Preece, Katie and Mark, Darren F. and Barclay, Jenni and Cohen, Benjamin E. and Chamberlain, Katy J. and Jowitt, Claire and Vye-Brown, Charlotte and Brown, Richard J. and Hamilton, Scott (2018) 'Bridging the gap : 40Ar/39Ar dating of volcanic eruptions from the ‘Age of Discovery’.', Geology., 46 (12). pp. 1035-1038.
Many volcanoes worldwide still have poorly resolved eruption histories, with the date of the last eruption often undetermined. One such example is Ascension Island, where the timing of the last eruption, and consequently, the activity status of the volcano, is unclear. Here, we use the 40Ar/39Ar dating technique to resolve ages of the three youngest lava flows on the island, which are hawaiites and mugearite with 1.5 – 1.9 wt% K2O. In dating these lavas, we provide the first evidence of Holocene volcanic activity on Ascension (0.51 ± 0.18 ka; 0.55 ± 0.12 ka; 1.64 ± 0.37 ka), determining that it should be classed as an active volcanic system. In addition, we demonstrate that the 40Ar/39Ar method can reproducibly date mafic lava flows younger than 1 ka, decreasing the gap between recorded history and geological dating. These results offer new prospects for determining patterns of late-Holocene volcanic activity; critical for accurate volcanic hazard assessment.
|Full text:||(AM) Accepted Manuscript|
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|Publisher Web site:||https://doi.org/10.1130/G45415.1|
|Date accepted:||08 October 2018|
|Date deposited:||27 November 2018|
|Date of first online publication:||09 November 2018|
|Date first made open access:||09 November 2019|
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