DOI: 10.1111/gbi.12225
Scopus记录号: 2-s2.0-85010208924
论文题名: Biologically agglutinated eukaryotic microfossil from Cryogenian cap carbonates
作者: Moore K.R. ; Bosak T. ; Macdonald F.A. ; Lahr D.J.G. ; Newman S. ; Settens C. ; Pruss S.B.
刊名: Geobiology
ISSN: 1472-4677
EISSN: 1472-4669
出版年: 2017
卷: 15, 期: 4 起始页码: 499
结束页码: 515
语种: 英语
Scopus关键词: aluminosilicate
; carbonate
; chemical analysis
; dolomite
; eukaryote
; feldspar
; fine grained sediment
; glacial deposit
; illite
; iron
; lamination
; microfossil
; mineralogy
; muscovite
; Postglacial
; quartz
; titanium
; transgression
; type locality
; Mongolia
; Zambia
; Eukaryota
; carbonic acid derivative
; aquatic species
; chemistry
; eukaryote
; fossil
; isolation and purification
; Namibia
; sediment
; Aquatic Organisms
; Carbonates
; Eukaryota
; Fossils
; Geologic Sediments
; Namibia
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: Cryogenian cap carbonates that overlie Sturtian glacial deposits were formed during a post-glacial transgression. Here, we describe microfossils from the Kakontwe Formation of Zambia and the Taishir Formation of Mongolia—both Cryogenian age, post-Sturtian cap carbonates—and investigate processes involved in their formation and preservation. We compare microfossils from these two localities to an assemblage of well-documented microfossils previously described in the post-Sturtian Rasthof Formation of Namibia. Microfossils from both new localities have 10 ± 1 μm-thick walls composed of carbonaceous matter and aluminosilicate minerals. Those found in the Kakontwe Formation are spherical or ovoid and 90 ± 5 μm to 200 ± 5 μm wide. Structures found in the Taishir Formation are mostly spherical, 50 ± 5 μm to 140 ± 5 μm wide, with distinct features such as blunt or concave edges. Chemical and mineralogical analyses show that the walled structures and the clay fraction extracted from the surrounding sediments are composed of clay minerals, especially muscovite and illite, as well as quartz, iron and titanium oxides, and some dolomite and feldspar. At each locality, the mineralogy of the microfossil walls matched that of the clay fractions of the surrounding sediment. The abundance of these minerals in the walled microfossils relative to the surrounding carbonate matrix and microbial laminae, and the presence of minerals that cannot precipitate from solution (titanium oxide and feldspar), suggests that the composition represents the original mineralogy of the structures. Furthermore, the consistency in mineralogy of both microfossils and sediments across the three basins, and the uniformity of size and shape among mineral grains in the fossil walls indicate that these organisms incorporated these minerals by primary biological agglutination. The discovery of new, mineral-rich microfossil assemblages in microbially laminated and other fine-grained facies of Cryogenian cap carbonates from multiple localities on different palaeocontinents demonstrates that agglutinating eukaryotes were widespread in carbonate-dominated marine environments in the aftermath of the Sturtian glaciation. © 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/85052
Appears in Collections: 影响、适应和脆弱性
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作者单位: The Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States; The Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, United States; Department of Zoology, University of São Paulo, São Paulo, SP, Brazil; Center for Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States; Department of Geosciences, Smith College, Northampton, MA, United States
Recommended Citation:
Moore K.R.,Bosak T.,Macdonald F.A.,et al. Biologically agglutinated eukaryotic microfossil from Cryogenian cap carbonates[J]. Geobiology,2017-01-01,15(4)