Depositional environments and sequence stratigraphy of paralic glacial, paraglacial and postglacial Upper Ordovician siliciclastic deposits in the Murzuq Basin, SW Libya

Depositional sequence three (DS-3) corresponds to the upper part of the Mamuniyat Formation and is bounded below by an erosional surface (SB) that was formed as a result of isostatic rebound, associated with relative sea-level fall. DS-3 LST comprises Gilbert-type, deltaic conglomeratic sandstones grading upwards into sandstones. Subsequent relative sea-level rise during the late Ordovician resulted in deposition of shoreface TST sandstone. Further rise in the relative sea level resulted in sediment starvation in deep water areas and the formation of thin hardground layer (i.e. condensed section) that marks the upper boundary of late Ordovician deposits. This study provides predictive model for the spatial and temporal distribution of ancient glaciogenic depositional facies that may have important implications in hydrocarbon explorations.