CERUSSITE ON BARITE & GALENA

A particularly sharp growth of cerussite, with terminations on both ends and reticulated growth visible along the sides, is perched well atop a matrix of intergrown orange barite and galena. Unusually fine for the locale!

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The Les Dalles deposit displays characteristic Mississippi Valley-type mineralization within Lower Jurassic dolomitic sequences, where early-stage galena crystallization was followed by successive episodes of barite and cerussite formation through supergene alteration processes. Primary galena occurs as cubic crystals reaching 3 cm, while later-stage barite displays tabular habits in vugs and fractures, often associated with iron oxide phases suggesting oxidizing conditions during precipitation. Cerussite, forming through the weathering of primary galena, exhibits prismatic to acicular crystals and commonly preserves pseudomorphic textures after the parent sulfide. Fluid inclusion data from barite indicates formation temperatures between 60-80°C, while the presence of oxidation zones and carbonate-rich fluids controlled the subsequent development of cerussite through interaction with meteoric waters, representing a classic example of multi-stage Pb mineralization in carbonate-hosted deposits.