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Modeling of Evolution of Transgressive Sediments on the Northern Adriatic Sea after the Last Glacial Maximum*

By

James P.M. Syvitski, 1, Yu'suke Kubo2, Eric W.H. Hutton1, and

Albert J. Kettner3

 

Search and Discovery Article #50036 (2006)

Posted August 3, 2006

 

*Oral presentation at AAPG Annual Convention, Houston, Texas, April 8-12, 2006

 

Click to view presentation in PDF format (8.5 mb).

 

1INSTAAR, University of Colorado, Boulder, CO ([email protected])

2Ocean Research Institute, the University of Tokyo, Tokyo, Japan

3Delft University of Technology, Delft, Netherlands

 

Abstract 

A coupled-simulation by the hydrologic model HydroTrend and the stratigraphic model SedFlux is used to investigate the transgressive deposits in the north Adriatic Sea area over the last 21,000 years. Synthetic sediment fluxes from the Po River show an increase of more than 70% during late Pleistocene (i.e. due to glacier melt and enlarged drainage area), compared to modeled sediment loads of the Holocene. These simulations were used as input to the process-based forward-model 2DSedFlux. Paleo-morphology was reconstructed in a pseudo-inverse manner by comparing the predicted deposit distribution and the modern bathymetry. Accommodation space for the thick, prograding deposits in the modern Po and L. Pleistocene Po-lowstand deltas was accounted for by drawing back the modern bathymetric profile. This revised bathymetric profile is then re-adjusted for aggradational deposition. A modified sea-level curve was then used to complete the inversion. The final simulation is a good match with the modern bathymetry. The subsurface architecture of the Po delta was successfully reconstructed despite the lack of three-dimensional features in the model.

 

Selected Figures 

HydroTrend is used to simulate daily Q and Qs since the Late Glacial Maximum (LGM). The paleo Po basin is reconstructed by merging a DEM and bathymetry. Climate for the LGM came from the CCSM climate model, and modern climate records, interpolated between using a normalized d18O ice core curve. The Pleistocene (21-10 kyr) suspended load is 32.5 MT/y; bedload is 0.91 MT/y, 1.7 times the Holocene flux of 18.8 MT/yr and 0.53 MT/yr, respectively. 

Paleomorphology is reconstructed first by running SedFlux with the modern bathymetry and the HydroTrend (LGM to modern) discharge output, using a generic global sea level curve.