CALIBRATING A LANDSCAPE EVOLUTION MODEL: LATE QUATERNARY SEDIMENT ROUTING SYSTEMS IN THE GULF OF PAPUA

Continental margin sediment routing systems are the source of a wealth of resources, such as groundwater, agricultural land, fisheries and hydrocarbons, upon which populations are dependent for both habitation and trade purposes. Studying and modeling surface processes and landscape evolution in source-to-sink systems is crucial for sustainably managing these resources. The Papua New Guinean (PNG) landscape is young and rapidly evolving, with high uplift rates and precipitation rates that exceed 10 m/yr producing high erosion rates. Consequently, the Gulf of Papua, an active foreland basin in southern PNG, receives a large terrigenous sediment flux of ∼384 Mt/yr. The fresh and tectonically active Papuan landscape makes the Gulf an ideal location for studying tectonic and climatic impacts on source-to-sink surface processes and basin stratigraphy.

We use the open-source landscape evolution code Badlands (Salles, 2016) to simulate erosion, transportation and depositional processes in PNG. However, in order to simulate the surface evolution of the Gulf of Papua, the landscape evolution model must first be calibrated by ground-truthing the model with geological and tectonic constraints. We constrain a range of parameters, including tectonic uplift rates, lithology-specific upland erodibility and marine sediment distribution, in order to calibrate a numerical model simulating the Late Quaternary landscape evolution of the Gulf of Papua foreland basin. Our results suggest that orogenic uplift rates in PNG exceed 600 m/Myr, lithology-specific erodibility coefficients are highest for soft sediment (~13.0 x 10⁻⁶ yr⁻¹) and lowest for granites and metamorphics (~6.5 x 10⁻⁶ yr⁻¹) and marine sediment deposition is primarily focused proximal to the coastline. The calibrated model is then used to evaluate Late Quaternary sediment transfer patterns in the Gulf of Papua source-to-sink system. Simulation results suggest that siliciclastics derived from the Papuan Orogen dominate sediments delivered to the Gulf of Papua marine environment.