Luca Bindi | Università degli Studi di Firenze (University of Florence) (original) (raw)
Papers by Luca Bindi
Journal of …, Jan 1, 2010
CITATIONS 40 READS 124 7 authors, including: Some of the authors of this publication are also wor... more CITATIONS 40 READS 124 7 authors, including: Some of the authors of this publication are also working on these related projects: Mineralogy and genesis of precious-, rare-, and critical metals in hydrothermal ore deposits of Greece View project Mineralogy and geochemistry of advanced argillic alteration zones -lithocaps in Greece View project
Acta Crystallographica Section B Structural Science, 2001
Marine Geology, 2013
Keywords: fungi modeling orpiment realgar submarine hydrothermal
Lithos, 2014
Trace and rare-earth elements Garnet/melt partitioning coefficients High-pressure experiment Eclo... more Trace and rare-earth elements Garnet/melt partitioning coefficients High-pressure experiment Eclogite New experimental data on trace element partitioning between Na-bearing majoritic garnet and melt at P = 8.5 GPa and T = 1500-1900°C applicable to partial melting of Na-rich eclogite are presented. We have found that Na-bearing garnet is a liquidus phase of the system at 1850-1650°C being accompanied by enstatitic pyroxene at lower temperatures. With decreasing temperature, Na concentration in garnet increases up to N 1 wt.% Na 2 O due to progressive incorporation of a Na majorite component (Na 2 MgSi 5 O 12 ). Most of the studied trace elements are incompatible, except for Er, Tm, Yb (in some runs), Lu, and Sc (in all runs), which are distributed into garnet. The main characteristic of the trace-element partitioning in our experiments is a different behaviour of the LREE (La, Ce, Pr) in comparison with MREE and HREE (Nd, Sm, Eu, Gd, Tb, Dy, Y, Ho, Er, Tm, Yb, and Lu). In particular, a significant increase of D values for LREE with the increase of Na 2 O concentration in garnet is observed. As predicted from lattice strain, partitioning coefficients for REEs entering the X site of garnet exhibit a near-parabolic dependence on ionic radius. The results of the study are applied to the formation of inclusions of Na-bearing majoritic garnets in diamonds, and equilibrium melts significantly enriched in LREEs.
Acta Crystallographica Section B Structural Science, 2001
Journal of Solid State Chemistry, 2006
Additional X-ray diffraction effects yielding an eightfold commensurate superstructure ½a ¼ 20:97... more Additional X-ray diffraction effects yielding an eightfold commensurate superstructure ½a ¼ 20:974ð5ÞÅ of the ideal pyrochlore structure were observed after annealing at 873 K of a thallium-doped bariopyrochlore single crystal. Electron diffraction indicated the coexistence of two cubic phases, the pyrochlore structure and a new F-centred, cubic phase. The superstructure was solved and refined in the space group F 4 3 m. The two phases were combined together and refined as independently diffracting to R ¼ 0:0628. The resulting unit-cell content is (A,&) 20 Nb 16 Ti 2 O 53 ðZ ¼ 8Þ, with A ¼ Ba, Tl, Ce, Th. For some atomic positions of the superstructure, third-and fourth-order anharmonic ADP's were used to account for the specific density shape having a continuous character as typical for ionic conductors. There are three distinct clusters in the superstructure, leading to a new structure type no longer strictly of pyrochlorestructure type. r
Acta Crystallographica Section B Structural Science, 2006
The structure of natural fresnoite, Ba 2 TiSi 2 O 8 , from the sanbornite deposits of eastern Fre... more The structure of natural fresnoite, Ba 2 TiSi 2 O 8 , from the sanbornite deposits of eastern Fresno County, California, has been solved and refined as an incommensurate structure in five-dimensional superspace. The structure is tetragonal, superspace group P4bm ; ; 1=2 ð ÞÀ ; ; 1=2 ð Þ 0gg, cell parameters a = 8.5353 (6), c = 10.4128 (7) Å , modulation vectors
Journal of Solid State Chemistry, 2006
Additional X-ray diffraction effects yielding an eightfold commensurate superstructure ½a ¼ 20:97... more Additional X-ray diffraction effects yielding an eightfold commensurate superstructure ½a ¼ 20:974ð5ÞÅ of the ideal pyrochlore structure were observed after annealing at 873 K of a thallium-doped bariopyrochlore single crystal. Electron diffraction indicated the coexistence of two cubic phases, the pyrochlore structure and a new F-centred, cubic phase. The superstructure was solved and refined in the space group F 4 3 m. The two phases were combined together and refined as independently diffracting to R ¼ 0:0628. The resulting unit-cell content is (A,&) 20 Nb 16 Ti 2 O 53 ðZ ¼ 8Þ, with A ¼ Ba, Tl, Ce, Th. For some atomic positions of the superstructure, third-and fourth-order anharmonic ADP's were used to account for the specific density shape having a continuous character as typical for ionic conductors. There are three distinct clusters in the superstructure, leading to a new structure type no longer strictly of pyrochlorestructure type. r
Solid State Ionics, 2008
A careful electron diffraction investigation of pearceite-Tac and polybasite-Tac samples in the A... more A careful electron diffraction investigation of pearceite-Tac and polybasite-Tac samples in the Ag + fast ion conducting state reveals that the average hexagonal [Ag I 9 ] 9+ sub-structure in these mineral solid electrolyte systems is mutually incommensurable with respect to the remaining [(Ag I ,Cu I ) 6 (As III ,Sb III ) 2 S 7 ] 2− [Cu I S 4 ] 7− framework sub-structure. It is shown how the mutual incommensurability of the two component substructures can be compatible with crystal chemical commonsense, with previously reported average structure refinements of these phases as well as providing an insight into their Ag + fast ion conductivity at such low temperatures. In addition, Ag + /Cu + ion ordering (and associated displacive shifts of the centreing S 2− ions) in the S 2− (Ag,Cu) 6 octahedral sites is shown to provide a mechanism for low temperature superstructure ordering.
To verify the oxidation-dehydrogenation reaction induced by heat treatment of ilvaite in air, a c... more To verify the oxidation-dehydrogenation reaction induced by heat treatment of ilvaite in air, a crystal from Elba Island, Italy, was selected for annealing experiments and crystal chemical study. X- ray intensity data were collected and structure refinement was performed after each heat treatment (temperatures ranged from 400 to 700 °C). Oxidation of Fe 2+ as well as loss of H
European Journal of Mineralogy
Paseroite, ideally PbMn2+(Mn2+,Fe2+)2(V5+,Ti,Fe3+,□)18O38, is a new mineral (IMA 2011–069) from f... more Paseroite, ideally PbMn2+(Mn2+,Fe2+)2(V5+,Ti,Fe3+,□)18O38, is a new mineral (IMA 2011–069) from fossil wood in the upper part of the Molinello mine, Val Graveglia, Italy. Paseroite occurs in direct association with quartz, chalcocite, volborthite, metatyuyamunite and pyrophanite, and was also found as zones within V-rich senaite crystals to which it forms a solid-solution series. Paseroite forms as isolated submetallic, dark grey to black, elongated scalenohedral crystals between 50 and 100 µm in length, with the forms {001} and {102} present. The tenacity is brittle, the fracture conchoidal, and the streak is black. The Vickers hardness is 847 kg mm-2 (load 500g), which is equivalent to 6–6.5 on the Mohs scale. The calculated density is 4.315 g/cm3 (on the basis of the empirical formula). In plane-polarised incident light, paseroite is greyish in colour, weakly bireflectant and non-pleochroic. Internal reflections are absent. Between crossed polars, paseroite is anisotropic, withou...
American Mineralogist, 2014
ABSTRACT Steinhardtite is a new mineral from the Khatyrka meteorite; it is a new allotropic form ... more ABSTRACT Steinhardtite is a new mineral from the Khatyrka meteorite; it is a new allotropic form of aluminum. It occurs as rare crystals up to ~10 μm across in meteoritic fragments that contain evidence of a heterogeneous distribution of pressures and temperatures during impact shock, in which some portions of the meteorite reached at least 5 GPa and 1200 °C. The meteorite fragments contain the high-pressure phases ahrensite, coesite, stishovite, and an unnamed spinelloid with composition Fe3–xSixO4 (x ≈ 0.4). Other minerals include trevorite, Ni-Al-Mg-Fe spinels, magnetite, diopside, forsterite, clinoenstatite, nepheline, pentlandite, Cu-bearing troilite, icosahedrite, khatyrkite, cupalite, taenite, and Al-bearing taenite. Given the exceedingly small grain size of steinhardtite, it was not possible to determine most of the physical properties for the mineral. A mean of 9 electron microprobe analyses (obtained from two different fragments) gave the formula Al0.38Ni0.32Fe0.30, on the basis of 1 atom. A combined TEM and single-crystal X-ray diffraction study revealed steinhardtite to be cubic, space group Im3̄m, with a = 3.0214(8) Å, and V = 27.58(2) Å3, Z = 2. In the crystal structure [R1 = 0.0254], the three elements are disordered at the origin of the unit cell in a body-centered-cubic packing (α-Fe structure type). The five strongest powder-diffraction lines [d in Å (I/I0) (hkl)] are: 2.1355 (100) (110); 1.5100 (15) (200); 1.2329 (25) (211); 0.9550 (10) (310); 0.8071 (30) (321). The new mineral has been approved by the IMA-NMNC Commission (2014-036) and named in honor of Paul J. Steinhardt, Professor at the Department of Physics of Princeton University, for his extraordinary and enthusiastic dedication to the study of the mineralogy of the Khatyrka meteorite, a unique CV3 carbonaceous chondrite containing the first natural quasicrystalline phase icosahedrite. The recovery of the polymorph of Al described here that contains essential amounts of Ni and Fe suggests that Al could be a contributing candidate for the anomalously low density of the Earth’s presumed Fe-Ni core.
Scientific reports, 2014
The first natural-occurring quasicrystal, icosahedrite, was recently discovered in the Khatyrka m... more The first natural-occurring quasicrystal, icosahedrite, was recently discovered in the Khatyrka meteorite, a new CV3 carbonaceous chondrite. Its finding raised fundamental questions regarding the effects of pressure and temperature on the kinetic and thermodynamic stability of the quasicrystal structure relative to possible isochemical crystalline or amorphous phases. Although several studies showed the stability at ambient temperature of synthetic icosahedral AlCuFe up to ~35 GPa, the simultaneous effect of temperature and pressure relevant for the formation of icosahedrite has been never investigated so far. Here we present in situ synchrotron X-ray diffraction experiments on synthetic icosahedral AlCuFe using multianvil device to explore possible temperature-induced phase transformations at pressures of 5 GPa and temperature up to 1773 K. Results show the structural stability of i-AlCuFe phase with a negligible effect of pressure on the volumetric thermal expansion properties. In...
Scientific Reports, 2015
We report the first occurrence of a natural quasicrystal with decagonal symmetry. The quasicrysta... more We report the first occurrence of a natural quasicrystal with decagonal symmetry. The quasicrystal, with composition Al 71 Ni 24 Fe 5 , was discovered in the Khatyrka meteorite, a recently described CV3 carbonaceous chondrite. Icosahedrite, Al 63 Cu 24 Fe 13 , the first natural quasicrystal to be identified, was found in the same meteorite. The new quasicrystal was found associated with steinhardtite (Al 38 Ni 32 Fe 30 ), Fe-poor steinhardtite (Al 50 Ni 40 Fe 10 ), Al-bearing trevorite (NiFe 2 O 4 ) and Al-bearing taenite (FeNi). Laboratory studies of decagonal Al 71 Ni 24 Fe 5 have shown that it is stable over a narrow range of temperatures, 1120 K to 1200 K at standard pressure, providing support for our earlier conclusion that the Khatyrka meteorite reached heterogeneous high temperatures [1100 , T(K) # 1500] and then rapidly cooled after being heated during an impact-induced shock that occurred in outer space 4.5 Gya. The occurrences of metallic Al alloyed with Cu, Ni, and Fe raises new questions regarding conditions that can be achieved in the early solar nebula.
Nature communications, 2014
The discovery of a natural quasicrystal, icosahedrite (Al63Cu24Fe13), accompanied by khatyrkite (... more The discovery of a natural quasicrystal, icosahedrite (Al63Cu24Fe13), accompanied by khatyrkite (CuAl2) and cupalite (CuAl) in the CV3 carbonaceous chondrite Khatyrka has posed a mystery as to what extraterrestrial processes led to the formation and preservation of these metal alloys. Here we present a range of evidence, including the discovery of high-pressure phases never observed before in a CV3 chondrite, indicating that an impact shock generated a heterogeneous distribution of pressures and temperatures in which some portions reached at least 5 GPa and 1,200 °C. The conditions were sufficient to melt Al-Cu-bearing minerals, which then rapidly solidified into icosahedrite and other Al-Cu metal phases. The meteorite also contains heretofore unobserved phases of iron-nickel and iron sulphide with substantial amounts of Al and Cu. The presence of these phases in Khatyrka provides further proof that the Al-Cu alloys are natural products of unusual processes that occurred in the earl...
... di Mineralogia, Università degli Studi di Firenze, Via La Pira, 4-I-50121 Firenze, Italy. ...... more ... di Mineralogia, Università degli Studi di Firenze, Via La Pira, 4-I-50121 Firenze, Italy. ... We thank F. Olmi (CNRIstituto di Geoscienze e Georisorsesezione di Firenze) for his help during the electron ... Proceedings of Russian Mineralogical Society, 128, 6472 (in Russian). ...
Journal of …, Jan 1, 2010
CITATIONS 40 READS 124 7 authors, including: Some of the authors of this publication are also wor... more CITATIONS 40 READS 124 7 authors, including: Some of the authors of this publication are also working on these related projects: Mineralogy and genesis of precious-, rare-, and critical metals in hydrothermal ore deposits of Greece View project Mineralogy and geochemistry of advanced argillic alteration zones -lithocaps in Greece View project
Acta Crystallographica Section B Structural Science, 2001
Marine Geology, 2013
Keywords: fungi modeling orpiment realgar submarine hydrothermal
Lithos, 2014
Trace and rare-earth elements Garnet/melt partitioning coefficients High-pressure experiment Eclo... more Trace and rare-earth elements Garnet/melt partitioning coefficients High-pressure experiment Eclogite New experimental data on trace element partitioning between Na-bearing majoritic garnet and melt at P = 8.5 GPa and T = 1500-1900°C applicable to partial melting of Na-rich eclogite are presented. We have found that Na-bearing garnet is a liquidus phase of the system at 1850-1650°C being accompanied by enstatitic pyroxene at lower temperatures. With decreasing temperature, Na concentration in garnet increases up to N 1 wt.% Na 2 O due to progressive incorporation of a Na majorite component (Na 2 MgSi 5 O 12 ). Most of the studied trace elements are incompatible, except for Er, Tm, Yb (in some runs), Lu, and Sc (in all runs), which are distributed into garnet. The main characteristic of the trace-element partitioning in our experiments is a different behaviour of the LREE (La, Ce, Pr) in comparison with MREE and HREE (Nd, Sm, Eu, Gd, Tb, Dy, Y, Ho, Er, Tm, Yb, and Lu). In particular, a significant increase of D values for LREE with the increase of Na 2 O concentration in garnet is observed. As predicted from lattice strain, partitioning coefficients for REEs entering the X site of garnet exhibit a near-parabolic dependence on ionic radius. The results of the study are applied to the formation of inclusions of Na-bearing majoritic garnets in diamonds, and equilibrium melts significantly enriched in LREEs.
Acta Crystallographica Section B Structural Science, 2001
Journal of Solid State Chemistry, 2006
Additional X-ray diffraction effects yielding an eightfold commensurate superstructure ½a ¼ 20:97... more Additional X-ray diffraction effects yielding an eightfold commensurate superstructure ½a ¼ 20:974ð5ÞÅ of the ideal pyrochlore structure were observed after annealing at 873 K of a thallium-doped bariopyrochlore single crystal. Electron diffraction indicated the coexistence of two cubic phases, the pyrochlore structure and a new F-centred, cubic phase. The superstructure was solved and refined in the space group F 4 3 m. The two phases were combined together and refined as independently diffracting to R ¼ 0:0628. The resulting unit-cell content is (A,&) 20 Nb 16 Ti 2 O 53 ðZ ¼ 8Þ, with A ¼ Ba, Tl, Ce, Th. For some atomic positions of the superstructure, third-and fourth-order anharmonic ADP's were used to account for the specific density shape having a continuous character as typical for ionic conductors. There are three distinct clusters in the superstructure, leading to a new structure type no longer strictly of pyrochlorestructure type. r
Acta Crystallographica Section B Structural Science, 2006
The structure of natural fresnoite, Ba 2 TiSi 2 O 8 , from the sanbornite deposits of eastern Fre... more The structure of natural fresnoite, Ba 2 TiSi 2 O 8 , from the sanbornite deposits of eastern Fresno County, California, has been solved and refined as an incommensurate structure in five-dimensional superspace. The structure is tetragonal, superspace group P4bm ; ; 1=2 ð ÞÀ ; ; 1=2 ð Þ 0gg, cell parameters a = 8.5353 (6), c = 10.4128 (7) Å , modulation vectors
Journal of Solid State Chemistry, 2006
Additional X-ray diffraction effects yielding an eightfold commensurate superstructure ½a ¼ 20:97... more Additional X-ray diffraction effects yielding an eightfold commensurate superstructure ½a ¼ 20:974ð5ÞÅ of the ideal pyrochlore structure were observed after annealing at 873 K of a thallium-doped bariopyrochlore single crystal. Electron diffraction indicated the coexistence of two cubic phases, the pyrochlore structure and a new F-centred, cubic phase. The superstructure was solved and refined in the space group F 4 3 m. The two phases were combined together and refined as independently diffracting to R ¼ 0:0628. The resulting unit-cell content is (A,&) 20 Nb 16 Ti 2 O 53 ðZ ¼ 8Þ, with A ¼ Ba, Tl, Ce, Th. For some atomic positions of the superstructure, third-and fourth-order anharmonic ADP's were used to account for the specific density shape having a continuous character as typical for ionic conductors. There are three distinct clusters in the superstructure, leading to a new structure type no longer strictly of pyrochlorestructure type. r
Solid State Ionics, 2008
A careful electron diffraction investigation of pearceite-Tac and polybasite-Tac samples in the A... more A careful electron diffraction investigation of pearceite-Tac and polybasite-Tac samples in the Ag + fast ion conducting state reveals that the average hexagonal [Ag I 9 ] 9+ sub-structure in these mineral solid electrolyte systems is mutually incommensurable with respect to the remaining [(Ag I ,Cu I ) 6 (As III ,Sb III ) 2 S 7 ] 2− [Cu I S 4 ] 7− framework sub-structure. It is shown how the mutual incommensurability of the two component substructures can be compatible with crystal chemical commonsense, with previously reported average structure refinements of these phases as well as providing an insight into their Ag + fast ion conductivity at such low temperatures. In addition, Ag + /Cu + ion ordering (and associated displacive shifts of the centreing S 2− ions) in the S 2− (Ag,Cu) 6 octahedral sites is shown to provide a mechanism for low temperature superstructure ordering.
To verify the oxidation-dehydrogenation reaction induced by heat treatment of ilvaite in air, a c... more To verify the oxidation-dehydrogenation reaction induced by heat treatment of ilvaite in air, a crystal from Elba Island, Italy, was selected for annealing experiments and crystal chemical study. X- ray intensity data were collected and structure refinement was performed after each heat treatment (temperatures ranged from 400 to 700 °C). Oxidation of Fe 2+ as well as loss of H
European Journal of Mineralogy
Paseroite, ideally PbMn2+(Mn2+,Fe2+)2(V5+,Ti,Fe3+,□)18O38, is a new mineral (IMA 2011–069) from f... more Paseroite, ideally PbMn2+(Mn2+,Fe2+)2(V5+,Ti,Fe3+,□)18O38, is a new mineral (IMA 2011–069) from fossil wood in the upper part of the Molinello mine, Val Graveglia, Italy. Paseroite occurs in direct association with quartz, chalcocite, volborthite, metatyuyamunite and pyrophanite, and was also found as zones within V-rich senaite crystals to which it forms a solid-solution series. Paseroite forms as isolated submetallic, dark grey to black, elongated scalenohedral crystals between 50 and 100 µm in length, with the forms {001} and {102} present. The tenacity is brittle, the fracture conchoidal, and the streak is black. The Vickers hardness is 847 kg mm-2 (load 500g), which is equivalent to 6–6.5 on the Mohs scale. The calculated density is 4.315 g/cm3 (on the basis of the empirical formula). In plane-polarised incident light, paseroite is greyish in colour, weakly bireflectant and non-pleochroic. Internal reflections are absent. Between crossed polars, paseroite is anisotropic, withou...
American Mineralogist, 2014
ABSTRACT Steinhardtite is a new mineral from the Khatyrka meteorite; it is a new allotropic form ... more ABSTRACT Steinhardtite is a new mineral from the Khatyrka meteorite; it is a new allotropic form of aluminum. It occurs as rare crystals up to ~10 μm across in meteoritic fragments that contain evidence of a heterogeneous distribution of pressures and temperatures during impact shock, in which some portions of the meteorite reached at least 5 GPa and 1200 °C. The meteorite fragments contain the high-pressure phases ahrensite, coesite, stishovite, and an unnamed spinelloid with composition Fe3–xSixO4 (x ≈ 0.4). Other minerals include trevorite, Ni-Al-Mg-Fe spinels, magnetite, diopside, forsterite, clinoenstatite, nepheline, pentlandite, Cu-bearing troilite, icosahedrite, khatyrkite, cupalite, taenite, and Al-bearing taenite. Given the exceedingly small grain size of steinhardtite, it was not possible to determine most of the physical properties for the mineral. A mean of 9 electron microprobe analyses (obtained from two different fragments) gave the formula Al0.38Ni0.32Fe0.30, on the basis of 1 atom. A combined TEM and single-crystal X-ray diffraction study revealed steinhardtite to be cubic, space group Im3̄m, with a = 3.0214(8) Å, and V = 27.58(2) Å3, Z = 2. In the crystal structure [R1 = 0.0254], the three elements are disordered at the origin of the unit cell in a body-centered-cubic packing (α-Fe structure type). The five strongest powder-diffraction lines [d in Å (I/I0) (hkl)] are: 2.1355 (100) (110); 1.5100 (15) (200); 1.2329 (25) (211); 0.9550 (10) (310); 0.8071 (30) (321). The new mineral has been approved by the IMA-NMNC Commission (2014-036) and named in honor of Paul J. Steinhardt, Professor at the Department of Physics of Princeton University, for his extraordinary and enthusiastic dedication to the study of the mineralogy of the Khatyrka meteorite, a unique CV3 carbonaceous chondrite containing the first natural quasicrystalline phase icosahedrite. The recovery of the polymorph of Al described here that contains essential amounts of Ni and Fe suggests that Al could be a contributing candidate for the anomalously low density of the Earth’s presumed Fe-Ni core.
Scientific reports, 2014
The first natural-occurring quasicrystal, icosahedrite, was recently discovered in the Khatyrka m... more The first natural-occurring quasicrystal, icosahedrite, was recently discovered in the Khatyrka meteorite, a new CV3 carbonaceous chondrite. Its finding raised fundamental questions regarding the effects of pressure and temperature on the kinetic and thermodynamic stability of the quasicrystal structure relative to possible isochemical crystalline or amorphous phases. Although several studies showed the stability at ambient temperature of synthetic icosahedral AlCuFe up to ~35 GPa, the simultaneous effect of temperature and pressure relevant for the formation of icosahedrite has been never investigated so far. Here we present in situ synchrotron X-ray diffraction experiments on synthetic icosahedral AlCuFe using multianvil device to explore possible temperature-induced phase transformations at pressures of 5 GPa and temperature up to 1773 K. Results show the structural stability of i-AlCuFe phase with a negligible effect of pressure on the volumetric thermal expansion properties. In...
Scientific Reports, 2015
We report the first occurrence of a natural quasicrystal with decagonal symmetry. The quasicrysta... more We report the first occurrence of a natural quasicrystal with decagonal symmetry. The quasicrystal, with composition Al 71 Ni 24 Fe 5 , was discovered in the Khatyrka meteorite, a recently described CV3 carbonaceous chondrite. Icosahedrite, Al 63 Cu 24 Fe 13 , the first natural quasicrystal to be identified, was found in the same meteorite. The new quasicrystal was found associated with steinhardtite (Al 38 Ni 32 Fe 30 ), Fe-poor steinhardtite (Al 50 Ni 40 Fe 10 ), Al-bearing trevorite (NiFe 2 O 4 ) and Al-bearing taenite (FeNi). Laboratory studies of decagonal Al 71 Ni 24 Fe 5 have shown that it is stable over a narrow range of temperatures, 1120 K to 1200 K at standard pressure, providing support for our earlier conclusion that the Khatyrka meteorite reached heterogeneous high temperatures [1100 , T(K) # 1500] and then rapidly cooled after being heated during an impact-induced shock that occurred in outer space 4.5 Gya. The occurrences of metallic Al alloyed with Cu, Ni, and Fe raises new questions regarding conditions that can be achieved in the early solar nebula.
Nature communications, 2014
The discovery of a natural quasicrystal, icosahedrite (Al63Cu24Fe13), accompanied by khatyrkite (... more The discovery of a natural quasicrystal, icosahedrite (Al63Cu24Fe13), accompanied by khatyrkite (CuAl2) and cupalite (CuAl) in the CV3 carbonaceous chondrite Khatyrka has posed a mystery as to what extraterrestrial processes led to the formation and preservation of these metal alloys. Here we present a range of evidence, including the discovery of high-pressure phases never observed before in a CV3 chondrite, indicating that an impact shock generated a heterogeneous distribution of pressures and temperatures in which some portions reached at least 5 GPa and 1,200 °C. The conditions were sufficient to melt Al-Cu-bearing minerals, which then rapidly solidified into icosahedrite and other Al-Cu metal phases. The meteorite also contains heretofore unobserved phases of iron-nickel and iron sulphide with substantial amounts of Al and Cu. The presence of these phases in Khatyrka provides further proof that the Al-Cu alloys are natural products of unusual processes that occurred in the earl...
... di Mineralogia, Università degli Studi di Firenze, Via La Pira, 4-I-50121 Firenze, Italy. ...... more ... di Mineralogia, Università degli Studi di Firenze, Via La Pira, 4-I-50121 Firenze, Italy. ... We thank F. Olmi (CNRIstituto di Geoscienze e Georisorsesezione di Firenze) for his help during the electron ... Proceedings of Russian Mineralogical Society, 128, 6472 (in Russian). ...