We present isotopic and morphometric evidence suggesting the migration of farmers in the southern Andes in the period AD 1270–1420, leading up to the Inka conquest occurring ~ AD 1400. This is based on the interdisciplinary study of human remains from archaeological cemeteries in the Andean Uspallata Valley (Argentina), located in the southern frontier of the Inka Empire. The studied samples span AD 800–1500, encompassing the highly dynamic Late Intermediate Period and culminating with the imperial expansion. Our research combines a macro-regional study of human paleomobility and migration based on a new strontium isoscape across the Andes that allows identifying locals and migrants, a geometric morphometric analysis of cranio-facial morphology suggesting separate ancestral lineages, and a paleodietary reconstruction based on stable isotopes showing that the migrants had diets exceptionally high in C4 plants and largely based on maize agriculture. Significantly, this migration influx occurred during a period of regional demographic increase and would have been part of a widespread period of change in settlement patterns and population movements that preceded the Inka expansion. These processes increased local social diversity and may have been subsequently utilized by the Inka to channel interaction with the local societies.

The magmatic history and tectonic evolution of the Valle del Cura region has received the attention of several studies in recent years, particularly as part of a larger area of interest named the Indio Belt. These studies have suggested an Eocene volcanic sequence known as the Valle del Cura Formation. The present study, based on extensive field work, robust geochronological and geochemical datasets, shows an Oligocene to early Miocene age for this unit, similar to the Doña Ana Group. The tectonic setting that controlled the volcanism of the Valle del Cura Formation was extensional and corresponds to a retro-arc position of the main arc volcanism of the Doña Ana Group. The field evidence combined with radiometric and geochemical data demonstrate the synextensional characteristic of the volcanic sequence of the Valle del Cura Formation and the Doña Ana Group at these latitudes. This characteristic was dominant at the central part of the Pampean Flat Slab (29°–30°S).

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Se presentan resultados sobre técnicas constructivas y patrones de ocupación del espacio, cronología, tecnología lítica, tipología y tecnología cerámica, zooarqueología de camélidos, antracología y arte rupestre, correspondientes a un conjunto de sitios arqueológicos del Área Natural Protegida Laguna del Diamante (Mendoza, Argentina). Esta área se ubica en la cordillera Principal y vincula las cuencas altas de los ríos Diamante y Maipo. Los registros obtenidos corresponden al período de consolidación de la ocupación inca de la región y prueban que el Tawantinsuyu controló este sector de la cordillera para explotar una fuente de obsidiana y mantener en funcionamiento una red de tráfico especializado que vinculaba al valle central chileno con los valles orientales de Uco y Jaurúa. Por otra parte, las manifestaciones de arte rupestre halladas permiten inferir un proceso de sacralización y apropiación de este espacio dominado por el volcán Maipo y la laguna del Diamante.