Video — 1 videodisc (37 min.) : sd., col. ; 4 3/4 in.
"The Sulurian 'hot shale' is the most important Palaeozoic hydrocarbon source rock in North Africa and Arabia. The film gives an easily digestible, comprehensive overview of the characteristics and origin of this prominent black shale. The current knowledge of the subject is presented in animated graphics, combined with outcrop video footage from the western margin of the SW Libyan Murzuq Basin. controlling mechanisms such as sea level, palaeorelief and climate are discussed. A predictive depositional model is proposed that distinguishes a lower from an upper hot shale. also features in the film is a new field technique based on spectral gamma-ray measurements that for the first time allows mapping of the Silurian hot shale in Saharan outcrops. Commonly, weathering destroys the organic matter and characteristic black colour of this unit on the desert surface making it complicated to identify by traditional techniques.