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Amount and controls of the quaternary denudation in the Ardennes massif (western Europe)
Author(s) -
Demoulin A.,
Hallot E.,
Rixhon G.
Publication year - 2009
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/esp.1834
Subject(s) - denudation , geology , massif , structural basin , tectonics , geomorphology , quaternary , early pleistocene , tectonic uplift , pleistocene , paleontology
It is still debated whether the primary control on the middle Pleistocene denudation of the uplifted Ardennes massif (western Europe) is tectonic or climatic. Here, based on geomorphological observations, we calculate the amount of river incision and interfluve denudation in the Meuse basin upstream of Maastricht since 0·7 Ma and we show that the main response to tectonic forcing was incision. This allows us to provide first‐order estimates of the tectonic and climatic contributions to the denudation of the Ardennes. From a dataset of 71 remnants of a terrace level dated ∼0·7 Ma, we first derive a basin‐scale functional relationship linking incision with distances to the regional base level ( L c ) and to the source ( L s ) in the Ourthe basin (pertaining to the Ardennian part of the Meuse basin). Expressed as I = I 0 *(1 – a * L c b / L s c ), I 0 being the incision measured at the basin outlet, this relationship calculates that river incision has removed 84 km 3 of rock in the Meuse basin upstream of Maastricht since 0·7 Ma. In the same time, 292 km 3 were eroded from the interfluves. A comparison of these volumes shows that the tectonically forced river incision accounts for ∼22% of the total post‐0·7 Ma denudation. Furthermore, the mean denudation rate corresponding to our geomorphological estimate of the overall denudation in the Meuse basin since 0·7 Ma amounts to 27 mm/ky, a figure significantly lower than the ∼40 mm/ky mean rate derived from 10 Be studies of terrace deposits of the Meuse (Schaller et al ., 2004). This suggests that, taken as a basin average, the 10 Be‐derived rate is overestimated, probably due to an overrepresentation of the erosion products of the rapidly incising valleys in the alluvial deposits. Copyright © 2009 John Wiley & Sons, Ltd.