Quantifying rock uplift rates using channel steepness and cosmogenic nuclide–determined erosion rates: Examples from northern and southern Italy

Rock uplift rates can be diffi cult to measure over 103–105 yr time scales. If, however, a landscape approaches steady state, where hillslope\uderosion and rock uplift rates are steady and locally similar, then it should be possible to quantify rock uplift rates from hillslope erosion rates.\udHere, we test this prediction by comparing channel steepness index values and 10Be catchment-averaged erosion rates to well-constrained\udrock uplift rates in two landscapes in Italy. The fi rst fi eld area is the Romagna Apennines, northern Italy, where rock uplift rates are relatively\uduniform, between 0.2 and 0.5 mm/yr (regional mean 0.40 ± 0.15 [SE] mm/yr), and have been steady since 0.9 Ma. The second area is the\udregion around northeastern Sicily and the southernmost Italian peninsula, where rock uplift rates are higher and exhibit a strong spatial\udgradient, from ~0.7 to ~1.6 mm/yr (regional mean 1.09 ± 0.13 [SE] mm/yr). In both regions, channel steepness indices and 10Be erosion rates\udvary directly with rock uplift rates. Although there is considerable variability in erosion rates, regionally averaged rates in both the northern\ud(0.46 ± 0.04 [SE] mm/yr) and southern (1.21 ± 0.24 [SE] mm/yr) areas accurately measure rock uplift rates. Although channel steepness indices\uddo not quantify rock uplift rates, they are useful for (1) identifying regional patterns of rock uplift, (2) identifying areas where uplift rates\udmight be expected to be uniform, and (3) informing 10Be sampling strategies. This study demonstrates that, together, channel steepness and\udhillslope erosion rates can provide a powerful tool for determining rock uplift rates