Premium
Dislocation structures of olivine from Pallasite meteorites
Author(s) -
Matsui Takafumi,
Karato Shunichiro,
Yokokura Takanobu
Publication year - 1980
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl007i011p01007
Subject(s) - olivine , meteorite , dislocation , dislocation creep , geology , deformation (meteorology) , slip (aerodynamics) , annealing (glass) , condensed matter physics , materials science , mineralogy , composite material , physics , thermodynamics , astrobiology
Dislocation structures in olivines from three pallasite meteorites (Admire, Brenhan and Dora) were observed. Results are as follows: (1) Dislocation densities are very low (≤ 1 × 10 6 cm −2 ) compared to those of terrestrial olivine. (2) Dislocations are mostly curved. (3) Subboundaries are well developed. (4) The slip system determined from the dislocation dipole and sub‐boundaries is (010)[100]. (5) There are helical dislocations. (6) Dislocation densities and spacing of sub‐boundaries have either a power‐law relation or one characteristic of annealing. These observations all imply that the olivines from pallasites were annealed, that they have experienced high temperature deformation at low strain rate within parent bodies during the course of cooling, and that differential stresses which cause deformation can not have exceeded several times ten bars since then. Dislocations in olivine grains from pallasites are not of impact origin but are due to deformation within parent bodies.