Bermuda Pedestal

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The Bermuda Pedestal is an oval-shaped geological feature in the northern Atlantic Ocean containing the topographic highs of the Bermuda Platform, the Plantagenet (Argus) Bank, and the Challenger Bank. The pedestal is 50 km (31 mi) long and 25 km (16 mi) wide at the 100 fathom line (-185 m), while the base measures 130 km by 80 km at -4200 m. Surrounding the pedestal is a much larger mid-basin swell known as the Bermuda Rise, measuring 900 km by 600 km at the 5000 m depth contour. The islands of Bermuda are located on the southeastern margin of the Bermuda Pedestal.[1][2]

The oceanic crust surrounding the Bermuda is about 120 Ma, while the initial uplift of the Bermuda Rise occurred in the Middle to Late Eocene. Erosion continued from that time until the Early Oligocene. Volcaniclastic deposition and erosion ended with subsidence below sea level in the Late Oligocene. Volcanic basement is at -75 m across the platform, and -50 m on the island, except for a highpoint near Castle Harbour, at -15 m. These volcanics consist of tholeiitic lavas and intrusive lamprophyric sheets.[2]

Scientists have long considered the Bermuda Pedestal to be the remains of a large extinct shield volcano that formed between 45  and 35  million years ago. A number of theories have been established to explain the origin of the Bermuda Pedestal. According to one of these theories, it was formed by the volcanic activity of the Bermuda hotspot. However, a hotspot origin for the Bermuda Pedestal has never been strongly supported and has been largely shut out by a detailed and tightly argued paper by Peter R. Vogt of the University of California and Woo-Yeol Jung of the United States Naval Research Laboratory. In contrast, Vogt and Jung propose that the Bermuda Pedestal possibly formed as a result of a worldwide reorganization of the Earth's tectonic plates due to the closing of the Tethys Ocean when the Indian subcontinent collided with Eurasia.[1]

The size of the Bermuda Pedestal combined with knowledge of other mid-ocean volcanoes tells us that the Bermuda volcano originally reached 1,000 m (3,300 ft) above sea level and that it took three to ten million years to reduce it to sea level.[3]

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References[edit]

  1. ^ a b Vogt, P. R.; Jung, W. Y. (2007). "Origin of the Bermuda volcanoes and Bermuda Rise: History, Observations, Models, and Puzzles" (PDF). Geological Society of America Special Papers. 430: 553–591. Retrieved 9 October 2016.
  2. ^ a b Vacher, H.L.; Rowe, Mark (1997). Vacher, H.L.; Quinn, T., eds. Geology and Hydrogeology of Bermuda, in Geology and Hydrogeology of Carbonate Islands, Developments in Sedimentology 54. Amsterdam: elsevier Science B.V. pp. 35–90. ISBN 9780444516442.
  3. ^ "Origin of Bermuda and Its Caves". NOAA. January 2013. Retrieved 9 October 2016.

Coordinates: 32°20′N 64°45′W / 32.333°N 64.750°W / 32.333; -64.750