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230 Th Normalization: New Insights on an Essential Tool for Quantifying Sedimentary Fluxes in the Modern and Quaternary Ocean
Author(s) -
Costa Kassandra M.,
Hayes Christopher T.,
Anderson Robert F.,
Pavia Frank J.,
Bausch Alexandra,
Deng Feifei,
Dutay JeanClaude,
Geibert Walter,
Heinze Christoph,
Henderson Gideon,
HillaireMarcel Claude,
Hoffmann Sharon,
Jaccard Samuel L.,
Jacobel Allison W.,
Kienast Stephanie S.,
Kipp Lauren,
Lerner Paul,
Lippold Jörg,
Lund David,
Marcantonio Franco,
McGee David,
McManus Jerry F.,
Mekik Figen,
Middleton Jennifer L.,
Missiaen Lise,
Not Christelle,
Pichat Sylvain,
Robinson Laura F.,
Rowland George H.,
RoyBarman Matthieu,
Tagliabue Alessandro,
Torfstein Adi,
Winckler Gisela,
Zhou Yuxin
Publication year - 2020
Publication title -
paleoceanography and paleoclimatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.927
H-Index - 127
eISSN - 2572-4525
pISSN - 2572-4517
DOI - 10.1029/2019pa003820
Subject(s) - geology , glacial period , sedimentary rock , oceanography , last glacial maximum , quaternary , authigenic , holocene , paleontology
230 Th normalization is a valuable paleoceanographic tool for reconstructing high‐resolution sediment fluxes during the late Pleistocene (last ~500,000 years). As its application has expanded to ever more diverse marine environments, the nuances of 230 Th systematics, with regard to particle type, particle size, lateral advective/diffusive redistribution, and other processes, have emerged. We synthesized over 1000 sedimentary records of 230 Th from across the global ocean at two time slices, the late Holocene (0–5,000 years ago, or 0–5 ka) and the Last Glacial Maximum (18.5–23.5 ka), and investigated the spatial structure of 230 Th‐normalized mass fluxes. On a global scale, sedimentary mass fluxes were significantly higher during the Last Glacial Maximum (1.79–2.17 g/cm 2 kyr, 95% confidence) relative to the Holocene (1.48–1.68 g/cm 2 kyr, 95% confidence). We then examined the potential confounding influences of boundary scavenging, nepheloid layers, hydrothermal scavenging, size‐dependent sediment fractionation, and carbonate dissolution on the efficacy of 230 Th as a constant flux proxy. Anomalous 230 Th behavior is sometimes observed proximal to hydrothermal ridges and in continental margins where high particle fluxes and steep continental slopes can lead to the combined effects of boundary scavenging and nepheloid interference. Notwithstanding these limitations, we found that 230 Th normalization is a robust tool for determining sediment mass accumulation rates in the majority of pelagic marine settings (>1,000 m water depth).