The Canary Islands are a chain of seven intra-plate volcanic islands located off the NW African coast, ~100 km west of Morocco. La Palma Island is one of the youngest and westernmost islands in the Canary archipelago, with seven recorded historical eruptions, the three most recent of which include the 1949 San Juan eruption, the 1971 Teneguía eruption, and the 2021 Tajogaite eruption. The 2021 eruption occurred in close proximity to, and started with a similar composition to, the 1949 eruption, but ended with eruption of a more mafic magma. Here we focus on the potential relationship between the most recent three eruptions by analyzing a suit of samples from the 2021 eruption and comparing it to data of the 1949 and 1971 eruptions taken from the literature. Lavas and tephras from the 2021 eruption range from MgO = 5 to 11 wt.%, and in general follow the major element compositional trends exhibited by the 1949 and 1971 eruptions. Trace elements such as Nb and La display a wider range in the 1949 eruption, but the 1971 and 2021 eruptions are encompassed within the general trace element trends of the 1949 eruption, consistent with cogenetic relationships among the magmas in the three eruptions. However, the isotopic compositions (Sr-Nd-Pb) of the 2021 samples are distinct from those of the 1949 and 1971 eruptions, indicating that they are generated from a different mantle source, but one that is similar to other historical eruptions in La Palma. Ongoing Sr-Nd-Pb isotopic analyses and major and trace element modeling for the 1949, 1971, and 2021 eruptions will provide additional constraints on the sources, processes of magma evolution, and magmatic timescales, to better understand the petrogenetic relationship between the historic eruptions of La Palma.
Author: Sophia Ioli, Geology Major
Mentors: Elisabeth Widom, Geology and Environmental Earth Science
Nanci Reyes-Guzman, Geology and Environmental Earth Science
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