'Emi Koussi' is a high
shield volcano that lies at the south end of the
Tibesti Mountains in the central
Sahara of northern
Chad. It is the highest mountain in Chad, and the highest in the Sahara. The volcano is one of several in the Tibesti massif, and reaches 3445 m in altitude, rising 2.3 km above the surrounding sandstone plains. The volcano is 60 by 80 km wide.
Two nested
calderas cap the volcano, the outer one being about 12 by 15 km in size. Within it on the southeast side is a smaller caldera, about 2-3 km wide and 350 m deep. Numerous
lava domes,
cinder cones,
maars, and
lava flows are found both within the calderas and along the outer flanks of the shield.
Emi Koussi has been used as a close analog to the famous
Martian volcano
Elysium Mons. One of the most important morphological differences between volcanoes on
Mars and
Earth is the widespread furrowing of the surface due to flowing water on terrestrial volcanoes. The furrows are shallow valleys. Larger channels have a different origin. Major channels can be seen on volcanoes on both planets and indicate low points in
caldera rims where
lava spilled out of pre-collapse craters.
''Original entry was from the
NASA Earth Observatory;
[1]''
References
★
NASA Earth Explorer page
★ Gourgaud A. and P. M. Vincent.
2004. Petrology of two continental alkaline intraplate series at Emi Koussi volcano, Tibesti, Chad. ''Journal of Volcanology and Geothermal Research'' 129(4): 261-290.
★
Global Volcanism Program: Emi Koussi
★
Peakware: Emi Koussi