First row: [O i/ Fe i] vs. [Fe i/ H]. Second row: [Mg i/ Fe i] vs. [Fe i/ H]. Third row: [O i + Mg i/ 2Fe i] vs. [Fe i/ H]. Legend: black filled circles: LMC bar (this work); blue open pentagons: LMC inner disc (this work); green asterisk: Arcturus (this work, data for median S/Nratio); red downward triangle: LMC GC (Johnson et al. 2006; Mucciarelli et al. 2008, 2010); black tiny dots: MW thin and thick disc (Bensby et al. 2005; Reddy et al. 2003, 2006), halo (Fulbright 2000; Stephens & Boesgaard 2002; Reddy et al. 2006), and additional MW data for O from Carretta et al. (2000). Typical random (left) and systematic (right) error bars on both coordinates are provided for our LMC samples.