As testimonies of pre-Columbian Cultures, Archaeological sites of the province of Tucumán conserve emblematic fragments of the history of South America. There are Inca settlements and vestiges of previous aboriginal cultures where their practices before the Spanish conquest remain explicit.
María Marta Sampietro Vattuone, CONICET independent researcher at the Geoarcheology Laboratory of the National University of Tucumán, has done intensive research into the ways of practising agriculture before the hispanic colonization and the particular uses of space.
The study published in the specific magazine Quaternary Research shows that phosphorus concentrations in pre-hispanic agricultural soils of Tafí Valley reflect the use of fertilizers. Besides, the remains of eroded ceramic reveal the process of the formation of sites. The characteristics of the soils allow reconstructing the climate of the time, more favourable for agriculture than the current. All this reflects the behaviour of the populations that inhabited the valley and provides clues about their socio-economic development.
In the last decade of geoarchaeology investigations in Tucumán, several studies over the paleoenvironmental conditions that prevailed during the last 3 thousand years have been conducted. The focus was placed on the Tafí Valley, the area of one of the first socio-cultural agricultural developments of the Argentine Northwest (NOA).
“Essentially, we work with geoarchaeology, using the methods and techniques of geosciences to solve archaeological problems. Our investigation is based on the finding and analysis of new sites in diverse places of the Calchaquí valleys”, Sampietro explains.
The team used a series of physicochemical indicators of soils – either current or old ones – to try understand agricultural practices implemented from the beginning of agriculture in the Calchaquí Valleys to the first hispanic-indigenous contact. Sampietro states “this time margin ranges from the year 1.000 BC to 1.500 AD, when the Spanish approximately arrived”.
Apart from trying to describe how the soils were, the team seeks to know about the preferences for settlement in the available areas, taking into consideration the existing resources. For the researcher, the cultures changed according to the variation of the technological capabilities and the climate.
“During the first sedentary settlements, the climate was more humid, but towards the year 1.000 BC it turned drier and it went on like that for the following 500 years, with a tendency to become arid”, Sampietro says.
According to the study, the lack of water made populations adapt and come up with new ways of inhabiting the territory: marginal areas and towns that had disperse settlements became more united and concentrated in the proximity of water courses.
When science provides a glimpse into history
The investigation promoted the paleoenvironmental reconstruction of the last three thousand years in relation to the cultural evolution of the archaeological sites of the Calchaquí valleys.
These terrains have vast history that narrates the life of the prehispanic populations that learnt to work the land, administer water resources and the development of livestock as source of livelihood.
“This reconstruction provided ideas and elements to explain what happened throughout the last 3.000 years regarding the occupation of the soils and the organization of the populations”, Sampietro affirms.
The research began with the analysis of the formative period – which covers 500 BC to 1.000 AD. – characterized as the earliest sedentary period in the Argentine northwest. It is during this stage that the ceramic was used as an ubiquitous material, and agricultural and farming practices strengthened.
“It is not that the agriculture was invented in that period because the work with the land comes from previous stages; nevertheless, it reaches a more sophisticaded dimension. Besides, a great dispersion of the breeding of camelids such as the llama and the alpaca was produced”, she adds.
The research shows that the following period is the one of Regional Developments (1000 BC to 1400 AD). At that moment, agglomerated villages were formed together with chiefdoms as a way of organization and the fights for the territory in the village centres appeared. Furthermore, the use of the agro-pastoral resource was stressed.
In 1.400 BC the Inca Empire, which exercised a strong domination over the existing cultures of the region, reached this territory. “There were populations that were moved to have better control over them”, the researcher analysed.
The Incas modified the existing forms of domination and spatial management. They built the ‘Inca road system’, a complex transportation system that comprised a series of religious and control administration centres for important spaces among the Inca reign, the Argentine northwest till Mendoza.
“Our research work seeks to find the vestiges of the prehispanic habitat to address them from several disciplines and reach a greater understanding of how those cultures lived and developed”, Sampietro affirms.
Geoarchaeology as pathway to knowledge
In the researchers’ words, archaeology is the study of past societies and it analyses evidences of different nature. That is why her study requires the use of methods and techniques of different scientific disciplines. Considering this need, geoarhaeology appeared as an instrument that provides answers posed by archaeological analysis through the earth sciences.
“We carry out a reconnaissance of the areas of interest which is called prospection; then we determine the excavation sites and finally we process the data and materials obtained with in-depth knowledge of the medium by which the findings at various scales are conducted”, Sampietro explains.
The investigation also uses geographic information Systems that involve the application of software developed to generate cartographies with aerial photographs and satellite images, Geomorphology, Pedology, Sedimentology, Paleoclimatology, and Palynology, among others, all applied to the reconstruction of past societies.