Volcano-sedimentary processes and deposits
Diagenesis of volcaniclastic sediments
Mrs Rikke Weibel1, Professor Kathleen M. Marsaglia2
1GEUS, Copenhagen, Danmark, 2California State University, Northridge, USA
Volcaniclastic particles, whether as single fragments or the majority of framework grains, provide unstable minerals and glassy groundmass in sedimentary successions which undergo diagenetic changes upon burial. Various factors may influence the degree of diagenetic modification, such as mineralogical and chemical composition of the volcanic particles, particle size, and the overall proportion of volcanic material. Some scenarios of volcaniclastic occurrence and resulting influence on diagenesis in stratigraphic successions are: 1) as beds of pure volcaniclastic/tuffaceous sediments; 2) within hybrid sandstones consisting of mixed siliciclastic and volcanic particles; or 3) within interbedded non-volcaniclastic beds affected by pore waters from adjacent altered volcaniclastic intervals. Here we ask for presentations on sedimentary successions of all ages and tectonic settings that document early diagenetic changes associated with the presence of volcaniclastic material or show how these early changes assist in the interpretation of diagenetic changes occurring upon deeper burial, as well as reconstructing volcaniclastic sediment provenance in diagenetically modified successions.
Marine volcaniclastic sediments as archives of diverse volcanic processes
Dr Sebastian Watt1, Dr Rodrigo Fernandez2, Dr Lorna Strachan3, Dr Anke Zernack4
1University of Birmingham, United Kingdom, 2Universidad de Chile, Santiago, Chile, 3University of Auckland, Auckland, New Zealand, 4Massey University, New Zealand
A major proportion of the world’s volcanoes lie in shallowly submerged, island or coastal settings. A wide variety of volcanic processes in these settings will leave an imprint in adjacent depocentres: explosive activity may introduce tephra directly and via secondary transportation; effusive eruptions may impact sediment pathways and sources; and growth and mass-wasting of volcanoes will impart both long- and short-term signals in sediment provenance and accumulation rates. Unravelling and interpreting volcaniclastic signatures adjacent to active volcanoes is challenging. This session aims to explore these challenges by bringing together sedimentologists and volcanologists working in volcanically active and in ancient volcanic environments, investigating the potential of volcaniclastic sediments to reconstruct and interpret volcanic processes.
Marine sedimentary reconstructions of volcanic processes have tended to focus on distal tephra fall deposits and, to a lesser extent, turbidites generated by large-scale mass wasting. Proximal marine volcaniclastic sequences are, however, likely to hold a rich but underexploited archive of volcanic behaviour that is both more complete than distal records, and that can be used to generate coupled volcanic, climatic and environmental records, enabling reconstructions of volcanic behaviour and eruption rates across a range of timescales. In this session, we invite contributions that are exploring marine volcaniclastic records to investigate the spectrum of volcanic processes. We are particularly interested in any work drawing on novel techniques and approaches to reconstructing volcanism, going beyond primary tephra fall deposit stratigraphies. We welcome contributions drawing on clastic sedimentological, physical volcanological, geomorphological and geophysical approaches, and studies taking source-to-sink approaches to understanding how terrestrial volcanic processes are recorded in the marine realm.
Relationship between volcanism and carbonate sedimentation on Earth and beyond
Dr Federica Barilaro1,2, Dr Andrea Di Capua2, Dr Daniel Petráš3
1DiBEST - UniCAL, Rende, Italy, 2CNR - IGAG, Milano, Italy, 3Department of Environmental Geochemistry and Biogeochemistry, Czech Geological Survey, Prague, Czech Republic
The interaction between volcanic and carbonate sedimentation is a fundamental process observed in both continental and marine environments. Spanning Earth's deep time, this interplay has been integral to sedimentary basin evolution, though its role is often underestimated in sedimentological studies. Geodynamic processes, especially those in continental rifts, have influenced long-term climate dynamics by mobilizing deep carbon reservoirs and driving atmospheric CO₂ oscillations. Large explosive eruptions normally disperse large volumes of particles that interact with sedimentary processes at different scales. Therefore, the influence of volcanic activity on carbonate deposits involves a complex interplay of physical, chemical, and biological processes that impact depositional environments and can drive key post-depositional transformations. In this regard, such interaction serves as essential (paleo)environmental proxies. In addition, volcanic sediments serve as vital nutrients in modern ecosystems, supporting diverse biological and biomineralization processes (including carbonate minerals). By examining case studies from ancient and modern settings, this session is dedicated to exploring the dynamic interplay between volcanic and carbonate sedimentation, emphasizing mechanisms through which volcanic activity impacts carbonate production, sedimentation, preservation, and lithification, and vice versa. Particular attention will be given, but not limited to how this interaction creates unique lithofacies with peculiar diagenetic processes, influences geochemical signatures, develops key stratigraphic features, and controls reservoir properties in hydrocarbon and geothermal systems. Contributions addressing similar interactions on Mars and other planetary bodies are also welcome.
Shaping landscapes in fire and ash: Sedimentology of large silicic caldera systems
Professor Karoly Nemeth1, Dr Szabolcs Kosik2
1Saudi Geological Survey, Jeddah, Saudi Arabia, 2Horizon Regional Council, Palmerston North, New Zealand
Caldera-forming eruptions produce large quantities of pyroclastic material, resulting in distinctive depositional records that illustrate both the catastrophic primary processes during the eruption and the complex secondary sedimentary dynamics that follow. These systems are characterized by the deposition of ignimbrites and fallout tephra from significant events, as well as products associated with explosive and effusive activities from dispersed volcanism and polygenetic volcanoes within the caldera system, establishing the initial sedimentary architecture. Large-scale caldera-forming eruptions often reset landscapes, while post-eruptive processes significantly influence the reshaping of sedimentary systems. Caldera collapse disrupts drainage networks, reorganizes fluvial systems, and leads to the formation of alluvial fans and intracaldera lakes. These environments are distinguished by the reworking of pyroclastic material through fluvial and mass-wasting processes, resulting in stratigraphic records that reflect sediment transport, deposition, and remobilization. In arid caldera systems, aeolian processes redistribute fine-grained pyroclastic material, creating sedimentary structures and deposits indicative of wind-driven dynamics. Over time, subaqueous basins within calderas accumulate laminated sediments, deltaic sequences, and turbidites, which provide insights into the long-term sedimentary evolution of these systems. Additionally, sedimentary records offer valuable data on past climatic conditions, ecological responses, and the global impacts of eruptions. Understanding the sedimentology of silicic caldera systems is essential for comprehending their broader geological significance, including their role in preserving volcanic and sedimentary successions in the stratigraphic record. This session will examine the stratigraphic evolution of caldera-related deposits, focusing on the sedimentological processes that shape these dynamic environments in both subaerial and subaquatic settings. Presentations will highlight the textural, compositional, and structural characteristics of primary and reworked deposits, providing new insights into depositional mechanisms and reworking processes. By integrating sedimentology, stratigraphy, and geochronology, this session aims to enhance our understanding of silicic calderas as sedimentary systems and their importance in reconstructing Earth's volcanic and sedimentary history.
Terrestrial sedimentary records of intraplate monogenetic volcanism
Professor Karoly Nemeth1, Dr Hugo Murcia2, Dr Gabriel Ureta3
1Saudi Geological Survey, Jeddah, Saudi Arabia, 2Departamento de Ciencias Geológicas, Instituto de Investigaciones en Estratigrafía (IIES), Universidad de Caldas, Manizales, Colombia, 3 Centro de Investigación para la Gestión Integrada del Riesgo de Desastres, Universidad Católica del Norte, Antofagasta, Chile, Antofagasta, Chile
Monogenetic volcanism results in the formation of small-volume, ephemeral volcanoes typically found within volcanic fields in continental environments. While individual volcanoes contribute minimally to the sedimentary budget, collectively they play a significant role in terrestrial basin evolution. Additionally, monogenetic volcanic fields often generate extensive lava fields that interact with the sedimentary environment. These volcanoes are particularly sensitive to external environmental conditions, producing specific types of volcanism indicative of the prevailing conditions during their period of activity. Consequently, systematic studies of monogenetic volcanic fields can serve as proxies for broader terrestrial environmental conditions. Maar volcanoes are especially important as they create deep sedimentary basins capable of accumulating terrestrial detritus over tens of thousands of years, thereby preserving comprehensive records of the environment, climate, and habitat in continental regions where other sedimentary records may be absent. This session invites contributions that explore the preservation potential of monogenetic volcanoes within the terrestrial sedimentary record across various geoenvironments. We also seek research on the climate record in geological deep time based on sedimentary archives from maar lakes. Submissions that examine eruption style variations as indicators of past hydrogeological and climatic changes are particularly welcome. Furthermore, we encourage presentations on research focused on characterising the erosion and disappearance of small monogenetic volcanic landforms.
Terrestrial to marine volcaniclastic sedimentation in arc settings: How arc-volcanism and tectonic-climatic controls shape volcaniclastic sediment routing systems?
Professor Karoly Nemeth1, Professor Leandro D’Elia2, Dr Manuel López2
1Saudi Geological Survey, Jeddah, Saudi Arabia, 2Centro de Investigaciones Geológicas - Concejo Nacional de Investigaciones Científicas y Técnicas, CONICET – Universidad Nacional de La Plata, UNLP, La Plata, Argentina
At convergent plate boundaries, arc-volcanism plays a crucial role in controlling sedimentation from terrestrial to marine environments. Sediment routing systems (SRS) determine the journey of particulate sediments from their source to their final deposition site. The key issue is whether arc-volcanism imprints event-scale environmental signals preserved in traditional sedimentary environments or creates comprehensive volcaniclastic SRS that influence transient storage along arc margins and deposition areas in oceans. The characteristics of volcanism—its composition, magnitude, and frequency—act as a "volcanic engine" within the classic SRS model encompassing erosion, sediment transfer, temporary storage, and long-term deposition. Concurrently, tectonic and climatic factors shape the relief of convergent margins, influencing how sedimentary systems respond to volcanic activity. Historical observations of volcanic eruptions and studies of ancient arc settings have enriched our understanding of volcaniclastic processes and the organization of sedimentary environments in the geological record, identifying steady-state to flare-up scenarios of arc systems. However, a comprehensive understanding of the interactions between volcanism and various tectonic-climate conditions as short- to long-term controls in SRS remains incomplete. This session seeks contributions from geoscience professionals on recent advancements in understanding the impact of arc-volcanism under different tectonic-climatic conditions at convergent plate margins, covering temporal and spatial scales from terrestrial transient storage to ocean sink areas.
Volcano-sedimentary processes in modern and ancient environments
Dr Anke Zernack1, Prof Jonathan Procter1, Dr Stuart Mead1, Dr Andrea Di Capua2, Dr Rebecca Williams3
1Massey University, Palmerston North, New Zealand, 2CNR Istituto di Geologia Ambientale e Geoingegneria, Milan, Italy, 3University of Hull, United Kingdom
Volcanoes are inherently complex and dynamic geological systems able to generate and distribute vast volumes of sediment to surrounding environments, thereby controlling the evolution of sedimentary systems during their entire lifetime and beyond. Such processes result in the accumulation of primary volcaniclastic deposits, entirely formed by volcanic mechanisms (e.g., pyroclastic density currents), and the subsequent accumulation of a broad spectrum of secondary and volcanic epiclastic deposits triggered by reworking and/or redeposition of volcanic material other secondary landscape-shaping processes (e.g., lahars, debris avalanches, or fluvial). Variations within the produced lithofacies reflect the respective influences of volcanic activity, climate, and geomorphic setting, while features like unconformities and paleosols offer insights into temporal gaps in depositional records.
Understanding the origin, transport and emplacement mechanisms of such a wide range of deposits is fundamental for accurately reconstructing accumulation histories of ancient and modern volcano-sedimentary successions, and for assessing future hazards and their potential economic impacts. However, the interpretation of volcaniclastic successions still presents many knowledge gaps that could be reduced by bringing together multidisciplinary experts and methods as well as by combining classical (e.g., field-based works) with novel (e.g., numerical modelling) approaches.
This session aims at fostering dialogue between volcanologists, sedimentologists, natural hazard experts, and computer/statistical modelers to discuss recent advances in understanding volcano-sedimentary processes in ancient and modern stratigraphic records and their impact on the environments. We invite contributions that address all aspects of volcaniclastic sedimentation including, but not limited to:
- Field studies of volcaniclastic features in ancient sedimentary records aimed at interpreting transport processes and depositional conditions.
- Multidisciplinary (e.g., stratigraphic, petrographic, and/or geophysical) studies of modern volcaniclastic sequences as analogue sites.
- Statistical and computer modelling approaches focused on depicting physical processes occurring during the accumulation of volcaniclastic deposits.
This session is supported by the IAVCEI Commission of Volcanogenic Sediments.