Alteration of high alkaline and alkaline basaltic rocks: parent rocks in the Lava Durian orchard, Sisaket Province, NE Thailand

The metasedimentary-hosted Nyangoubé gold prospect, northwest Côte d'Ivoire: Geochemical and mineralogical characterization of associated hydrothermal alteration

The Nyangoubé gold prospect, located in northwestern northwest of Côte d'Ivoire in Africa, is a feature of the Bagoé furrow of the Birimian of the West African Craton. This study is aimed at characterizing the geochemical and mineralogical signatures of hydrothermal alterations associated with the gold mineralization of Nyangoubé gold prospect to provide guidelines for mining exploration. Microscopic petrographic analysis and geochemical characteristics from elemental contents analyzed by X-ray fluorescence (XRF) and inductive coupled-plasma mass spectrometer (ICP-MS) were studied using alteration diagrams and by calculating mass balances and describing thin sections. The results indicate that the host rocks have been affected by silicification, carbonation, sericitization, chloritization, sulphidation and albitization. Hydrothermal alterations associated with the mineralization systems resulted in the destruction of plagioclase in the metasediments studied. The latter was replaced by sericite, chlorite, carbonates, quartz, and sulphides in varying proportions, depending on the intensity of each type of alteration linked to the formation of each mineral. The mass balance calculations show a gradual increase in the concentrations of Au, W, V, As and Pb as well as K2O, CaO, Na2O and Fe2O3 which could be vectoring parameters towards gold mineralization. The mineralogical assemblage as sericite-chlorite-pyrite, chlorite-pyrite±sericite, carbonate-sericite and chlorite-carbonate revealed by hydrothermal alteration trends in the host rocks could also help identify potential gold corridors in the area of study and its peripheries.