Constraining Water Depth Influence on Organic Paleotemperature Proxies Using Sedimentary Archives

Varma, Devika; Hättig, Katrin; Meer, Marcel T. J. van der; Reichart, Gert‐Jan; Schouten, Stefan

doi:10.1029/2022pa004533

Cited by 7 publications

(1 citation statement)

References 135 publications

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“…Such GDGT‐2/GDGT‐3 values indicate dominant production of‐ and/or export of GDGTs from between ∼50–200 m water depth (Hurley et al., 2018; Rattanasriampaipong et al., 2022; Taylor et al., 2013; van der Weijst et al., 2022). Even though GDGT‐2/GDGT‐3 values exceeding 5 suggest a small component of GDGTs derived from slightly deeper in the water column (Rattanasriampaipong et al., 2022; Taylor et al., 2013), we do not exclude the corresponding TEX 86 values from our record because their influence on TEX 86 is rather small (Varma et al., 2023). Rather, we acknowledge a small, but relatively constant contribution to the GDGT pool by deeper dwelling archaea during the Early and Middle Miocene at Site 959.…”

Section: Resultsmentioning

confidence: 99%

Tropical Warming and Intensification of the West African Monsoon During the Miocene Climatic Optimum

Wubben,

Spiering,

Veenstra

et al. 2024

Paleoceanog and Paleoclimatol

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Studying monsoon dynamics during past warm time periods such as the Miocene Climatic Optimum (MCO; ∼16.9–14.5 Ma) could greatly aid in better projecting monsoon intensity, in the context of future greenhouse warming. However, studies on regional MCO temperature change and its effect on the monsoons during this time period are lacking. Here, we present the first high‐resolution, low‐latitude record of sea surface temperature (SST) and paleoceanographic change covering the Miocene Climatic Optimum, in the eastern equatorial Atlantic, at Ocean Drilling Program Site 959, based on TEX86 paleothermometry. SSTs were ∼1.5°C warmer at the onset of the MCO (16.9 Ma) relative to the pre‐MCO (∼18.3–17.7 Ma). This warming was accompanied by a transient increase in %total organic carbon. Prior to the MCO, sediment composition, geochemical proxy data as well as dinoflagellate cyst assemblages imply a productive surface ocean at Site 959. Immediately following the MCO onset (∼16.9–16.5 Ma), we record an intensification of the West African Monsoon (WAM) characterized by higher amplitude variability in all proxy records on precession to obliquity timescales. We interpret increased orbital‐scale SST, biogenic Ba and dinocyst assemblage variability to represent intensification of equatorial upwelling, forced by the WAM strength. Furthermore, higher SSTs during eccentricity maxima correlate to increased relative abundances of the warm and stratification‐favoring dinocyst Polysphaeridium zoharyi, during periods of low WAM intensity. Finally, while long‐term SSTs decline toward the middle Miocene, maximum SSTs and Polysphaeridium zoharyi abundances occur during MCO peak warming at ∼15.6 Ma.

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Section: Resultsmentioning

confidence: 99%

Tropical Warming and Intensification of the West African Monsoon During the Miocene Climatic Optimum

Wubben,

Spiering,

Veenstra

et al. 2024

Paleoceanog and Paleoclimatol

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Sources and implications of hydroxylated isoprenoid GDGTs on the northwest shelf of Australia through the Pliocene-Pleistocene era

He,

Zhao,

Wang

2024

Chemical Geology

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Evaluating isoprenoidal hydroxylated GDGT-based temperature proxies in surface sediments from the global ocean

Varma,

Hopmans,

van Kemenade

et al. 2024

Geochimica et Cosmochimica Acta

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Constraining Water Depth Influence on Organic Paleotemperature Proxies Using Sedimentary Archives

Abstract: The TEX 86 (TetraEther indeX of 86 carbons;Schouten et al., 2002), based on glycerol dialkyl glycerol tetraethers (GDGTs), has proven invaluable especially with regard to reconstructing sea water temperatures from deep geologic history (e.g.,

Cited by 7 publications

References 135 publications

Tropical Warming and Intensification of the West African Monsoon During the Miocene Climatic Optimum

Tropical Warming and Intensification of the West African Monsoon During the Miocene Climatic Optimum

Sources and implications of hydroxylated isoprenoid GDGTs on the northwest shelf of Australia through the Pliocene-Pleistocene era

Evaluating isoprenoidal hydroxylated GDGT-based temperature proxies in surface sediments from the global ocean

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