US EPA

1286655 

Journal Article 

Quantifying rock uplift rates using channel steepness and cosmogenic nuclide-determined erosion rates; examples from northern and southern Italy 

Cyr, AJ; Granger, DE; Olivetti, V; Molin, P 

2010 

1 

Lithosphere
ISSN: 1941-8264 

Geological Society of America 

United States (USA) 

2 

3 (June 2010) 

188-198 

Rock uplift rates can be difficult to measure over 10 (super 3) -10 (super 5) yr time scales. If, however, a landscape approaches steady state, where hillslope erosion and rock uplift rates are steady and locally similar, then it should be possible to quantify rock uplift rates from hillslope erosion rates. Here, we test this prediction by comparing channel steepness index values and (super 10) Be catchment-averaged erosion rates to well-constrained rock uplift rates in two landscapes in Italy. The first field area is the Romagna Apennines, northern Italy, where rock uplift rates are relatively uniform, between 0.2 and 0.5 mm/yr (regional mean 0.40+ or -0.15 [SE] mm/yr), and have been steady since 0.9 Ma. The second area is the region around northeastern Sicily and the southernmost Italian peninsula, where rock uplift rates are higher and exhibit a strong spatial gradient, from approximately 0.7 to approximately 1.6 mm/yr (regional mean 1.09+ or -0.13 [SE] mm/yr). In both regions, channel steepness indices and (super 10) Be erosion rates vary directly with rock uplift rates. Although there is considerable variability in erosion rates, regionally averaged rates in both the northern (0.46+ or -0.04 [SE] mm/yr) and southern (1.21+ or -0.24 [SE] mm/yr) areas accurately measure rock uplift rates. Although channel steepness indices do not quantify rock uplift rates, they are useful for (1) identifying regional patterns of rock uplift, (2) identifying areas where uplift rates might be expected to be uniform, and (3) informing (super 10) Be sampling strategies. This study demonstrates that, together, channel steepness and hillslope erosion rates can provide a powerful tool for determining rock uplift rates. 

erosion rates; Southern Europe; metals; channels; case studies; Cenozoic; Sicily Italy; quantitative analysis; cosmogenic elements; Emilia-Romagna Italy; Aspromonte Massif; shore features; rates; Northern Apennines; slopes; southern Italy; marine terraces; beryllium; Europe; uplifts; Calabria Italy; dates; terraces; absolute age; northern Italy; steepness; alkaline earth metals; isotopes; Be-10; Italy; Apennines; Quaternary; exhumation; radioactive isotopes; Peloritani Mountains