The Central Andes is a geographical barrier that exceeds the elevation of 5000 m a.s.l. The Central Andes is constituted by two mountain ranges: the Eastern Cordillera and the Western Cordillera. Between them, the Central Andres plateau is well known for its fresh and salty lakes and its salt flats. During the austral summer, the strong easterly winds bring moisture from the Atlantic Ocean to the Central Andes. In the Eastern Cordillera (i.e. Bolivia) the strong continental and altitude effect component on the rainfall isotopic composition suggests the high influence of moisture sources from the Atlantic Ocean in the Eastern Cordillera during the austral summer.
The Pacific Ocean is considered a secondary and limited source of moisture to the Western Cordillera. During the austral winter, the Western Cordillera and the high plateau receives from the Pacific Ocean a precipitation less than 20% of annual precipitation. The limited rainfall isotope data and isotope mapping studies from northern Chilean translates into difficulties in the interpretation of changes in moisture sources. Despite this, we hypothesise that the northern Chilean Central Andes (latitudes 18° S to 24,6° S; elevation >3000 m a.s.l.) rainfall is enriched in heavy isotopes towards higher latitudes.