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The diffusivity and diffusion mechanisms of hydrogen together with with deuterium and lithium, parallel to the c axis of quartz, were investigated experimentally at 800 degrees C, 0.1 GPa with the activity of H2O or (H2O)-H-2 approximate to 1 [H-2 is used throughout this work to describe deuterium rather than D, to avoid confusion with the diffusion coefficient, D]. The pH was set using mixtures of H2O (or (H2O)-H-2) and HCl. Three types of experiment were conducted: (1) H-in/Li-out; (2) H-2-in/H-out; and (3) H-2-in/H + Li out, using three different natural quartz crystals as starting materials. Profiles of H, H-2 and Li were measured using Fourier-transform infrared (FTIR) spectroscopy and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). H, H-2 and Li are charge-compensated by Al3+ replacing Si4+, or by excess O2-. The total atomic concentration of monovalent cations appears to remain constant over the duration of the experiments. The resulting diffusion profiles are different for the three experimental designs and three starting materials, and some show complex shapes inconsistent with simple diffusion. A multi-site diffusion-reaction model is developed, with the theory based on previous models that have been derived mainly on the basis of conductivity measurements. In these models, the monovalent cations move away from their charge-balancing ion then diffuse rapidly to another site. The mobility of the monovalent cations is described by both a diffusion coefficient and an equilibrium constant that enables dissociation of the immobile charge-balanced defects. This model can describe complex step-shaped profiles formed in H-in/Li-out experiments, profiles with local maxima ('humped' profiles) in H-2-in/H + Li out experiments, and error function-shaped profiles in H-2-in/H-out and previously published Li-in/H-out experiments. Our data provide support for models previously proposed for quartz. Studies of the lengths and forms of diffusion profiles from such experiments provide a useful complement to assertions from conductivity experiments., Mineralogical Magazine, 86 (1)

The processes that facilitate the production of granitoids are elucidated by the study of exposed lower crustal sections. The focus of this study is an exposure of the lower crustal portion of Albany-Fraser-Orogen (AFO) of Western Australia. This outcrop, located at Whale Head Rock in the western AFO, preserves the interface between an intrusive body and migmatised sedimentary rocks. Detailed mapping, petrography and thermodynamic modelling are combined to characterize the sources and distribution of melt generations in the aureole. U-Pb dating of zircon indicates that the tonalite crystallisation and migmatization of the metapelitic units were coeval at ca. 1.3 Ga. While thermodynamic modelling yields conditions of ca. 820°C and 0.5 GPa, in metapelites throughout the area. The contact zone evolves from igneous dominated textures to migmatitic sediments, dominated by concordant, internally derived leucosomes. The distribution of mineral assemblages and mineral chemistry across this section indicates that the mixing between intrusive and internally generated melt is structurally constrained. The back reaction with late stage, more evolved, melts within this mixing zone indicates that it acts as a pathway for continued melt removal and transport. This study represents and outcrop scale model for the complex processes that are involved in the production of granitoids at high temperature, medium pressure conditions. Giving further insight into the generation and extrapolation of melt from thinned crustal settings.

This roadmap is the product of a grassroots effort by the Swiss Geosciences community. It is the first of its kind, outlining an integrated approach to research facilities for the Swiss Geosciences. It spans the planning period 2025-2028. Swiss Geoscience is by its nature leading or highly in-volved in research on many of the major national and global challenges facing society such as climate change and meteorological extreme events, environmental pol-lution, mass movements (land- and rock-slides), earth-quakes and seismic hazards, global volcanic hazards, and energy and other natural resources. It is essential to under- stand the fundamentals of the whole Earth system to pro-vide scientific guidelines to politicians, stakeholders and society for these pressing issues. Here, we strive to gain efficiency and synergies through an integrative approach to the Earth sciences. The research activities of indivi- dual branches in geosciences were merged under the roof of the 'Integrated Swiss Geosciences'. The goal is to facilitate multidisciplinary synergies and to bundle efforts for large research infrastructural (RI) requirements, which will re-sult in better use of resources by merging sectorial acti- vities under four pillars. These pillars represent the four key RIs to be developed in a synergistic way to improve our understanding of whole-system processes and me- chanisms governing the geospheres and the interactions among their components. At the same time, the roadmap provides for the required transition to an infrastructure adhering to FAIR (findable, accessible, interoperable, and reusable) data principles by 2028.The geosciences as a whole do not primarily profit from a single large-scale research infrastructure investment, but they see their highest scientific potential for ground-break-ing new findings in joining forces in establishing state-of-the-art RI by bringing together diverse expertise for the benefit of the entire geosciences community. Hence, the recommendation of the geoscientific community to policy makers is to establish an integrative RI to support the ne- cessary breadth of geosciences in their endeavor to ad-dress the Earth system across the breadth of both temporal and spatial scales. It is also imperative to include suffi-cient and adequately qualified personnel in all large RIs. This is best achieved by fostering centers of excellence in atmospheric, environmental, surface processes, and deep Earth projects, under the roof of the 'Integrated Swiss Geosciences'. This will provide support to Swiss geo-sciences to maintain their long standing and internatio- nally well-recognized tradition of observation, monitor-ing, modelling and understanding of geosciences process-es in mountainous environments such as the Alps and beyond.