Tibesti
Friday, 23. March 2007, 14:24:07
The Tibesti Mountain Range in northern Chad is one of the world’s least-studied intra-continental volcanic regions. Satellite remote sensing is an increasingly practical way to study these types of remote places.
Tarso Toussidé, erupted violently during the Quaternary Period, the geologic age spanning the most recent 1.8 million years of Earth’s history. The eruption blanketed the surrounding area with volcanic tephra, which is unconsolidated (loosely packed) pulverized rock, volcanic glass fragments, and ash. Typically, tephra erodes more quickly than consolidated volcanic rocks such as tuff or hardened lava; therefore, the smooth appearance of the area suggests relatively recent activity. During the eruptions, the high walls of the volcano collapsed to form two overlapping calderas. Even younger than these features is Pic Toussidé, a steep lava dome that erupted on the western side of the larger caldera. The white splotch - roughly 2 km long - inside the smaller caldera could be salt.
Image by Robert Simmon. Image interpretation provided by Lauren VanArsdall and Robert L. Nusbaum, Geology and Environmental Geosciences, College of Charleston, Charleston, SC. http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17586 (With further information)
In contrast to the smoothly blanketed landscape of Tarso Toussidé, the rugged landscape of Tarso Abeki, to the east, (to the right on the picture below) indicates that this volcano was inactive during the Quaternary. Here, erosion has been at work for millions of years. Water-carved canyons radiating away from Abeki’s summit have degraded the volcano’s slopes. These rugged slopes may also suggest a wetter past for northern Chad.
Image by Robert Simmon, based on data from Lauren VanArsdall and Robert L. Nusbaum, Geology and Environmental Geosciences, College of Charleston, Charleston, SC. Image interpretation provided by Lauren VanArsdall and Robert L. Nusbaum. http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17571 (With further information)
At http://volcano.und.edu/vwdocs/volc_images/img_Tibesti.html there is a satellite image covering a larger area.
Other volcanoes dominating the Tibesti volcanic complex are Toon, Oyoye, Tierok, Yega and Voon. Further information and satellite image of Tarso Voon is found at http://www.volcano.si.edu/world/volcano.cfm?vnum=0205-02=. Further information and satellite image of Emi Koussi (to the south) is found at http://www.volcano.si.edu/world/volcano.cfm?vnum=0205-021
Tarso Toussidé, erupted violently during the Quaternary Period, the geologic age spanning the most recent 1.8 million years of Earth’s history. The eruption blanketed the surrounding area with volcanic tephra, which is unconsolidated (loosely packed) pulverized rock, volcanic glass fragments, and ash. Typically, tephra erodes more quickly than consolidated volcanic rocks such as tuff or hardened lava; therefore, the smooth appearance of the area suggests relatively recent activity. During the eruptions, the high walls of the volcano collapsed to form two overlapping calderas. Even younger than these features is Pic Toussidé, a steep lava dome that erupted on the western side of the larger caldera. The white splotch - roughly 2 km long - inside the smaller caldera could be salt.
Image by Robert Simmon. Image interpretation provided by Lauren VanArsdall and Robert L. Nusbaum, Geology and Environmental Geosciences, College of Charleston, Charleston, SC. http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17586 (With further information)
In contrast to the smoothly blanketed landscape of Tarso Toussidé, the rugged landscape of Tarso Abeki, to the east, (to the right on the picture below) indicates that this volcano was inactive during the Quaternary. Here, erosion has been at work for millions of years. Water-carved canyons radiating away from Abeki’s summit have degraded the volcano’s slopes. These rugged slopes may also suggest a wetter past for northern Chad.
Image by Robert Simmon, based on data from Lauren VanArsdall and Robert L. Nusbaum, Geology and Environmental Geosciences, College of Charleston, Charleston, SC. Image interpretation provided by Lauren VanArsdall and Robert L. Nusbaum. http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17571 (With further information)
At http://volcano.und.edu/vwdocs/volc_images/img_Tibesti.html there is a satellite image covering a larger area.
Other volcanoes dominating the Tibesti volcanic complex are Toon, Oyoye, Tierok, Yega and Voon. Further information and satellite image of Tarso Voon is found at http://www.volcano.si.edu/world/volcano.cfm?vnum=0205-02=. Further information and satellite image of Emi Koussi (to the south) is found at http://www.volcano.si.edu/world/volcano.cfm?vnum=0205-021
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