--> Abstract: Variation in Sediment Supply and accommodation in Sedimentary Basins: Implications for Sequence Development, by R. Gawthorpe; #90937 (1998)

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Abstract: Variation in Sediment Supply and accommodation in Sedimentary Basins: Implications for Sequence Development

GAWTHORPE, ROB, Ian Sharp & Stuart Hardy, Dept. of Earth Sciences, The University, Manchester, M13 9Pl UK

Developing topography and rates of subsidence/uplift around growing faults and folds exert a major influence on accommodation development, physiography, sediment supply and sediment transport. All of these parameters act as major ‘local' controls on sequence development and lead to marked variation in key stratal surfaces and intervening stratal units. Understanding this sequence variability is crucial for prediction of facies and subtle traps in rift, strike-slip and piggy-back basins.

Measurements of rates of uplift and subsidence in the vicinity of active faults show that these rates (0.5-5 m/ka) have a significant effect on accommodation development. Subsidence/uplift also show marked spatial changes over length-scales of 5 to 50 km along normal, strike-slip and thrust fault systems. Thus an understanding of the characteristics of three-dimensional subsidence and uplift patterns in different structural settings is crucial for predicting the geometry of sedimentary sequences within active fault/fold-bounded basins.

Sequence geometries are also profoundly influenced by rates of sediment supply. Modern fault bounded basins show that fault generated uplift influences sediment supply through affecting (i) the location and size of drainage basins developed on basin margin topography, and (ii) the path of large externally sourced rivers.

The interaction of variable accommodation and sediment supply leads to complex sequence development around growing faults and folds within which contemporaneous facies stacking patterns vary markedly and key stratal surfaces may be only locally developed. These variations in sequence development are illustrated by outcrop, subsurface and simulations studies.

AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah