The comparatively lower contribution of the Frasnian source rocks to hydrocarbon generation may be explained by their less widespread regional distribution and their lower thermal maturity due to their higher stratigraphic position. The lower Silurian hot shales in the Ghadames and Murzuq basins rarely exceed 25 m in thickness. Their origin is assumed to be associated with restricted circulation with flow barriers formed by emergent or shallow highs associated with the late Ordovician palaeorelief. In addition, high primary productivity conditions may have prevailed along the shelf edge at this time. In contrast, the Frasnian hot shales are interpreted to have been deposited during peak sea-level in association with a rise of the oxygen minimum zone.
More work has to be carried out on the two hot shale units in Libya.
The exact distribution and depositional mechanisms of this latter hot shale event are largely unknown and need to be investigated in more detail. Then click the BUGS logo to continue your search.