Is the boundary between Chile and Argentina an example of a frontier?

No. The boundary between Chile and Argentina is not an example of a frontier. A frontier is a region where two cultures meet and interact, often leading to conflict and assimilation. The boundary between Chile and Argentina, on the other hand, is a well-defined political border that has been established for over a century. While there have been some disputes over the boundary, these have been resolved peacefully through diplomacy.