Cathodoluminescence of quarz and its application to sandstone petrology

Cathodoluminescence investigations of quartz-bearing rocks lead to the definition of three luminescence types of quartz: „violet“, brown, and non-luminescing quartz, whose occurrence is characteristic for rocks of distinct temperature history: „violet“ luminescing quartz in igneous rocks, brown luminescing quartz in regional metamorphic rocks, non-luminescing quartz formed diagentically in sediments. This is demonstrated by several geological case histories, e. g. contact metamorphic rocks of the Wiborg-Rapakivi-Massif, Finland, weakly metamorphized or tempered sandstones with diagenetic quartz. Differences in the luminescence of diagenetic and detritial quartz make possible to count them separately. Apparantly, quartz cementation is the most important diagenetic fabric in sandstones, while the influence of pressure solution at quartz-quartz contacts is less determinant. Chemical dissolution processes of quartz are mostly younger than quartz cementation.