RESOLVING SOURCE-TO-SINK DYNAMICS BY MULTI-PROXY DATA FROM THE NORTH AND SOUTH AMERICAN CONTINENTAL SEDIMENTARY ARCHIVES (Invited Presentation)

Continental sedimentary basins preserve multi-million year records of active tectonics and erosion of source regions. Understanding source-to-sink dynamics requires knowledge of rates of source erosion and sediment deposition. New geochemical approaches applied to the continental sedimentary record can provide unique information including the timing and rates of sedimentary and erosional processes and paleohydrology contributing to our understanding of the role of paleoclimate changes and tectonics on source-to-sink dynamics. For example, sedimentological data from the North and South American Cordilleras show that thermochronological and sedimentation rates together with changes in architectural elements of alluvial deposits can be used to recognize allogenic processes in the geological past. Both in the North and South America Cordilleras, detrital thermochronological ages show rapid source erosion (lag times between 0-10 My) and a quasi-instantaneous response of the sedimentary system to tectonic processes at the million-year scale. In the Andes, changes in sedimentation rates and depositional environments correlate with more variable and humid climate conditions during the late Miocene, which amplify the signal of tectonic forcing in the sedimentary record. Higher channel mobility in the North American Cordilleran foreland during the late Cretaceous is attributed to a more seasonal climate and less vegetation, enhancing sediment flux and channel instability, supporting the idea that the details preserved in continental alluvial deposits provide a record of allogenic processes.