Volcanic history of Mount Sidley, a major alkaline volcano in Marie Byrd Land, Antarctica

Panter, K. S.; McIntosh, W. C.; Smellie, J. L.. 1994 Volcanic history of Mount Sidley, a major alkaline volcano in Marie Byrd Land, Antarctica. Bulletin of Volcanology, 56 (5). 361-376.

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Mount Sidley is a complex, polygenetic stratovolcano composed primarily of phonolitic and trachytic lavas and subordinate pyroclastic lithologies at the southern extremity of the Executive Committee Range, a linear chain of volcanoes in central Marie Byrd Land, Antarctica. Detailed field investigation coupled with 14 high precision 40Ar/39Ar age determinations reveal a 1.5 million year life span between 5.7 and 4.2 Ma in which three major phonolitic central vent edifices (Byrd, Weiss and Sidley volcanoes) and their calderas were developed (5.7–4.8 Ma). This was followed (4.6–4.5 Ma) by the eruption of trachytic magmas from multiple vent localities further south, and then by small volume benmoreite-mugearite lavas and tephras around 4.4–4.3 Ma at the southern end of Mount Sidley. The final phase of activity was the eruption of basanite cones at approximately 4.2 Ma. The southward migration of volcanic activity was accompanied by distinct changes in magma composition and is best explained by the sequential release of magmas stored within an intricate system of conduits and chambers in the crust by tectonically driven (magma assisted?) fracture propagation. The style of volcanic migration at Mount Sidley is emulated on a larger scale by other volcanoes in the Executive Committee Range, in which progressive southward displacement of volcanic activity corresponds with significant petrological variations between major centers.

Item Type: Publication - Article
Digital Object Identifier (DOI):
Programmes: BAS Programmes > Pre 2000 programme
ISSN: 0258-8900
Additional Keywords: volcanism, stratigraphy, 40Ar/39Ar geochromology, migration, Marie Byrd Land
Date made live: 29 Mar 2017 10:23 +0 (UTC)

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