Aspectos petrográficos, mineralógicos y geoquímicos del gossan del tajo Zulay (Turrubares, Costa Rica)

The Zulay quarry located by San Pedro de Turrubares (San José), represents an excellent example of gossan (supergene modification process), where the iron cap (leached cap) is represented by lavas and breccias pervasively silicified (micro-vuggy silica, alfa quartz and rare moganite) with secondary minerals as zeolites, goethite and hematite (iridescent and earthy) forming a type of iron rock that collectors called turgite or turite, and traces of microrutiles. Rarer is the presence of alum-K. The geological unit is part of Grifo Alto Formation, part of an area of intense past hydrothermal activity (high-sulfidation epithermal), perhaps in correspondence with the proximal facies of an ancient eruptive focus.