Prof. BjornMysen [ Carnengie Instn.Washington ]

 [Colloquium]    

Prof. BjornMysen [ Carnengie Instn.Washington ]

Title: Geochemical and Geophysical Properties of the Earth's Interior Resulting from Materials Transport via Aqueous Fluids

Language: English presentation with English slides

Time: 10:00~11:30, Aug. 28, 2026 

Place:  Offline: Conference room 410, HPSTAR (Shanghai)

        Online: Tencent Meeting: https://meeting.tencent.com/dm/wafOdJraRizm Meeting ID: 581-949-968

Host:  Dr. Dave Mao

Abstract:

Fluids are the primary agents of planetary differentiation and facilitates the exchange of mass and energy between reservoirs in the interior of the Earth. The transport ability of aqueous fluids in the Earth's interior, therefore, are at the core of fluid-driven mass and energy transport during formation and evolution of the Earth.

Solubility of major, minor, and trace elements as a function of temperature, pressure, fluid composition, redox conditions, and pH, is the dominant factor governing mass transport in the Earth. Those factors, in turn, reflect the structure of fluid solvents and its solutes.

As SiO2 is the dominant oxide in most rocks, the characterization of fluid and melt structure in the SiO2-H2O system is fundament for our understanding of how H2O interacts with silicate components and the properties of silicate-rich fluids. Dissolved SiO2 forms complexes in aqueous fluids by replacing bridging oxygens with OH-groups via equilibria of the type 2Q4+nH2O=2Q3(OH)n, where n increases with increasing H2O content. Addition of metal oxide to SiO2-H2O, to form the Mn+On/2-SiO2-H2O results in competition between protons, H+ and metal cations, Mn+, for nonbridging oxygens in aqueous fluids. The solubility behavior of aluminosilicate in aqueous fluids is complex because of the extent to which Al3+ is charge-balanced ion 4-fold coordination and by how Al3+ may between Qn-species of different degrees of polymerization. In general, aluminosilicate solubility in aqueous fluids is positively correlated with proportion of charged-balanced Al3+ and the electronic properties of the charge-balancing cation. Equivalent relations govern aluminosilicate solubility in aqueous fluids.

Fluid composition, including the nature of oxide solutes, are central factors in these processes because the extent of fluid infiltration in a solid matrix is positively correlated with solute content. The extent to which fluids can act as transport media is governed by interconnectivity of fluid in a crystalline matrix, and fluid properties such as viscosity, density and compressibility, viscosity, diffusion, and conduction. Furthermore, geochemical signatures of mantle-derived rocks such as, for example, magmatic liquids, also can reflect alteration caused by infiltration of aqueous fluids that are saturated in major, minor, and trace elements. The kind and abundance of solutes, in turn, reflect the conditions and composition of the fluid source. Isotope ratios such as H/D, for example, also depend on those variables.

Biography of the Speaker: Please see attached cv.

CV_Bjorn Mysen.pdf

P.S.:Dr. Mysen will schedule individual talks with HPSTAR staffs on 8/27, and will be available from 8/25-27.