Proximal tephra characterization in Northern Victoria Land, Antarctica: Insights into eruptive history and future implications

We don’t always have direct access to volcanoes especially those located in hostile and remote areas of our planet, such as Antarctica. Moreover, the knowledge of the Antarctic continent and its volcanoes is still limited by the scarce exposure of volcanic rocks due to the extensive glacial cover, since only 1% of the total area is ice-free. Pyroclastic deposits (i.e. tephra) represent a very effective and powerful tool for petrological and volcanological studies. Through the study and characterization of tephra we can get information about the evolution of magmas, including their physical, chemical and mineralogical characteristics. Additionally, we can get a new understanding of the architecture of volcanic plumbing systems, the nature and intensity of eruptions as well as the emplacement dynamics, their aerial transportation and their impacts on Earth. This work focuses on the characterization of tephra originating from three distinct volcanoes of the Northern Victoria Land, Mount Melbourne, Mount Rittmann and The Pleiades.

According to previous studies, the activity of Mount Melbourne can be dated back to approximately 1892 CE, this is also confirmed by the presence of several tephra layers in the summit and flanks of the volcano (Lyon, 1986). Evidence for explosive eruptions of Mount Melbourne volcano between 1615 cal. yrs BP and 1677 cal. yrs BP were recently acquired (Di Roberto et al. 2023). Also, Mount Rittmann erupted in historical time (696 ± 2 cal. yrs BP) and the presence of fumaroles and summit geothermal activity indicate that the volcano is still active. However, we still know very little about the volcanic history of this volcano. The Pleiades volcanoes instead show evidence of activity during the Holocene (Di Roberto et al. 2020).

Despite the abundance of rock samples collected in this area, there is still a scarcity of both geochemical and petrological data and studies.

We analysed 23 samples that have been collected over the last 30 years during Antarctic expeditions. The analyzed data will provide a more detailed understanding of past explosive volcanic activity including source, magnitude, intensity, chemical evolution and eruptive dynamics. Finally, this will also improve the correlation between proximal and distal tephra.

In addition, an extensive database containing major and trace elements is crucial for a precise geochemical characterization to provide invaluable insights to enhance our understanding of the Northern Victoria Land.

The comprehension of Antarctic volcanism is crucial not only to understand the eruptive dynamics and plumbing system but also to build new knowledge of the history of explosive volcanic activity through time and space. This understanding is critical in evaluating and defining potential impacts associated with future eruptions, which could potentially be affected by ice dynamics and ice load covering the volcanic structures, with wider implications for our planet.

 

Lyon, G.L., 1986. Doi: 10.1080/00288306.1986.10427528.

Di Roberto et al. 2020. Doi: 10.1016/j.quascirev.2020.106629

Di Roberto et l. 2023. Doi: 10.1016/j.qsa.2023.100079