Evidence for fluid migration following pockmark formation: Examples from the Nile Deep Sea Fan

A large number of pockmarks have been identified in the Rosetta Region of the Western Nile Deep Sea Fan. Co-located high resolution 2D and Chirp datasets have been used to identify seabed and buried pockmarks which are interpreted to span the Holocene to Pleistocene period. The pockmarks range in size and stratigraphic position from large buried pockmarks to small unit seabed pockmarks. Clusters of small unit pockmarks are stratigraphically positioned above the centre of large buried Pleistocene pockmarks and are used to infer: 1) rejuvenation of the larger pockmark conduit once burial has occurred, and 2) a change in the frequency and magnitude of pockmark formation events. ► 142 Palaeocene pockmarks and 1728 Holocene pockmarks are interpreted from the NDSF. ► Seabed pockmarks cluster in the residual topography of larger buried pockmarks. ► Buried pockmarks are interpreted to have formed between 60–80,000 yrs BP. ► Buried pockmark conduits permit post pockmark formation and burial, fluid migration. ► Buried pockmark conduits can remain viable after lengthy periods of dormancy.