| 英文摘要: | Erebus Volcano, Antarctica, is the world's southernmost currently active volcano, with fully glaciated flanks, and an active, long-lived lava lake. It is a natural laboratory for the study of magmatic processes due to its consistent volcanic activity, location in an area with extremely dry atmospheric conditions, lack of liquid water at the surface, and superb logistical support. As such, it is the ideal place to investigate magma degassing. At Erebus volcanic degassing occurs through the main crater and lava-lake but also, as at many volcanoes, along its flanks. In contrast to non-glaciated volcanoes where flank degassing is often diffuse and difficult to measure, the ice-towers and ice caves on Erebus are direct indicators of sites of active degassing. This project will investigate gas and steam discharges in approximately 20 ice caves. Preliminary results show that the composition of gases within the ice caves is a mixture of magmatic gases and air, and further that the gases are likely interacting with, and dissolving in, a liquid, warm, hydrothermal system below the glacier. The amount of carbon dioxide degassing from the volcano's flanks to the atmosphere and the ability of the hydrothermal system (if present) to dissolve magmatic gases will both be quantified. The results will have implications for better quantifying carbon dioxide and other gas emissions from glaciated volcanoes, which is relevant for better understanding of colder periods in Earth's history, including potentially explaining the transition from colder periods to warmer ones. The project will train a post-doctoral researcher in volcanic and hydrothermal gas sampling and analyses, measurements of carbon dioxide emissions from the volcano, and interpretation of the results. Images, concepts, and data from the expedition will be used in classroom teaching at the University of New Mexico, a minority serving institution.
The precise quantification of the relative abundances of carbon dioxide (CO2), methane (CH4), and the noble gases will allow us to characterize the extent and temperature distribution of the liquid hydrothermal system below the glaciated volcano. Combination of these data with measurement of CO2 flux in the ice caves provides information on the processes of CO2 absorption and sequestration by the liquid-dominated hydrothermal system at depth. By applying geochemical techniques and modeling, the temperature, pH, and volatile content of the hydrothermal system can be determined, the amount of CO2 that dissolves into the liquid phase, and the ultimate source of the CO2 that is degassing from the volcano's flanks will be assessed. These results can inform, and improve, models of volcanic CO2 contributions to the Earth's atmosphere from glaciated volcanoes. In addition to training a post-doc, outreach efforts will include utilization of materials and visuals for introductory Geology and volcanology classes. UNM is a majority-minority institution and federally classified Hispanic-serving institution. Therefore, a comparatively large proportion of undergraduates from culturally diverse backgrounds take introduction classes and will be exposed to these teaching materials. |