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ATLANTIS & the Atlantic Ocean


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Author Topic: ATLANTIS & the Atlantic Ocean  (Read 22104 times)
dhill757
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« Reply #345 on: March 30, 2009, 12:11:27 am »



Hierro

The massive Hierro shield volcano is truncated by a large NW-facing escarpment, seen here from the east, which formed as a result of gravitational collapse of the volcano. The steep-sided 1500-m-high scarp towers above a low lava platform bordering 12-km-wide El Golfo Bay, which is barely visible at the extreme left. Holocene cones and flows are found both on the outer flanks and in the El Golfo depression. The latest eruption, during the 18th century, produced a lava flow from a cinder cone on the NW side of El Golfo.

Photo by Yasuo Miyabuchi, 1997 (Forestry and Forest Products Research Institute, Kyushu).

 
 Country: Spain
Subregion Name: Canary Islands
Volcano Number: 1803-02-
Volcano Type: Shield volcano
Volcano Status: Radiocarbon
Last Known Eruption: 550 BC ± 75 years 
Summit Elevation: 1500 m 4,921 feet
Latitude: 27.73°N  27°44'0"N
Longitude: 18.03°W 18°2'0"W


The triangular island of Hierro is the SW-most and least studied of the Canary Islands. The massive Hierro shield volcano is truncated by a large NW-facing escarpment formed as a result of gravitational collapse of El Golfo volcano about 130,000 years ago. The steep-sided 1500-m-high scarp towers above a low lava platform bordering 12-km-wide El Golfo Bay, and three other large submarine landslide deposits occur to the SW and SE. Three prominent rifts oriented NW, NE, and south at 120 degree angles form prominent topographic ridges. The subaerial portion of the volcano consists of flat-lying Quaternary basaltic and trachybasaltic lava flows and tuffs capped by numerous young cinder cones and lava flows. Holocene cones and flows are found both on the outer flanks and in the El Golfo depression. Hierro contains the greatest concentration of young vents in the Canary Islands. Uncertainty surrounds the report of an historical eruption in 1793. 

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