In situ rapid quantitative geochemical measurements of carbonate using handheld XRF.

It is now widely accepted that rivers modify their erosion rates in response to variable rock uplift rates, resulting in changes in channel slope that propagate upstream through time. Therefore, present-day river morphology may contain a record of tectonic history. The simple stream power incision model can, in principle, be used to quantify past uplift rates over a variety of spatial and temporal scales. Nonetheless, the erosional model's exponents of area and slope (m and n respectively) and 'bedrock erodibility' (k) remain poorly constrained. In this paper, we will use a geologically and geomorphically well constrained Plio-Pleistocene volcanic landscape in central Sardinia, Italy, to calibrate the stream power erosion equation and to investigate the slip rate of faults that have been seismically quiescent in the historic past. By analysing digital elevation models, geological maps and

Landscapes can record elevation changes caused by multiple tectonic processes. Here, we show how coeval histories of spatially coincident normal faulting and regional uplift can be deconvolved from river networks. We focus on Calabria, a tectonically active region incised by rivers containing knickpoints and knickzones. Marine fauna indicate that Calabria has been uplifted by >1 km since ∼0.8–1.2 Ma, which we used to calibrate parameters in a stream power erosional model. To deconvolve the local and regional uplift contributions to topography, we performed a spatiotemporal inversion of 994 fluvial longitudinal profiles. Uplift rates from fluvial inversion replicate the spatial trend of rates derived from dated Mid‐Late Pleistocene marine terraces, and the magnitude of predicted uplift rates matches the majority of marine terrace uplift rates. We used the predicted uplift history to analyze long‐term fault throw, and combined throw estimates with ratios of footwall uplift to hanging wall subsidence to isolate the nonfault related contribution to uplift. Increases in fault throw rate—which may suggest fault linkage and growth—have been identified on two major faults from fluvial inverse modeling, and total fault throw is consistent with independent estimates. The temporal evolution of nonfault related regional uplift is similar at three locations. Our results may be consistent with toroidal mantle flow generating uplift, perhaps if faulting reduces the strength of the overriding plate. In conclusion, fluvial inverse modeling can be an effective technique to quantify fault array evolution and can deconvolve different sources of uplift that are superimposed in space and time.

The evolution of normal faults has important implications for long-term seismic hazard, and changes in topography during the development of a fault array impact upon a range of factors including plate rheology and sediment routing (e.g., Cowie et al., 2017;Li et al., 2016;Marc et al., 2016). Techniques such as trenching and cosmogenic dating of fault scarps can constrain fault throw rates over time scales of ∼10 2 -10 3 years and can successfully estimate earthquake recurrence intervals (e.g., Cowie et al., 2017;Pantosti et al., 1993;Roberts & Michetti, 2004). Fault throw over longer time scales (>10 3 years) can be investigated using stratigraphic data and structural cross sections (e.g., Ford et al., 2013;Mirabella et al., 2011;Shen et al., 2017); however, a complete temporal and spatial record of throw rates may be limited by the absence of datable stratigraphy.Fortunately, fluvial networks provide an opportunity to overcome these limitations and constrain throw rate on the length and time scales that may be pertinent to the development of a fault array, i.e., ∼10 2 -10 5 m and ∼10 4 -10 7 years (e.g., Cowie et al., 2000;McLeod et al., 2000). Quantitative fluvial erosion models can elucidate tectonic changes without necessarily relying upon the stratigraphic archive, signifying their importance in low-mid latitude terrestrial settings where fluvial landscapes are ubiquitous. The morphology and erosion rates of individual rivers have been used to confirm the location of active faults, estimate increases in throw rate, and understand fault interaction or relay ramp development (e.g., Commins et al., 2005;Hopkins & Dawers, 2015). These studies have successfully shown that drainage morphology is sensitive to the evolution of individual fault strands. Nonetheless, active faulting rarely occurs in isolation from other tectonic processes (e.g., mantle flow, plate flexure, isostatic rebound), which often modify topography over larger spatial scales (e.g., 10 5 m). Therefore, separating the effect of faulting from the other factors that generate topography remains a wider challenge in tectonic and geomorphic research.