Contribution to the chemical composition of minerals of the mimetite-pyromorphite series from the Guatomo mine near Tham Thalu, Bannang Sata District, Yala Province (Thailand)

The Guatomo mine is considered as one of the classic localities of mimetite worldwide. The chemical composition of six samples of minerals of mimetite-pyromorphite series from the Guatomo mine, representing different morphologies, colours as well as various geological environments/host rocks, was studied in detail by EMPA-WDS. This study revealed that both mimetite as well as pyromorphite are present at the Guatomo mine, representing rather variable compositional series ranging from the nearly end member mimetite (sample M1 - up to 0.03 apfu of P, sample M4 - up to 0.23 apfu of P and sample M5 with up to 0.18 apfu of P), through P-enriched mimetite (with 0.38 apfu of P) and As-rich pyromorphite (with 0.82 apfu of As, sample M2) up to As-enriched pyromorphite (sample M3 with As content reaching up to 1.03 apfu and sample M6 with up to 0.80 apfu of As). Besides of Pb, As, P and Cl only negligible amounts of Ca, V and S were detected in studied samples.