Objectives

The word "calamine", designating non-sulfides Zn-ores of supergene origin in carbonate rocks, originates from the Belgian locality "La Calamine" (Kelmis in German) where an ore deposit was continuously exploited from the 14th century up to 1884, with a production of more than 600,000 tons of Zn metal.

La Calamine is described in the scientific literature as a paleokarstic type of ore deposit, although its genesis as well as its age has never been fully understood. Likewise, the age of the deep supergene alteration of many Zn-Pb veins exploited in the Belgian and German neighbouring mining districts has never been clearly determined. This study aims at identifying the geological constraints responsible for the genesis of the La Calamine deposit, as well as of the deep-reaching gossans of the surrounding Zn-Pb vein-type deposits. The paleoweathering stages in Belgium and Western Germany and their metallogenetic implications are therefore being examined.

Realisation

Calamines from the collections of the RBINS and the SGB have been sampled to analyze their fluid inclusions and their isotopic composition.

Additional field work aims at selecting outcrops which are still weakly mineralized to constrain the genetical model.