Alexandria, Va. — When Francisco Pizarro landed in Peru in 1532, his band of Spanish conquistadors set off a chain of far-reaching consequences for the people and economics of western South America. The Chira Beach-Ridge Plain in northwestern Peru is rippled by a set of nine ridges — several meters tall by up to 300 meters wide and 40 kilometers long, and large enough to be visible from space — running parallel to the shoreline. The pattern, observed along at least five other Peruvian beaches, was thought to have formed naturally over the past 5,000 years. New research shows, however, that left on its own, Chira Beach does not form ridges. Instead, these ridges are formed by the huge quantities of mollusk shells left by pre-colonial coastal communities.
Read more about how the Spanish conquistadors actually changed the shoreline of northern Peru by ending a several-thousand-year cycle of anthropogenic alteration in the October issue of EARTH magazine: http://bit.ly/XNt7cm.
For more stories about the science of our planet, check out EARTH magazine online or subscribe at http://www.earthmagazine.org. The October issue, now available on the digital newsstand, features stories on acid rain recovery in Northeastern waterways, how clouds have changed since the industrial revolution, and a commentary on how humanity should consider building sanctuaries to increase our resilience to catastrophes, plus much, much more.
Source: American Geosciences Institute