Channel-levee evolution in combined contour current-turbidity current flows from flume-tank experiments
|Author(s)||Miramontes Elda1, 2, Eggenhuisen Joris T.3, Silva Jacinto Ricardo2, Poneti Giovanni4, Pohl Florian3, 5, Normandeau Alexandre6, Campbell D. Calvin6, Hernandez-Molina F. Javier7|
|Affiliation(s)||1 : Univ Bretagne Occidentale, IUEM, CNRS, Lab Geosci Ocean,UMR 6538, F-29280 Plouzane, France.
2 : IFREMER, Inst Francais Rech Exploitat Mer, Geosci Marines, F-29280 Plouzane, France.
3 : Univ Utrecht, Fac Geosci, NL-3584 CB Utrecht, Netherlands.
4 : Univ Florence, Dept Earth Sci, I-50121 Florence, Italy.
5 : Univ Durham, Dept Earth Sci, Durham 1DH 3LE, England.
6 : Nat Resources Canada, Geol Survey Canada Atlantic, Dartmouth, NS B2Y 4A2, Canada.
7 : Royal Holloway Univ London, Dept Earth Sci, Egham TW20 0EX, Surrey, England.
|Source||Geology (0091-7613) (Geological Soc Amer, Inc), 2020-04 , Vol. 48 , N. 4 , P. 353-357|
|WOS© Times Cited||20|
Turbidity currents and contour currents are common sedimentary and oceanographic processes in deep-marine settings that affect continental margins worldwide. Their simultaneous interaction can form asymmetric and unidirectionally migrating channels, which can lead to opposite interpretations of paleocontour current direction: channels migrating against the contour current or in the direction of the contour current. In this study, we performed three-dimensional flume-tank experiments of the synchronous interaction between contour currents and turbidity currents to understand the effect of these combined currents on channel architecture and evolution. Our results show that contour currents with a velocity of 10-19 cm s(-1) can substantially deflect the direction of turbidity currents with a maximum velocity of 76-96 cm s(-1), and modify the channel-levee system architecture. A lateral and nearly stationary front formed on the levee located upstream of the contour current, reduced overspill and thus restrained the development of a levee on this side of the channel. Sediment was preferentially carried out of the channel at the flank located downstream of the contour current. An increase in contour-current velocity resulted in an increase in channel-levee asymmetry, with the development of a wider levee and more abundant bedforms downstream of the contour current. This asymmetric deposition along the channel suggests that the direction of long-term migration of the channel form should go against the direction of the contour current due to levee growth downstream of the contour current, in agreement with one of the previously proposed conceptual models.