摘要:

AbstractThis paper contains a detailed account of the finding, identification,etc., of the meteorite discovered by Mr. Jerry E. Best on his farm about a mile north of the town of Washougal, Clark County, Washington, on July 3, 1939, the day after the audible Portland, Oregon, meteor appeared. The meteorite, which is about as large as a tennis ball, is covered by a thin, black, glazed crust and is an aërolite of the comparatively rare Howardite variety. This is the first meteorite on record for the State of Washington

ISSN:0096-2813    

DOI:10.1111/j.1945-5100.1939.tb00237.x

出版商:Blackwell Publishing Ltd    

年代:1939

数据来源: WILEY

ISSN:0096-2813    

DOI:10.1111/j.1945-5100.1939.tb00238.x

出版商:Blackwell Publishing Ltd    

年代:1939

数据来源: WILEY

摘要:

AbstractThe method of detection, appearance, hardness,etc., of carbonadoes (so‐called “black diamonds”), in Canyon Diablo, Arizona, meteorites, are described. In the past nine years, carbonadoes have been encountered in about twenty specimens. These carbonadoes were usually imbedded in nodules or veins of dark sulfide and carbonaceous material, though in some instances they occurred in schreibersite inclusions; in one case, they were associated with a small cavity which occupied the central part of a schreibersite inclusion. The occurrence of diamonds near a cavity lends apparently no support to the common belief that their presence in meteorites constitutes conclusive evidence of cooling under high pre

ISSN:0096-2813    

DOI:10.1111/j.1945-5100.1939.tb00239.x

出版商:Blackwell Publishing Ltd    

年代:1939

数据来源: WILEY

ISSN:0096-2813    

DOI:10.1111/j.1945-5100.1939.tb00240.x

出版商:Blackwell Publishing Ltd    

年代:1939

数据来源: WILEY

ISSN:0096-2813    

DOI:10.1111/j.1945-5100.1939.tb00241.x

出版商:Blackwell Publishing Ltd    

年代:1939

数据来源: WILEY

摘要:

AbstractTwo crystallographic mechanisms have been established for the transformation from the high‐temperature, face‐centered cubic lattice of γ‐iron to the low‐temperature, body‐centered cubic lattice of α‐iron. Published researches on meteorites were not adequate to establish which of these two mechanisms operated in the formation of the coarse Widmanstätten patterns found in meteorites. It was felt that a study of these patterns in meteoritic irons would contribute to the understanding of these mechanisms.An investigation of the macro‐and micro‐crystalline perfection of an Amalia Farm [= Bethany, Great Namaqualand], South Africa, and a Canyon Diablo, Arizona, meteorite established that the latter was far better suited for an X‐ray study of the orientation relationships in the structure. In the course of the research it was established that one of the mechanisms operated at high transformation temperatures, while the other operated at much lower temperatures. The orientations in the Canyon Diablo sample corresponded to those predicted by the high‐temperature mechanism. This, and other metallurgical evidence, is in accord with the theory that the Widmanstätten patterns in meteorites are formed by extremely slow cooling from high temperatures.Recent advances in physical metallurgy have developed very useful correlations between rates of solid reactions and the resultant structures (coarseness of pattern) and between speed and temperature of plastic deformation and the type of deformation which occurs (slip, twinning, and cleavage). The application of this knowledge, in conjunction with adequate experiments on alloys of meteoritic composition, would undoubtedly lead to definite knowledge concerning the origin and th

ISSN:0096-2813    

DOI:10.1111/j.1945-5100.1939.tb00242.x

出版商:Blackwell Publishing Ltd    

年代:1939

数据来源: WILEY

ISSN:0096-2813    

DOI:10.1111/j.1945-5100.1939.tb00243.x

出版商:Blackwell Publishing Ltd    

年代:1939

数据来源: WILEY

ISSN:0096-2813    

DOI:10.1111/j.1945-5100.1939.tb00244.x

出版商:Blackwell Publishing Ltd    

年代:1939

数据来源: WILEY