GRE阅读高频机经原文：美洲人起源

　　5. 美洲人起源 新题

　　Recent discoveries in New World archaeology along with new scientific methods for analyzing data have led to new ideas regarding the origin of the first peoples of the Americas and their time of arrival.

　　The traditional theory held that the first Americans crossed the land bridge from Siberia to Alaska around 11,500 years ago and followed an ice-free corridor between two large Canadian ice sheets to reach unglaciated lands to the south. These first inhabitants, whose archaeological sites are scattered across North and South America, were called the Clovis people, named after the town in New Mexico where their fluted spear points used for hunting mammoth were first found in 1932.

　　There is now convincing evidence of human habitation sites that date earlier than the Clovis culture including sites located in South America. Monte Verde, a well-studied site located along a river near southern central Chile, dates 12,500 years ago. This site contains the buried remnants of dwellings, stone tools including large bifacial projectile points, and preserved medicinal and edible plants. How did people manage to settle this far south at such an early date? A coastal migration route is now gaining more acceptance, rather than the older view of small bands moving on foot across the middle of the land bridge between Siberia and Alaska and into the continents. Emerging evidence suggests that people with boats moved along the Pacific coast into Alaska and northwestern Canada and eventually south to Peru and Chile by 12,500 years agoand perhaps much earlier. Archaeological evidence in Australia, Melanesia, and Japan indicate boats were in use as far back as 25,000 to 40,000 years ago. Sea routes would have provided abundant food resources and easier and faster movement than land routes. Many coastal areas were unglaciated at this time, providing opportunities for landfall along the way. Several early sites along the coast of Canada, California, Peru, Ecuador, and Chile date between 10,000 and 12,000 years ago. Many potential coastal sites are now submerged, making investigation difficult.