Soft‐sediment deformation structures induced by cyclic stress of storm waves in tempestites (Miocene, Guadalquivir Basin, Spain)

Abstract

The identification of triggering agents for soft‐sedimentation structures is an enigmatic geological problem. Mainly seismic‐induced soft‐sediment structures have been recognized in ancient sediments, rather than those resulting from storm waves. We analyse soft‐sediment deformation structures in Upper Miocene calcarenitic tempestites of the Guadalquivir Basin (Southern Spain). The most common structures are load‐casts which vary in height and width from 10 centimetres to several metres. The structures are always restricted to a small part of the stratigraphic sections, in exclusive association with tempestites. The analysed soft‐deformation structures are interpreted to be the result of liquidization processes. Chiefly from their inferred depositional environment, and subordinately from the deformation style, we have devised basic criteria to identify the trigger mechanism. In these soft‐sediment deformation structures the liquefaction was triggered by pore pressure changes induced by cyclic and residual stress of storm waves.

High-Frequency Rhythmicity in a Mixed Siliciclastic-Carbonate Shelf (Late Miocene, Guadix Basin, Spain): A Model of Interplay Between Climatic Oscillations, Subsidence, and Sediment Dispersal

“…The regular presence of hummocky cross-stratification indicates that these tempestites were deposited below fair-weather wavebase and above storm wave-base by stormebb surges (see similar models in Walker 1979;Cheel 1991;and Brenchley et al 1993). The soft-sediment deformation structures associated with the tempestites are interpreted to be due to the loading effect of waves during the deposition of storm beds, similar to the model proposed by Molina et al (1998) and Alfaro et al (2002).…”

Liquefaction and fluidization structures in Messinian storm deposits (Bajo Segura Basin, Betic Cordillera, southern Spain)

“…Martel and Gibling (1993) mentioned storm coeval effects, such as cyclic loading and microseisms, as well as overloading, to explain the origin of clastic dykes in Devono-Carboniferous muddy lacustrine sediments in Canada. Recently, a direct relationship between softsediment deformation structures and the cyclic effect of storm waves has been suggested by Molina et al (1998).…”

Sedimentary record of mid-Miocene seismotectonic activity in the Sinop Peninsula, north-central Turkey

“…This process is the main agent for the development of hydroplastic deformation structures in water-saturated cohesionless sediments (Lowe, 1975;Allen, 1986;Collinson, 1994;Rossetti, 1999;Jones and Omoto, 2000;McLaughlin and Brett, 2004;Neuwerth et al, 2006;Montenat et al, 2007;Moretti and Sabato, 2007). The triggering factor may be an overloading or differential loading, gravitational slumping, seismic shaking, groundwater movement, cyclic and/or impulsive effect of storm wave loading, shear stress of an overriding current, or possibly an abrupt change in relative sea level or ground-water level (Jones, 1972;Lowe, 1975;Allen, 1982;Glennie and Buller, 1983;Mills, 1983;Owen, 1987;Molina et al, 1998;Moretti, 2000).…”