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| Wit, J. C.; De Nooijer, L. J.; Barras, C.; Jorissen, F. J.; Reichart, G. J.. |
| The reconstruction of past temperatures is often achieved through measuring the Mg/Ca value of foraminiferal test carbonate. The diversity in foraminiferal Mg/Ca-temperature calibrations suggests that there is also a biological control on this proxy. This study presents a new Mg/Ca-temperature calibration for the benthic foraminifer Bulimina marginata, based on cultures under a range of temperatures (4-14 degrees C). Measured Mg/Ca values for B. marginata correlate with temperature (Mg/Ca = (1.10+/-0.10) e((0.045+/-0.009)) T, R-2 = 0.28 p < 0.01). The inter-individual variability is, however, also significant (standard deviation is 10-35% of the average). Before applying this or any calibration, the effect of the inter-individual variability on the... |
| Tipo: Text |
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| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00249/36045/34589.pdf |
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| Fontanier, Christophe; Koho, K. A.; Goni-urriza, M. S.; Deflandre, Bruno; Galaup, S.; Ivanovsky, A.; Gayet, Nicolas; Dennielou, Bernard; Gremare, Antoine; Bichon, S.; Gassie, C.; Anschutz, P.; Duran, R.; Reichart, G. J.. |
| We present ecological and isotopic (δ18O and δ13C) data on benthic foraminifera sampled from 4 deep-sea stations in a pockmark field from the deep-water Niger delta (Gulf of Guinea, Equatorial Atlantic Ocean). In addition, a series of sedimentological and (bio)geochemical data are shown to back up foraminiferal observations. All stations are located within 1.2 km of each other, so prevailing oceanographic conditions can be assumed to be similar at each site. Two of the sites (GMMC-01 and GMMC-02) are located in a pockmark (named “pockmark A”) where current methane seepages were recorded by ROV observations. A third station (GMMC-03) is located in the topographic depression interpreted as a collapsed pockmark (named “pockmark B”). The fourth site (GMMC-04)... |
| Tipo: Text |
Palavras-chave: Niger delta; Hydrate pockmark; Foraminifera; Stable isotopes; Bacteria. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00211/32194/30628.pdf |
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