DOI: 10.1111/gbi.12164
Scopus记录号: 2-s2.0-84955632193
论文题名: Nanoscale petrographic and geochemical insights on the origin of the Palaeoproterozoic stromatolitic phosphorites from Aravalli Supergroup, India
作者: Papineau D. ; De Gregorio B. ; Fearn S. ; Kilcoyne D. ; Mcmahon G. ; Purohit R. ; Fogel M.
刊名: Geobiology
ISSN: 1472-4677
EISSN: 1472-4669
出版年: 2016
卷: 14, 期: 1 起始页码: 3
结束页码: 32
语种: 英语
Scopus关键词: apatite
; biomass
; biomineralization
; cyanobacterium
; geochemical method
; isotopic composition
; microbial activity
; organic matter
; petrography
; phosphorite
; Proterozoic
; stromatolite
; succession
; Aravalli Range
; India
; Rajasthan
; Cyanobacteria
; carbon
; mineral
; nitrogen
; organic compound
; phosphate
; phosphorite
; carbon cycle
; chemistry
; cyanobacterium
; fossil
; India
; nitrogen fixation
; pentose phosphate cycle
; Raman spectrometry
; transmission electron microscopy
; Carbon Cycle
; Carbon Isotopes
; Cyanobacteria
; Fossils
; India
; Microscopy, Electron, Transmission
; Minerals
; Nitrogen Fixation
; Nitrogen Isotopes
; Organic Chemicals
; Pentose Phosphate Pathway
; Phosphates
; Spectrum Analysis, Raman
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: Stromatolites composed of apatite occur in post-Lomagundi-Jatuli successions (late Palaeoproterozoic) and suggest the emergence of novel types of biomineralization at that time. The microscopic and nanoscopic petrology of organic matter in stromatolitic phosphorites might provide insights into the suite of diagenetic processes that formed these types of stromatolites. Correlated geochemical micro-analyses of the organic matter could also yield molecular, elemental and isotopic compositions and thus insights into the role of specific micro-organisms among these communities. Here, we report on the occurrence of nanoscopic disseminated organic matter in the Palaeoproterozoic stromatolitic phosphorite from the Aravalli Supergroup of north-west India. Organic petrography by micro-Raman and Transmission Electron Microscopy demonstrates syngeneity of the organic matter. Total organic carbon contents of these stromatolitic phosphorite columns are between 0.05 and 3.0 wt% and have a large range of δ13Corg values with an average of -18.5‰ (1σ = 4.5‰). δ15N values of decarbonated rock powders are between -1.2 and +2.7‰. These isotopic compositions point to the important role of biological N2-fixation and CO2-fixation by the pentose phosphate pathway consistent with a population of cyanobacteria. Microscopic spheroidal grains of apatite (MSGA) occur in association with calcite microspar in microbial mats from stromatolite columns and with chert in the core of diagenetic apatite rosettes. Organic matter extracted from the stromatolitic phosphorites contains a range of molecular functional group (e.g. carboxylic acid, alcohol, and aliphatic hydrocarbons) as well as nitrile and nitro groups as determined from C- and N-XANES spectra. The presence of organic nitrogen was independently confirmed by a CN- peak detected by ToF-SIMS. Nanoscale petrography and geochemistry allow for a refinement of the formation model for the accretion and phototrophic growth of stromatolites. The original microbial biomass is inferred to have been dominated by cyanobacteria, which might be an important contributor of organic matter in shallow-marine phosphorites. Copyright © 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/85118
Appears in Collections: 影响、适应和脆弱性
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作者单位: London Centre for Nanotechnology, University College London, London, United Kingdom; Department of Earth Sciences, University College London, London, United Kingdom; Material Science and Technology Division, Naval Research Laboratory, Washington, DC, United States; Department of Material Sciences, Imperial College, London, United Kingdom; Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, United States; School of Materials, The University of Manchester, Manchester, United Kingdom; Department of Geology, Government College Sirohi, Sirohi, Rajasthan, India; University of California at Merced, Merced, CA, United States
Recommended Citation:
Papineau D.,De Gregorio B.,Fearn S.,et al. Nanoscale petrographic and geochemical insights on the origin of the Palaeoproterozoic stromatolitic phosphorites from Aravalli Supergroup, India[J]. Geobiology,2016-01-01,14(1)