Recent spectroscopic observations of globular clusters ( GCs ) in the Large Magellanic Cloud ( LMC ) have discovered that one of the intermediate-age GC , NGC 1718 with [ Fe/H ] =-0.7 has an extremely low [ Mg/Fe ] ratio of \sim -0.9 .
We propose that NGC 1718 was formed from the ejecta of type Ia supernovae ( SNe Ia ) mixed with very metal-poor ( [ Fe/H ] < -1.3 ) gas about \sim 2 Gyr ago .
The proposed scenario is shown to be consistent with the observed abundances of Fe-group elements such as Cr , Mn , and Ni .
In addition , compelling evidence for asymptotic giant branch stars playing a role in chemical enrichment during this GC formation is found .
We suggest that the origin of the metal-poor gas is closely associated with the efficient gas-transfer from the outer gas disk of the Small Magellanic Cloud to the LMC disk .
We anticipate that the outer part of the LMC disk contains field stars exhibiting significantly low [ Mg/Fe ] ratios , formed through the same process as NGC 1718 .