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A highly productive subarctic Atlantic during the last interglacial and the role of diatoms

O. E. Romero, G. E. A. Swann, D. A. Hodell, P. Helmke, D. Rey and B. Rubio
A highly productive subarctic Atlantic during the last interglacial and the role of diatoms
Geology (Boulder) (November 2011) 39 (11): 1015-1018


The Last Interglacial (LIG), corresponding to Marine Isotope Stage (MIS) 5e, provides a reference of interglacial climate variability in the absence of anthropogenic forcing. Using an expanded section of the LIG gained at Integrated Ocean Drilling Program Site U1304 in the Subarctic Atlantic, we demonstrate that the early MIS 5e was marked by oceanographic conditions conducive for high diatom production and accumulation. The appearance of diatom-dominated laminated oozes approximately 3 k.y. after the beginning of MIS 5e at ca. 125 ka coincides with a shift to higher delta (super 30) Si (sub diat) values together with the dominance of Thalassiothrix longissima, indicative of increased nutrient availability and silicic acid utilization in surface waters. Though the Subarctic Front provided the physical conditions for high diatom production and deposition, these processes alone are insufficient to explain the high rates of siliceous productivity and the formation of diatomaceous sediments. Instead, the additional presence of an increased nutrient pool provided by Subantarctic Mode Water played the decisive role in initiating and sustaining diatom production. The high diatom productivity and the occurrence of diatomaceous sediments in the late Quaternary challenge the current hypothesis of a silica-depleted North Atlantic during the LIG.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 39
Serial Issue: 11
Title: A highly productive subarctic Atlantic during the last interglacial and the role of diatoms
Affiliation: Universidad de Granada, Instituto Andaluz de Ciencias de la Tierra, Granada, Spain
Pages: 1015-1018
Published: 201111
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 27
Accession Number: 2012-007667
Categories: Quaternary geology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: With GSA Data Repository Item 2011301
Illustration Description: sketch map
N53°02'60" - N53°02'60", W33°31'60" - W33°31'60"
Secondary Affiliation: University of Nottingham, GBR, United KingdomUniversity of Cambridge, GBR, United KingdomFederal Institute of Hydrology, DEU, GermanyUniversidad de Vigo, ESP, Spain
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201204
Program Name: IODPIntegrated Ocean Drilling Program
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