--> Abstract: Sediment Mass Extraction as a Key to Quantifying the Interplay of Tectonic Subsidence and Sedimentation; #90063 (2007)

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Sediment Mass Extraction as a Key to Quantifying the Interplay of Tectonic Subsidence and Sedimentation

 

Paola, Chris1, John Martin1, Sean Connnell2, Wonsuck Kim1 (1) University of Minnesota, Minneapolis, MN (2) Univesity of New Mexico, Albuquerque,

 

The most direct influence of tectonics on sedimentation, nicely illustrated by Crowell's work on the Ridge Basin, is through downstream sediment mass extraction in response to tectonic subsidence. For example, in sedimentary basins, the classical idea of fluvial “grade” is replaced by an overall balance between subsidence and sedimentation, in which the transport surface is adjusted to provide the downstream rate of sediment loss required to balance subsidence. It is this persistent mass loss, not changes in slope or stream power per se, that are responsible for most downstream changes in depositional environments and architecture. We illustrate some of the main effects of downstream sediment extraction via theoretical analysis and data from the field and from an experimental basin with a fully programmable subsiding floor. Primary among these effects are downstream decreases in grain size and channel stacking density. We also show how to quantify the mass extraction via a bypass ratio or extracted fraction. Finally, we illustrate how mass extraction determines the relative extents of transverse and longitudinal depositional packages in a system with multiple interacting sediment sources.

 

AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California