- © 2013 Mineralogical Society of America
Aqueous fluids are important and essential mass-transfer agents in the Earth’s crust and mantle. They are produced by sediment compaction, metamorphic devolatilization and magmatic activity in a variety of settings, including continental and accretionary orogens, subduction zones with magmatic arcs as well as by hydrothermal systems at mid-oceanic ridges and sea floor (Wilson et al. 2000; Kerrick and Connolly 2001; Manning 2004; Breeding et al. 2004; Palandri and Reed 2004; Bucher and Stober 2010). The fluid-mediated mass transfer produces specific major- and trace-element and isotopic patterns in source regions of mantle melting and it imparts characteristic geochemical signatures to magmas in various geodynamic settings, which are used to interpret geodynamic processes (Baier et al. 2008; Beinlich et al. 2010; Mysen 2010). At the final stages of magmatic activity, aqueous fluids are released as a single supercritical phase, a high-density saline brine, or a low-density vapor, each of which can play different roles in hydrothermal and geothermal processes, ore formation or by providing local input to the atmosphere (Yardley 2005; Audétat et al. 2008). Similarly, mass transport by aqueous fluids has now been detected in a number of high-grade metamorphic rocks, providing evidence for flow patterns and chemical changes during devolatilization reactions that accompany metamorphism during plate convergence (Gorman et al. 2006; Zack and John 2007; John et al. 2008). The efficiency of these fluid-mediated interactions, their time scales and implications for fluid flow patterns, have only started to be explored by applications of transport theories (e.g., Konrad-Schmolke et al. 2011).
The mobility and transport of inorganic and organic solutes in aqueous fluids is manifested by alteration or veining, distinct element depletion-enrichment patterns or isotopic disturbances (e.g., Coltorti and Grégoire 2009; Yardley 2013). In addition, high buoyancy and low …