SEGH Articles

Global dispersion of trace metals in South America

04 November 2014
Pre-Hispanic metallurgical activities released enough metals to be transported throughout the entire South American continent.

Our recent study of a peat bog in remote Tierra del Fuego and published in PLOS ONE revealed that a part of trace metals – namely copper, lead, antimony and tin – originating from pre-Hispanic metallurgical activities can be recorded in Southern South America. It highlights for the first time that although of relatively small scale, pre-Hispanic metallurgical activities released enough metals to be transported throughout the entire South American continent through favourable wind trajectories. We also found that recent coal, gold and oil rushes released substantial amounts of local lead in the Southern American atmosphere. The uniqueness of these finding connects a number of different fields of research (geochemistry, archaeology, geology, atmospheric sciences) and has many important implications for our understanding of ancient metallurgy, and its legacy on trace metal emission, transport and deposition. First, it provides a scientific answer to a series of observations and questions that have puzzled the archaeological community for decades: (i) how large were the metal exploration and processing in pre-Hispanic times (as only point sources or artefacts have been found); (ii) was there a continuum between the metallurgical activities from different civilizations; and (iii) how far were metallurgical by-products transported via the atmosphere, and how they impacted the environment. Second, our finding will lead to a general agreement that past atmospheric circulation had a secondary North to South wind trajectory, which is opposed to the actual Westerly wind system dominating in South America. This mechanism evidenced by our HYSPLIT modelling and the fact that pre-Hispanic metals were transported to Tierra del Fuego, directly connects the geological cycles of trace elements with past atmospheric dust cycles, wind circulation and climate. 

Picture 1. A partial view of the Karukinka peat bog complexe. Photo Courtesy J-Y De Vleeschouwer

Picture 2. F. De Veeschouwer and colleagues open a peat core containing several thousands of years of information about past metal and dust deposition, climate and environment. Photo Courtesy G. Le Roux

Picture 3. Outcrop of the ancient coal mine “Mina Elena” in South Patagonia. Photo Courtesy G. Le Roux

You can download our article in open access in PLOS ONE.

For more information about trace metals in peat, read our review in PAGES.

To know more about our research in South America and in peatlands in general, connect to our project webpage and our facebook page.

 

F. De Vleeschouwer - SEGH Member and former SEGH 2013 Conference Chairman

Webpage: http://www.ecolab.omp.eu/profils/DE-VLEESCHOUWER_Francois

Reference:

De Vleeschouwer F, Vanneste H, Mauquoy D, Piotrowska N, Torrejon F, et al. (2014) Emissions from Pre-Hispanic Metallurgy in the South American Atmosphere. PLoS ONE 9(10): e111315. doi:10.1371/journal.pone.0111315