[S-VC28] International volcanology

[SVC28-P12] Assessing causality between deglaciation and eruptive activity at arc stratovolcanoes – a review

*Chris Conway¹、Leo Pure²、Osamu Ishizuka¹ (1.Geological Survey of Japan, AIST、2.Department of Agriculture, Water and the Environment, Australia)

キーワード：stratovolcanoes, volcano-ice interaction, Quaternary, glacier

The chronostratigraphic records of glacierized stratovolcanoes provide archives of eruption frequencies, sizes, and styles that can be compared against long-term fluctuations in regional ice volume imposed by climate change. This allows us to explore a question fundamental to understanding the evolution of Earth: do causal relationships exist between ice volume and volcanic activity in such settings? Eruption archives are usually not continuous or complete, however, and they can contain subtle but significant traps that impact the interpretation of whether deglaciation leads to enhanced volcanism. For this review, we have assessed time-volume-composition trends for the eruptive products of well-studied stratovolcanoes in glaciated arc settings. Our evaluation of the materials and methods used in those studies highlighted four main caveats that should be considered in future investigations of the relationships between deglaciation and volcanism. These issues are (1) the relative imprecision of geochronological constraints for volcanic products when compared with high-resolution climate-proxy records; (2) the potential for biased preservation of eruptive materials within certain periods of a volcano’s lifespan (e.g. interglacial periods); (3) the lack of consideration that time-volume-composition trends may be influenced by mantle and crustal processes that operate independently of ice-loading/unloading; and (4) the predominant reliance on data only from immediately before and after the Last Glacial Maximum (ca. 20 ka), which are rarely compared with time-volume-composition trends during earlier Pleistocene glacial-interglacial cycles to test the reproducibility of eruptive patterns. Working to overcome these challenges will lead to significant advances in the fields of geochronology, paleoclimatology, and volcanic risk assessment. As many mid-to-high latitude arc stratovolcanoes continue to undergo further deglaciation in today’s warming climate, these endeavours are becoming increasingly important as we aim to understand volcano–climate feedback processes and improve our ability to forecast future volcanic activity.