This place is called Payunia or Payen, and it's located in MalargŁe, the southest county in the province of Mendoza. This area is a huge volcanic field, (I think the biggest in the world) with more than 1600 volcanoes (many of them still active). It is a National Park and it is believed to be the best place to study volcanoes, as it has 5 diferent types of them.
The landscape is unreal, the colors are unbelievable. Its the most amazing place I've ever been to.