Bárcenas-Gascón, P. (Patricia)

Fernández-Salas, L.M. (Luis Miguel)

Lobo, F.J.

López-González, N. (Nieves)

Macías, J.

English

Lobo, F.J. (Francisco J.)

Repositorio Institucional Digital del IEO

Geophysical Research AbstractsVol. 18, EGU2016-15985, 2016EGU General Assembly 2016© Author(s) 2016. CC Attribution 3.0 License.The influence of basin slope and fluvial flow on deltaic built-up processesoff mountainous, seasonal riversPatricia Bárcenas (1), Jorge Macías (1), Luis Miguel Fernández-Salas (2), Nieves López-González (3), andFrancisco José Lobo (4)(1) Dpto. Análisis Matemático, Facultad de Ciencias, Universidad de Málaga, 29080 Málaga, Spain (pbarcenas@uma.es), (2)Instituto Español de Oceanografía, Centro Oceanográfico de Cádiz, 11006, Cádiz, Spain, (3) Instituto Español deOceanografía, Centro Oceanográfico de Málaga, 29640, Fuengirola, Málaga, Spain, (4) Instituto Andaluz de Ciencias de laTierra (CSIC-Universidad de Granada), 18100, Armilla, Granada, Spain.The construction and evolution of submarine deltaic deposits are influenced by a combination of allogenic fac-tors, such as fluvial flow (Q), and autogenic factors, such as basin slope (BS). Numerical simulations of turbiditycurrents are used to propose a morphodynamic model that quantifies the effect of both the slope and river inputvariations on the development of small deltaic environments in the northern shelf of the Alborán Sea, westernMediterranean Basin, that are linked to short and mountainous fluvial systems controlled by a seasonal Mediter-ranean climate. Traditionally, this type of model has been used for simulating hyperpycnal flows (Parker et al.(1986), Kubo (2004), Khan et al. (2005) & Morales et al. (2009)). In this study, the turbidity-HySEA model hasbeen used taken into account the parameter settings and the numerical resolution specified in Bárcenas (2013) andMorales et al. (2009), respectively. These simulations were performed along a time period of eight days undertwo different fluvial flow conditions (constant and variable flow during the simulation period). Two different typesof bathymetric profiles have been considered: a) piecewise linear profile and b) real bathymetric profiles fromEM3000D multibeam echosounder data obtained off the present-day and artificial mouths of the Adra River. Fivemorphometric parameters were measured for each simulation (time and slope necessary for the formation of thetopset, offlap break distance to the coastline, distal boundary depth and submarine delta length). The numericalexperiments performed demonstrate the nonlinear relationship between the input variables (Q and BS) and themeasured morphometric parameters. The morphodynamic of the sedimentary wedges considering the sedimentdispersion and the offlap-break distance to the coastline can be represented by two extreme cases with many in-termediate cases in between. The first case would be conditioned by proximal sedimentation while in the secondcase sedimentation is dominated by dispersion. From the morphodynamic model and the simulation results, someimplications can be outlined: a) both Q and BS contribute to the basinward progradation of sedimentary wedges;and b) the dominant condition is a balance of the accommodation space (A) and the sediment discharge less than1 (A/S<1) which implies a regression and the progradation of the deltaic system, except for high values of Q andBS, that lead to vertical aggradation (A/S=1). We conclude that both the river flow and the basin slope are keyfactors for the development of large-scale morpho-stratigraphic features of submarine deltas at different spatialscales. ACKNOWLEDGMENTS: This research has been partially supported by the Junta de Andalucía researchTESELA project (P11-RNM7069).

The influence of basin slope and fluvial flow on deltaic built-up processes off mountainous, seasonal rivers

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The influence of basin slope and fluvial flow on deltaic built-up processes off mountainous, seasonal rivers

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