Processes responsible for formation and development of the early Earth (> 2500Ma) are not
well understood and strongly debated, reflecting in part the poorly preserved, altered, and
incomplete nature of the geological record from this time.
In this session we encourage the presentation of new approaches and models for the development of Earth's early crust and mantle and their methods of interaction. We encourage contributions from the study of the preserved rock archive as well as geodynamic models of crustal and mantle dynamics so as to better understand the genesis and evolution of continental crust and the stabilization of cratons.
We invite abstracts from a large range of disciplines including geodynamics, geology, geochemistry, and petrology but also studies of early atmosphere, biosphere and early life relevant to this period of Earth history.

Tectonic models represent hypothesised approximations of past geological events that best fit and explain a pre-defined collection of data points. Incorporation of geological observations with an understanding and consideration of geodynamic concepts, geological processes, and physical properties of geological materials ensures that empirical models are consistent with physics and mechanics, and that numerical models are consistent with field observations and petrological constraints. Integrating these constraints and concepts within a plate kinematic framework that considers the size, distribution and past and present motions of tectonic plates ensures that models are consistent with global plate tectonics. Incorporating this information with interpretations of the distribution of subducted slabs and plumes in the upper and lower mantle allows for construction of tectonic models that consider the global tectonic-mantle system. We welcome state-of-the-art, multi-disciplinary, and multi-scale studies that combine geological and geophysical constraints from the bedrock record with interpretations of deep mantle structure and/or plate kinematic datasets to investigate geodynamic events of past and present. These may include, but are not limited to studies of rifting and ocean spreading, subduction, orogeny and terrane accretion, and dynamic topography. We expect this session to include a diverse range of multi-disciplinary studies united by a common goal of understanding the geological evolution of our planet’s tectonic-mantle system.

The nature of science has changed: it has become more interconnected, collaborative, multidisciplinary, and data intensive. The main aim of this session, now in its third edition, is to create a common space for interdisciplinary scientific discussion where EGU-GA delegates involved in recent and ongoing COST (European Cooperation in Science and Technology)* Actions can share ideas and present the research activities carried out in their networks. The session represents an invaluable opportunity for different Actions and their members to identify possible synergies and establish new collaborations, find novel links between disciplines, and design innovative research approaches. So far, this session has hosted contributions stemming from 26 Actions, covering different areas of the geosciences (sky, earth and subsurface monitoring, terrestrial life and ecosystems, earth's changing climate and natural hazards, sustainable management of resources and urban development, environmental contaminants, and big data); we are looking forward to receiving new contributions this year.

Same as in past editions, part of this session will be dedicated to presenting and discussing activities carried out in further national and international scientific networks, associations, and collaborative projects.

Moreover, this session is of course open to everyone and abstracts authored by individual scientists or small research teams are most welcome, too. Actually, in 2018 and 2019 we received a very good number of such abstracts, submitted by researchers who wanted to disseminate the results of their studies in front of the multidisciplinary audience that characterizes this session, as an alternative to making a presentation in a thematic session. In fact, contributing to this session can be a productive way to broaden the perspective and find new partners for future interdisciplinary research ventures.

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* COST (www.cost.eu) is funded by the EU and enables researchers to set up their interdisciplinary and international scientific networks (the “Actions”). Academia, industry, public- and private-sector laboratories work together in the Actions, sharing knowledge, leveraging diversity, and pulling resources. Every Action has a main objective, defined goals and deliverables. This session is a follow-up initiative of COST Action TU1208 “Civil engineering applications of Ground Penetrating Radar” (www.gpradar.eu).

The dynamics of the solid Earth and its surface are strongly affected by their interplays as well as biota and climate. These constant feedback systems operate at a variety of spatial and temporal scales that are regulated in a complex system of interactions. For instance, in the critical zone -the terrestrial surface environment ranging from the lower atmosphere to the solid parent material- interplays not only regulate manifold ecosystems and bio-geochemical cycles, but also shape the Earth’s surface at the interface between atmosphere and lithosphere, where soils develop. At much larger scales, plate tectonics and global geodynamics control the physiography, climate and hydrosphere, which in turn strongly affect the surface feedback processes via tectonic, biological, geochemical and hydrological processes. Ultimately, climate and tectonics are prominent macro-ecological drivers of landscape development. But even though the underlying geology and tectonic processes have long been recognized as driving parameters, this is much less so for biological processes. The driving force of microorganisms, plants and animals on the shape of land surfaces is still poorly understood.
Understanding the links between the solid Earth and the external spheres of the Earth has experienced a recent upswing due to advanced analytical techniques, but also thanks to fostered interactions between researchers from different disciplines. This session aims to bring together geoscientists, soil scientists, climatologists and biologists working at different spatial and temporal scales on the feedback interactions between geology, topography, soils, climate and biosphere at the surface of the Earth. The session covers a multitude of topics from the microbial to the geodynamics time and space scales.

Solicited speakers are:
Carina Hoorn, University of Amsterdam, The Netherlands
Alexia Stokes, French National Institute for Agricultural Research – INRA, France
Veerle Vanacker, University of Louvain, Belgium