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| DOI | 10.1111/gbi.12321 |
| Microbially influenced formation of Neoarchean ooids | |
| Flannery D.T.; Allwood A.C.; Hodyss R.; Summons R.E.; Tuite M.; Walter M.R.; Williford K.H. | |
| 发表日期 | 2019 |
| ISSN | 14724677 |
| 起始页码 | 151 |
| 结束页码 | 160 |
| 卷号 | 17期号:2 |
| 英文摘要 | Ooids are accretionary grains commonly reported from turbulent, shallow-water environments. They have long been associated with microbially dominated ecosystems and often occur in close proximity to, or embedded within, stromatolites, yet have historically been thought to form solely through physicochemical processes. Numerous studies have revealed both constructive and destructive roles for microbes colonizing the surfaces of modern calcitic and aragonitic ooids, but there has been little evidence for the operation of these processes during the Archean and Proterozoic, when both ooids and microbially dominated ecosystems were more widespread. Recently described carbonate ooids from the 2.9 Ga Pongola Supergroup, South Africa, include well-preserved examples composed of diagenetic dolomite interpreted to have formed from a high-Mg-calcite precursor. Spatial distributions of organic matter and elements associated with metabolic activity (N, S, and P) were interpreted as evidence for a biologically induced origin. Here, we describe exceptionally well-preserved ooids composed of calcite, collected from Earth's oldest known carbonate lake system, the ~2.72 Ga Meentheena Member (Tumbiana Formation), Fortescue Group, Western Australia. We used optical microscopy, Raman spectroscopy, XRD, SEM-EDS, LA-ICP-MS, EA-IRMS, and a novel micro-XRF instrument to investigate an oolite shoal deposited between stromatolites that preserve abundant evidence for microbial activity. We report an extremely fine, radial-concentric, calcitic microfabric that is similar to the primary and early diagenetic fabrics of calcitic ooids reported from modern temperate lakes. Early diagenetic silica has trapped isotopically light and thermally mature organic matter. The close association of organic matter with mineral phases and microfabrics related to primary and early diagenetic processes suggest incorporation of organic matter occurred during accretion, likely due to the presence of microbial biofilms. We conclude that the oldest known calcitic ooids were likely formed through processes similar to those that mediate the accretion of ooids in similar environments today, including formation within a microbial biosphere. © 2018 John Wiley & Sons Ltd |
| 关键词 | Archeancalcitediagenesisdolomitemetabolismmicrobialitemicrofaciesooidphysicochemical propertyProterozoicsoil organic matterstromatoliteAustraliaKwaZulu-NatalPongolaSouth AfricaWestern Australiacalcium carbonatecarbonic acidbacterial phenomena and functionsbiofilmchemistrylakepaleontologysedimentWestern AustraliaBacterial Physiological PhenomenaBiofilmsCalcium CarbonateCarbonatesGeologic SedimentsLakesPaleontologyWestern Australia |
| 语种 | 英语 |
| 来源机构 | Geobiology |
| 文献类型 | 期刊论文 |
| 条目标识符 | http://gcip.llas.ac.cn/handle/2XKMVOVA/133239 |
| 推荐引用方式 GB/T 7714 | Flannery D.T.,Allwood A.C.,Hodyss R.,et al. Microbially influenced formation of Neoarchean ooids[J]. Geobiology,2019,17(2). |
| APA | Flannery D.T..,Allwood A.C..,Hodyss R..,Summons R.E..,Tuite M..,...&Williford K.H..(2019).Microbially influenced formation of Neoarchean ooids.,17(2). |
| MLA | Flannery D.T.,et al."Microbially influenced formation of Neoarchean ooids".17.2(2019). |
| 条目包含的文件 | 条目无相关文件。 | |||||
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