Universität zu Köln

Le Houedec, Sandrine ORCID: 0000-0002-4938-5613, Mojtahid, Meryem, Ciobanu, Maria, Jorry, Stephan J. ORCID: 0000-0001-8240-9042, Bouhdayad, Fatima Zohra, Guyonneau, Emma, Sourice, Stephane and Toucanne, Samuel ORCID: 0000-0002-4858-8953 (2021). Deglacial to Holocene environmental changes in the northern Ligurian Sea: The dual influence of regional climate variability and large-scale intermediate Mediterranean circulation. Paleogeogr. Paleoclimatol. Paleoecol., 576. AMSTERDAM: ELSEVIER. ISSN 1872-616X

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Abstract

The sedimentary archives of the Mediterranean Sea record periodic deposits of organic-rich deposits, called sapmpels in the eastern basin and organic-rich layers (ORL) in the western basin. Changes in both the Mediterranean circulation and inputs of fresh water through borderlands rivers under more humid climate, are important mechanisms to explain those events. The last ORL and sapropel 51 have different timing, respectively from similar to 14.5 to 9 Ka and from similar to 10 to 6 Ka, presumably due to different forcing factors in the western basin (i.e., melting of Alps ice). Here we present a high-resolution study of a marine sediment core located off the mouth of the Var River, one of the most dynamic river system of the northern borderland of the western Mediterranean Sea. We applied a multi-proxy approach based on benthic foraminiferal assemblages, foraminiferal delta O-18 and delta O-13, grain size analyses, organic carbon content and XRF elemental data to decipher the regional climate signals from the basin-scale intermediate circulation signature. Our results do not show large river inputs at the timing of the last ORL deposit. On the opposite, foraminiferal and geochemical evidence indicate that the 11-6 kyr period, concomitant to Sapropel S1 event in the Eastern Mediterranean, was characterised by high river activity and low ventilated bottom waters at the studied location. Additionally, our results characterized the last 6 ka with large scale episodes of more active bottom water ventilation due perhaps to enhanced wind activity under an overall cooler climate. Time series analyses were computed from stable isotopes, Ca/Ti XRF ratio and foraminifera abundances. They show common frequencies peaks (2.2-3, 1.1-1.2, 0.9-1.0, and 0.4-0.5 kyr) most likely related to the solar activity. Also, a specific frequency band (1.5-1.6 kyr) was only recorded in benthic foraminiferal abundance and stable isotopic records. This was preferentially attributed to an oceanic-driven internal forcing.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Le Houedec, Sandrine UNSPECIFIED orcid.org/0000-0002-4938-5613 UNSPECIFIED Mojtahid, Meryem UNSPECIFIED UNSPECIFIED UNSPECIFIED Ciobanu, Maria UNSPECIFIED UNSPECIFIED UNSPECIFIED Jorry, Stephan J. UNSPECIFIED orcid.org/0000-0001-8240-9042 UNSPECIFIED Bouhdayad, Fatima Zohra UNSPECIFIED UNSPECIFIED UNSPECIFIED Guyonneau, Emma UNSPECIFIED UNSPECIFIED UNSPECIFIED Sourice, Stephane UNSPECIFIED UNSPECIFIED UNSPECIFIED Toucanne, Samuel UNSPECIFIED orcid.org/0000-0002-4858-8953 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-592441
DOI:	10.1016/j.palaeo.2021.110500
Journal or Publication Title:	Paleogeogr. Paleoclimatol. Paleoecol.
Volume:	576
Date:	2021
Publisher:	ELSEVIER
Place of Publication:	AMSTERDAM
ISSN:	1872-616X
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language BAIE-DES-ANGES; SAPROPEL S1; BENTHIC FORAMINIFERA; AFRICAN MONSOON; ECOSYSTEM VARIABILITY; HYDROLOGICAL CHANGES; ATLANTIC CLIMATE; WATER FORMATION; BALEARIC SEA; ALBORAN SEA Multiple languages Geography, Physical; Geosciences, Multidisciplinary; Paleontology Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/59244