Michail Petaev - Academia.edu (original) (raw)

Papers by Michail Petaev

Research paper thumbnail of Search for Extraterrestrial and Impact Materials in the PT Boundary Samples from Graphite Peak, Antarctica

Research paper thumbnail of The Oxygen Isotope Evolution of Our Galaxy: Implications for the Interpretation of Early Solar System Heterogeneities

Research paper thumbnail of I-Xe Ages and the Thermal History of the Toluca IAB Meteorite

Research paper thumbnail of Metasomatism and Metamorphism in the CV3 Asteroid: Formation of Pure Fayalite, Diopside-hedenbergite Pyroxenes, Andradite and Magnetite in Kaba and Mokoia

Research paper thumbnail of Magnetic Fe,Si,Al-rich Spherules From the PT Boundary Layer at Graphite Peak, Antarctica

Research paper thumbnail of Chondritic Meteoritic Fragments Associated With the Permian-Triassic (PT) Boundary in Antarctica: Evidence for an end-Permian Bolide Impact

We report the discovery of meteoritic fragments, as large as 400mu m in size, in an end-Permian s... more We report the discovery of meteoritic fragments, as large as 400mu m in size, in an end-Permian sedimentary bed in Graphite Peak, Central Transantarctic Mountains, Antarctica. Here, the P-T boundary is well constrained isotopically and paleontologically, and its lithology is well documented. The boundary at this site is also characterized by fullerenes containing extraterrestrial 3He and shocked quartz grains. We found meteoritic fragments in two samples of a claystone-breccia bed (separated stratigraphically by 23cm) that rests directly above the coal horizon with the last occurrence of Glossopteris. The meteoritic fragments display poikilitic or granular texture with euhedral-subhedral forsterite crystals enclosed in larger clinoenstatite grains showing polysynthetic twinning. Some silicate grains contain tiny inclusions of Fe, Ni-metal grains with chondritic Ni/Fe and Co/Ni ratios. Overall, Ni/Fe, Co/Ni and P/Fe ratios in the metal grains, Fe/Mg and Mn/Fe ratios in olivines and pyroxenes, and the chemistry of Fe, Ni, P, S-bearing oxides within the meteoritic fragments are typical of CM chondritic meteorites. The meteoritic grains found in magnetic separates of the sediments are accompanied by abundant metal nuggets, which are also found in an end-Permian bed from Meishan, south China. The common occurrence of these Fe-Ni-Si metal grains at Graphite Peak and at the Meishan P-T section provides further evidence that we sampled the P-T boundary at Graphite Peak. The association of metal grains with discrete meteoritic fragments at the Graphite Peak P-T boundary along with previous reports of such metal grains from other P-T localities leads us to support a catastrophic collision of a celestial body with the Earth at the end-Permian. We believe that this is what caused the global extinction event at the P-T boundary. Thus it appears that the two largest mass extinctions in Earth history at the K-T and P-T boundaries were both caused by catastrophic collisions with chondritic meteoroids.

Research paper thumbnail of Different Zoning Patterns in Metal Grains from the CH and CBb Chondrites: Evidence for a Complicated Cooling History of Their Nebular Source Regions

Research paper thumbnail of Experimental simulation of post giant impact processing of protoplanetary materials

Experimental simulation of post giant impact processing of protoplanetary materials. ... Journal ... more Experimental simulation of post giant impact processing of protoplanetary materials. ... Journal Name: Proposed for publication in Science.

Research paper thumbnail of Terrestrial and Extraterrestrial Mafic Silicates from the PT Boundary Claystone Breccia of Graphite Peak, Antarctica: Evidence from Oxygen Isotopes and Mineral Chemistry

Research paper thumbnail of Search for Microfossils in Carbonaceous Chondrites

We present the preliminary results of FESEM and NanoSIMS studies of extraterrestrial "fossil... more We present the preliminary results of FESEM and NanoSIMS studies of extraterrestrial "fossils" aimed at the development of a technique for distinguishing biotic from abiotic objects.

Research paper thumbnail of Formation of CAIs: Constraints from the Calcium Isotope Composition of CAI (SJ101) from the Allende CV3 Chondrite

Research paper thumbnail of Enstatite Chondrites and the Composition of the Earth

Mineralogical Magazine

High concentrations of atmospheric ClO 4 -, ClO 3 -, and NO 3 occur in the Atacama Desert where d... more High concentrations of atmospheric ClO 4 -, ClO 3 -, and NO 3 occur in the Atacama Desert where dry and oxic conditions allow oxyanions to accumulate near the surface over long periods. We collected sediment samples from vertical profiles (~1-3 m depth) over a 1000 km longitudinal transect along the central depression in the Atacama.

Research paper thumbnail of Pyrite in an EH3 Metal-Sulfide Nodule

We report the occurrence of pyrite and pyrrhotite interspersed among porous silica in the core of... more We report the occurrence of pyrite and pyrrhotite interspersed among porous silica in the core of a metal-sulfide nodule from the EH3 chondrite ALH 84170.

Research paper thumbnail of IMPACT PLUME ORIGIN OF FERROAN CHONDRULES IN CH CARBONACEOUS CHONDRITES

Meteoritics & planetary science

Research paper thumbnail of An Isotopically Homogeneous Region of the Inner Terrestrial Planet Region (Mercury to Earth): Evidence from E Chondrites and Implications for Giant Moon-Forming Impact Scenarios

Mineralogical Magazine

E chondrites and Earth suggests an isotopically homogeneous inner terrestrial planet region. This... more E chondrites and Earth suggests an isotopically homogeneous inner terrestrial planet region. This explains identical isotope compositions for the Moon and Earth.

Research paper thumbnail of Redox State of Partly Sulfidized EH3 Chondrule Constrained by Fe Exsolution from Olivine

Exsolution of chromite and Fe metal from partly sulfidized forsterite constrains chondrule condit... more Exsolution of chromite and Fe metal from partly sulfidized forsterite constrains chondrule conditions to above 1700 K with log fO2 changing from IW-2 to -7.

Research paper thumbnail of Origin of Fine-Grained Albite in an EH3 Sulfidized Chondrule

We report evidence that nanocrystalline albite in an Al-rich, Cl-bearing mesostasis from EH3 chon... more We report evidence that nanocrystalline albite in an Al-rich, Cl-bearing mesostasis from EH3 chondrite SAH 97072 formed as a byproduct of augite sulfidation.

Research paper thumbnail of Preliminary SEM Studies of Dust Particles from the L2021 and L2036 NASA Collectors: Are All TCNs Terrestrial Contaminants?

Among five particles from the L2021 (E8; E9; D1; D16) and L2036 (C7) collectors, three - L2021 E8... more Among five particles from the L2021 (E8; E9; D1; D16) and L2036 (C7) collectors, three - L2021 E8, L2021 D16, and L2036 C7 - are reclassified as C-type. It is possible that more particles labeled as TCNs may also be of extraterrestrial origin.

Research paper thumbnail of Oxygen isotopic compositions of the Allende FoBs CAI SJ101

O-isotopic data confirm that the origin of precursors of SJ101 and their melting occurred in a re... more O-isotopic data confirm that the origin of precursors of SJ101 and their melting occurred in a relatively closed system in an 16O-rich region of the solar nebula.

Research paper thumbnail of Laser Simulation of High PT Planetary Processes

We describe a new experimental technique involving high energy density lasers that allows measure... more We describe a new experimental technique involving high energy density lasers that allows measurements of equations of state and momentum coupling coefficients at very high T and P in recovered targets to be made.

Research paper thumbnail of Search for Extraterrestrial and Impact Materials in the PT Boundary Samples from Graphite Peak, Antarctica

Research paper thumbnail of The Oxygen Isotope Evolution of Our Galaxy: Implications for the Interpretation of Early Solar System Heterogeneities

Research paper thumbnail of I-Xe Ages and the Thermal History of the Toluca IAB Meteorite

Research paper thumbnail of Metasomatism and Metamorphism in the CV3 Asteroid: Formation of Pure Fayalite, Diopside-hedenbergite Pyroxenes, Andradite and Magnetite in Kaba and Mokoia

Research paper thumbnail of Magnetic Fe,Si,Al-rich Spherules From the PT Boundary Layer at Graphite Peak, Antarctica

Research paper thumbnail of Chondritic Meteoritic Fragments Associated With the Permian-Triassic (PT) Boundary in Antarctica: Evidence for an end-Permian Bolide Impact

We report the discovery of meteoritic fragments, as large as 400mu m in size, in an end-Permian s... more We report the discovery of meteoritic fragments, as large as 400mu m in size, in an end-Permian sedimentary bed in Graphite Peak, Central Transantarctic Mountains, Antarctica. Here, the P-T boundary is well constrained isotopically and paleontologically, and its lithology is well documented. The boundary at this site is also characterized by fullerenes containing extraterrestrial 3He and shocked quartz grains. We found meteoritic fragments in two samples of a claystone-breccia bed (separated stratigraphically by 23cm) that rests directly above the coal horizon with the last occurrence of Glossopteris. The meteoritic fragments display poikilitic or granular texture with euhedral-subhedral forsterite crystals enclosed in larger clinoenstatite grains showing polysynthetic twinning. Some silicate grains contain tiny inclusions of Fe, Ni-metal grains with chondritic Ni/Fe and Co/Ni ratios. Overall, Ni/Fe, Co/Ni and P/Fe ratios in the metal grains, Fe/Mg and Mn/Fe ratios in olivines and pyroxenes, and the chemistry of Fe, Ni, P, S-bearing oxides within the meteoritic fragments are typical of CM chondritic meteorites. The meteoritic grains found in magnetic separates of the sediments are accompanied by abundant metal nuggets, which are also found in an end-Permian bed from Meishan, south China. The common occurrence of these Fe-Ni-Si metal grains at Graphite Peak and at the Meishan P-T section provides further evidence that we sampled the P-T boundary at Graphite Peak. The association of metal grains with discrete meteoritic fragments at the Graphite Peak P-T boundary along with previous reports of such metal grains from other P-T localities leads us to support a catastrophic collision of a celestial body with the Earth at the end-Permian. We believe that this is what caused the global extinction event at the P-T boundary. Thus it appears that the two largest mass extinctions in Earth history at the K-T and P-T boundaries were both caused by catastrophic collisions with chondritic meteoroids.

Research paper thumbnail of Different Zoning Patterns in Metal Grains from the CH and CBb Chondrites: Evidence for a Complicated Cooling History of Their Nebular Source Regions

Research paper thumbnail of Experimental simulation of post giant impact processing of protoplanetary materials

Experimental simulation of post giant impact processing of protoplanetary materials. ... Journal ... more Experimental simulation of post giant impact processing of protoplanetary materials. ... Journal Name: Proposed for publication in Science.

Research paper thumbnail of Terrestrial and Extraterrestrial Mafic Silicates from the PT Boundary Claystone Breccia of Graphite Peak, Antarctica: Evidence from Oxygen Isotopes and Mineral Chemistry

Research paper thumbnail of Search for Microfossils in Carbonaceous Chondrites

We present the preliminary results of FESEM and NanoSIMS studies of extraterrestrial "fossil... more We present the preliminary results of FESEM and NanoSIMS studies of extraterrestrial "fossils" aimed at the development of a technique for distinguishing biotic from abiotic objects.

Research paper thumbnail of Formation of CAIs: Constraints from the Calcium Isotope Composition of CAI (SJ101) from the Allende CV3 Chondrite

Research paper thumbnail of Enstatite Chondrites and the Composition of the Earth

Mineralogical Magazine

High concentrations of atmospheric ClO 4 -, ClO 3 -, and NO 3 occur in the Atacama Desert where d... more High concentrations of atmospheric ClO 4 -, ClO 3 -, and NO 3 occur in the Atacama Desert where dry and oxic conditions allow oxyanions to accumulate near the surface over long periods. We collected sediment samples from vertical profiles (~1-3 m depth) over a 1000 km longitudinal transect along the central depression in the Atacama.

Research paper thumbnail of Pyrite in an EH3 Metal-Sulfide Nodule

We report the occurrence of pyrite and pyrrhotite interspersed among porous silica in the core of... more We report the occurrence of pyrite and pyrrhotite interspersed among porous silica in the core of a metal-sulfide nodule from the EH3 chondrite ALH 84170.

Research paper thumbnail of IMPACT PLUME ORIGIN OF FERROAN CHONDRULES IN CH CARBONACEOUS CHONDRITES

Meteoritics & planetary science

Research paper thumbnail of An Isotopically Homogeneous Region of the Inner Terrestrial Planet Region (Mercury to Earth): Evidence from E Chondrites and Implications for Giant Moon-Forming Impact Scenarios

Mineralogical Magazine

E chondrites and Earth suggests an isotopically homogeneous inner terrestrial planet region. This... more E chondrites and Earth suggests an isotopically homogeneous inner terrestrial planet region. This explains identical isotope compositions for the Moon and Earth.

Research paper thumbnail of Redox State of Partly Sulfidized EH3 Chondrule Constrained by Fe Exsolution from Olivine

Exsolution of chromite and Fe metal from partly sulfidized forsterite constrains chondrule condit... more Exsolution of chromite and Fe metal from partly sulfidized forsterite constrains chondrule conditions to above 1700 K with log fO2 changing from IW-2 to -7.

Research paper thumbnail of Origin of Fine-Grained Albite in an EH3 Sulfidized Chondrule

We report evidence that nanocrystalline albite in an Al-rich, Cl-bearing mesostasis from EH3 chon... more We report evidence that nanocrystalline albite in an Al-rich, Cl-bearing mesostasis from EH3 chondrite SAH 97072 formed as a byproduct of augite sulfidation.

Research paper thumbnail of Preliminary SEM Studies of Dust Particles from the L2021 and L2036 NASA Collectors: Are All TCNs Terrestrial Contaminants?

Among five particles from the L2021 (E8; E9; D1; D16) and L2036 (C7) collectors, three - L2021 E8... more Among five particles from the L2021 (E8; E9; D1; D16) and L2036 (C7) collectors, three - L2021 E8, L2021 D16, and L2036 C7 - are reclassified as C-type. It is possible that more particles labeled as TCNs may also be of extraterrestrial origin.

Research paper thumbnail of Oxygen isotopic compositions of the Allende FoBs CAI SJ101

O-isotopic data confirm that the origin of precursors of SJ101 and their melting occurred in a re... more O-isotopic data confirm that the origin of precursors of SJ101 and their melting occurred in a relatively closed system in an 16O-rich region of the solar nebula.

Research paper thumbnail of Laser Simulation of High PT Planetary Processes

We describe a new experimental technique involving high energy density lasers that allows measure... more We describe a new experimental technique involving high energy density lasers that allows measurements of equations of state and momentum coupling coefficients at very high T and P in recovered targets to be made.