HISTORY

We had been at sea for two months, taking ocean-bottom cores in the Pacific Ocean off South America to learn more about the geology of the Peru–Chile trench and subduction zone, the world's longest convergent plate boundary. Now we were headed for Callao, the main port of Lima, Peru. Most of our core samples had been collected from the Nazca plate, a little-known oceanic slab that is being tectonically driven eastward beneath the continent of South America. There is a small town in southern Peru named Nazca, or Nasca, but the name of the tectonic plate comes from a mysterious set of lines drawn as much as 2000 years ago in the soil of the world's driest desert. Some of the Nasca lines are arrow-straight; others depict hummingbirds, spiders, monkeys, sharks, llamas, and lizards. They were not recognized at all until people viewed them from the air in the 1920s, and because they were not accompanied by a written record, speculation arose about their origin. Because they can be viewed only from the air, one theory was advanced that they are extraterrestrial, marking the landing sites of space ships!

Peru is a country I had always wanted to visit. The Nasca lines were one of the attractions, but another was the fact that Peru was the center of the largest pre-Columbian empire in the Americas, founded in AD 1438. The Inca empire, the largest in the world in the fifteenth century, was centered on the Andes and the plateau called the Altiplano, and it extended nearly 2500 miles (4000 km) from central Chile and Argentina north to Ecuador and southern Colombia. The Incas called this empire Tawantin Suyu, Land of the Four Quarters, and its capital was Cusco, at an altitude higher than 10,000 feet (3400 m) above sea level in the Andes (Figure 21.1). Much of the empire was governed by local tribes that had pledged loyalty to the Inka, as the emperor was called. The empire was more like the British Commonwealth than the Japanese empire of World War II. If the Spanish had not intervened, Tawantin Suyu might have evolved into a multicultural nation like India is today.