Geochemical characterization of thermal springs in the Tete Province, Northern Mozambique.

Abstract

A first geochemical survey was carried out in the Northern Mozambique in March-April 2013, with the aim to investigate chemistry and origin of some thermal springs in the Tete Province. The investigated area is located in the East African Rift, adjacent to the marginal sedimentary Mozambique Basin. This area is crossed by the Rio Zambezi, one of the main river in Africa and explored during the 19th century by Davi Livingstone. Figure 1: Location of the study area. Many thermal springs are present in this province due to the proximity with the rift, but considerably little geochemical and geothermal studies have been done, due to the difficulties related both to the site accessibility and social interaction with local tribes. Three thermal springs were sampled close to the Missao de Boroma, Tete, crossing the Rio Zambezi by a traditional pirogue. Collected samples are being analysed to determinate major, minor and trace elements, d18O and dD, dissolved gas, carbon isotopic ratios of TDIC (Total Dissolved Inorganic Carbon) (expressed as d13C‰vs. VPDB), the 3He/4He and the dissolved Radon. The measured temperature ranges between 66°C to 42°C and the pH from 7.9 to 8. The conductivity is around 2400 1S/cm and the Eh is between -208 to -404 mV. The chemical and isotopical analysis are in progress, anyway this first sampling suggests the need to plan and perform a national geochemical survey of the thermal springs in Mozambique. Data should be organized in organic geodatabase and geographic information systems. This information could have a big relevance not only for the geochemical, hydrogeological and geological knowledge of the Country but also for a potential geothermal exploration and exploitation.