Tarso Yega ("well",

tedaga The Teda language, also known as Tedaga, is a Nilo-Saharan language spoken by the Teda, a northern subgroup of the Toubou people that inhabits southern Libya, northern Chad and eastern Niger ) , official_languages = , languages_type ...

) is a

stratovolcano A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and per ...

Tibesti The Tibesti Mountains are a mountain range in the central Sahara, primarily located in the extreme north of Chad, with a small portion located in southern Libya. The highest peak in the range, Emi Koussi, lies to the south at a height of and is ...

, with a summit caldera that is wide and deep. The summit of the volcano reaches a height of , and its caldera is the largest caldera of the Tibesti. Neighbouring volcanoes include Doudriki east, Ehi Dosoatou south and Ehi Fodoboro southwest of the caldera. The Enneri Yega river drains the caldera westward and then south, before joining the Enneri Debarsar; in the past (

Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togethe ...

) the rivers reached

Lake Chad Lake Chad (french: Lac Tchad) is a historically large, shallow, endorheic lake in Central Africa, which has varied in size over the centuries. According to the ''Global Resource Information Database'' of the United Nations Environment Programme, ...

and lakes formed in Tarso Yega. The history of the volcano is characterized by the emission of

tephra Tephra is fragmental material produced by a volcanic eruption regardless of composition, fragment size, or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts. Once clasts have fallen to the ground, they rem ...

s, with the downsagging of the caldera floor generating a depression.

Basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...

ic vents and

lava dome In volcanology, a lava dome is a circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions on ...

s were emplaced within this caldera, and an

intrusion In geology, an igneous intrusion (or intrusive body or simply intrusion) is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth. Intrusions have a wide variety of forms and com ...

named Ehi Yodéï developed farther south. The caldera is heavily eroded, with almost the entire southern side eroded away, and the younger Voon ignimbrite has been emplaced inside of it; it belongs to a different volcano,

Tarso Voon The Tarso Voon is a high stratovolcano in the north of the Republic of Chad. It is located in the western center of the Tibesti Mountains. The summit of the mountain is dominated by the relatively flat caldera. Extensive basaltic flows lie o ...

. Humans have used the caldera for

irrigated Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow crops, landscape plants, and lawns. Irrigation has been a key aspect of agriculture for over 5,000 years and has been devel ...

agriculture Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people to ...

References

Sources

* * * * {{refend Volcanoes of Chad Calderas of Chad