NSF Award
2219430
Iceland is positioned where a mid-ocean ridge and a mantle plume intersect at high latitude, resulting in dynamic and dangerous volcano-ice interactions. Two of Iceland’s four most historically active volcanoes (Grímsvötn and Bárðarbunga) occur near the intersection of the ridge and plume, but they are largely obscured from view by Vatnajökull, an ice cap that covers ~10% of Iceland’s surface area. There are indications that glacial retreat can lead to increased eruption rates by destabilizing existing magma bodies and even prompting new magma generation. As climate continues to change and Iceland’s ice caps continue to thin, there is increasing concern about the impacts on subglacial volcanic systems and their associated hazards. It is important to better understand past and present behavior of subglacial volcanic systems to better prepare for future volcanic threats. The primary objective of this study is to explore the origin, evolution, age, and longevity of magmas under Vatnajökull in order to better understand Iceland’s glacio-volcanic hazard potential, while simultaneously learning about a geologically unique part of the world. This work will strengthen existing, and facilitate new, collaborations with domestic and international scientists in the field and in analytical labs. It will also create opportunity for community engagement and public education, and provide rigorous research experiences for 6+ undergraduate students, a majority of whom are from traditionally under-represented backgrounds.<br/><br/>In Iceland, silicic material accounts for ~10% of the exposed crust; at central volcanoes, this amount increases to ~30%. Volcanic systems beneath Vatnajökull appear to have a paucity of silicic material relative to their subaerial counterparts. This may be a consequence of the proximity to the ridge-plume intersection, or (more likely) a consequence of poor exposure leading to sample bias. Since silicic magmas have the potential to erupt more explosively and with greater associated hazards than basaltic magmas, it is important to understand the role they may play at the productive, active, systems obscured from view by Vatnajökull. The research questions to be investigated are: To what extent are silicic materials associated with Bárðarbunga, Grímsvötn, and neighboring Kverkfjöll? Are collected silicic materials from active magmatic systems, older bedrock, or a combination? How do the geochemical characteristics of these systems’ silicic materials compare to those in the known rock record elsewhere in Iceland? What hazards do silicic magmas present in this dynamic rift-mantle plume-ice environment? Data generated in this study will facilitate mapping the regional distribution of subglacial silicic materials (both those associated with active volcanic systems and those from older bedrock). Evidence from nunatak and moraine rocks (major and trace elements; Hf, Nd, and Pb isotopes; petrography) and their accessory minerals (zircon: U-Th and U-Pb dates, O and Hf isotopes, trace elements; apatite: trace elements, volatiles) will make it possible to decipher the petrogenetic origins and evolution of silicic systems at Iceland’s most plume-affected, and most active, central volcanoes.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
