What is one major goegraphic feature of pacific south america

it is The Andes, The Andes are the main physical feature of Pacific South America.

Explanation:

The Andes Mountains run through all of the pacific south American country's, with some peaks above 20,000 ft. In the south, the mountains are rugged and covered by ice caps, In the North, they are rounded, and the range splits into two ranges . A high plateau called the altiplano, lies between the two ranges.