Sr/Ca and Mg/Ca ratios in Niger Delta sediments: Implications for authigenic carbonate genesis in cold seep environments

Bayon, Germain; Cartigny, Pierre; Étoubleau, Joël; Voisset, M.; Cauquil, E.; Marsset, Tania; Sultan, Nabil; Drezen, E. Le; Fouquet, Yves

doi:10.1016/j.margeo.2007.03.007

Cited by 164 publications

(117 citation statements)

References 29 publications

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“…Occurrence of this CaCO 3 form could imply an increased water supply, as melt water from surrounding glaciers, or as runoff from higher precipitation, leading to dilution of the other minerals (Müller et al 1972). Alternatively, as proposed by Bayon et al (2007), low-Mg calcite may be of biogenic origin, formed by infaunal organisms such as ostracodes, which are abundant during this interval. Aquatic (nC 21 ) n-alkanes show the most depleted dD values in this unit, with a mean of -262% (Fig.…”

Section: Mineral Compositionmentioning

confidence: 90%

A multi-proxy approach to reconstruct hydrological changes and Holocene climate development of Nam Co, Central Tibet

et al. 2009

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Holocene lake level fluctuations were reconstructed from a 2.7-m sediment core from Nam Co, Central Tibet, China dating to [7.2 cal ka BP. Results were compared to existing lake records from the Tibetan Plateau to infer variations in the strength of the Asian Monsoon. Geomorphological features in the Nam Co catchment, such as beach ridges and lake terraces, indicate high lake stands during the late Glacial. A major low stand is suggested for the Last Glacial Maximum (LGM). Sands and sandy silts at the base of the core are transgressive facies, with material transported by melt water and deposited under rising lake level conditions that followed the LGM low stand. Variations in grain size, major elements, biomarker stable isotopes and minerals in the core suggest a climate evolution reflected in at least five depositional units and subunits. Sediments in Unit I (*7.2 to *5.4 cal ka BP) were deposited at highest lake levels. Large amounts of allogenic minerals and allochthonous organic matter suggest high precipitation and melt water input, implying positive water balance. Increasing aquatic productivity points to favourable environmental conditions. Unit II (*5.4 to *4.0 cal ka BP) marks a transition between favourable, stable hydrological conditions and lake level decrease. Lower lake levels were a consequence of drier climate with less monsoonal precipitation, higher evaporation rates, and increased moisture recycling in the catchment. Unit III (*4.0 to *1.4 cal ka BP) reflects the driest periods recorded, at *3.7 cal ka BP and 1.6 cal ka BP. Lake shrinkage and salinization was interrupted as suggested by the deposition of Unit IV (*1.4 to *0.8 cal ka BP), when increased precipitation and runoff that might be related to the Medieval Warm Period, led to a stable, but still low lake level. Unit V (800 cal years BPpresent) is characterized by progressive lake shrinkage due to intense evaporation. Paleolimnol (2010) 43:625-648 DOI 10.1007 data indicate the lake level is rising. Comparison of the Nam Co record with other lake records from the Tibetan Plateau suggests general agreement with the broader picture of Holocene environmental evolution. The timing of dry and wet climate conditions at lake sites across Tibet indicates a gradually decreasing influence of the southern monsoon during the Holocene, from NW to SE. Nevertheless, further research is needed to improve our understanding of Holocene spatio-temporal hydrological variations across the Asian continent.

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Section: Mineral Compositionmentioning

confidence: 90%

A multi-proxy approach to reconstruct hydrological changes and Holocene climate development of Nam Co, Central Tibet

et al. 2009

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“…5e, and Sr/Ca, Fig. 5f) commonly used in the literature to trace terrestrial sources in marine environments (Schnetger et al, 2000;Bayon et al, 2007). Elements present in detrital silicate minerals such as Fe, Ti or Al showed increased values synchronous to the Ca peak (Fig.…”

Section: Gulf Of Lionmentioning

confidence: 94%

Sedimentological imprint on subseafloor microbial communities in Western Mediterranean Sea Quaternary sediments

et al. 2012

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Abstract. An interdisciplinary study was conducted to evaluate the relationship between geological and paleoenvironmental parameters and the bacterial and archaeal community structure of two contrasting subseafloor sites in the Western Mediterranean Sea (Ligurian Sea and Gulf of Lion). Both depositional environments in this area are well-documented from paleoclimatic and paleooceanographic point of views. Available data sets allowed us to calibrate the investigated cores with reference and dated cores previously collected in the same area, and notably correlated to Quaternary climate variations. DNA-based fingerprints showed that the archaeal diversity was composed by one group, Miscellaneous Crenarchaeotic Group (MCG), within the Gulf of Lion sediments and of nine different lineages (dominated by MCG, South African Gold Mine Euryarchaeotal Group (SAGMEG) and Halobacteria) within the Ligurian Sea sediments. Bacterial molecular diversity at both sites revealed mostly the presence of the classes Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria within Proteobacteria phylum, and also members of Bacteroidetes phylum. The second most abundant lineages were Actinobacteria and Firmicutes at the Gulf of Lion site and Chloroflexi at the Ligurian Sea site. Various substrates and cultivation conditions allowed us to isolate 75 strains belonging to four lineages: Alpha-, Gammaproteobacteria, Firmicutes and Actinobacteria. In molecular surveys, the Betaproteobacteria group was consistently detected in the Ligurian Sea sediments, characterized by a heterolithic facies with numerous turbidites from a deep-sea levee. Analysis of relative betaproteobacterial abundances and turbidite frequency suggested that the microbial diversity was a result of main climatic changes occurring during the last 20 ka. Statistical direct multivariate canonical correspondence analyses (CCA) showed that the availability of electron acceptors and the quality of electron donors (indicated by age) strongly influenced the community structure. In contrast, within the Gulf of Lion core, characterized by a homogeneous lithological structure of upper-slope environment, most detected groups were Bacteroidetes and, to a lesser extent, Betaproteobacteria. At both site, the detection of Betaproteobacteria coincided with increased terrestrial Published by Copernicus Publications on behalf of the European Geosciences Union. 3492M.-C. Ciobanu et al.: Sedimentological imprint on subseafloor microbial communities inputs, as confirmed by the geochemical measurements (Si, Sr, Ti and Ca). In the Gulf of Lion, geochemical parameters were also found to drive microbial community composition. Taken together, our data suggest that the palaeoenvironmental history of erosion and deposition recorded in the Western Mediterranean Sea sediments has left its imprint on the sedimentological context for microbial habitability, and then indirectly on structure and composition of the microbial communities during the late Quaternary.

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“…Aragonite cement formed at methane seeps in the Black Sea exhibits Sr contents as high as 9500 ppm, the associ− ated high−Mg−calcite revealed values of approximately 1200 ppm (Peckmann et al 2001). Similarly, aragonite cement of seep carbonates from the Niger Delta showed Sr contents of up to 12 000 ppm, much higher than the contents of 100 ppm to 1000 ppm found for other carbonate mineralogies including calcite and dolomite (Bayon et al 2007). Savard et al (1996) reported as much as 11 000 ppm Sr in aragonite cement of Cre− taceous seep limestone rocks.…”

mentioning

confidence: 90%

A Late Devonian Hydrocarbon-Seep Deposit Dominated by Dimerelloid Brachiopods, Morocco

Peckmann¹,

Campbell²,

Walliser³

et al. 2007

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Sr/Ca and Mg/Ca ratios in Niger Delta sediments: Implications for authigenic carbonate genesis in cold seep environments

Cited by 164 publications

References 29 publications

A multi-proxy approach to reconstruct hydrological changes and Holocene climate development of Nam Co, Central Tibet

A multi-proxy approach to reconstruct hydrological changes and Holocene climate development of Nam Co, Central Tibet

Sedimentological imprint on subseafloor microbial communities in Western Mediterranean Sea Quaternary sediments

A Late Devonian Hydrocarbon-Seep Deposit Dominated by Dimerelloid Brachiopods, Morocco

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