DOI: 10.1111/gbi.12177
Scopus记录号: 2-s2.0-84975745553
论文题名: Perspectives on heterococcolith geochemical proxies based on high-resolution X-ray fluorescence mapping
作者: Suchéras-Marx B. ; Giraud F. ; Simionovici A. ; Daniel I. ; Tucoulou R.
刊名: Geobiology
ISSN: 1472-4677
EISSN: 1472-4669
出版年: 2016
卷: 14, 期: 4 起始页码: 390
结束页码: 403
语种: 英语
Scopus关键词: chemical analysis
; clay
; coccolith
; cytoplasm
; fossil record
; geochemical survey
; Jurassic
; paleoceanography
; polysaccharide
; seawater
; X-ray fluorescence
; Cape Mondego
; Coimbra [Portugal]
; Portugal
; Haptophyceae
; Watznaueria britannica
Scopus学科分类: Earth and Planetary Sciences: General Earth and Planetary Sciences
; Environmental Science: General Environmental Science
; Agricultural and Biological Sciences: Ecology, Evolution, Behavior and Systematic
英文摘要: Heterococcoliths are micron-scale calcite platelets produced by coccolithophores. They have been the most abundant and continuous fossil record over the last 215 million years (Myr), offering great potential for geochemical studies, although the heterococcolith fossil record remains underutilised in this domain. We have mapped heterococcoliths' composition using X-ray fluorescence (XRF) with a 100-nm resolution beam to decipher element distributions in heterococcoliths and to investigate the potential development of geochemical proxies for palaeoceanography. The study presents two Middle Jurassic Watznaueria britannica heterococcoliths from Cabo Mondego, Portugal. XRF analysis was performed with a 17 keV incident energy beam at the European Synchrotron Radiation Facility ID22NI beamline to study elements from Sr down to S. Ca, Sr and Mn are distributed following the heterococcolith crystalline arrangement. Cl, Br and S display an homogeneous distribution, whereas K, Fe, Cu, Zn and Rb are concentrated at the edges and in the central area of the heterococcoliths. Distributions of K, Fe, Ti, Fe, Cu, Zn, Rb and to a lesser extent V and Cr are highly influenced by clay contamination and peripheral diagenetic overgrowth. Mn is related to diagenetic Mn-rich CaCO3 overgrowth on top of or between heterococcoliths shields. Cl and Br are likely to be present in heterococcoliths inside interstitial nano-domains. We assume that the cytoplasm [Cl−] and [Br−] are mediated and constant during heterococcolithogenesis. Assuming a linear correlation between cytoplasm [Cl−] and sea water [Cl−], heterococcolith Cl may have potential as a salinity proxy. As S is incorporated into heterococcoliths by sulphated polysaccharides, our study suggests a role for such polysaccharides in heterococcolithogenesis for at least 170 Myr. The low Sr/Ca in the W. britannica specimens studied here may either highlight an unusual cellular physiology of Mesozoic coccolithophores or result from low growth rates in oligotrophic environments. © 2016 John Wiley & Sons Ltd Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/85104
Appears in Collections: 影响、适应和脆弱性
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作者单位: UMR CNRS 5276 LGL, Université Claude Bernard Lyon 1, Ecole Normale Supérieure Lyon, Villeurbanne Cedex, France; Université de Lyon, Université Jean Monnet and UMR-CNRS 6524, Laboratoire Magmas et Volcans, Saint Etienne, France; CEREGE UM34, Aix-Marseille Université, CNRS, IRD, Aix-en-Provence, France; Université Grenoble Alpes, ISTerre, Grenoble, France; CNRS, ISTerre, Grenoble, France; ESRF – The European Synchrotron, Grenoble Cedex 9, France
Recommended Citation:
Suchéras-Marx B.,Giraud F.,Simionovici A.,et al. Perspectives on heterococcolith geochemical proxies based on high-resolution X-ray fluorescence mapping[J]. Geobiology,2016-01-01,14(4)