We are grateful to several researchers, who suggested a total of 7 potential special sessions for the MetSoc 2026 meeting. 2 out of these 7 special sessions have already been chosen to become individual sessions. This means, if you want to submit an abstract for these submissions, you can choose these during the abstract submission process. The other 5 sessions partly overlap with either other submissions or typical sessions of the MetSoc conference.
If you believe your abstract fits into one of these sessions, please indicate this in the additional info box during your abstract submission process. We will then see whether we have additional special sessions, or combine these with other sessions.
The sequence of the sessions reflects the time of submission of the session, and no other criteria.
Antarctic Meteorite Collection – A Celebration of 50 Years of ANSMET
Cari Corrigan & Michael S. Kelley
This session will welcome presentations on meteorite collection in Antarctica (both by ANSMET and other Antarctic meteorite collection programs), highlighting the programs, the collection process and how it has evolved, and the significant science that has come from the samples collected as part of these programs. After an overview talk or two including how these samples have enabled and supported numerous planetary missions, special attention will be drawn to talks about meteorites that have been collected relatively recently, emphasizing how the programs continue to be relevant and important to research by retrieving samples that are scientifically interesting and useful for addressing current research questions.
Honoring the Legacy of Dimitri Papanastassiou: Advances in Isotope Geochemistry, Cosmochemistry and Early Solar System Evolution
Yuri Amelin, Qing-Zhu Yin, and Francois Tissot
Dimitri Papanastassiou (1943–2025) was one of the last great pioneers of isotope cosmochemistry from the Apollo era—a scientist whose intellect, creativity, and technical innovations helped define the foundations of our field. From his early days at Caltech working with Jerry Wasserburg, through his long career both at Caltech and the Jet Propulsion Laboratory, Dimitri’s work reshaped our understanding of the chronology and evolution of the solar system. Dimitri’s thesis research was truly groundbreaking, including the construction and first uses of the world’s first digital mass spectrometer, the Lunatic I as part of his PhD thesis. This instrument revolutionized the speed and precision of isotope ratio mass spectrometry, vastly expanding the scope of geochronology and other applications to geo- and cosmochemistry. Dimitri went on to make seminal contributions to the field: from the dating of basaltic achondrites, establishing the lunar chronology, studying the evolution of radiogenic Sr and Pb isotopes, to the pioneering identification and application of short-lived radionuclides and nucleosynthetic isotope effects, on Earth and beyond
To honor Dimitri’s lasting scientific and community contributions, we invite submissions for a special session at the 2026 Meteoritical Society Meeting dedicated to isotope cosmochemistry and the formation and evolution of the early solar system. We welcome work spanning all aspects of isotope cosmochemistry, including but not limited to: early solar nebula chronology; planetary differentiation; nucleosynthetic anomalies and stellar heritage of solar system matter; isotope systematics in meteorites, lunar samples, returned samples, and planetary materials; analytical innovations in mass spectrometry; and applications of isotopes to planetary formation and evolution.
This session will celebrate not only Dimitri’s scientific impact but also the enduring legacy of curiosity, rigor, and unconventional thinking that he championed. In conjunction with the session, we are coordinating a Special Volume of Geochimica et Cosmochimica Acta, inviting contributions from session participants and the broader scientific community. This volume will honor Dr. Papanastassiou’s profound influence and highlight current advances inspired by the research pathways he helped establish.
Returned asteroid sample analysis
Nicholas E. Timms, Michelle S. Thompson, and Lan-anh N. Nguyen
Samples returned from asteroids Itokawa and Ryugu by the JAXA Hayabusa and Hayabusa 2 missions, respectively, and asteroid Bennu by the NASA OSIRIS-REx mission are amongst the rarest and most pristine astromaterials available for study. The analysis of returned asteroidal materials continues to inform on the origin and evolution of the solar system, advancing our understanding of: the diversity of planetary building blocks of our solar system, including presolar stardust; accretion of the earliest material in the protoplanetary disk; the evolution of prebiotic organic compounds and environments; alteration processes on primitive bodies; catastrophic collisions and solar system dynamics; and timescales of solar system processes. This session aims to showcase the most recent research on returned asteroid samples via isotopic, geochemical, and mineralogical laboratory studies. We also welcome coordinated studies of asteroidal samples, along with research linking remote sensing observations to laboratory analysis.
Shock processes in meteorites and terrestrial impact structures
Joerg Fritz and John Spray
Shock waves travelling through rocky materials may produce irreversible changes in minerals and rocks. Shock loading and unloading typically last seconds or less, depending on the size, density and velocities of the colliding bodies. The shock-induced changes in pressure and temperature over time produce so-called “shock effects” that can be classified and quantified in meteorites, mission return samples and terrestrial rocks affected by hypervelocity collisions. We invite contributions that not only describe shock effects in meteorites, terrestrial rocks, and experimental samples, but also consider the mechanisms and processes at play. This may include shock pressure effects in the whole rock as well as more localized and complementary high temperature (HT) effects. Localized HP and HT effects are prominently manifest as shock veins and melt pockets. Shock veins and melt pockets are relatively common in meteorites, and shock veins have more recently been described from the central uplifts of terrestrial impact structures. We welcome contributions that consider shock metamorphism in the whole rock and/or localized shock melting and solid-state phase transformations, through to localized effects with the goal of better understanding shock wave-heterogenous materials interactions in planetary materials.
Rocks from Mars: Insights from Meteorites and Samples Collected for Return to Earth
Chris Herd and Arya Udry
The number of samples of Mars continues to grow at a rapid pace. There are now over 270 martian meteorites (when pairings are included). While the majority of these meteorites are igneous rocks, new discoveries have increased their diversity in age and lithology. Recent studies have proposed links between meteorites and their source units on the martian surface, providing a framework for these important samples. Meanwhile, the NASA Mars 2020 Perseverance rover carries 21 samples reflecting a range of rock types (igneous, sedimentary, and regolith) and inferred ages from the Jezero crater fluviolacustrine system. Most recently, the rover has collected samples of potential Noachian age (~4 Ga) from the Jezero crater rim. This session highlights recent advances in the geology of Mars through studies of meteorites and investigation and sampling of rocks at the martian surface.
Dynamite and Laser Beam: Advances in Experimental Approaches to Shock Metamorphism
Tianqi Xie, Christopher Hamann, and Christoph Otzen
Shock features are important indicators for collisions and impact events on rocky planetary bodies in our solar system. Shock waves from these events caused internal changes in terrestrial rocks and meteorites, ranging from elastic and plastic deformation, amorphization, phase changes and melting. Investigating the formation process of these features is key for gauging their pressure-temperature conditions and recreating the history of the impact events.
Historically, our understanding of their formation has long been driven by experimental approaches to mimic the shock process, such as shock common crustal minerals using dynamic gas guns following Rankine–Hugoniot conditions. These results lead to the development of early shock classification system. Later, the development of static high-pressure techniques and in situ investigation using synchrotron facilities help further our understanding on the mineral properties and phase changes under extreme pressure and temperature conditions, such as the development of phase diagrams of quartz and feldspar.
The combination of these dynamic and static results helps the development of current shock classification system. However, there are still many gaps between dynamic shock results, static results and natural observations from both terrestrial and planetary missions, resulting in confusion and controversy when interpreting shock features. In the last decade, there have been many advances in experimental approaches to create various pressure-temperature-time conditions along compression and decompression paths, together with many more advanced analysis techniques with diffraction, scattering, spectroscopy, and imaging using synchrotron facilities around the world. Knowing these advances will provide our community with new perspectives with their current and future studies, leading to new understanding of shock metamorphism and impact cratering process. New experimental results will also provide new factors for modeling the impact process.
This session invites contributions that showcase cutting-edge developments in both static and dynamic compression experimental methodologies, and novel analytical approaches for probing the physical and chemical properties of planetary materials. By bridging experimental breakthroughs with natural observations, this session aims to deepen our understanding on the evolution history of our solar system.
Early evolution of the Moon: magmatic evolution and cratering history
Renaud Merle and Cécile Deligny
Understanding the early history of the Moon–particularly its mantle–crust differentiation, the evolution of its magmatic systems, and the potential influence of large impact events on those systems–is critical for refining existing models of terrestrial planet formation and planetary evolution during the first billion years of Solar System history. For the Moon specifically, the overarching goal is to develop comprehensive models that coherently integrate petrological observations, multiple isotope systems, and numerical modelling constraints from both returned samples and meteorites.
In recent years, renewed analyses of Apollo samples, lunar meteorites, and experimental analogues, combined with advances in analytical precision and improved geochronological methods, have opened new avenues for investigating the timing and extent of magma-ocean crystallisation, the formation and overturn of mantle reservoirs, and the generation of crustal lithologies. Parallel investigations in impact simulations and crater chronology has provided new insight into the timing and subsequent effects of meteorite bombardment.
We welcome contributions to this session that address impact chronology, the petrology and geochemistry of lunar rocks, and the timing of lunar magmatism. We also invite studies that describe or apply new analytical developments and geochemical methods aimed at better identifying and constraining lunar mantle processes and crustal evolution. Interdisciplinary submissions that link sample-based observations with experimental, numerical, or remote-sensing approaches are encouraged. This session aims to foster a cohesive understanding of the Moon’s evolution and to reinforce its role as a cornerstone for interpreting the formative histories of inner Solar System bodies.