The age-metallicity relationship of the Large Magellanic Cloud field
  star population from wide-field Washington photometry
  We analyze ages and metallicities for some 5.5 million stars distributed
throughout the Large Magellanic Cloud (LMC) main body, obtained from CCD
Washington CT1 photometry. We produce a comprehensive field star
Age-Metallicity Relationship (AMR) from the earliest epoch until ~1 Gyr ago.
This AMR reveals that the LMC has not evolved chemically as either a closed-box
or bursting system, exclusively, but as a combination of both scenarios that
have varied in relative strength over the lifetime of the galaxy, although the
bursting model falls closer to the data in general. Furthermore, while old and
metal-poor field stars have been preferentially formed in the outer disk,
younger and more metal-rich stars have mostly been formed in the inner disk,
confirming an outside-in formation. We provide evidence for the formation of
stars between 5 and 12 Gyr, during the cluster age gap, although chemical
enrichment during this period was minimal. We find no significant metallicity
gradient in the LMC. We also find that the range in the metallicity of an LMC
field has varied during the lifetime of the LMC. In particular, we find only a
small range of the metal abundance in the outer disk fields, whereas an average
range of Delta([Fe/H]) = +0.3\pm0.1 dex appears in the inner disk fields.
