The story of the Mapuche, as I learnt in school, was that the Mapuche were (and are) a rather homogeneous group, settled in a given area, which was attacked first by the Incas, then by the Spanish conquistadors and then by the Chilean and Argentine Governments (as legal inheritors of the territory, following their independence from Spain). But the story in Wikipedia is not so clear. Some quotes:
Archaeological finds have shown the existence of a Mapuche culture in Chile as early as 600 to 500 BC.1 Genetically Mapuches differ from the adjacent indigenous peoples of Patagonia. This is interpreted as suggesting either a "different origin or long lasting separation of Mapuche and Patagonian populations".
Then, regarding potential movements across areas, the article says:
A hypothesis put forward by Ricardo E. Latcham, and later expanded by Francisco Antonio Encina, theorizes that the Mapuche migrated to present-day Chile from the Pampas east of the Andes.1 The hypothesis further claims that previous to the Mapuche, there was a "Chincha-Diaguita" culture, which was geographically cut in half by the Mapuche penetrating from mountain passes around the head of the Cautín River.1 Albeit the Latcham hypothesis is consistent with linguistic evidence it is rejected by modern scholars due to the lack of conclusive evidence, and the possibility of alternative hypotheses.1
Tomás Guevara has postulated another unproven hypothesis claiming that early Mapuches dwelled at the coast due to abundant marine resources and did only later moved inland following large rivers. Guevara adds that Mapuches would be descendants of northern Changos, a poorly known coastal people, who moved southwards. This hypothesis is supported by tenuous linguistic evidence linking a language of 19th century Changos (called Chilueno or Arauco) with Mapudungun.
Furthermore (and what started my interest on the issue), this entry regarding Patagonia says:
Towards the end of the 16th century, Mapuche-speaking agriculturalists penetrated the western Andes and from there across into the eastern plains and down to the far south. Through confrontation and technological ability, they came to dominate the other peoples of the region in a short period of time, and are the principal indigenous community today. The Mapuche model of domination through technological superiority and armed confrontation was later repeated as Europeans implemented a succeeding but conceptually identical cycle, essentially replacing the position of the former dominators with a new, albeit predominately European class.
This is a strange claim, specially given its date (late 16th century), a time in which the Mapuches were already fighting the Spaniards. There is no mention of this movement in the article about the history of the Mapuches (see first link), neither have I heard of it.
Is this story about Mapuches conquering other tribes true? Most of the quotes in the articles are rather old. Has anyone found texts with new evidence on these issues?