This reference is for an abstract only. A full paper was not submitted for this conference. The abstract contains the text below and eight figures.


The sequence stratigraphy of "hot shales" of the Silurian, determined from well-log correlation, is the basis for mapping the distribution and thickness of these organic-rich intervals. The sequences have been tied to a sea-level curve using published age control.

The Silurian is a thick wedge of marine shale, with near shore sandstones mainly in the upper part. Several intervals of organic-rich "hot shales" occur within the Silurian. A widespread basal "hot shale" up to 30 meters thick lies directly above and thins by on lap onto an erosional surface. The overlying unit of organic-lean shale and siltstone thins as it progrades in a basinward direction, forming a subtle clinoform geometry. Above this lies a basinally restricted interval of shale, which laps onto the underlying progradational shales. This pattern is repeated many times. The basinally restricted shales may be organic rich, especially in the lower part of the Silurian.

The basal "hot shale" and basinally restricted shales are interpreted as lowstand-transgressive units above sequence boundaries. The basinward-thinning progradational shalesiltstone units are interpreted as highstand deposits. As the highstand units thin, the basinally restricted shales come closer together and distally merge to form thicker units of shale. These merged "hot shales"are interbedded with limestones that formed due to the reduction in detrital sedimentation in a distal setting.

Proximal basins (southern Ghadames Basin, Murzuq, Widyan and Rub Al Khalibasins) contain only the basal "hot shale", which is absent on paleohighs within and around the margins of the basin. Basins updip of the proximal basins(Kufra, Western Desert) lack the basal "hot shale" or any other "hot shales".More distal areas (northern Ghadames Basin, northeastern Arabian Platform and Zagros Foldbelt) contain multiple "hot shales", improving the chance formigration of petroleum to sandstone reservoirs in the upper part of the Silurian or overlying Devonian.


I want to thank D.J. Curry and W.B. Maze of EMEC for assistance in interpretation of pyrolysis-gc/ms data; S. Luning for his assistance in providing samples from the BG-14 corehole and for discussions on black shales; GeoArabia for permission to use well information from their publications; Petroleum Geological Analysis Ltd., Quantock Geological Services, Saker Geological Services and The University of Reading for permission to use well information from their reports; and Exxon Mobil Exploration Company granted permission for publication of this extended abstract.

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