ROCK UPLIFT, TRANSIENT LANDSCAPES, AND SEDIMENT TRANSFER IN SOURCE-TO-SINK SYSTEMS

Abstract

Source-to-sink systems provide a framework for understanding how Earth-surface systems translate tectonic forcing into erosion, weathering, sediment production, sediment transfer, and stratigraphic architecture. In this view, sedimentary systems are not passive recorders of uplift or climate, nor are landscapes simple conveyors of sediment from mountain belts to basins. Instead, signals generated in source areas are modified as they move through coupled geomorphic and depositional domains. Rock uplift may initiate river incision, but the expression of that forcing depends on transient landscape adjustment, hillslope response, weathering efficiency, sediment supply, accommodation, inherited topography, and the ability of sediment-routing systems to store or bypass material. This dissertation uses that broader source-to-sink perspective to examine three linked components of the sedimentary pathway: tectonic forcing and rock uplift in the Calabrian forearc, geomorphic and geochemical response within the Fiumara Allaro catchment, and modeled sediment storage and bypass across high-relief shelf margins. These chapters do not reconstruct a single continuous sediment-routing system. Rather, they evaluate how different parts of the source-to-sink pathway govern the transfer, transformation, and preservation of tectonic signals from uplifting source areas to depositional sinks.Chapter 1 reconstructs spatial and temporal patterns of Quaternary rock uplift across the Calabrian forearc of southern Italy using river-profile analysis, knickpoint mapping, relict-topography characterization, and basin-averaged cosmogenic 10Be erosion rates. The results show that high-elevation, low-relief relict landscapes are separated from actively incising domains by regional slope-break knickpoints. Downstream increases in channel steepness and erosion rate indicate a transition from slower pre-Quaternary landscape evolution to more rapid late Quaternary incision. Uplift is earliest and greatest near the northern and southern margins of the forearc, in Sila and Aspromonte, and later or more subdued in the central Serre massif. These patterns are most consistent with uplift driven by slab fragmentation and associated mantle-flow reorganization, rather than by crustal thickening or local faulting alone. This chapter establishes the tectonic boundary condition for the dissertation: spatially variable rock uplift generates the topographic and erosional gradients from which downstream source-to-sink signals emerge. Chapter 2 focuses on the Fiumara Allaro catchment in the Serre Massif to quantify how a single source catchment responds to an increase in rock uplift rate. High-resolution topographic analysis, channel morphology, grain-size measurements, cosmogenic 10Be erosion rates, and water chemistry show that the catchment is divided into a slowly eroding relict upland and a lower actively incising domain. Below the knickpoint zone, channels steepen and narrow, bed material coarsens, hillslopes become steeper and more sharply curved, and erosion rates increase. These patterns demonstrate strong coupling between fluvial incision and hillslope adjustment during transient landscape response. However, silicate weathering fluxes do not increase linearly with physical erosion. Instead, they peak in the middle catchment and decline or plateau in the most rapidly eroding reaches, indicating partial decoupling between physical denudation and chemical weathering during rapid incision. This chapter shows that the erosional signal generated by uplift is internally transformed within the source catchment before sediment and solutes are exported downstream. Chapter 3 extends the source-to-sink framework into the depositional sink by using forward stratigraphic models to test how inherited shelf-margin geometry, sediment supply, accommodation generation, and sediment mobility influence the transition from shelf-margin storage to basinward bypass. The models are simplified two-dimensional sensitivity experiments motivated by the Oveja-Puma succession of the Magallanes Basin, rather than direct reconstructions of that system. Results show that inherited foreset geometry preconditions where clinoforms steepen and how sediment is distributed along the shelf-to-slope profile. Sediment supply and accommodation regulate the timing and style of shelf-edge growth, but do not independently generate sustained bypass. Sediment mobility exerts the strongest control on whether sediment remains stored near the shelf edge or is transferred basinward into deeper-water environments. This chapter demonstrates that the sedimentary record of upstream forcing depends not only on how much sediment is produced, but also on the efficiency with which depositional systems transmit sediment across physiographic boundaries. Together, these chapters show that tectonic perturbations propagate through source-to-sink systems in a structured but non-uniform way. Rock uplift establishes the boundary condition for incision; river incision drives hillslope adjustment, sediment production, and erosion-rate contrasts; chemical weathering responds nonlinearly to physical denudation; and sediment-transfer efficiency determines whether sediment is stored near the shelf margin or exported basinward. The central implication is that source-to-sink systems do not transmit tectonic signals unchanged. They filter, amplify, dampen, and reorganize those signals across linked geomorphic and stratigraphic domains. By integrating tectonic geomorphology, cosmogenic nuclides, topographic analysis, geochemistry, and stratigraphic forward modeling, this dissertation provides a framework for linking source-area uplift to sediment production, weathering response, and depositional-system behavior.