The Chaîne du Thaljah is a range of mountains in the

Gafsa Governorate Gafsa Governorate ( '; ) is one of the 24 Governorates of Tunisia, governorates of Tunisia. It is situated in central Tunisia, bordering Algeria. It covers an area of 7807 km2 and has a population of 337,331 (2014 census).Gafsa Gafsa (; ; ') is the capital of Gafsa Governorate in Tunisia. With a population of 120,739, Gafsa is the ninth-largest Tunisian city and is 335 km from the country's capital, Tunis. Overview Gafsa is the capital of Gafsa Governorate, in ...

in Tunisia to Negrine in Algeria, crossing the border not far from the small oasis of Tamerza. The highest point is the Jebel-Bliji. On the north side, at a place called Es Safia south-southeast of Tamerza, a rock painting was found on an overhanging rock wall at the entrance of a deep ravine. It depicts animals and men in silhouette, in blood on a yellow-ochre background, all slightly glazed. It was probably made by Berbers between the Stone and Bronze Ages. In 1885–86 the geologist

Philippe Thomas Philippe Thomas (4 May 1843 – 12 February 1910) was a French veterinarian and amateur geologist who discovered large deposits of phosphates in Tunisia. Despite the huge economic importance of his discovery, he received little recognition during ...

explored the southern area of Tunisia between the meridian of

Kairouan Kairouan (, ), also spelled El Qayrawān or Kairwan ( , ), is the capital of the Kairouan Governorate in Tunisia and a UNESCO World Heritage Site. The city was founded by the Umayyads around 670, in the period of Caliph Mu'awiya (reigned 661� ...

and the Saharan chotts, covering a vast area. He also explored the western area, which his colleagues had neglected, particularly the Chaîne du Thaljah or Chaîne du Tseldja mountains that stretch westward from

Gafsa Gafsa (; ; ') is the capital of Gafsa Governorate in Tunisia. With a population of 120,739, Gafsa is the ninth-largest Tunisian city and is 335 km from the country's capital, Tunis. Overview Gafsa is the capital of Gafsa Governorate, in ...

into Algeria. He identified the geology of the Gafsa chain with that of the M'fatah massif in Algeria and on 18 April 1885 found phosphates at Jebel Tselja. Thomas observed that at the junction of the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

limestone axis of the chain with its

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

foundations there was a dark

marl Marl is an earthy material rich in carbonate minerals, Clay minerals, clays, and silt. When Lithification, hardened into rock, this becomes marlstone. It is formed in marine or freshwater environments, often through the activities of algae. M ...

and a brown or greenish-gray limestone with a tricalcium phosphate content that averaged 60%. This was found where the Jebel Tseldja opens into the plain at Fous-Tseldja, near Métlaoui.

Notes

Sources

* * * * {{DEFAULTSORT:Thaljah, Chaine du Mountain ranges of Tunisia