CAREER: Reactivation controls, timescales, and styles at quiescent hotspot volcanoes: Insights from the Canary Islands

Cuny Queens College, Flushing NY

Investigators

Abstract

This CAREER award seeks to quantify the nature and timescales of processes by which quiescent volcanoes reactivate to erupt again. Understanding this rejuvenation process remains a challenging, but important goal of modern volcano science. General relationships between the duration of precursory activity (that is, eruption run-up) and other variables, such as repose period and magma composition, are promising for improved eruption forecasting and understanding of the life cycles of volcanoes, but need further testing at “controlled” case studies. With available data on 13 historic eruptions across four different islands providing constraints on crustal structure, magmatic system configuration, magma composition, repose period, and eruption style, the Canary Islands represent an ideal natural laboratory to test ideas on the behavior of quiescent hotspot volcanoes fed from deep within Earth. Preliminary data suggest that (1) reactivation of Canary Island volcanoes is controlled by new influx of deep-sourced magma into the upper mantle magmatic system and that (2) the time lapse between this deep recharge and eruption is typically on the order of a few months. In order to test these hypotheses, this study will document the style of compositional zoning of a large number of olivine and clinopyroxene crystals across all 13 eruptions, through analysis of crystal images and integration of research in the classroom. This will be complemented by quantitative micro-analysis on a subset of representative crystals and small inclusions of volcanic glass trapped within them. These data will be utilized to identify magmatic processes leading to volcano reactivation and to calculate eruption run-up for all eruptions. The design of this project will further allow testing whether eruption run-up is dependent upon crustal structure, repose period, and magma composition and whether it has an incidence on eruption style, which will improve our understanding of the inner workings of these volcanoes and associated hazards. The educational component of this CAREER project centers on the implementation of a course-based undergraduate research experience, which will involve students in research design, sample preparation, data collection, and interpretation and dissemination of results and, whereby, will directly inform the scientific goals of the work. A tiered and near-peer mentoring plan between the principal investigator, graduate students, and undergraduate students will foster student success and will be supported by an established mentor training program. On-site and online outreach activities will be coordinated with a volcano interpretive center in the Canary Islands. Finally, video tutorials will be produced and made openly available to facilitate the use of our approach by other researchers, educators, and students. The natural experiment of this project exploits available data on historic Canary Island eruptions and systematic petrologic analyses of their products to isolate variables that cause reactivation — and control its duration and style — at quiescent hotspot volcanoes. Grayscale analysis of backscatter electron images of numerous crystals will be combined with high-precision electron probe analysis on selected crystals. In addition, Raman, ion microprobe and LA-ICP-MS measurements of volatile and trace element concentrations of melt inclusions within these same crystals will be performed. Diffusion chronometry will be used to quantify eruption run-up for all 13 historic eruptions in the Canary Islands, which will provide important data for hazard assessment and future eruption forecasting efforts in the archipelago. This approach will in turn allow testing postulated global relationships between eruption run-up, repose period, magma composition, and eruption style at individual volcanoes across a single hotspot. The work will advance the understanding of how olivine and clinopyroxene record magmatic processes and their timescales and will reveal new insights into the crystal cargo of basaltic magmas. 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.