Process-based Modelling of Late Quaternary Morphology and Stratigraphy of the Northern Adriatic Basin
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Abstract
The thesis is devoted to calibration of a process-based numerical model and its application to simulation of the Late Quaternary history and stratigraphy of the Northern Adriatic Sea. Tests aimed at assessing the sensitivity of the model to initial and boundary conditions were conducted, based on geomorphologic and stratigraphic data culled from literature. Based on these tests, wave-generated erosion and diffusion coupled with current-induced removal and transportation algorithms were adopted to simulate intensification of the Western Adriatic Coastal Current (WACC) by the Bora Wind during the Late Holocene. Different scenarios have been assessed to examine the model’s ability to reproduce the stratigraphic architecture of the Adriatic Basin. Model results for the prodelta of the Po River at the north-western low-gradient shelf are represented by a continuous subaqueous delta, which forms an elongated coast-hugging deposit. The central Apennine part of the western shelf, which has a comparatively steep gradient, is characterized by the presence of fluvio-deltaic lobes deposited by the Apennine Rivers. The sediment budget has been calculated based on the isopach maps of modelled stratigraphy. A total sediment mass of abut 800 Gt was supplied to the basin over the time span corresponding to TST and HST (~19 kyr). Volumetric estimates indicate that roughly 87% of the supplied sediments have been preserved on the shelf. This suggests an export of ~13% to the MAD and to the southern part of the basin. The result is compatible with literature, where 10% of the sediment has been reported to move south of the Gargano promontory. Over the past 5.5 kyr, 256 Gt of sediment has been preserved on the shelf and is stored in the HST, corresponding to an average rate of deposition about 46 Mt yr-1, which is ~4 Mt yr-1 more than study reports. The rate of fluvial sediment supply (52 Mt yr-1) during formation of the HST suggests an export of ~6 Mt yr-1 to deeper parts of the basin below the effective hydrodynamic base.