ABSTRACT: Genetic Model for Development of Growth Faults within a Sequence Stratigraphic Context

DUNCAN, EDWARD A., BP Exploration Operating Co. Ltd., Uxbridge, England

Analysis of seismic reflection data and high resolution sequence stratigraphic interpretation of Niger delta well logs has led to a genetic model for growth fault development. Traditional models for growth fault development have inadequately explained the initiating event in a context other than somewhat random in frequency. The proposed model ties initiation to relative falls in sea level with sequence and systems tract architecture varying locally with subsidence rate. Downward shifts appear to trigger synchronous load induced growth faults at the highstand offlap break. The resultant systems tract is interpreted as an aggrading shelf margin system in the hanging wall of the growth fault floored by an apparent type 2 sequence boundary. In the footwall, lower subsidence rates allow f rmation of a type 1 boundary with lowstand incised valley systems developed.

The model proposed suggests that relative sea level fluctuations may play an important role in growth fault development and that local subsidence rates will have a profound effect on sequence boundary and systems tract characteristics. It is likely that this model represents one of several possibilities and is not proposed as all encompassing. Rates of sea level fluctuation, type of basin margin depositional systems and mechanical properties of the fill will have an effect on this process-response model. The model supports sequence and systems tract concepts but suggests that synchronous events need not have identical expression at a regional, much less global, scale.

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)