Isotopic anomalies of molybdenum in iron meteorites

2006 ◽  
Vol 70 (18) ◽  
pp. A668
Author(s):  
M.D. Varner ◽  
M.E. Wieser ◽  
J.R. De Laeter
Keyword(s):  
Iron Meteorites ◽  
Isotopic Anomalies

The partitioning of the inner and outer solar system by a structured protoplanetary disk

2020 ◽  
Author(s):  
Ramon Brasser ◽  
Stephen Mojzsis
Keyword(s):  
Solar System ◽  
Protoplanetary Disk ◽  
Giant Planets ◽  
Iron Meteorites ◽  
Effective Barrier ◽  
Dynamical Simulations ◽  
Pressure Maximum ◽  
Ringed Structure ◽  
Isotopic Anomalies ◽  
Multiple Rings

<p>Mass-independent isotopic anomalies in planets and meteorites define two cosmochemically distinct regions: the carbonaceous and non-carbonaceous meteorites, implying that the non-carbonaceous (terrestrial) and carbonaceous (jovian) reservoirs were kept separate during and after planet formation. The iron meteorites show a similar dichotomy.</p><p>The formation of Jupiter is widely invoked to explain this compositional dichotomy by acting as an effective barrier between the two reservoirs. Jupiter’s solid kernel possibly grew to ~20 Mearth in ~1 Myr from the accretion of sub meter-sized objects (termed “pebbles”), followed by slower accretion via planetesimals. Subsequent gas envelope contraction is thought to have led to Jupiter’s formation as a gas giant.</p><p>We show using dynamical simulations that the growth of Jupiter from pebble accretion is not fast enough to be responsible for the inferred separation of the terrestrial and jovian reservoirs. We propose instead that the dichotomy was caused by a pressure maximum in the disk near Jupiter’s location, which created a ringed structure such as those detected by the Atacama Large Millimeter/submillimeter Array(ALMA). One or multiple such long-lived pressure maxima almost completely prevented pebbles from the jovian region reaching the terrestrial zone, maintaining a compositional partition between the two regions. We thus suggest that our young solar system’s protoplanetary disk developed at least one and likely multiple rings, which potentially triggered the formation of the giant planets [1].</p><p><br>[1] Brasser, R. and Mojzsis, S.J. (2020) Nature Astronomy doi: 10.1038/s41550-019-0978-6</p>

A search for nickel isotopic anomalies in iron meteorites and chondrites

2009 ◽  
Vol 73 (5) ◽  
pp. 1461-1471 ◽  
Author(s):  
J.H. Chen ◽  
D.A. Papanastassiou ◽  
G.J. Wasserburg
Keyword(s):  
Iron Meteorites ◽  
Isotopic Anomalies

Endemic silver isotopic anomalies in iron meteorites

1988 ◽  
Vol 70 (1-2) ◽  
pp. 24
Author(s):  
J.H. Chen ◽  
G.J. Wasserburg
Keyword(s):  
Iron Meteorites ◽  
Isotopic Anomalies

Nickel isotopic anomalies in troilite from iron meteorites

2008 ◽  
Vol 35 (1) ◽  
Author(s):  
David L. Cook ◽  
Robert N. Clayton ◽  
Meenakshi Wadhwa ◽  
Philip E. Janney ◽  
Andrew M. Davis
Keyword(s):  
Iron Meteorites ◽  
Isotopic Anomalies

Electron Microscope Observations of Mechanical Metamorphism in Iron Meteorites

1970 ◽  
Vol 28 ◽  
pp. 488-489
Author(s):  
D. Faulkner ◽  
G.W. Lorimer ◽  
H.J. Axon
Keyword(s):  
Electron Microscope ◽  
Defect Structure ◽  
Shock Loading ◽  
List Type ◽  
Iron Meteorites

It is now generally accepted that meteorites are fragments produced by the collision of parent bodies of asteroidal dimensions. Optical metallographic evidence suggests that there exists a group of iron meteorites which exhibit structures similar to those observed in explosively shock loaded iron. It seems likely that shock loading of meteorites could be produced by preterrestrial impact of their parent bodies as mentioned above.We have therefore looked at the defect structure of one of these meteorites (Trenton) and compared the results with those made on a) an unshocked ‘standard’ meteorite (Canyon Diablo)b) an artificially shocked ‘standard’ meteorite (Canyon Diablo) andc) an artificially shocked specimen of pure α-iron.

Evidence for ordered Fe3Ni

1987 ◽  
Vol 45 ◽  
pp. 216-217
Author(s):  
K.B. Reuter ◽  
D.B. Williams ◽  
J.I. Goldstein
Keyword(s):  
Experimental Data ◽  
Martensitic Transformation ◽  
Electron Diffraction ◽  
Room Temperature ◽  
Direct Evidence ◽  
Transformation Product ◽  
Iron Meteorites ◽  
X Ray ◽  
Ni Content ◽  
Temperature Transformation

In the Fe-Ni system, although ordered FeNi and ordered Ni3Fe are experimentally well established, direct evidence for ordered Fe3Ni is unconvincing. Little experimental data for Fe3Ni exists because diffusion is sluggish at temperatures below 400°C and because alloys containing less than 29 wt% Ni undergo a martensitic transformation at room temperature. Fe-Ni phases in iron meteorites were examined in this study because iron meteorites have cooled at slow rates of about 10°C/106 years, allowing phase transformations below 400°C to occur. One low temperature transformation product, called clear taenite 2 (CT2), was of particular interest because it contains less than 30 wtZ Ni and is not martensitic. Because CT2 is only a few microns in size, the structure and Ni content were determined through electron diffraction and x-ray microanalysis. A Philips EM400T operated at 120 kV, equipped with a Tracor Northern 2000 multichannel analyzer, was used.

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