Refinement of the late Quaternary geologic history of Erebus volcano,Antarctica using Ar/Ar and Cl age determinations |
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| Authors: | Peter J Kelly Nelia W Dunbar Philip R Kyle William C McIntosh |
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| Institution: | 1. Department of Earth & Environmental Science, New Mexico Institute of Mining and Technology, Socorro, NM 87801-4796, United States;2. New Mexico Bureau of Geology and Mineral Resources, New Mexico Institute of Mining and Technology, Socorro, NM 87801-4796, United States |
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| Abstract: | Six new 40Ar/39Ar and three cosmogenic 36Cl age determinations provide new insight into the late Quaternary eruptive history of Erebus volcano. Anorthoclase from 3 lava flows on the caldera rim have 40Ar/39Ar ages of 23 ± 12, 81 ± 3 and 172 ± 10 ka (all uncertainties 2σ). The ages confirm the presence of a second, younger, superimposed caldera near the southwestern margin of the summit plateau and show that eruptive activity has occurred in the summit region for 77 ± 13 ka longer than previously thought. Trachyte from “Ice Station” on the eastern flank is 159 ± 2 ka, similar in age to those at Bomb Peak and Aurora Cliffs. The widespread occurrences of trachyte on the eastern flank of Erebus suggest a major previously unrecognized episode of trachytic volcanism. The trachyte lavas are chemically and isotopically distinct from alkaline lavas erupted contemporaneously in the summit region < 5 km away. |
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| Keywords: | Erebus volcano geochronology 40Ar/39Ar ages 36Cl ages Antarctica eruptive history |
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