The Solutrean hypothesis
The Solutrean hypothesis contends that Europeans may have been in Americas before the arrival of a later wave of people from Asia. Stone tool technology of the Solutrean culture in prehistoric Europe may have later influenced the development of the Clovis tool-making culture in the Americas. Some of its key proponents include Dr. Dennis Stanford of the Smithsonian Institution and Dr. Bruce Bradley of the University of Exeter.
In this hypothesis, peoples associated with the Solutrean culture migrated from Ice Age Europe to North America, bringing their methods of making stone tools with them and providing the basis for later Clovis technology found throughout North America. The hypothesis rests upon particular similarities in Solutrean and Clovis technology that have no known counterparts in Eastern Asia, Siberia or Beringia, areas from which or through which early Americans are known to have migrated.
Solutrean culture was dominant in Europe and present-day France and Spain from roughly 21,000 to 17,000 years ago. It was known for its distinctive toolmaking characterized by bifacial, pressure-flaked points. Traces of the Solutrean tool-making industry disappear completely from Europe around 15,000 years ago, when it was replaced by the less complex stone tools of the Magdalenian culture.
Clovis tools are typified by a distinctive rock spear point, known as the Clovis point. Like Solutrean points, Clovis points are thin and bifacial; they share so-called “overshot” flaking characteristics that yield wide, flat blades. Clovis tool-making technology seems to appear in the archaeological record in North America roughly 13,500 years ago, and similar predecessors in Asia or Alaska have not yet been discovered.
The hypothesis proposes that Ice Age Europeans could have crossed the North Atlantic along the edge of the pack ice that extended from the Atlantic coast of France to North America during the last glacial maximum. The model envisions these people making the crossing in small watercraft, using skills similar to those of the modern Inuit people, hauling out on ice floes at night, getting fresh water by melting iceberg ice or the first-frozen parts of sea ice, getting food by catching seals and fish, and using seal blubber as heating fuel.
Supporters of the hypothesis suggest that stone tools found at Cactus Hill (an early American site in Virginia) indicate a transitional style between the Clovis and Solutrean cultures. Artifacts from this site are estimated to date from 17,000 to 15,000 years ago, although some researchers dispute their definitive age. Other sites that may indicate transitional, pre-Clovis occupation include the Page-Ladson site in Florida and the Meadowcroft rockshelter in Pennsylvania.
MtDNA Haplogroup X
The idea is also supported by mitochondrial DNA analysis insofar as the fact that some members of some native North American tribes share a common yet distant maternal ancestry with some present-day individuals in Europe identified by mtDNA Haplogroup X. Unlike other Native American mtDNA Haplogroups A, B, C and D, Haplogroup X is not common in Northeastern Asia or Siberia (although occurence of Haplogroup X2 of more recent origin has been identified in the Altai Republic). The New World haplogroup X DNA (now called subgroup X2a) is as different from any of the Old World X2 lineages as they are from each other, indicating a very ancient origin. Although haplogroup X occurs only at a frequency of about 3% for the total current indigenous population of the Americas, it is a major haplogroup in northeastern North America, where among the Algonquian peoples it comprises up to 25% of mtDNA types.