Resumen de Análisis de estratigrafía sísmica y secuencial para el estudio de ciclicidad en el Faro Drift durante el Cuaternario
Estefanía Llave Barranco, Francisco Javier Hernández Molina, Luis Somoza, Víctor Díaz del Río Español, A.C. García
A Quaternany stratigraphic stacking pattern on the Quaternary contourite deposits of the Faro Drift has been determined by analysing and comparing a dense network of low-, medium-, high- and very high-resolution mono-channel and multi-channel reflection seismic lines and welllog data. Two major low-resolution depositional sequences related to a 3rd-order cycle at 800 ky (Ql and Qll), have been recognised in the Quaternary sedimentary record. They are separated by the most prominent sea-level fall at the Middle Pleistocene at 900-920 ky (MPR).
In more detail the Quaternary stratigraphy can be divided into asymmetric 3rd-order sequences of and into 4th-order asymmetric sequences of approximately 400 ky (Ql, Q2, Q3 and Q4), 200 ky (A to H) and 100 ky. An important change in the overall architectural stacking of the contourite deposits shows a clear change after the MPR discontinuity, to a clear progradational body, composed into 10 sequences related to approximately WO ky sealevel cycles. This change in the configuration of the shelf wedges during the Quaternary is attributed to the onset of the 100 ky eccentricity orbital cycles, which abruptly increased the amplitude of sea-level variations (100-120 m) during the last 900920 ky.
