DOI: 10.1111/gbi.12238
Scopus记录号: 2-s2.0-85017629911
论文题名: Proterozoic microbial mats and their constraints on environments of silicification
作者: Manning-Berg A.R. ; Kah L.C.
刊名: Geobiology
ISSN: 1472-4677
EISSN: 1472-4669
出版年: 2017
卷: 15, 期: 4 起始页码: 469
结束页码: 483
语种: 英语
Scopus关键词: brine
; coastal zone
; halite
; marine environment
; microbial mat
; microfossil
; nearshore environment
; Proterozoic
; seawater
; sediment-water interface
; silicification
; thermodynamics
; Baffin Island
; Canada
; Nunavut
; fresh water
; sea water
; silicon dioxide
; chemistry
; fossil
; microbiology
; sediment
; tsunami
; Fossils
; Fresh Water
; Geologic Sediments
; Seawater
; Silicon Dioxide
; Tidal Waves
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: The occurrence of microfossiliferous, early diagenetic chert in Proterozoic successions is broadly restricted to peritidal marine environments. Such coastal environments are amongst the most environmentally variable of marine environments, experiencing both enhanced evaporation and potential influx of terrestrial freshwaters. To better understand potential conditions under which silicification occurs, we focus on microfossiliferous early diagenetic chert from the Mesoproterozoic Bylot Supergroup, northern Baffin Island. Spectacular preservation of silicified microbial mats, their associated mineral phases, and the petrographic fabrics of the chert itself require that silicification occurred at the sediment–water interface, penecontemporaneously with mat growth. In some cases, silica is the primary precipitated mineral phase and is not associated with replacement of precursor mineral phases. In other cases, silica deposition includes the mimetic replacement of carbonate, gypsum, and halite mineral phases. These petrographic constraints suggest that silicification potentially occurred under a range of fluid chemistries associated with environmental variability in nearshore peritidal environments. Here we provide the first direct thermodynamic modeling of hypothetical Proterozoic seawater solutions, seawater-derived brines, and mixed seawater-freshwater solutions, and demonstrate that peritidal environments are capable of providing a wide range of fluid chemistries under which early diagenetic silica can both precipitate and replace primary mineralogical phases. Despite the thermodynamic potential for silica deposition under a wide range of fluid compositions, chert is not ubiquitous in Proterozoic nearshore environments, suggesting that the kinetics of silica polymerization exert a primary control over deposition. © 2017 John Wiley & Sons Ltd Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/85050
Appears in Collections: 影响、适应和脆弱性
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作者单位: Department of Earth and Planetary Science, University of Tennessee, Knoxville, TN, United States
Recommended Citation:
Manning-Berg A.R.,Kah L.C.. Proterozoic microbial mats and their constraints on environments of silicification[J]. Geobiology,2017-01-01,15(4)