A eukaryote assemblage intercalated with Marinoan glacial deposits in South Australia. / le Heron, Daniel; Alderton, David; Collinson, Margaret; Grassineau, Nathalie; Dan, Sykes; Trundley, A.E.

In: Journal of the Geological Society, Vol. 173, No. 3, 05.2016, p. 560-568.

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A eukaryote assemblage intercalated with Marinoan glacial deposits in South Australia. / le Heron, Daniel; Alderton, David; Collinson, Margaret; Grassineau, Nathalie; Dan, Sykes; Trundley, A.E.

In: Journal of the Geological Society, Vol. 173, No. 3, 05.2016, p. 560-568.

Research output: Contribution to journalArticlepeer-review

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le Heron, Daniel ; Alderton, David ; Collinson, Margaret ; Grassineau, Nathalie ; Dan, Sykes ; Trundley, A.E. / A eukaryote assemblage intercalated with Marinoan glacial deposits in South Australia. In: Journal of the Geological Society. 2016 ; Vol. 173, No. 3. pp. 560-568.

BibTeX

@article{745fa13c38ad4a21bab53ac2758a0581,
title = "A eukaryote assemblage intercalated with Marinoan glacial deposits in South Australia",
abstract = "Composite hematite–silica structures recovered from a siltstone bed in the Elatina Formation of South Australia include (1) sub-circular to whorl-shaped forms, (2) elongate to half-moon-shaped forms and (3) and lozenge-shaped forms locally linked into chains. They range from 200 to 500 µm in diameter and are interpreted as eukaryote tests. Evidence for internal etching of a calcite core of some tests indicates that at least some of the hematite–silica fabrics were acquired through replacement. Carbon isotope values of −20‰ δ13C are suggestive of precipitation by microbial activity, and imply a change in ambient fluid chemistry associated with a pH reduction. The tests occur within sandstone beds that were deposited on a tidally modulated braidplain during the Marinoan glaciation at the end of the Cryogenian. The quartz grains in the sandstone sample lack the typical textures (surface striae, internal fractures or irregular grain boundaries) expected for glacially transported material. Thus, on textural grounds we argue that the eukaryote tests represent a proglacial ecosystem during a late Cryogenian snowball Earth event.",
author = "{le Heron}, Daniel and David Alderton and Margaret Collinson and Nathalie Grassineau and Sykes Dan and A.E. Trundley",
year = "2016",
month = may,
doi = "10.1144/jgs2015-156",
language = "English",
volume = "173",
pages = "560--568",
journal = "Journal of the Geological Society",
issn = "0016-7649",
publisher = "Geological Society of London",
number = "3",

}

RIS

TY - JOUR

T1 - A eukaryote assemblage intercalated with Marinoan glacial deposits in South Australia

AU - le Heron, Daniel

AU - Alderton, David

AU - Collinson, Margaret

AU - Grassineau, Nathalie

AU - Dan, Sykes

AU - Trundley, A.E.

PY - 2016/5

Y1 - 2016/5

N2 - Composite hematite–silica structures recovered from a siltstone bed in the Elatina Formation of South Australia include (1) sub-circular to whorl-shaped forms, (2) elongate to half-moon-shaped forms and (3) and lozenge-shaped forms locally linked into chains. They range from 200 to 500 µm in diameter and are interpreted as eukaryote tests. Evidence for internal etching of a calcite core of some tests indicates that at least some of the hematite–silica fabrics were acquired through replacement. Carbon isotope values of −20‰ δ13C are suggestive of precipitation by microbial activity, and imply a change in ambient fluid chemistry associated with a pH reduction. The tests occur within sandstone beds that were deposited on a tidally modulated braidplain during the Marinoan glaciation at the end of the Cryogenian. The quartz grains in the sandstone sample lack the typical textures (surface striae, internal fractures or irregular grain boundaries) expected for glacially transported material. Thus, on textural grounds we argue that the eukaryote tests represent a proglacial ecosystem during a late Cryogenian snowball Earth event.

AB - Composite hematite–silica structures recovered from a siltstone bed in the Elatina Formation of South Australia include (1) sub-circular to whorl-shaped forms, (2) elongate to half-moon-shaped forms and (3) and lozenge-shaped forms locally linked into chains. They range from 200 to 500 µm in diameter and are interpreted as eukaryote tests. Evidence for internal etching of a calcite core of some tests indicates that at least some of the hematite–silica fabrics were acquired through replacement. Carbon isotope values of −20‰ δ13C are suggestive of precipitation by microbial activity, and imply a change in ambient fluid chemistry associated with a pH reduction. The tests occur within sandstone beds that were deposited on a tidally modulated braidplain during the Marinoan glaciation at the end of the Cryogenian. The quartz grains in the sandstone sample lack the typical textures (surface striae, internal fractures or irregular grain boundaries) expected for glacially transported material. Thus, on textural grounds we argue that the eukaryote tests represent a proglacial ecosystem during a late Cryogenian snowball Earth event.

U2 - 10.1144/jgs2015-156

DO - 10.1144/jgs2015-156

M3 - Article

VL - 173

SP - 560

EP - 568

JO - Journal of the Geological Society

JF - Journal of the Geological Society

SN - 0016-7649

IS - 3

ER -