About this Research Topic
Topical areas and associated questions include as per below.
1. The frequency of M 8-9 events:
• Besides Toba (M9?), were there others in recent times (last 2 Ma, or since the beginning of the Pleistocene)? Previously recognized examples of the upper end of this scale of eruption were ~ 27 my ago (Fish Canyon Tuff / Monotony Tuff). Many eruption volumes need to be revisited and the results could change our perceived frequency of magnitude 8 and 9 eruptions.
• Is there a continuum of eruptions from "normal" all the way to LEVEs with just increasing magma body size or are LEVEs fundamentally different as a class of volcanic systems?
• What do our volume estimates mean for geophysical prospecting and monitoring of LEVE systems?
2. How are large magma volumes assembled:
• What were the deep melt supply rates, what was the role of tectonic stresses, was the magma present in a high-melt-fraction magma chamber or a magma mush, and what were the associated timescales?
• Some recent work suggests that huge magma bodies empty very quickly but other work suggests stops and starts (for example, recent work on Yellowstone eruptive units), but they probably still had a very high mean output rate (MOR) when erupting. Is there a consistent pattern?
• How does our understanding of time scales and processes of pre-eruptive magmatic evolution and assembly translate to geophysical expressions of eruption initiation and triggering?
3. Triggers for these eruptions, and how do such huge magma volumes erupt:
• These questions can be potentially addressed by thermo-mechanical and petrological models for magmatic systems as well as detailed analysis of eruption deposits to reconstruct MORs - what are the full-time sequences of such eruptions?
• What are the relative roles of internal versus external processes in triggering LEVEs? Are LEVEs distinct volcano-tectonic events that are triggered externally or are internal processes still viable?
• What does our understanding of magma assembly and evolution mean for potential eruption triggers?
• What do the deposits reveal about eruption triggering and eruption mechanisms?
4. One of the most poorly understood aspects of LEVEs is post-eruption magmatic recovery, often referred to as resurgence. Most active supervolcanoes are in this stage and pose significant hazard:
• What are the mechanisms that drive resurgence and what does that mean for hazards from Earth’s currently active supervolcanoes?
• Are resurgence and unrest synonymous or are they distinct? How do we define this distinction and what does this mean for driving processes and monitoring active systems?
• What does resurgent mean for the cyclical nature of many of the largest supervolcanoes? How do we address this when the timescales challenge current geochronological capabilities?
5. The potential of such large volumes of silicic magma to release sulfur, chlorine, and other climate-perturbing gases:
• How important are CO2 and H2O releases?
• Besides the self-limiting mechanism for sulfate aerosols, why is the present consensus of opinion for, for example, Toba, that the huge eruption had relatively little impact on climate and humans?
• What does our understanding of the petrology of the magmas tell us about volatile budgets, behaviour, fragmentation, and eruption mechanisms?
6. Are such huge volumes erupted by magmas in any other part of the compositional range of evolved magmas (it's a “yes” for basaltic magmas – continental flood basalts / basaltic LIPS, but not presently on Earth)?
• Can we utilize our knowledge of exposed continental flood basalts magmatic plumbing systems (e.g., layered mafic intrusions) as analogs for the parental zones of large silicic magma systems?
• Do silicic LIPS (SLIPS) differ from regular outpourings of silicic magmas along subduction zones in any other ways than just scale?
We seek papers addressing any, some, of all of the above points, including review papers of our current state-of-knowledge, and welcome enquiries as to the relevance of your particular idea to this Research Topic.
Keywords: ignimbrite, calderas, magma, climate, sulfur
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