Interface-coupled dissolution-precipitation is an important pseudomorphic replacement process in the shallow crust that involves the simultaneous dissolution of an original mineral in the presence of a fluid and the precipitation of a new mineral retaining the original crystal shape and structure. Previous studies have experimentally observed characteristic criteria of these replacements such as the generation of porosity in the replacement minerals and retention of original mineral shape and structure (crystallographic controls) among others.

The secondary alteration process of low temperature K-metasomatism is common in a variety of diverse geologic settings such as Creede, CO, Socorro, NM, and the Harcuvar Mountains, AZ, and results in the replacement of igneous feldspars in existing rocks by low temperature potassium feldspars. Low temperature K-metasomatism provides a good model mineral system in which to study the mechanisms of interface-coupled dissolution-precipitation involving K feld-spars. Because K feldspars are a major constituent of the crust, understanding the mechanisms of interface-coupled dissolution-precip- itation processes produced by low temperature K-metasomatism has important implications in our understanding of a wide variety of processes such as crustal deformation, element transport and redistribution during fluid rock interaction, environmental remediation, weathering processes, and the formation of building materials.

My project utilizes mineralogical and geochemical data from the investigation of naturally-occurring K feldspar replacements in the above three localities and the predetermined set of criteria to identify interface-coupled dissolution-precipitation as the replacement process and further understand its mechanisms. A variety microscopy techniques were applied with a focus on scanning electron microscopy (SEM) techniques such as energy dispersive x-ray spectroscopy (EDS) for major, minor, and trace element distributions and electron backscatter diffraction (EBSD) for comparisons of crystallographic orientation.