GMPV25/GD1.8

New insights into the mineralogy and petrology of the Deep Earth (co-sponsored by EMU) (co-organized)
Convener: Yingwei Fei  | Co-Conveners: Larissa Dobrzhinetskaya , Daniel Frost , Jannick Ingrin , Monika Koch-Müller , Sylvia-Monique Thomas , Richard Wirth 
Oral Programme
 / Wed, 05 May, 08:30–12:00  / Room 25
Poster Programme
 / Attendance Wed, 05 May, 17:30–19:00  / Hall XL
Part I: Discontinuities, phase relations, mineralogy and petrology of the Earth’s crust, mantle and core, and the role of deep carbon.
Recent advances in high-pressure techniques, synchrotron radiation based diffraction and spectroscopic methods, and micro-/nano-scale analytical techniques have provided new capabilities for of characterizing the structure, physical properties, and chemistry of Earth materials at high pressure and temperature, leading to a better understanding of the nature of seismic discontinuities and element distributions in the deep Earth. In addition, there is a renewed interest in characterizing the nature of carbon reservoirs and fluxes in the Earth’s interior. This part of the session will focus on the following topics, including the particular role carbon may play in each, (1) the nature of seismic discontinuities, (2) element partitioning and chemical reactions at high pressure and temperature, (3) phase equilibrium relations applicable to Earth’s crust, mantle, and core, (4) subduction zone and deep interior recycling processes, especially as they relate to deep carbon cylcing, and (5) global models of the Earth's interior and interior processes.
Part II: Hydration and dehydration of the Earth’s crust and mantle - mechanisms and consequences.
The presence of water in solids of the Earth's crust and mantle has enormous effects on the dynamics of processes in the Earth. Hydrogen may be stored in hydrous minerals such as amphibole, serpentine and talc as well as in nominally anhydrous minerals (NAMs). The hydrogen incorporated in these minerals may change their stability fields and physical properties such as electrical conductivity, chemical diffusion, rheological behavior (hydrolytic weakening), transformation kinetics and phase transitions but also their elasticity. The release of water through dehydration processes may enhance melt generation and trigger earthquakes. The formation of dense hydrous magnesium silicates (DHMS) may be an effective way to recycle water deep into the Earth's mantle. The aim of this part of the session is to bring together scientists from several disciplines to discuss some of the following topics: hydrogen solubility in minerals as a function of P, T and paragenesis; hydrogen and deuterium analysis in deep crust and mantle minerals from rocks with different geodynamic histories; effect of hydrogen on properties of NAMs; hydrogen mobility in minerals; high-pressure stability and behavior of hydrous minerals.
Part III: Ultrahigh pressure metamorphism and deep subduction: observations on natural rocks and experimental modeling.
Ultrahigh Pressure Metamorphism is an integral characteristic of collisional orogens, recording transient or even permanent subduction of continental margins into the mantle. Recently, the emphasis of studies on microstructures, atomic scale mineral properties, experimentally established phase transformations, mineral reaction kinetic principles, the extent and rates of metamorphic and tectonic events during deep subduction, elements partioning and geochemical diversity of mantle-crustal rocks-fluid interactions have provided new insights into global geodynamic processes operating in Earth's deep interior. The processes of tectonic accretion taking place under varying physico-chemical and thermo-mechanical conditions change the densities and mechanical behavior of the rocks transported through the subduction channel. The re-distribution of radioactive heat sources by crustal thickening, partial melting and melt transport to the upper crust defines metamorphic P-T-t paths and result in thermal stabilization of the lithosphere. Because thickened crust may become gravitationally unstable, leading to syn- or post-orogenic extension, such processes bridge together the exhumation of UHPM crustal and mantle rocks which are among the most enigmatic questions of UHPM geology. In this part of the session we invite contributions presenting new developments in studies of mineral submicronic structures, mineral reactions, kinetics, thermobarometry, geochemistry, geochronology, and general topics of UHPM geology and tectonics which represent a frontier of knowledge in understanding the significance of UHPM for reshaping the lithospheric plates through mountain buildings, mantle convection, subduction, and exhumation of UHPM rocks in diverse geological situations.