Difference between revisions of "Mount Berlin"

Mount Berlin (view source)

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Westarctica

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 Mount Berlin belongs to a group of large volcanoes in West Antarctica, together with [[Mount Takahe]]. A number of other volcanoes may exist there as well but do not extend above the ice sheets.
-Older volcanics are exposed at Brandenburger Bluff, dates range around 2,738,000 ± 63,000 years ago. Brandenburger Bluff lies northwest of the main summit. Unlike the rest of Mount Berlin, which is formed by flow rocks, [[Brandenburger Bluff]] is formed by layered hyaloclastite tuffs. One interpretation is that Mount Berlin is formed by two trachytic volcanoes on top of a hydroclastic base. Incipient glacial cirques have been identified. Mount Berlin has erupted trachytes. These have a noticeable peralkaline composition. Additional rocks that were erupted from Berlin are basanite, hawaiite and mugearite.
+Phonolithic and phonotephritic rocks are found at [[Brandenberger Bluff]]. Over time, the contents of iron in the rocks erupted by Mount Berlin increased and that of silica and potassium. This might indicate that eruptions of Mount Berlin were fed by a large magma chamber, but the more likely explanation is that different eruptions tapped different "batches" of magma which were progressively less evolved.
-Phonolithic and phonotephritic rocks are found at [[Brandenburger Bluff]]. Over time, the contents of iron in the rocks erupted by Mount Berlin increased and that of silica and potassium. This might indicate that eruptions of Mount Berlin were fed by a large magma chamber, but the more likely explanation is that different eruptions tapped different "batches" of magma which were progressively less evolved.
 In the Mount Moulton tephra layers, Berlin rocks assume the form of obsidian and pumice. The pumice fragments can reach sizes of about 3 centimeters (1.2 in).