Glacio-eustatic sea-level control on Red Sea salinity

Thunell, Robert C.; Locke, Sharon; Williams, Douglas F.

doi:10.1038/334601a0

Cited by 77 publications

(40 citation statements)

References 25 publications

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“…In summary, the enhancement of oxygen isotope ratios by evaporation and the great sensitivity of this enhancement to exchange over the sill (which critically depends on sea level as the first‐order cause of change in the area of the sill passage (Figure 6)) strongly links Red Sea oxygen isotope ratios with sea level. This strong linkage is best exemplified by the fact that the full glacial‐interglacial range of change in stable oxygen isotope ratios is 5.5–6‰, versus roughly 1–1.2 ‰ in the open ocean [ Thunell et al , 1988; Hemleben et al , 1996; Rohling et al , 1998; Fenton et al , 2000; Siddall et al , 2003; Arz et al , 2003a].…”

Section: Stable Oxygen Isotope Ratiosmentioning

confidence: 99%

“…The residence time effect in the Red Sea also affects salinity in the basin; in fact, this salinity effect was studied before the accompanying impact on the oxygen isotopes. It was found that the times of full glacial sea level lowstands were characterized by hypersaline conditions in the Red Sea, which caused development of chemical precipitates, benthic foraminiferal faunas indicative of very high salinities, and aplanktic zones [e.g., Milliman et al , 1969; Deuser et al , 1976; Ivanova , 1985; Winter et al , 1983; Reiss et al , 1980; Locke and Thunell , 1988; Thunell et al , 1988; Almogi‐Labin et al , 1991; Rohling , 1994; Hemleben et al , 1996; Rohling et al , 1998; Fenton et al , 2000]. Aplanktic zones are intervals during which basin salinities in excess of 49 PSU caused widespread (local) extinction of planktic foraminifera, when sea level stood below about −100 m (for an overview, see Fenton et al [2000]).…”

Section: Stable Oxygen Isotope Ratiosmentioning

confidence: 99%

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Marine isotope stage 3 sea level fluctuations: Data synthesis and new outlook

Siddall¹,

Rohling²,

Thompson³

et al. 2008

Reviews of Geophysics

276

208

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[1] To develop a better understanding of the abrupt Dansgaard-Oeschger mode of climate change, it is essential that we establish whether the ice sheets are actively involved, as trigger or amplifier, or whether they merely respond in a passive manner. This requires careful assessment of the fundamental issues of magnitude and phasing of global ice volume fluctuations within marine isotope stage 3 (MIS 3), which to date remain enigmatic.We review recent advances in observational studies pertaining to these key issues and discuss the implications for modeling studies. Our aim is to construct a robust stratigraphic framework for the MIS 3 period regarding sea level variability, using the most up-to-date arguments available by combining insights from both modeling and observational approaches.

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Section: Stable Oxygen Isotope Ratiosmentioning

confidence: 99%

Section: Stable Oxygen Isotope Ratiosmentioning

confidence: 99%

Marine isotope stage 3 sea level fluctuations: Data synthesis and new outlook

Siddall¹,

Rohling²,

Thompson³

et al. 2008

Reviews of Geophysics

276

208

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“…[2] Recently, the Red Sea has been used to derive powerful constraints on the fundamental problem of global sea level throughout most of the last glacial cycle [Thunell et al, 1988;Rohling, 1994;Rohling et al, 1998;Arz et al, 2003Arz et al, , 2007Siddall et al, 2003;Sirocko, 2003]. Key to estimating the uncertainty range of these authors' method is northern Red Sea (NRS) evaporation rate.…”

Section: Introductionmentioning

confidence: 99%

Climatological evaporation seasonality in the northern Red Sea

Eshel

Heavens

2007

Paleoceanography

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[1] The dynamic and thermodynamic processes that underlie the exceptionally high evaporation over the northern Red Sea are examined. Through a combination of data analysis and a simple numerical model we show that the key boundary layer dehumidifier is ageostrophic cross-channel sea breezes. This circulation develops semidiurnally in response to thermal gradients across the Red Sea's coasts because of disparate land-ocean heat capacities. During the summer day the thermally induced high-pressure center over the Red Sea axis results in near-surface flows from the Red Sea toward the neighboring deserts. The strong divergence associated with these flows is maximized along the Red Sea axis and is accompanied by strong subsidence that suppresses boundary layer relative humidity by both reducing specific humidity and increasing temperatures. Because the summer nighttime reversed thermal gradients are smaller in magnitude, the daytime circulation dominates over the nighttime in summer and thus dominates over the daily and seasonal means. Following similar reasoning, we also devise a winter dehumidifier. We conclude by advancing a simple means of estimating Red Sea evaporation under diverse paleoinsolation regimes, and we show small but clear evaporation changes during the course of the Holocene. Our estimates represent lower bounds, and we plan to refine them in follow-up work.

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“…Numerous studies of Holocene and Upper Pleistocene Red Sea sediments have revealed highly variable sediment compositions representing major changes in fauna and flora, which suggests significant climatic and paleoceanographical changes (e.g. Milliman et al, 1969;Deuser and Degens, 1969;Rossignol-Strick, 1987;Thunell et al, 1988;Almogi-Labin et al, 1991). In particular, the Red Sea sediment record contains aplanktonic intervals that represent glacial periods when Red Sea salinities were in excess of the lethal limit for planktonic foraminifera (Hemleben et al, 1996b;Siddall et al, 2004 and literature cited thereunder).…”

Section: Generalmentioning

confidence: 99%

“…The present work, however, focuses on the formation of organic-rich sediments in the Shaban-and Kebrit deeps and their relations to paleoceanographic variations in the northern Red Sea. Sapropelic layers of Red Sea sediments have formerly been recognized (Rossignol-Strick et al, 1982;Ivanova, 1985;Rossignol-Strick, 1987;Locke and Thunell, 1988;Thunell et al, 1988). Basically two models of sapropel formation exist: "high-production" vs. "good-preservation/stagnation" (Olausson, 1961;Calvert, 1983;Almogi-Labin et al, 1991).…”

Section: Sediments Of the Shaban And Kebrit Deepsmentioning

confidence: 99%

Organic-rich sediments in brine-filled Shaban- and Kebrit deeps, northern Red Sea

Botz¹,

Schmidt²,

Wehner³

et al. 2007

Chemical Geology

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The element compositions Si, Ca and Al of up to 21.1 ka old sediments in about 10 m long cores from the southern basin of the Shaban and Kebrit deeps in the northern Red Sea allowed a classification of major sediment types in carbonate sands and -muds and siliceous oozes. A FeOOH-enriched sediment horizon and a few samples with high Zn values in the Kebrit core indicate a hydrothermal origin probably near the brine-sea water interface with subsequent transport of hydrothermal compounds into the deep sediments.High organic carbon contents up to 8.4% are positively correlated with the Ba concentrations, which suggests that high bioproductivity and rapid deposition ( 14 C dating suggests a sedimentation rate near 70 cm/ka) led to the formation of sapropelic sediments between 11.8 and 13.6 ka (Younger Dryas). Organic petrological observations showed that the sediment organic material largely consists of b 20 μm-sized roundish fecal pellets (intimate mixtures of organic matter and inorganic constituents) and bituminite. Terrestrial organic matter (pollens of land plants, fusinite etc.) is very rare in the sediment cores from both deeps.Organic-geochemical investigations of kerogens and organic extracts show that a significant (hydrothermal) hydrocarbon production did not occur in near-surface sediments of the Shaban and Kebrit deeps. Rock Eval pyrolysis of kerogens characterised the organic matter to be of type II quality. The δ 13 C values of the kerogens from the most prominent sapropel in the Shaban deep indicate an enrichment of ( 12 C-rich) nutrients in the water column during postglacial sapropel formation in the Younger Dryas. The n-alkane spectra are dominated by short chain lengths between n-C 15 and n-C 25 . Prevailing n-C 15 to n-C 25 alkanes in low mature sediments are indicative of algal and microbial source. Pristane/phytane ratios are generally low (b1 to ∼ 1) which suggests that anoxic conditions prevailed within the anaerobic brine-filled deeps for the whole time covered by the sediments. This again indicates that sapropel formation was caused by high bioproductivity in the northern Red Sea rather than episodic stagnation with better preservation of the organic matter.Long-chain alkenones and sterols are the dominating compounds of the lipid fraction. Cholesterol contents in the sediment cores reflect phases of eukaryotes production in the water column, whereas the positive correlations of dinosterol with TOC and the amounts of total extract suggests that the major organic carbon source in the northern Red Sea during postglacial high-productivity stages were dinoflagellates. Another important carbon source, however, is indicated by the occurrence of 22,29,30-trisnorhopan-21-one (TNH). Although the formation of TNH from its precursors is not fully understood, this compound probably results from microbial degradation of intact bacteriohopanepolyols (BHP), which can be used as indicators for bacterial abundances and phyla. TNH is most likely produced at the brine-sea water interface where sedime...

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Glacio-eustatic sea-level control on Red Sea salinity

Cited by 77 publications

References 25 publications

Marine isotope stage 3 sea level fluctuations: Data synthesis and new outlook

Marine isotope stage 3 sea level fluctuations: Data synthesis and new outlook

Climatological evaporation seasonality in the northern Red Sea

Organic-rich sediments in brine-filled Shaban- and Kebrit deeps, northern Red Sea

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