Overprinting Textures

Abstract

Many of our concepts concerning the nature of hydrothermaal systems and their relationship with rock fracturing arise from the common observation that hydrothermal fluids seem to precipitate different mineral assemblages at different times. Practically every mineral deposit will provide an example of crosscutting vein, which are conventionally interpreted as two (or a single) generations of hydrothermal fluids with an intervening period of rock fracturing. The crosscutting relationship is an example of an overprinting texture and the implied timing relationship allows the two veins to be catalogued as a temporal sequence, such as Stage 1 and Stage 2. The process of constructing a time sequence is referred to as establishing the paragenetic sequence.