1 Aug 2021

Black & White Volcanos – Khaybar

The black & white volcanos are an amazing sight and should definitely be visited if you are in the area and care is taken. The volcanic field of Harrat Khaybar north of Al-Madinah, Saudi Arabia contains rare examples of white volcanoes comprised mainly of the calcium rich felsic rock comendite. Although situated only 60 km from a busy highway, the volcanic area is remote and one should take extreme care in order to visit the volcanoes, as the lava is very sharp and can shred a car tyre easily. Following the tracks is also not straight forward as Google Maps is intermittent here and many tracks lead in different directions, often to dead ends. The white volcanoes are surrounded by more recent black basaltic lava fields that follow the pre-existing topography and display both aa and pahoehoe lava flow structures. The jewels of the Harrat Khaybar are found in its centre of the field 40 kilometres off-road from the nearest tarmac road, where a very rare kind of white volcano occur with the two largest being Jebel Abiadh and Jebel Bayda, which are really stunning to see. Jebel Abiadh (literally “white mount”) is the highest crater of the harrah at 2093 meters above sea level and Jebel Bayda (in Arabic the feminine of “white mount”) is the largest with a 1.5 kilometre diameter cone. Here you can see a striking contrast between the whitish creamy lava of Jebel Bayda and the deep black one of Jebel Qidr. Once at Jebel Bayda it is best to stop at the bottom and walk up the side. Several tracks have been made by local Bedouin driving their vehicles up the side but I suggest you do not follow suit as the beduoins are extremely skilful off-road drivers. It can get very windy here so be prepared. Once at the top the view is amazing and you can see two small cinder cones inside the main cone. The below information and photograph are from the NASA Earth Observatory. The western half of the Arabian Peninsula contains not only large expanses of sand and gravel, but extensive lava fields known as haraat (harrat for a named field). One such field is the 14,000-square-kilometer Harrat Khaybar, located approximately 137 kilometers to the northeast of the city of Al Madinah (Medina). The volcanic field was formed by eruptions along a 100-kilometer, north-south vent system over the past 5 million years. The most recent recorded eruption took place between 600–700 AD. Khaybar contains a wide range of volcanic rock types and spectacular landforms. Jabal (“mountain” in Arabic) al Qidr is built from several generations of dark, fluid basalt lava flows. Jabal Abyad, in the center of the image, was formed from a more viscous, silica-rich lava classified as a rhyolite. While the 322-meter high Jabal al Qidr exhibits the textbook cone shape of a stratovolcano, Jabal Abyad is a lava dome—a rounded mass of thicker, more solidified lava flows. To the west (image top center) is the impressive Jabal Bayda’. This symmetric structure is a tuff cone, formed by eruption of lava in the presence of water. The combination produces wet, sticky pyroclastic deposits that can build a steep cone structure, particularly if the deposits consolidate quickly. White deposits visible in the crater of Jabal Bayda’ and two other locations to the south are sand and silt that accumulate in shallow, protected depressions. The tuff cones in the Harrat Khaybar suggest that the local climate was much wetter during some periods of volcanic activity. Today, however, the regional climate is hyperarid—little to no yearly precipitation—leading to an almost total lack of vegetation.















 

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