Impact of synsedimentary metre-scale normal fault scarps on sediment gravity flow dynamics: An example from the Gre's d'Annot Formation, SE France

Research areas:
Year:
2007
Authors:
Journal:
SEDIMENTARY GEOLOGY
Volume:
202
Number:
4
Pages:
796-820
Month:
DEC 15
ISSN:
0037-0738
BibTex:
Abstract:
Synsedimentary faults result in the direct interaction between tectonic and sedimentary processes at similar spatio-temporal scales. Sedimentological analysis of sediment-laden gravity flows in the northern part of the Gres d'Annot Formation (Sanguiniere sub-basin, Col de la Moutiere/Tete Ronde) has revealed the presence of fault scarps of metre-scale height. These synsedimentary fault scarps were sufficient to disturb the sediment gravity flow dynamics resulting in (i) a strong variation of the erosive behaviour of a concentrated flow and (ii) the transformation of a strongly stratified, laminar hyperconcentrated flow into a turbulent flow, in short distance (less than 500 m). These disturbances develop without the flows being deviated by the fault scarps but produce great facies heterogeneity, the least homogeneous facies (mixing sand and clay) being localized on the upstream obstacle side, the most homogeneous (massive sand) downstream. (c) 2007 Published by Elsevier B.V.