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Abstract: Deep Offshore Niger Delta Structural Framework

Michel Carbonnie, Marc Kompalitch, Jean-Jacques Jarrige, Tristan Rossi

Typically, the large Niger Delta sedimentary pile is deposited on a gently oceanward dipping slope that provides a gravitational potential for the pile to move downslope (greatly facilitated by the presence of major overpressured shale layers inducing decollement zones).

The delta displays three main structural domains:

- A landward zone dominated by horizontal motion as the sedimentary pile is translated oceanwards. The dominant structural style is listric growth faulting.

- An intermediary zone dominated by shale diapirism (vertical motion); and

- An oceanward zone dominated by gravitational compressional structures. The thrust zone is characterized by small displacement imbricates that pile up or form broad, evenly spaced zone up to 70 km wide.

The interpretation of the TGSI/MABON regional seismic survey shows that this well known pattern presents considerable spatial differences possibly influenced by basement controls (demonstrated by gravi-mag methods) and mobile shale thickness. Therefore nine structural provinces can be differentiated and are illustrated.

AAPG Search and Discovery Article #90956©1995 AAPG International Convention and Exposition Meeting, Nice, France