Lake Yoa

Country:

Chad

Region:

Eastern Central Sahara

Lake type:

depression with groundwater-fed lake

Category: endogenic varves

Elevation:

380 m asl

Max depth:

26 m

Surface area:

4.3 km2

Length of record:

6100 years

Archive type:

lacustrine sediments

Author of images:

Stefan Kröpelin

Reference:

Francus P., Suchodoletz H. v., Dietze M., Donner R., Bouchard, F., Roy A.-J., Fagot M., Verschuren D., Kröpelin S., 2013. Varved sediments of Lake Yoa (Ounianga Kebir, Chad) reveal progressive drying of the Sahara during the last 6100 years. Sedimentology 60, 911–934.

Link to reference or DOI:

http://dx.doi.org/10.1111/j.1365-3091.2012.01370.x

Example of a varve sequence from a totally groundwater-fed lake in the hyper-arid core of the Sahara (3 mm precipitation vs. 6200 mm evaporation). Light reddish-brown laminas consist of clastic material (matrix-supported and rounded medium-to-very-fine sand and finer grains), dark reddish-brown laminas are mainly made of organic material > max. resolution