Autogenic-Allogenic Interactions in Lab Experiments: What We Have Learned
The stratigraphic record is our window to the long view of surface dynamics. Information preserved within stratigraphy allows us to image alternative surface configurations, measure rates of change, study large-scale connections that are only weakly expressed on human time scales, and give context to the snapshot that is the Earth’s surface today. Unfortunately, autogenic (internally generated) processes impose a filter on the record of allogenic (externally generated) processes in the stratigraphic record. Our ability to interpret the record of these allogenic processes requires us to 1) determine the time and space scales at which autogenic processes occur and 2) quantify how autogenic processes interact with various types of allogenic processes. We report results from reduced scale laboratory experiments in which self-organized sediment transport systems were subjected to relative subsidence. These experiments allow us to characterize the full range of time and space scales at which autogenic processes occur and how they interact with external forcings. Importantly, they also allow us to study how the interaction of these processes on the Earth’s surface gets transferred into the stratigraphic record. Specific examples of these interactions will include quantifying: 1) the time required for individual depositional events to average to basin-scale stratal patterns, 2) the stratigraphic architecture resulting from the interaction of autogenic processes and compensational stacking, and 3) the time-scales of tectonic and fluvial influence and their consequences for channel steering. In each example we will demonstrate how observations from the reduced scale experiments can be “up-scaled” to field settings.
AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009