1992 Fiscal Year Final Research Report Summary
Planetary and Earth Scientific Study of Shock Metamorphism
| Project/Area Number |
03452071
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
鉱物学(含岩石・鉱床学)
|
|---|
| Research Institution | Yamaguchi University |
|---|
Principal Investigator |
MIURA Yasunori Fac. Sci. Yamaguchi University Associate Professor, 理学部, 助教授 (10034729)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
KATO Toshio Fac. Liberal Arts, Yamaguchi University, Professor, 教養部, 教授 (40034714)
|
|---|
| Project Period (FY) |
1991 – 1992
|
| Keywords | Shock metamorphism / Shock metamorphosed mineral aggregates / Shocked high-density quartz / Shock metamorphosed graphites / Shocked metamorphosed plagioclases / Quenched materials from gas-melt states / Lunar impact aggregates / Impact layered structure |
|---|
| Research Abstract |
New results in this study from 1991(FY) to 1992 (FY) are summarized as follows:
1) New shocked high-density data of Earch and planetary materials are obtained from structural, compositional and textural changes of shock metamorphosed minerals.
2) Shock metamorphosed quartz (i.e. shocked quartz) materials are almost mixture of six silica phases as a whole. Among them characteristic high-density shocked quartz formed by impact shows maximum density of fine-grained ejecta of impact.
3) High-density shocked quartz can be obtained from maximum X-ray peak-intensity of weak X-ray peaks. Crystalline parts show remarkable shrinkage of mean atomic distances and clear stacking-fault at the lattice image micrographs, whereas silica glassy parts showing diffuse lattice images contain much more foreign elements.
4) Shock metamorphosed plagioclases shows shocked quartz by minerla change after evaporation process at fine-grained ejecta, or compositional change to non-stoichiometric composition and remarkable decreases of anorthite(An)-content.
5) Shock metamorphosed graphite aggregates with high-density can be formed by impact from limestone target-rock or by artificial impact with organic projectiles.
6) Metamorphic degree of shock metamorphism or metamorphic evolution can be discussed by the density-deviation of shocked quartz. Terrestrial continental and K/T boundary impact-samples show various maximum-density by sedimentary process where all shocked data of artificial impacts are used as standard values.
7) Two-layer structure with core-mantle can be formed by artificial impact process, and provides formation of planetesimal by large impact with iron-projectile.
8) Shock metamorphosed materials are various quenched mixtures which are formed instantly at dynamic and open system from gas - melt - high pressure solid.
9) Shocked material aggregates on the Moon and asteroids contain largely new cosmic shocked-materials and cosmic resource-elements of the solar-wind components.
|
