breccia found in Australia, comprising 60− 75% metal with silicate and chondritic clasts 1− 4 in a shock-welded matrix 5, 6, has been shown 7− 9 ...
Analytical Chemistry, 2002
We have developed a new technique in which a solid reagent, cobalt(III) fluoride, is used to prep... more We have developed a new technique in which a solid reagent, cobalt(III) fluoride, is used to prepare oxygen gas for isotope ratio measurement from water derived either from direct injection or from the pyrolysis of solid samples. The technique uses continuous flow, isotope ratio monitoring, gas chromatography/mass spectrometry (irmGC/ MS) to measure the δ 18 O and δ 17 O of the oxygen gas. Water from appropriate samples is evolved by a procedure of stepped pyrolysis (0-1000°C, typically in 50°C increments) under a flowing stream of helium carrier gas. The method has considerable advantages over others used for water analysis in that it is quick; requires only small samples, typically 1-50 mg of whole rock samples (corresponding to ∼0.2 µmol of H 2 O); and the reagent is easy and safe to handle. Reproducibility in isotope ratio measurement obtained from pyrolysis of samples of a terrestrial solid standard are δ 18 O ( 0.54, δ 17 O ( 0.33, and ∆ 17 O ( 0.10‰, 1σ in all cases. The technique was developed primarily for the analysis of meteorites, and the efficiency of the method is illustrated herein by results from water standards, solid reference materials, and a sample of the Murchison CM2 meteorite.
Introduction: Sahara 99201 (provisional name) is a new ureilite weighing 91g collected from the S... more Introduction: Sahara 99201 (provisional name) is a new ureilite weighing 91g collected from the Sahara desert during 1999. The sample has been analysed to determine both mineralogy and petrography and also its light element stable isotopic composition.
A single stone weighing 1456 g was found in November 2002 in the Acfer area, Algeria. Oxygen isot... more A single stone weighing 1456 g was found in November 2002 in the Acfer area, Algeria. Oxygen isotope, chondrules-matrix ratio as well as other petrographic features point to a classification as CH carbonaceous chondrite.
Many small fragments, totally weighing 118 g were found in the Acfer area by an Italian dealer. C... more Many small fragments, totally weighing 118 g were found in the Acfer area by an Italian dealer. Chondrules size and types (predominance of granular olivine type), occurrence of twinned clinoenstatite and absence of plagioclase suggested a classification as CO carbonaceous chondrite.
TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN, 2010
We are entering in a new era of space exploration defined by sample return missions. The study of... more We are entering in a new era of space exploration defined by sample return missions. The study of extraterrestrial samples in the laboratory has given us many insights to Solar System formation and evolution, but is hampered by having to rely on the arrival of meteorites -fairly random samples from asteroids, the Moon and Mars. There is now increased interest
Science, 1992
One hypothesis for the origin of the nanometer-size diamonds found at the Cretaceous-Tertiary (K-... more One hypothesis for the origin of the nanometer-size diamonds found at the Cretaceous-Tertiary (K-T) boundary is that they are relict interstellar diamond grains carried by a postulated asteroid. The I3C/l2C and I5N/l4N ratios of the diamondsfrom two sites in North America, however, show that the diamonds are two component mixtures differing in carbon and nitrogen isotopic composition and nitrogen abundance. Samples from a site from Italy show no evidence for either diamond component. All the isotopic signatures obtained from the K-T boundary are material well distinguished from known meteoritic diamonds, particularly the fine-grain interstellar diamonds that are abundant in primitive chondrites. The K-T diamonds were most likely produced during the impact of the asteroid with Earth or in a plasma resulting from the associated fireball.
Rapid Communications in Mass Spectrometry, 1999
ABSTRACT
Meteoritics & Planetary Science, 2002
Sayh al Uhaymir (SaU) 094 is a 223.3 g, partially crusted, strongly to very strongly shocked mela... more Sayh al Uhaymir (SaU) 094 is a 223.3 g, partially crusted, strongly to very strongly shocked melanocratic olivine-porphyric rock of the shergottite group showing a microgabbroic texture. The rock consists of pyroxene (52.0-58.2 vol%)-dominantly prismatic pigeonite (En 60-68 Fs 20-27 Wo 7-9 ) associated with minor augite (En 46-49 Fs 15-16 Wo 28-31 )-brown (shock-oxidized) olivine (Fo 65-69 ; 22.1-31%), completely isotropic interstitial plagioclase glass (maskelynite; An 50-64 Or 0.3-0.9 ; 8.6-13.0%), chromite and titanian magnesian chromite (0.9-1.0%), traces of ilmenite (Ilm 80-86 ), pyrrhotite (Fe 92-100 ; 0.1-0.2%), merrillite (<<0.1%), and pockets (4.8-6.7%) consisting of green basaltic to basaltic andesitic shock glass that is partially devitrified into a brown to black product along boundaries with the primary minerals. The average maximum dimensions of minerals are: olivine (1.5 mm), pyroxene (0.3 mm) and maskelynite (0.3 mm). Primary melt inclusions in olivine and chromite are common and account for 0.1-0.6% of the rock. X-ray tomography revealed that the specimen contains ∼0.4 vol% of shock-melt associated vesicles, up to 3 mm in size, which show a preferred orientation. Fluidization of the maskelynite, melting and recrystallization of pyroxene, olivine and pyrrhotite indicate shock stage S6. Minor terrestrial weathering resulted in calciteveining and minor oxidation of sulfides. The meteorite is interpreted as paired with SaU 005/008/051. The modal composition is similar to Dar al Gani 476/489/670/735/876, with the exception that neither mesostasis nor titanomagnetite nor apatite are present and that all phases show little zonation. The restricted mineral composition, predominance of chromite among the oxides, and abundance of olivine indicate affinities to the lherzolitic shergottites.
Meteoritics & Planetary Science, 2002
Fines, microbreccias and agglutinates from the Luna 16 mature regolith 1635 and fines from the im... more Fines, microbreccias and agglutinates from the Luna 16 mature regolith 1635 and fines from the immature/submature Luna-24 regolith have been analysed for N and argon isotopes in order to understand the origin of isotopically distinct N released at different temperatures. All high-resolution runs reveal a similarity in the release of 36Ar, 40Ar and N over a wide temperature interval. The
Meteoritics & Planetary Science, 1998
... S., PALME, H., PILLINGER, CT, SCHULTZ, L., SEXTON, AS, SPETTEL, B., VERCHOVSKY, AB, WEBER, HW... more ... S., PALME, H., PILLINGER, CT, SCHULTZ, L., SEXTON, AS, SPETTEL, B., VERCHOVSKY, AB, WEBER, HW, WECKWERTH, G. and WOLF, D. (1998 ... Abstract Lunar meteorite Dar al Gani 262 (DG 262)found in the Libyan part of the Saharais a mature, anorthositic regolith ...
Meteoritics & Planetary Science, 2002
... Chang, 1993). A major component of the organics is thought to be derived directly from inters... more ... Chang, 1993). A major component of the organics is thought to be derived directly from interstellar organic molecules (eg, Alexander et al., 1993); parent-body processes (mainly aqueous) have altered the remainder. Up until ...
Thin layer growths of silicon on sapphire are proposed as a collector for carbon on the Genesis s... more Thin layer growths of silicon on sapphire are proposed as a collector for carbon on the Genesis solar wind sample return mission. An evaluation of the collectors and a laser extraction technique for the sample analysis is given.
Experimental Astronomy, 2009
How to cite: Barucci, M. A.; Yoshikawa, M.; Michel, P.; Kawaguchi, J.; Yano, H.; Brucato, J. R.; ... more How to cite: Barucci, M. A.; Yoshikawa, M.; Michel, P.; Kawaguchi, J.; Yano, H.; Brucato, J. R.; Franchi, I. A.; Dotto, E.; Fulchignoni, M.; Ulamec, S.; Boehnhardt, H.; Coradini, M.; Green, S. F.; Josset, J.-L.; Koschny, D.; Muinonen, K.; Oberst, J. and Marco Polo, Science Team (2008). Marco Polo: A near Earth object sample return mission.
Until now, light-element isotopic anomalies have been confined to primitive chondritic meteorites... more Until now, light-element isotopic anomalies have been confined to primitive chondritic meteorites. Bencubbin, an unusual breccia found in Australia, comprising 60− 75% metal with silicate and chondritic clasts 1− 4 in a shock-welded matrix 5, 6, has been shown 7− 9 ...
Analytical Chemistry, 2002
We have developed a new technique in which a solid reagent, cobalt(III) fluoride, is used to prep... more We have developed a new technique in which a solid reagent, cobalt(III) fluoride, is used to prepare oxygen gas for isotope ratio measurement from water derived either from direct injection or from the pyrolysis of solid samples. The technique uses continuous flow, isotope ratio monitoring, gas chromatography/mass spectrometry (irmGC/ MS) to measure the δ 18 O and δ 17 O of the oxygen gas. Water from appropriate samples is evolved by a procedure of stepped pyrolysis (0-1000°C, typically in 50°C increments) under a flowing stream of helium carrier gas. The method has considerable advantages over others used for water analysis in that it is quick; requires only small samples, typically 1-50 mg of whole rock samples (corresponding to ∼0.2 µmol of H 2 O); and the reagent is easy and safe to handle. Reproducibility in isotope ratio measurement obtained from pyrolysis of samples of a terrestrial solid standard are δ 18 O ( 0.54, δ 17 O ( 0.33, and ∆ 17 O ( 0.10‰, 1σ in all cases. The technique was developed primarily for the analysis of meteorites, and the efficiency of the method is illustrated herein by results from water standards, solid reference materials, and a sample of the Murchison CM2 meteorite.
Introduction: Sahara 99201 (provisional name) is a new ureilite weighing 91g collected from the S... more Introduction: Sahara 99201 (provisional name) is a new ureilite weighing 91g collected from the Sahara desert during 1999. The sample has been analysed to determine both mineralogy and petrography and also its light element stable isotopic composition.
A single stone weighing 1456 g was found in November 2002 in the Acfer area, Algeria. Oxygen isot... more A single stone weighing 1456 g was found in November 2002 in the Acfer area, Algeria. Oxygen isotope, chondrules-matrix ratio as well as other petrographic features point to a classification as CH carbonaceous chondrite.
Many small fragments, totally weighing 118 g were found in the Acfer area by an Italian dealer. C... more Many small fragments, totally weighing 118 g were found in the Acfer area by an Italian dealer. Chondrules size and types (predominance of granular olivine type), occurrence of twinned clinoenstatite and absence of plagioclase suggested a classification as CO carbonaceous chondrite.