The nature of Earth’s lithospheric mantle is largely constrained from the petrological and geochemical studies of xenoliths. They are complemented by studies of orogenic peridotites and ophiolites, which show the space relationships among various mantle rock kinds, missing in xenoliths. Mantle xenoliths from cratonic regions are distinctly different from those occurring in younger non-cratonic areas. Percolation of melts and fluids through the lithospheric mantle significantly modifies its petrological and geochemical features, which is recorded in mantle xenoliths brought to the surface by oceanic and continental volcanism. Basalts and other mantle-derived magmas provide us another opportunity to study the chemical and physical properties the mantle. These various kinds of information, when assembled together and coupled with experiments and geophysical data, enable the understanding of upper mantle dynamics.
This session’s research focus lies on mineralogical, petrological and geochemical studies of mantle xenoliths, orogenic and ophiolitic peridotites and other mantle derived rocks. We strongly encourage the contributions on petrology and geochemistry of mantle xenoliths and other mantle rocks, experimental studies, the examples and models of mantle processes and its evolution in space and time.

This session addresses the fundamental role that inclusions play to constrain geological processes in Planetary Science.
Inclusions hosted in crystals are parcels of melt(s) and/or fluid(s) that have the potential to unravel the P-T-X conditions under which igneous, metamorphic and volcanic processes take place. Moreover, inclusions provide critical constraints to the timescales of geological processes, (from millions of years to a few of seconds) occurred on Earth and other planetary bodies. Therefore, the study of melt and fluid inclusions contributes to develop chemically- and physically-based models of deep and surface processes acting under equilibrium and disequilibrium conditions.
We welcome contributions based on analytical and experimental approaches, as well as thermodynamic modelling, to study melt and fluid inclusions and the extent and significance of their post-entrapment modification. We strongly encourage the submission of multidisciplinary studies focused on linking inclusion datasets to field and geophysical observations (e.g., ground deformation, seismicity, gas emission) purposes.

Areas found at plate boundaries are characterized by the presence of seismic, volcanic and geothermal activity. These processes are enhanced by the circulation of hydrothermal fluids in the crust, which transport volatiles from the deep crust or mantle to the surface. Certainly not limited to plate boundaries, as magma rises from depth, decreasing pressure allows volatile species to partition to the gas phase. Bubbles form, grow, coalesce and gases start to flow through vesiculated magma. Eventually, fluids escape towards the surface using tectonic structures and are released in the atmosphere, in some cases diffused through a soil or bubbling through a water pool, in other cases forming large plumes or explosive eruption columns. Fluids play an important role in earthquake generation.
Geochemical and isotope composition of gases deriving from different settings can trace sources and chemical and physical processes, providing information about deep earth. Moreover, volatiles play a key role in magma transport and have significant impact on the style and timing of volcanic eruptions. In addition, noble gases deriving from the deep earth can provide important information about their crust or mantle origin because these gases hardly react with other materials during migration. While carbon dioxide is one of the major constituents in volcanic/geothermal areas, methane, dominating sedimentary low heat flow areas, is often linked to subsurface hydrocarbon reservoirs that due to tectonic discontinuities are released in the atmosphere. Furthermore, sulfur dioxide emissions that take place in volcanic environments can cause acid rain, influence aerosol formation and, if an eruption column reaches the stratosphere, cause global dimming and a decrease in Earth’s surface temperatures for years. Similarly, halogens can dramatically impact proximal ecosystems, influence the oxidation capacity of the troposphere and alter the stratospheric ozone layer. Gas composition and flux may change with time, reflecting variations in the system. Measuring gases therefore constitutes a powerful tool for monitoring and understanding Earth.
This session aims to merge different geo-disciplines and bring together researchers interested in the comprehension of the degassing processes that take place in various geodynamic regimes. Furthermore, identify the impact that the emissions can have on terrestrial environment, atmospheric composition, climate and human health at various temporal and spatial scales. We invite contributions discussing novel measurement techniques, field measurements, direct and remote ground- and space-based observations and modeling studies of degassing can provide new insights into volcanic, tectonic and atmospheric processes on local and global scales.

Subduction drives plate tectonics, generates the major proportion of subaerial volcanism, forms continents, and entrains surface material back to the deep Earth. Therefore, it is arguably the most important geodynamical phenomenon on Earth and the major driver of global geochemical cycles. Seismological data show a fascinating range in shapes of subducting slabs. Arc volcanism illustrates the complexity of geochemical and petrological phenomena associated with subduction. Surface topography provides insight in the orogenic processes related to subduction and continental collision.

Numerical and laboratory modelling studies have successfully built our understanding of many aspects of the geodynamics of subduction zones. Detailed geochemical studies, investigating compositional variation within and between volcanic arcs, provide further insights into systematic chemical processes at the slab surface and within the mantle wedge, providing constraints on thermal structures and material transport within subduction zones. However, with different technical and methodological approaches, model set-ups, inputs and material properties, and in some cases conflicting conclusions between chemical and physical models, a consistent picture of the controlling parameters of subduction-zone processes has so far not emerged.

This session aims to follow subducting lithosphere on its journey from the surface down into the Earth's mantle, and to understand the driving processes for deformation and magmatism in the over-riding plate. We aim to address topics such as: subduction initiation and dynamics; changes in mineral breakdown processes at the slab surface; the formation and migration of fluids and melts at the slab surface; primary melt generation in the wedge; subduction-related magmatism; controls on the position and width of the volcanic arc; subduction-induced seismicity; mantle wedge processes; the fate of subducted crust, sediments and volatiles; the importance of subducting seamounts, LIPs, and ridges; links between near-surface processes and slab dynamics and with regional tectonic evolution; slab delamination and break-off; the effect of subduction on mantle flow; and imaging subduction zone processes.

With this session, we aim to form an integrated picture of the subduction process, and invite contributions from a wide range of disciplines, such as geodynamics, modelling, geochemistry, petrology, volcanology and seismology, to discuss subduction zone dynamics at all scales from the surface to the lower mantle, or in applications to natural laboratories.

Subduction zones are arguably the most important geological features of our planet, where plates plunge into the deep, metamorphic reactions take place, large earthquakes happen and melting induces volcanism and creation of continental crust. None of these processes would be possible without the cycling of volatiles, and this session aims to explore their role in convergent margins. Questions to address include the following. Do Atlantic and Pacific subduction zones cycle volatiles in different ways? What dynamic or chemical roles are played by subducted fracture zones and plate bending faults? How do fluids and melts interact with the mantle wedge and overlying lithosphere? Why do some of the Earth’s largest mineral resources form in subduction settings? We aim to bring together geodynamicists, geochemists, petrologists, seismologists, mineral and rock physicists, and structural geologists to understand how plate hydration/slab dynamics/dehydration, and subsequent mantle wedge melting/fluid percolation, and ultimately melt segregation/accumulation lead to the diverse range of phenomena observed at convergence zones around the globe.

Invited speakers:
Lena Melekhova (Bristol University)
Ingo Grevemeyer (GEOMAR)

Mantle upwellings are an important component of the Earth’s convective system that can cause volcanism and anomalies in surface topography. Upwellings can rise from thermal boundary layers as hot “mantle plumes”. Alternatively, they can be the response to upper-mantle convective flow, subduction, or rifting. Clearly, different mechanisms sustain mantle upwellings of various temperature, vigour and composition, causing characteristic signals that can potentially be imaged using geophysical data, as well as expressed in the geochemistry and petrology of related magmatism.

This session invites contributions that focus on mantle upwellings from geophysics, geochemistry, and modelling perspectives. Our aim is to bring together constraints from multiple disciplines to understand the origin and dynamics of mantle upwellings, as well as their potential to trigger mantle melting, create volcanism, generate ore deposits, and build dynamic topography.

Since the 1960’s plate tectonics has been accepted as a surface expression of the earth's convecting mantle, and yet numerous geological features of plate interiors remain unexplained within the plate tectonic paradigm, including intraplate earthquakes and large-scale vertical motions of continents as epitomized by the uplift history of Africa. Kevin Burke (1929-2018), one of the greatest geologists of our time who published original and thought-provoking contributions for six decades, was one of the most vocal scientists to assert that plate tectonics is an incomplete theory without a clear understanding of its links with deep Earth processes, including the role of mantle plumes. In this session we commemorate the pioneering work of Kevin and explore contributions from across the diverse fields that interested him, including global tectonics, the Wilson Cycle, the origin of Precambrian greenstone belts, the evolution of the Caribbean, and the uplift history of Africa and other continents. We discuss the state-of-the art of the plume mode of mantle convection, its influence on the dynamics of the asthenosphere and the lithosphere, and its expression at the earth’s surface. We seek contributions from natural case studies (tectonic evolution, sedimentology, thermochronology, geophysics, palaeoclimate) and from geodynamics or geomaterials oriented (analog and numerical) modeling, which address the interplay of deep mantle – asthenosphere – lithosphere – basin – surface processes in all plate environments. In particular, we appreciate studies that contribute to the understanding of feedback processes causing the evolution of dynamic topography and welcome contributions that examine surface and deep Earth links based on observations and numerical models (although notably the latter never seduced Kevin).

Continental rifting is a multi-facetted process spanning from the inception of extension to continental rupture or the formation of a failed rift. This session aims at combining new data sets, concepts and techniques elucidating the structure and dynamics of rifts and rifted margins. We invite submissions highlighting the time-dependent evolution of processes such as initiation of faults and ductile shear zones, tectono-magmatic and sedimentary history, lithospheric necking and rift strength loss, influence of the pre-rift lithospheric structure, mantle dynamics and associated effects on rifting processes, as well as continental break-up and the transition to sea-floor spreading. We encourage contributions using multi-disciplinary and innovative methods from field geology, geochronology, seismology, geodesy, marine geophysics, plate reconstruction, or modeling. Focus regions may include but are not limited to the Atlantic, Indian Ocean, Mediterranean and South China Sea (e.g. IODP 367/368 area) rifted margins, or the East African, Eger, Baikal and Gulf of California rift systems. Special emphasis will be given to presentations that provide an integrated picture by combining results from active rifts, passive margins, failed rift arms or by bridging the temporal and spatial scales associated with rifting.