Analysis of pre-, syn-, and post-mineralization porphyry to pegmatitic dykes associated with various types of mineralization: dissecting source, fractionation, emplacement, and timing of complex magmatic hydrothermal systems.

Dyke systems in a wide range of settings have long been examined to help understand many aspects of complex magmatic hydrothermal systems from various porphyry to pegmatitic settings. Regional to detailed mapping of these superimposed magmatic systems in any specific region unravels that relative history, and with their geometry enhance our understanding of the controls on emplacement (far-field stresses to caldera collapse), and their relation to mineralization; that relative chronology is then tested with geochronology (dating), which now is often detailed petrochronology. Robust lithogeochemistry is used extensively with petrology to characterize each set of dyke systems against other intrusive and even extrusive magmatic systems within any particular region, i.e., analogous to chemostratigraphy. Petrology (groundmass, phenocrysts, phenoclasts, lithics) with mineral chemical analysis to determine physiochemical parameters have also been used increasingly; the lithogeochemistry and petrology helps place Temperature (Tzr, Tap, Tmz) and Pressure (Pqz, Phb, Pbt) constraints to help our understanding of the overall plumbing system, especially the hypabyssal environment of emplacement, but also the associations and evolution of the causative magmatic system. From the deeper level to subvolcanic realm is where volatile exsolution, then hypersolidus to subsolidus, endo-granitic to exogranitic alteration takes place as well as hydrothermal mineralization processes. The challenges of discerning magmatic fertility, and even magmatic enrichment versus hydrothermal enrichment processes in forming mineralization from lithogeochemistry and mineral chemical systematics has evolved considerably; however, the nature or character of dykes (pheno-crysts and groundmass), emplacement, and quenching allows further interpretation of these two fundamental processes. Pressure versus thermal quenching and undercooling related textures, in injecting melts to pyroclastic tuffisitic systems helps preserve features of interest in many dykes and dyke swarms, even zoning within dykes, that are often overlooked. Constraints from HEAT3D analysis of cooling rate of dykes and even their associated overall magmatic systems relative to known liquidi-solidi are under-utilized. [ABSTRACT FROM AUTHOR]