Late Quaternary folding in the Jura Mountains: evidence from syn-erosional deformation of fluvial meanders

摘要

P>The present tectonic activity of the Jura fold-and-thrust belt is a matter of scientific debate. At its north-western front, differentially uplifted palaeo-meanders of the Doubs River record Late Quaternary growth of the Citadelle Anticline, associated with a minimum rock uplift of 13 m. Local rock uplift rates estimated from optical stimulated luminescence dating of oxbow lake deposits measure 0.17 +/- 0.05 mm per annum. Reconstruction of the deformation history reveals that buckling took place simultaneously with focused Pleistocene river incision. The structural, geomorphic and temporal setting suggests that active deformation could possibly be sustained by incision-related erosion. These observations shed new light on the modes of recent deformation in the Jura Mountains and on the present-day dynamics of the Alpine orogenic front.