A preliminary geochemical study of the archaeological site of the Battle of Jenipapo (Piauí state, Brazil)

This paper presents, for the first time, geochemical data related to the Battle of Jenipapo, a significant event that occurred on March 13, 1823, marking a political activity favorable to Brazil's independence. The present work aimed to analyze the contents of lead and copper as markers of historical armaments in sediments for geochemical prospecting of the archaeological area in which the Battle of Jenipapo probably occurred. Nine sediment samples were collected: seven from the prospect area and two control samples. Sedimentological characteristics were evaluated, such as pH (6.1–6.9), acidity (0.19–3.00 mmol L⁻¹), organic matter (0.86–3.37% w/w), and granulometric classification (sandy predominance). The metals (lead and copper) were determined by inductively coupled plasma mass spectrometry (ICP-MS) after acid digestion of the sediments. Lead content ranged from 7.9 to 14.9 mg kg⁻¹ for samples and 5.4 mg kg⁻¹ for control samples. Copper content ranged from 14.2 to 29.3 mg kg⁻¹. The results showed that only lead could be used for the geochemical prospecting of the area that presented strong evidence of anthropic intervention allowing the carrying out of excavation steps.