From the uvby, H β photometry of intermediate population II F-stars in the catalogue of Olsen (1983), we derived age-metallicity relations for these stars, using Hejlesen's (1980) isochrone. The derived age-metallicity relations well coincide with the theoretical predictions by the unclosed two-zone model of Lee and Ann (1981). There are few extremely metal poor F-stars in the vicinity of the Sun, and it is very likely that the initial rapid metal enrichment in the galactic disk might have been processed through the fast collapse of the disk at the very early epoch.

ABSTRACT
Ⅰ. INTRODUCTION
Ⅱ. OBSERVATIONAL DATA
Ⅲ. PHYSICAL PARAMETERS
Ⅳ. AGE-METALLICITY RELATION
REFERENCES

• ANN HONG BAE(Department of Earth Science, Pusan National University)
• KANG YONG HEE(Department of Earth Science, Kyungpook National University)