Recent sedimentary facies of the Guadalfeo Turbidite System (North Alboran Sea, SW Mediterranean Sea)
Belén Alonso and Gemma Ercilla, Instituto de Ciencias del Mar, CSIC, Spain
The Guadalfeo turbidite system in the North Alboran Sea, SW Mediterranean Sea, is composed of two sub-systems termed System A (also called the Calahonda Turbidite System) and System B (also named the Sacratif Turbidite System). (Click here to see schematic map).

System A is defined by four relatively small canyons (termed V1 to V4), ten channel-levee complexes and one channelised lobe. System B is characterised by two larger canyons (called the Eastern and Western canyons), two channel-levee complexes and one channelised lobe. The recent depositional architecture of both systems has been governed by lateral and longitudinal migrations.

Recent sedimentologcal studies (textural analysis, analysis of carbonate content and sand fraction composition) of 18 gravity cores up to three metres long have allowed us to define five sedimentary facies within the Guadalfeo Turbidite System: these are canyon, intercanyon, channel, levee, and channelised lobe facies. The canyon facies consists of fining-upward successions from spill-over gravels and sands to turbidite sands and silts (Ta, Tb, and Tc Bouma divisions), with dispersed patches of biogenic debris. The intercanyon facies is also defined by fining upward sequences from spill-over gravels and sands to turbidite sands (Tb). 

The channel facies is characterised by alternating intervals of turbidite sands and silts (Ta, Tb, Tc and Td Bouma divisions), and turbidite sands (Ta and Tb divisions) and debris flow silts. The levee facies comprises fining-upward successions from turbidite sands to turbidite silts (Tc and Td Bouma divisions). The channelised lobe facies contains successions of turbidite sands and silts (Tb and Tc), and turbidite silts and muds (Td and Te) alternating with thin intervals of hemipelagic mud.

The spatial and temporal distribution of the recent sedimentary facies suggest that the development of  System A has been controlled by deposition from turbidity currents and debris flows in a first phase, and by hemipelagic and low-density turbidity currents in a second phase. System B has been dominated by spill-over processes and turbidity current deposition. The occurrence of these processes suggests that system B is presently active whereas within System A, the sedimentary activity has decreased with time.

If you require further information please contact:

Belén Alonso, Instituto de Ciencias del Mar, CSIC - belen@icm.csic.es
Gemma Ercilla, Instituto de Ciencias del Mar, CSIC gemma@icm.csic.es

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