La huella de las oscilaciones globales del nivel del mar durante los últimos 530 000 años en el Golfo de León y su variabilidad durante el estadio isotópico marino 3

Abstract

Borehole PRGL1-4, drilled in the upper slope, provided an exceptional, continuous and long record for investigating the impact of glacial/interglacial sea level oscillations during the Upper Pleistocene in the outbuilding of the Gulf of Lion continental margin, which was dominated by fluvial sedimentary inputs. The detailed analysis of temporal oscillations in grain-size and geochemical elemental composition, together with a robust chronostratigraphy based on the oxygen isotopic record of planktonic foraminifera, allowed reinterpreting the seismostratigraphy of the margin for the last 530 ky. Borehole PRGL1-4 consists of five stacked units that formed during the sea level lowerings of the last five glacial/interglacial 100 ky cycles. The areal extent of the Gulf of Lion’s continental shelf has played a decisive role in the development of the margin since sea level oscillations, in addition of modifying accommodation space, cyclically modified the margin depositional pattern through the highstand activation and lowstand deactivation of highly erosion and transport processes able to carry large amounts of sediment beyond the shelf edge. The PRGL1-4 record also shows the impact of millennial scale sea level oscillations during MIS 3, evidencing the occurrence of relative high sea levels during each of the Dansgaard-Oescheger Greenland warm interstadials. Hence, the PRGL1-4 record represents the first evidence of a consistent coupling between sea level oscillations and millennial scale climate variability associated with Dansgaard-Oeschger cycles.

Keywords

• variabilidad climatica de escala milenaria, estadio isotopico marino (mis 3), oscilaciones del nivel del mar, tamano de grano, golfo de leon,