From the Archean to the present, the dynamic evolution of the lithosphere is preserved in the metamorphic rock record. Each piece of evidence on mineral reactions, deformation and fluid-rock interaction helps to reconstruct the puzzle of lithospheric tectonics in all its complexity. Analytical and conceptual innovations in petrology, geochemistry, chronology, structural analysis and thermodynamic/thermomechanical modelling continue to improve our ability to read the metamorphic rock record and open new avenues for future development.

This session will highlight research in integrated metamorphic petrology and its application to solid earth behaviour in orogens, subduction zones and cratons throughout geological time. We welcome contributions across the breadth of this field—from petrology, (petro-)chronology, trace-element and isotope geochemistry to microstructures, modelling and geodynamics—with a focus on metamorphic and metasomatic processes that shape the lithosphere across a range of scales.

Invited speakers: Sarah Incel (University of Oslo), Richard Palin (University of Oxford) 

Public information:
We will have relatively few presentations in the 2nd slot, so we will transfer the last few of our 1st-slot presentations there (if authors are OK). This way we will have more time for further great discussions!

The goal of this session is to reconcile short-time/small-scale and long-time/large-scale observations, including geodynamic processes such as subduction, collision, rifting or mantle lithosphere interactions. Despite the remarkable advances in experimental rock mechanics, the implications of rock-mechanics data for large temporal and spatial scale tectonic processes are still not straightforward, since the latter are strongly controlled by local lithological stratification of the lithosphere, its thermal structure, fluid content, tectonic heritage, metamorphic reactions and deformation rates.

Mineral reactions have mechanical effects that may result in the development of pressure variations and thus are critical for interpreting microstructural and mineral composition observations. Such effects may fundamentally influence element transport properties and rheological behavior.
Here, we encourage presentations focused on the interplay between metamorphic processes and deformation on all scales, on the rheological behavior of crustal and mantle rocks and time scales of metamorphic reactions in order to discuss
(1) how and when up to GPa-level differential stress and pressure variations can be built and maintained at geological timescales and modelling of such systems,
(2) deviations from lithostatic pressure during metamorphism: fact or fiction?,
(3) the impact of deviations from lithostatic pressure on geodynamic reconstructions.
(4) the effect of porous fluid and partial melting on the long-term strength.
We therefore invite the researchers from different domains (rock mechanics, petrographic observations, geodynamic and thermo-mechanical modelling) to share their views on the way forward for improving our knowledge of the long-term rheology and chemo-thermo-mechanical behavior of the lithosphere and mantle.

Subduction zones are one of the key players in driving plate tectonics. They are also the locus of most mineral and rock transformations, mass/fluid transfer and seismicity. Understanding initiation, development and closure of subduction zones -including their evolution into collisional systems- is therefore a challenge facing Earth sciences. This session aims at covering the tectonic and metamorphic evolution from nascent to mature convergent systems in both space and time as well as studying the complex feedbacks of processes related to the thermo-mechanical history of subducted and exhumed rocks. This includes studies focusing on tectonic processes in oceanic and continental subduction setting over space and timescales (e.g. mechanical (de)coupling, rock accretion and exhumation...) in active and ancient convergent settings. We welcome contributions from a wide range of disciplines such as structural geology, tectonics, petrology, geophysics, experimental deformation and numerical modelling, with particular emphasis on the rock record.