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Difference between revisions of "Mount Berlin"
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Tephrochronology has been used to reconstruct the history of volcanic activity in [[Antarctica]]. Tephra from Mount Berlin has been identified in ice cores of the [[West Antarctic Ice Sheet]], in the Mount Moulton ice cap and Vostok ice core. Other rocks on Berlin have been dated directly. The oldest exposed ice in [[Marie Byrd Land]] has been determined through tephrochronology data stemming from Mount Berlin tephra as being older than 492,000 years. | Tephrochronology has been used to reconstruct the history of volcanic activity in [[Antarctica]]. Tephra from Mount Berlin has been identified in ice cores of the [[West Antarctic Ice Sheet]], in the Mount Moulton ice cap and Vostok ice core. Other rocks on Berlin have been dated directly. The oldest exposed ice in [[Marie Byrd Land]] has been determined through tephrochronology data stemming from Mount Berlin tephra as being older than 492,000 years. | ||
Volcanic activity commenced in the Pliocene. The oldest volcanic activity occurred 2.74 ± 0.06 million years ago at Brandenburger Bluff and involved subglacial and subaerial phreatomagmatic activity. Benmoreitic volcanism was active also at Wedemeyer Rocks south of the Berlin main edifice 2.58 ± 0.2 million years ago. Later, trachytic volcanism occurred at Mefford Knoll west of the main edifice 630,000 ± 30,000 and southwest at Kraut Rocks 620,000 ± 50,000 years ago. Volcanic activity then shifted to Merrem Peak, starting 571,000 ± 8,900 years ago. Activity on Merrem Peak was accompanied by flank eruptions forming ignimbrites. Activity finally shifted to Mount Berlin proper, raising the summit of the volcano. Mount Berlin had a phase of increased volcanic activity between 24,000 and 28,000 years ago, according to tephra data. Some eruptions at Berlin were large scale Plinian eruptions, forming eruption columns exceeding heights of 28 kilometers (17 mi) and depositing volcanic ash over large areas. | Volcanic activity commenced in the Pliocene. The oldest volcanic activity occurred 2.74 ± 0.06 million years ago at Brandenburger Bluff and involved subglacial and subaerial phreatomagmatic activity. Benmoreitic volcanism was active also at [[Wedemeyer Rocks]] south of the Berlin main edifice 2.58 ± 0.2 million years ago. Later, trachytic volcanism occurred at [[Mefford Knoll]] west of the main edifice 630,000 ± 30,000 and southwest at [[Kraut Rocks]] 620,000 ± 50,000 years ago. Volcanic activity then shifted to Merrem Peak, starting 571,000 ± 8,900 years ago. Activity on Merrem Peak was accompanied by flank eruptions forming ignimbrites. Activity finally shifted to Mount Berlin proper, raising the summit of the volcano. Mount Berlin had a phase of increased volcanic activity between 24,000 and 28,000 years ago, according to tephra data. Some eruptions at Berlin were large scale Plinian eruptions, forming eruption columns exceeding heights of 28 kilometers (17 mi) and depositing volcanic ash over large areas. | ||
Individual volcanic eruptions at Berlin occurred 135,600 ± 900 years ago, 118,100 ± 1,300 years ago, 92,100 ± 900 years ago, which was the origin of the so-called marine "Tephra A," 14,500 ± 3,800 and 10,300 ± 5,300 years ago. Two pyroclastic deposits in the Berlin crater wall are dated 25,500 ± 2,000 and 18,200 ± 5,800 years ago. Over time, volcanic activity migrated south-southwestward. Berlin further had volcanic activity in the Holocene, including a lava flow beneath an ice tower that is dated 10,300 ± 2,700 years ago. A tephra dated 7,756 BC is similar to a lava flow from Mount Berlin in terms of composition and may originate from an eruption there. Another similar tephra is dated 9,346 BCE. | Individual volcanic eruptions at Berlin occurred 135,600 ± 900 years ago, 118,100 ± 1,300 years ago, 92,100 ± 900 years ago, which was the origin of the so-called marine "Tephra A," 14,500 ± 3,800 and 10,300 ± 5,300 years ago. Two pyroclastic deposits in the Berlin crater wall are dated 25,500 ± 2,000 and 18,200 ± 5,800 years ago. Over time, volcanic activity migrated south-southwestward. Berlin further had volcanic activity in the Holocene, including a lava flow beneath an ice tower that is dated 10,300 ± 2,700 years ago. A tephra dated 7,756 BC is similar to a lava flow from Mount Berlin in terms of composition and may originate from an eruption there. Another similar tephra is dated 9,346 BCE. | ||