We are pleased to announce a Petrology Lunch with John Thompson on the topic of: Magmatic-hydrothermal systems - the rock record.
Abstract:
Magmas related to subduction and post-subduction collisional settings release large volumes of fluids during emplacement and crystallization in the upper crust, typically at depths of <10 km. The fluids undergo phase separation, cooling, extensive reactions with wallrocks, and potential mixing with other fluids, resulting in many km³ of altered rocks with distinct horizontal and vertical zoning patterns. Veining, breccias, and mineralogical assemblages and textures document complex processes and can be used to identify the general paleodepths, temperatures, pH, and the potential for base and precious metal mineralization. As will be illustrated, rock and field relationships, supported by geochemical and mineralogical data, provide the framework for understanding systems.