Universität zu Köln

Kienast, S. S., Winckler, G., Lippold, J., Albani, S. and Mahowald, N. M. (2016). Tracing dust input to the global ocean using thorium isotopes in marine sediments: ThoroMap. Glob. Biogeochem. Cycle, 30 (10). S. 1526 - 1542. WASHINGTON: AMER GEOPHYSICAL UNION. ISSN 1944-9224

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Abstract

Continental dust input into the ocean-atmosphere system has significant ramifications for biogeochemical cycles and global climate, yet direct observations of dust deposition in the ocean remain scarce. The long-lived isotope thorium-232 (Th-232) is greatly enriched in upper continental crust compared to oceanic crust and mid-ocean ridge basalt-like volcanogenic material. In open ocean sediments, away from fluvial and ice-rafted sources of continental material, Th-232 is often assumed to be of predominantly eolian origin. In conjunction with flux normalization based on the particle reactive radioisotope thorium-230 (Th-230), Th-232 measurements in marine sediments are a promising proxy for dust accumulation in the modern and past ocean. Here we present ThoroMap, a new global data compilation of Th-230-normalized fluxes of Th-232. After careful screening, we derive dust deposition estimates in the global ocean averaged for the late Holocene (0-4 ka) and the Last Glacial Maximum (LGM, 19-23 ka). ThoroMap is compared with dust deposition estimates derived from the Community Climate System Model (CCSM3) and CCSM4, two coupled atmosphere, land, ocean, and sea ice models. Model-data correlation factors are 0.63 (CCSM3) and 0.59 (CCSM4) in the late Holocene and 0.82 (CCSM3) and 0.83 (CCSM4) in the LGM. ThoroMap is the first compilation that is built on a single, specific proxy for dust and that exclusively uses flux-normalization to derive dust deposition rates.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Kienast, S. S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Winckler, G. UNSPECIFIED UNSPECIFIED UNSPECIFIED Lippold, J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Albani, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Mahowald, N. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-261507
DOI:	10.1002/2016GB005408
Journal or Publication Title:	Glob. Biogeochem. Cycle
Volume:	30
Number:	10
Page Range:	S. 1526 - 1542
Date:	2016
Publisher:	AMER GEOPHYSICAL UNION
Place of Publication:	WASHINGTON
ISSN:	1944-9224
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language EASTERN EQUATORIAL PACIFIC; MINERAL DUST; SOUTHERN-OCEAN; EOLIAN DUST; ATMOSPHERIC TRANSPORT; SIZE DISTRIBUTION; ATLANTIC-OCEAN; CLIMATE; FLUXES; DEPOSITION Multiple languages Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/26150