Changes in western Mediterranean thermohaline circulation in association with a deglacial Organic Rich Layer formation in the Alboran Sea

QUATERNARY SCIENCE REVIEWS

卷:228

Review

Perez-Asensio, Jose N.¹  Frigola, Jaime¹  Pena, Leopoldo D.¹  Sierro, Francisco J.²  Isabel Reguera, Maria³  Rodriguez-Tovar, Francisco J.⁴  Dorador, Javier⁵  Asioli, Alessandra⁶  Kuhlmann, Jannis⁷  Huhn, Katrin⁷  Cacho, Isabel¹ 

[1] Univ Barcelona, Fac Ciencies Terra, GRC Geociencies Marines, Dept Dinam Terra & Ocea, Carrer Marti & Franques S-N, E-08028 Barcelona, Spain

[2] Univ Salamanca, Dept Geol, E-37008 Salamanca, Spain

[3] IGME Geol Survey Spain, Madrid 28003, Spain

[4] Univ Granada, Dept Estratig & Paleontol, Fuente Nueva S-N, Granada 18002, Spain

[5] Royal Holloway Univ London, Dept Earth Sci, London TW20 0EX, England

[6] CNR ISMAR, Ist Sci Marine, I-40129 Bologna, Italy

[7] Univ Bremen, MARUM Ctr Marine Environm Sci, Bremen, Germany

关键词: Micropaleontology;    Foraminifers;    Ichnology;    Stable isotopes;    Organic matter flux;    Thermohaline circulation;    Paleoceanography;    Organic Rich Layer (ORL);    Western Mediterranean;    Late glacial;    Holocene;   

DOI  :  10.1016/j.quascirev.2019.106075

来源: Elsevier

【 摘 要 】

The accumulation of an Organic Rich Layer (ORL) during the last deglaciation in the Alboran Sea (western Mediterranean Sea) and its link to changes in deep and intermediate water circulation are here investigated. Benthic foraminiferal assemblages and the shallow infaunal foraminifer Uvigerina peregrina delta C-13 record support the establishment of sustained high organic matter fluxes, and thus eutrophic conditions at the sea floor, during the late phase of the ORL (Younger Dryas to early Holocene periods). Since organic matter fluxes were lower (mesotrophic conditions) during the Bolling-Allerod period, they cannot be solely responsible for the ORL initiation. Geochemical, sedimentological and micropalaeontological proxies support a major weakening of the deep-water convection in the Gulf of Lion as the main driver for the development of poorly-ventilated conditions from intermediate depths (946 m) to the deep western Mediterranean basin that promoted the beginning of the ORL deposition. Nevertheless, a better ventilation at intermediate depths was established during the late ORL, while the deep basin remained poorly ventilated. We propose that our data reflect the arrival of a new better-ventilated intermediate water mass analogue to the current Levantine Intermediate Water (LIW) and/or a new intermediate water mass from the Gulf of Lion. The ultimate source of this water mass needs to be further explored but chronologies of the changes recorded here indicate that intermediate and deep ventilation phases were decoupled between the western and eastern Mediterranean basins during the deglaciation and early-middle Holocene. (C) 2019 The Authors. Published by Elsevier Ltd.

【 授权许可】

Free