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First report of a newly discovered Ediacaran biota from the Irkineeva Uplift, East Siberia

  • A.P. Karpinsky Russian Geological Research Institute, Sredny pr. 74, Saint Petersburg, 199106, RUSSIA

Abstract and Figures

New Ediacara-type macrofossils are described from the Irkineeva Uplift of East Siberia, Russia. Preliminary field studies within the Taseeva Group reveal probable examples of the Ediacaran taxa Arkarua adami and Beltanelliformis minutae; the organo-sedimentary structure `Arumberia'; and `elephant skin' micro bial mat fabrics. These impressions are consistent with a latest Ediacaran age for the units of the upper Taseeva Group, suggesting that they are tens of millions of years younger than has previously been reported. Large discoidal specimens from the upper part of the Sukhoy Pit Group, likely to be Middle Riphean (Mesoproterozoic) in age, are tentatively assigned to the taxon Nimbia occlusa, and are suggested to be microbial in origin. These discs, and a contemporaneous acritarch assemblage of long-ranging sphaeromorphic taxa, cannot be precisely geochronologically constrained at present, but are highly likely to be pre-Ediacaran in age. The Irkineeva finds supplement a diverse suite of Russian Ediacaran (Vendian) fossil localities, and may be of considerable importance in correlating disparate Meso- and Neoproterozoic stratigraphic units across the Siberian Platform. This report emphasises the largely unexplored potential of the Irkineeva Uplift for palaeontological study, and provides tantalising evidence for the preservation of Late Ediacaran macro-organisms in this region
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1. Introduction
The Ediacaran biota is currently known from more
than 35 localities worldwide (Fedonkin et al. 2007),
with more fossil assemblages being discovered and
documented each year. The unusual morphological
attributes of many Ediacaran macrofossils, and the
difficulties encountered in attempting to identify their
phylogenetic position, mean that new sites and speci-
mens are of huge importance to our understanding of
these soft-bodied organisms. Given our ever improv-
ing knowledge of the stratigraphy of global Ediacaran
successions (e. g. Narbonne et al. 2012), such new
finds can also assist in constraining the age of Neo-
proterozoic strata, particularly in areas that have not
yet been radiometrically dated.
Russia has proven a particularly rich source of
Ediacaran material, with multiple localities preserving
taxa in a variety of depositional environments and
lithologies (cf. Fedonkin et al. 2007, fig. 65). Russian
Newsletters on Stratigraphy, Vol. 46/2 (2013), 95110 Article
Stuttgart, August 2013
First report of a newly discovered Ediacaran biota
from the Irkineeva Uplift, East Siberia
Alexander G. Liu
, Martin D. Brasier
, Olga K. Bogolepova
3, 5
Elena G. Raevskaya
, and Alexander P. Gubanov
With 4 figures
Abstract. New Ediacara-type macrofossils are described from the Irkineeva Uplift of East Siberia, Russia.
Preliminary field studies within the Taseeva Group reveal probable examples of the Ediacaran taxa Arkarua
adami and Beltanelliformis minutae; the organo-sedimentary structure ʻArumberiaʼ; and ʻelephant skinʼ micro -
bial mat fabrics. These impressions are consistent with a latest Ediacaran age for the units of the upper Taseeva
Group, suggesting that they are tens of millions of years younger than has previously been reported. Large dis-
coidal specimens from the upper part of the Sukhoy Pit Group, likely to be Middle Riphean (Mesoproterozoic)
in age, are tentatively assigned to the taxon Nimbia occlusa, and are suggested to be microbial in origin. These
discs, and a contemporaneous acritarch assemblage of long-ranging sphaeromorphic taxa, cannot be precisely
geochronologically constrained at present, but are highly likely to be pre-Ediacaran in age. The Irkineeva finds
supplement a diverse suite of Russian Ediacaran (Vendian) fossil localities, and may be of considerable impor-
tance in correlating disparate Meso- and Neoproterozoic stratigraphic units across the Siberian Platform. This
report emphasises the largely unexplored potential of the Irkineeva Uplift for palaeontological study, and pro-
vides tantalising evidence for the preservation of Late Ediacaran macro-organisms in this region.
Key words. Palaeontology, Ediacaran, Vendian, Irkineeva, Neoproterozoic, Mesoproterozoic
© 2013 Gebrüder Borntraeger, Stuttgart, Germany
DOI: 10.1127/0078-0421/2013/0031
0078-0421/2013/0031 $ 4.00
Authorsʼ addresses:
Corresponding author: Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ,
U.K. E-Mail:
Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, OX1 3AN, U.K. E-Mail: martinb@
CASP, West Building, 181a Huntingdon Road, Cambridge, CB3 0DH, U.K.
Geologorazvedka, 11 block 2 Knipovich Street, St. Petersburg, 192019, Russia
Museum of Evolution (Evolutionsmuseet), Uppsala Universitet, Norbyvägen 16, SE-75236 Uppsala, Sweden
Alexander G. Liu
Fig. 1. Map of the Siberian Platform, showing the new Siberian Ediacaran fossil localities in their geographical and geological context. (a) Modern Russia, showing the bound-
ary of the Siberian Platform (black outline) and the courses of major rivers (blue). Star indicates the position of the localities in (b). (b) Geological map of the Irkineeva Up-
lift region (redrawn based upon Kavitsky 2005). Stars indicate the fossil localities; 1) K025 Artyugino 1 road section, ʻArumberiaʼ locality. 2) K030 Moshakov Fm. Arkarua
locality, 3) K036, site of possible Bergaueria, 4) K041, Kartochka Fm. disc locality. (c) Stratigraphic columns showing the position of the Irkineeva Uplift successions, rela-
tive to the International Stratigraphic Chart, and the Russian Stratigraphic Chart. The levels of fossils found in this study are shown on the far right. Correlation between the
International and Siberian Chart (red lines) is based on Rozanov and Varlamov (2008) and Mel’nikov et al. (2005). Bold red dashed line shows the NeoproterozoicCam brian
boundary, bold red solid line shows correlation based on this study. Question mark indicates uncertainty in correlation. For interpretation of the references to colour in this art-
work, the reader is referred to the web version of the article.
Ediacaran palaeontological localities broadly outcrop
within two main Terranes; the Siberian Platform
(which includes sites around the Olenek Uplift, Lake
Baikal, Patom Uplift and Yudoma River; e. g. Sokolov
1975, Chumakov and Semikhatov 1981, Fedonkin et
al. 2007, Leonov and Rud’ko 2012, Zhuravlev et al.
2012), and the East European Platform (including the
White Sea, Podolia, and areas in the South and Central
Ural Mountains; Becker 1977, Grazhdankin 2004,
Fedonkin et al. 2007, Grazhdankin et al. 2009, 2011).
Palaeontological research in these regions has docu-
mented diverse assemblages of Ediacaran taxa (e. g.
Fedonkin 1981), with important discoveries including
carbonate-hosted and carbonaceous preservation of
Ediacaran organisms (within the Khatyspyt Forma-
tion; Grazhdankin et al. 2008), and detailed facies
analyses of the Ediacaran biota (Grazhdankin 2004).
Some of the earliest potential evidence for metazoan
locomotion and grazing in the fossil record comes
from Russian Ediacaran sections (Seilacher et al.
2005, Ivantsov 2011), as well as suggestions of meta-
zoan body fossils, such as the candidate stem-group
mollusc Kimberella (Fedonkin and Waggoner 1997,
though see Ivantsov 2010).
Although Russian stratigraphic sections of Edi-
acaran age are relatively common, reliable correlation
of Neoproterozoic sections across such a vast country
is challenging. This problem stems from a paucity of
palaeontological and reliable geochronological data
in many areas, as well as considerable variability in
facies, even within individual terranes (Mel’nikov et
al. 2005, Kochnev et al. 2007). Attempts have been
made to correlate sedimentary successions across the
Siberian Platform, and then to the rest of the world
(e. g. Pelechaty 1998), but the sheer size of the region,
the facies variation, diverse and disparate stratigraph-
ic records, and challenges in correlating the interior of
the region with the periphery (Mel’nikov et al. 2005)
have made this task difficult. Additional complications
are introduced when attempting to correlate sections
described under Russian stratigraphic terminology
(e. g. Vendian, Riphean; see Semikhatov et al. 2009,
and Sokolov 2011, for further information), with those
described under terms agreed by the Neoproterozoic
Subcommission of the International Commission on
Stratigraphy (Cryogenian, Ediacaran; cf. Gradstein et
al. 2012). Current difficulties in accurately correlating
the Russian and International Stratigraphic Charts ar-
guably make use of a single nomenclatural system
problematic. Therefore, in this publication we use the
terms Vendian and Riphean when describing and dis-
cussing Russian published material, but use Interna-
tional nomenclature wherever possible. Hopefully,
future stratigraphic work will be aided by the drilling
of new boreholes (e. g. Kochnev et al. 2007, Kon-
torovich et al. 2011), together with correlative studies
utilising data from industrial sources (e. g. Frolov et
al. 2011), and the expansion of chemostratigraphic
techniques across Russia (e. g. Podkovyrov et al.
2011). It should also be noted that geochronological
data for late Ediacaran fossil-bearing sections are
gradually becoming more comprehensive, particularly
from the East European Platform (e. g. Martin et al.
2000, Grazhdankin 2004, Llanos et al. 2005, Popov et
al. 2005, Ronkin et al. 2006, Grazhdankin et al. 2011),
which will significantly aid future attempts at region-
al correlation.
We here describe the discovery of apparent Edia -
caran macrofossils from the Irkineeva Uplift of the
East Angara terrane, an area that borders the south-
western Siberian Platform (Gallet et al. 2012). The
only previously reported occurrence of Ediacaran
macrofossils from this region is a single putative
Cyclomedusa specimen from the Redkolesnaya For-
mation (Chechel’ 1976). Fossils in this study were dis-
covered in the summer of 2009 by geologists under-
taking field reconnaissance work for CASP, U.K.
Stratigraphic units in this area have previously been
interpreted to be of Middle Riphean (Mesoprotero-
zoic) to Early Cambrian age (Kavitsky 2005), but pre-
cise geochronological constraints have been lacking.
Revised biostratigraphic understanding resulting from
the palaeontological finds presented herein may sug-
gest a Late Ediacaran age for the upper Taseeva Group,
whilst also extending the fossil record of Mesopro-
terozoic discoidal macrofossils into the Irkineeva re-
gion. Although these new assemblages do not current-
ly show significant taxonomic diversity, and their in-
terpretation is based only upon a handful of specimens,
aspects of their preservation suggest the region has
much promise for further detailed palaeontological in-
2. The geological setting
of the Irkineeva Uplift
The new fossil localities lie along the Irkineeva and
Nizhnyaya Terya Rivers (tributaries of the Angara
River), on the southwestern margin of the Siberian
Platform, to the southeast of the Yenisei Ridge (Fig. 1).
Fossils are found within several geological formations,
First report of a newly discovered Ediacaran biota from the Irkineeva Uplift, East Siberia
namely the Moshakov Formation (previously consid-
ered to be mid-Vendian, ~ 617
17 Ma, in age; K-Ar
date from the Agaleev-1 well, in Gutina 2007), the
Aleshino and Chistyakov Formations (mapped as ear-
ly Vendian, on the basis of poorly constrained Rb-Sr
dates ranging between 619740 Ma; Kavitsky 2005,
Gutina 2007), and the Kartochka and Alad’in Forma-
tions (which have been suggested to be late-Middle
Riphean in age; i. e. Mesoproterozoic, ~ 1.11.0 Ga,
based on K-Ar dating of glauconites in the Potoskuy
and Pogoryuy Formations; Shenfil’ 1991, Maslov et al.
2009; Fig. 1). No diamictite horizons indicative of gla-
cial events have yet been found within the Irkineeva
succession, precluding regional or global correlations
based on these prominent Neoproterozoic event beds.
It is worth noting that the precise names of these for-
mations vary across the literature as a result of differ-
ences in transliteration (e. g. Mel’nikov et al. 2005,
Kochnev et al. 2007, Sovetov et al. 2007). In this pub-
lication we use consistently transliterated versions of
the geological units.
The entire succession in the Irkineeva region is
~ 11.5 km thick, but this thickness includes several
mapped unconformities of uncertain temporal extent
(Kavitsky 2005). At the base of the succession, the
limestones of the Kartochka Formation are considered
to lie conformably upon the Pogoryuy Formation, and
beneath the Alad’in, with these three units together
comprising the shallow-water Upper Subgroup of the
Sukhoy Pit Group (Fig. 1c; Postel’nikov 1980). These
three formations have more recently been elevated
in rank to the Bol’shoi Pit Group (Khomentovsky
2007), though we follow Gallet et al. (2012) in utilis-
ing the prior terminology. A significant unconformity
separates this Group from the younger Potoskuy For-
mation, which is itself capped unconformably by the
Vendian Taseeva Group (comprising the Aleshino,
Chistyakov and Moshakov Formations; Fig. 1c). This
second, angular, unconformity is observed across
much of the Siberian Platform (Sovetov et al. 2007),
and has been ascribed to southern East Siberia being
located within the continental interior during the
early Neoproterozoic (Gladkochub et al. 2010). The
sedimentology of the Taseeva Group records a shallow
marine, largely terrigenous succession, passing through
numerous anhydrites and dolomites within the Chist -
yakov Formation, to coarse-grained fluvial arkosic
sandstones at the top of the Moshakov Formation (cf.
Mel’nikov et al. 2005, Gallet et al. 2012).
The Taseeva Group is conformably overlain by the
Redkolesnaya Fm., which contains ladder-like inter-
ference ripples within shallow marine red sandstones
and siltstones, indicating at least some tidal influence
in that depositional environment. The top of the
Redkolesnaya Fm. (previously part of the Ostrov For-
mation; Kochnev 2002), has yielded one specimen
assigned to Cyclomedusa davidi (Chechel’ 1976),
though no subsequent palaeontological finds have
been reported. The specimen described by Chechelʼ is
incomplete, but does show a broadly concentric dis-
coidal structure that is similar to those found in other
Late Ediacaran sections worldwide (e. g. Fedonkin et
al. 2007). However, correlation by some authors of the
Redkolesnaya Fm. with the Ust Tagul Fm. (Kochnev
and Karlova 2010), which may contain trace fossils
similar to Treptichnus pedum, would suggest the Edi-
acaran-Cambrian boundary lies either within or just
beneath the Redkolesnaya. The carbonates of the Os-
trov Formation, as most recently defined, have been
found to contain small shelly fossils, including Tik-
sitheca, along the southern Yenisei Ridge, indicating a
lower Cambrian age for that Formation (Koch nev and
Karlova 2010). Above the Ostrov are seen several
predominantly shallow marine carbonate formations,
which contain abundant trilobites and brachiopods
(Rozanov et al. 1992), and finally the Ver kho lensk
Formation at the top of the sequence contains numer-
ous bioturbated horizons. The palaeontological assem-
blages of all of these post-Ostrov units are consistent
with a Cambrian or younger age (Fig. 1c).
The Sukhoy Pit Group is found in outcrop along the
Irkineeva River (Fig. 1b), whereas the younger Tasee-
va Group of Vendian to Cambrian units outcrops in
the Nizhnyaya Terya sections. In this paper, the fossil
assemblages from these two geographic locations are
described separately.
3.1 Fossils from the Nizhnyaya Terya
Strata on the banks of the Nizhnyaya Terya River con-
stitute a conformable succession of late Neoprotero-
zoic to Cambrian units. Although the clastic units
within this succession have been extensively traced
around the Siberian Platform (Sovetov et al. 2007),
their perceived age in the Russian literature varies
considerably. For example, the Taseeva Group, which
contains the fossils we describe herein, has been
regarded as either Early (Mel’nikov et al. 2005) or
Late (Sovetov et al. 2007) Vendian in age, on the basis
of correlation and seismostratigraphy. The Ediacaran
macrofossil impressions we describe all come from
Alexander G. Liu
units beneath the Ostrov Formation, thus implying a
pre-Cambrian age for certain pre-Ostrov members of
the succession.
3.1.1 Arumberia-like markings
A specimen from the upper Moshakov Formation,
taken from a road-cut section (Artyugino 1; Fig. 1b.1),
possesses markings directly comparable with the late
Neoproterozoic impression Arumberia banksi Glaess-
ner and Walter 1975 (Fig. 2a). This specimen (K025/1)
occurs upon a fine to medium-grained, micaceous,
well-sorted red sandstone, within a unit of cross-bed-
ded fine to coarse-grained sandstones and conglomer-
ates. Preservation of these features on the lower sur-
face (base) of a bedding plane show parallels with the
taphonomy of biological impressions in the Ediacaran
units of central and southern Australia (e. g. Glaessner
and Walter 1975, Gehling 1999). The surface of the
specimen shows significant topographic undulation
due to the presence of large, isolated ripples. ʻArum-
beriaʼ is characterised by multiple divergent linear
features, spaced 15 mm apart, and is here found
alongside 13 mm diameter circular bumps (the latter
most common on the ridges of the specimen, i. e. in
the troughs of ripples, and seemingly randomly posi-
tioned; Fig. 2ab). Both the linear and discoidal im-
pressions are preserved only on the uppermost 0.5 mm
of the surface – observations of a layer directly be-
neath reveal that they are not transmitted through to
the next sediment layer. The linear ʻArumberiaʼ-like
features show a striking regularity within the hollows
on the specimen surface, but their appearance changes
on the ridges, and individual grooves can be seen to
branch and radiate in places (Fig. 2a).
ʻArumberiaʼ is a cosmopolitan Neoproterozoic
impression, described from Australia (Glaessner and
Walter 1975), the White Sea (Marusin et al. 2011),
Newfoundland (Bland 1984), India (Kumar and
Pandey 2009), the Urals (Fedonkin et al. 2007, p. 172),
China (Liu 1981), and the Long Mynd of the U.K.
(Callow et al. 2011b, Liu 2011). More recently, exam-
ples have also been described from ~ 1 Ga lacustrine
settings in Scotland (Callow et al. 2011a, fig. 10). All
of these occurrences occur in shallow marine to ter-
restrial deposits, and they are often associated with ʻpit
and moundʼ structures (e. g. Salter 1856, Bland 1984),
and microbial fabrics (McIlroy et al. 2005, Callow et
al. 2011a, Callow et al. 2011b, Liu 2011), as is also the
case here (Fig. 2). The biogenicity of ʻArumberiaʼ has
been a subject of much debate (e. g. Brasier 1979,
Bland 1984, McIlroy and Walter 1997, Kumar and
Pandey 2009). However, recent reviews seem to agree
that ʻArumberiaʼ is best explained as an organo-sedi-
mentary structure produced by the interaction of a
shallow water current with microbial mats (e. g. Mc -
Ilroy et al. 2005).
On the same bedding plane, millimetre-scale dis-
coidal impressions are observed (Fig. 2ab). These are
circular to elliptical in shape, and corresponding pits
were found on the counterpart specimen (which re-
mains in the field). Some pits show a pronounced pim-
ple in their centres, while others show a depression,
giving the overall morphology a ʻdonutʼ shape. These
morphological and taphonomic characteristics make
abiogenic interpretations such as raindrop impres-
sions, gas escape structures, or bubble imprints, high-
ly unlikely. The impressions are directly comparable
with specimens from the Long Mynd of Shropshire,
U.K., described as Medusinites aff. asteroides Sprigg
1949, and Intrites punctatus Fedonkin 1980 respec-
tively (cf. McIlroy et al. 2005), and are similarly pre-
served in positive hyporelief. The majority of the sim-
ple discoidal forms are more similar to the type speci-
mens of Beltanelliformis minutae McIlroy et al. 2005.
Their occurrence in association with ʻArumberiaʼ
(Bland 1984), and their resemblance to similar speci-
mens seen on sandstones in other Neoproterozoic lo-
calities (e. g. Kumar and Pandey 2009), support this
classification (though such simple discoidal structures
are not confined to the Ediacaran Period; e. g. Grazh-
dankin et al. 2012). Furthermore, the co-occurrence of
these discrete impressions is also seen in similar shal-
low-marine to fluvial settings of Ediacaran age in the
Long Mynd, U.K. (e. g. Liu 2011). None of the simple
discoidal specimens from the Moshakov Formation
exhibit concentric or radial structures within their in-
teriors (other than the dimples or depressions), and
they possess surface topographies of
1 mm. Discs
occur in both the ridges and troughs of the sample
surface, and do not appear to have a consistent spatial
relationship with the ʻArumberiaʼ features (Fig.
3.1.2 Microbial mats
Also occurring at this locality within the Moshakov
Fm., but on different bedding planes to the ʻArumbe-
riaʼ, are several wrinkle structures and sedimentary
features considered to represent the preserved surfaces
of microbial mats (e. g. Fig. 2c). The figured example
shows a 23 mm diameter polygonal mesh of sharp-
crested thin ridges, reminiscent of ʻelephant skinʼ tex-
tures (sensu Porada and Bouougri 2007, fig. 2bc).
Such impressions are common in Neoproterozoic sili-
First report of a newly discovered Ediacaran biota from the Irkineeva Uplift, East Siberia
Alexander G. Liu
Fig. 2. Impressions from the Artyugino 1 road-cut section, Moshakov Formation, East Siberia. (a) Specimen K025/1, show-
ing regularly spaced grooves, referred to ʻArumberiaʼ, and small positive relief bumps, on the base of a red sandstone.
(b) Close up image of the bumps, often similar to Beltanelliformis minutae, present on the surface of K025/1. White arrows
show specimens with a positive bump in the centre of the disc, similar to Medusinites aff. asteroides (cf. McIlroy et al.,
2005). Orange arrow indicates a specimen with a central depression, similar to that seen in Intrites punctatus. (c) Elephant
skin microbial mat fabric, observed in the field on the top surface of a bedding plane (this specimen remains in the field).
Scale bars in (a) and (b) = 10 mm, (c) = 50 mm.
ciclastic successions (e. g. Gehling 1999, Steiner and
Reitner 2001), and are part of a suite of surface fea-
tures termed Microbially Induced Sedimentary Struc-
tures (MISS, sensu Noffke et al. 2001). MISS also po-
tentially include biofilms, and wrinkle structures (ex-
hibiting reticulate and linear fabrics amongst others;
Hagadorn and Bottjer 1997, Gehling 1999, Porada and
Bouougri 2007), and are mostly found in shallow wa-
ter depositional environments. The Moshakov Forma-
tion examples are found through a ~ 20 m zone within
the succession, and include not only ʻelephant skinʼ
fabrics, but also more linear ʻKinneyiaʼ-like structures
(cf. Porada et al. 2008). Microbial mat fabrics are also
present within the Aleshino Formation on the tops of
fine-grained dark siltstones (e. g. specimen K036/1).
However, the broad stratigraphic ranges of such struc-
tures mean that, like ʻArumberiaʼ, their usefulness in
determining the precise age of the unit is limited.
3.1.3 Complex discoidal fossils
Potentially the most significant find comes from a
locality within the base of the Moshakov Formation,
on the Nizhnyaya Terya River (Fig. 1b.2). Specimen
K030/4 contains two discoidal impressions, each ex-
hibiting a four- or five-rayed star within their internal
structure (Figs. 3ac). Both circular impressions are
preserved in negative hypo-relief, on a micaceous grey
siltstone slab, and are 13 mm in diameter (Fig. 3a). The
depressed centres of the discs are smooth, apart from
the four- or five-rayed collection of ridges centred on
the middle of each impression (Fig. 3bc), and the
discs possess a pronounced lowered rim, 1 mm in
thickness, around their edges. They reach up to 3 mm
in depth, with the internal rays all ~ 1 mm in width, and
up to 4 mm in length. The two specimens both lie in
the centre of a symmetrical ripple. Although the exact
arrangement of internal ridges varies between speci-
mens, the gross morphological similarities between
the discs suggest that the impressions were made by
the same type of object, with variation being poten-
tially taphonomic in nature. Unfortunately, without
additional specimens, it is not possible to investigate
this hypothesis further at the present time.
Concretions or septarian nodules are found in this
region, and occur in underlying strata as 1520 mm
diameter pyrite concretions. However, these features
were rather evident in the field, and did not possess
pronounced rims as in these specimens. In septarian
nodules, calcite septa are typically positive in relief,
and therefore would produce negative relief ridges on
any external mould – the opposite relationship to that
seen here (Fig. 3ac). It is possible that similar struc-
tures could be formed by compaction of a domal struc-
ture, with the rays within the dome being cracks or
fractures. The rims of the two specimens, however, are
more difficult to explain abiogenically.
If biological, the five-rayed specimen is comparable
with the Australian Ediacaran organism Arkarua ada-
mi Gehling 1987, which was originally described as
a potential early echinoderm (Gehling 1987), largely
on the basis of its pentameral symmetry. Arkarua was
previously known only from three localities within the
Ediacara Member of the Rawnsley Quartzite, Flinders
Ranges, South Australia, where it ranges from 3.5 to
10.2 mm in diameter (Gehling 1987).
One specimen from the Aleshino Formation (K036/2;
Fig. 1b.3) possesses a disc, 19 mm in diameter, which
shows considerably more topographic relief (6 mm)
than any other specimen yet found by us from the
Taseeva Group (Fig. 3de). It is preserved in positive
relief on the lower surface of a siltstone bed, and is
similar in several respects to the predominantly
Palaeozoic trace fossil Bergaueria Prantl 1946. The
overall morphology of the impression is cylindrical
rather than conical, with a rounded base and a diame-
ter:height ratio of ~ 3, again consistent with Bergaue-
ria (Pemberton et al. 1988). There is also an obvious
concentricity (Fig. 3d), and one side of the impression
tapers more gently than the others. There is no pre-
served ornamentation or lining to the walls of the
impression, but there is a slight invagination in its
centre, leading us to tentatively suggest that in terms
of biological interpretations, this specimen most simi-
lar to Bergaueria perata Prantl 1946 (Pemberton et al.
1988). Although the specimen was found in float, its
lithological characteristics can be matched directly
with in situ beds of the Aleshino Fm. seen nearby.
Somewhat controversially, Bergaueria has previ-
ously been described from the Stirling Ranges of Aus-
tralia (Cruse and Harris 1994), but a date of
1.8 Ga
(Rasmussen et al. 2004), and the fact that those speci-
mens are quite unlike typical Phanerozoic Bergaueria
specimens (sensu Pemberton et al. 1988), would sug-
gest that the Stirling examples are not true examples
of Ber
gaueria. Several further Neoproterozoic Ber -
gaueria occurrences, in Namibia (Crimes and Germs
1982), the Mackenzie Mountains of Canada (Hofmann
and Aitken 1979), and the White Sea of Russia (Fe-
donkin 1981), can be either assigned to other taxa, or
explained as sedimentological structures (Hofmann
First report of a newly discovered Ediacaran biota from the Irkineeva Uplift, East Siberia
Alexander G. Liu
1985; AGL pers. obs.). Bergaueria specimens de-
scribed from the Zigan Formation of the Southern
Urals represent more promising occurrences, but these
are likely to be of very latest Ediacaran age (Grazh-
dankin et al. 2011). While there is currently no con-
vincing Ediacaran body-fossil evidence for actinian
anemones of the kind usually inferred to have created
Bergaueria s. s. impressions in the Phanerozoic (cf.
Alpert 1973), trace fossils from Mistaken Point in
Newfoundland raise the possibility that actinian-like
organisms inhabited Ediacaran palaeoenvironments
c. 565 Ma (Liu et al. 2010). The discovery of this new
specimen associated with nearby Arkarua specimens,
and beneath a demonstrably Cambrian biota seen in
younger units, could suggest a late Ediacaran age for
this specimen, and would generate considerable inter-
est. However, caution should always be exercised with
individual occurrences of this kind. The recognition of
nodules in younger units of the Taseeva Group serves
as a warning against interpreting simple discoidal im-
pressions as biological structures, and at this point in
time we are not prepared to formally assign this spec-
imen to Bergaueria until further, more convincing
specimens can been obtained.
3.1.4 Microfossils
Samples collected from the Aleshino and Chistyakov
Formations were examined for microfossil taxa, and
a range of simple sphaeromorphic acritarchs were
recovered. These include specimens comparable to
Leiosphaeridia crassa, L. jacutica, L. minutissima,
L. tenuissima, and L. spp. (cf. Jankauskas et al. 1989),
along with Synsphaeridium sp. cell clusters. All of
these taxa are long-ranging, being found in rocks of
Mesoproterozoic to Cambrian age worldwide, and
therefore they are of limited use for biostratigraphic
3.2 Fossils from the Irkineeva River
The successions examined in the vicinity of the Irki-
neeva River contain rocks purported to be considerably
older than those so far discussed. They belong to the
undifferentiated Kartochka and Alad’in Formations
of the Sukhoy Pit Group (a.k.a. Bolshoi Pit Group;
Khomentovsky 2007), which have previously been as-
signed to the Kerpylian strata of the Middle Riphean
(Kavitsky 2005, Gallet et al. 2012; Fig. 1c). The
Sukhoy Pit Group comprises silty shales, sandstones,
and carbonates, considered to represent shallow ma-
rine regressive cycles (Nozhkin et al. 2011). Our field
studies show that the Kartochka Formation is repre-
sented mainly by grey-green to pink, thinly laminated
siliciclastic siltstones alternating with lenses and thin
beds of limestones and dolostones. Hummocky cross-
stratification suggests deposition above storm wave
base (Gallet et al. 2012). Beds of intraformational car-
bonate breccia occur in the upper part of the succes-
sion. No macrofossils have previously been described
from this unit, but rare occurrences of the stromatolite
Malginella have been reported (Rund qvist and Mitro-
fanov 1992). The Sukhoy Pit Group also outcrops
along the Yenisei Ridge, and may show similarities
with the potentially correlative Kerpyl Regional Stage
of the Turukhansk Uplift some 400500 km to the
North (Chumakov and Semikhatov 1981), and the
Uchur-Maya Region far to the East (Gallet et al. 2012).
3.2.1 Discoidal fossils
The most notable fossils discovered by us in these beds
comprise relatively large, simple discs with smooth in-
terior surfaces, free from concentric, radial or invagi-
nated markings, and bounded by a raised (by no more
than 1 mm topographic relief) rim (Fig. 4). Such spec-
imens, found on the top surface of a single bedding
plane, seem to have undergone remarkably little tec-
tonic deformation, with several discoidal impressions
approaching an almost perfectly circular outline
(Figs. 4b, 4d). Interestingly, two specimens from the
same bedding plane are observed to have strikingly
ovate morphologies (Fig. 4b; these specimens remain
in the field; see Fig. 1b.4 for locality information). Of
the specimens collected, two complete circular speci-
mens are 70 and 81 mm in diameter respectively
(Fig. 4bc), with an additional fragmentary specimen
being 85 by 66 mm in maximum and minimum dia -
First report of a newly discovered Ediacaran biota from the Irkineeva Uplift, East Siberia
Fig. 3. Specimens from the Taseeva Group, Nizhnyaya Terya River, East Siberia. (a) Specimen K030/4, showing two small
discs with internal, four- or five-fold structure, similar to Arkarua adami. From the Moshakov Fm. (bc) Close-up images
of the two Arkarua specimens figured in (a). Insets show digitised overlays of the fossils, emphasising the internal symme-
try within each specimen. (de) Specimen K036/2, showing a high-relief discoidal impression similar to Bergaueria cf. per-
ata within a mudstone, in plan and lateral view respectively. The beige colouration is a modern lichen overgrowth. From the
Aleshino Formation. All scale bars = 10 mm.
meter. The variation observed in discoidal morpholo-
gy, amongst specimens in close proximity, suggests
that the original impressions had highly variable ellip-
The Sukhoy Pit discs bear some similarities, particu-
larly their flat and featureless interiors, to several spec-
imens described from the Neoproterozoic Miette Group
(Windermere Supergroup) of the Rocky Mountains;
namely Nimbia occlusa (Hofmann et al. 1991, fig. 6F),
Beltanella sp. cf. B. grandis (Hofmann et al. 1991,
fig. 6G), and “Dubiofossil A” (Hofmann et al. 1991,
fig. 6I). These macroscopic ʻTwitya discs’ (named after
the formation from which they are described) are small-
er than those described here, but are likely to be at least
pre-Marinoan (i. e. pre-Ediacaran) in age (Hofmann et
al. 1990). Somewhat older discoidal specimens of sim-
ilar morphology exist in Kazakhstan (Meert et al. 2011).
The Kazakh fossils are again considerably smaller than
Alexander G. Liu
Fig. 4. Simple discoidal fossils from the upper part of the Sukhoy Pit Group, Irkineeva River, East Siberia. (a) Field local-
ity, with the bed containing the discoidal fossils arrowed. (b) Specimen K041/5, Nimbia occlusa. (c) Two elliptical (uncol-
lected) specimens. (d) Unlabelled specimen, showing a simple spherical discoidal impression, assigned to Nimbia occlusa.
Scale bars: (b) and (d) = 10 mm, (c) = 50 mm.
those seen in East Siberia (only reaching about 20 mm
diameter; Meert et al. 2011), but they occur in sections
considered to be pre-Sturtian in age, i. e., 750 Ma
(Levashova et al. 2011, Meert et al. 201
1). Additional
examples of simple discoids documented from such
Proterozoic successions are discussed in Grazhdankin
et al. 2012. A precedent therefore exists for simple
macroscopic discoidal forms in rocks of pre-Ediacaran
age, though existing dates for units from the Sukhoy
Pit Group are not sufficiently accurate to geochrono-
logically constrain them (7011390 Ma; K-Ar dating
of Gutina 2007).
These large discoidal fossils are here assigned
to Nimbia occlusa (Fedonkin 1980), a species also
known from the White Sea of Russia, the Dniester
River Basin of Ukraine, and the Mackenzie Mountains
of north-western Canada (Fedonkin et al. 2007 and
references therein). For the most part, the term Nimbia
has been applied to forms that are broadly circular in
outline with a flat, featureless interior and a slight
raised rim or depression (e. g. Hagadorn and Waggoner
2000), with few taxonomic connotations. The mor-
phology of Nimbia is very unlike that of known Edi-
acaran frond holdfasts, and we do not consider Nimbia
to represent such a feature. Simple and annulated
Neoproterozoic discoidal fossils have previously been
suggested to represent preserved microbial colonies
(Grazhdankin and Gerdes 2007). We feel that the spec-
imens described herein are also likely to represent mi-
crobial colonies, due to their extremely simple internal
structure, low surface relief, and considerable varia-
tion in gross morphology within single populations
(Fig. 4c). There is currently no additional positive
evidence for the preservation of microbial fabrics or
filaments on this particular bedding plane, though
Kinneyia-like mat fabrics were observed by us from
the Kartochka Fm. elsewhere.
3.2.2 Microfossils
A well-preserved acritarch assemblage of simple
leiosphaerid taxa was recovered from two samples
from the Kartochka and Alad’in Formations, compris-
ing specimens similar to Leiosphaeridia crassa, L. ja-
cutica, L. minutissima, L. tenuissima, L. spp., and Syn-
sphaeridium sp. These are long-ranging acritarchs,
exhibiting ranges spanning Middle Riphean to Late
Vendian ages (Golubkova and Raevskaya 2005). Giv-
en the uncertain extent of taphonomic variation with-
in Proterozoic acritarch assemblages, we cannot con-
strain the age of these successions further until more
characteristic acritarchs can be confidently identified.
4. General discussion
Correlation of many Siberian sections to the Neo -
proterozoic stratigraphy outlined by the International
Stratigraphic Subcommission (Gradstein et al. 2012),
remains largely unresolved in the geological literature.
Although many localities on the periphery of the Siber-
ian Platform exhibit a similar gross stratigraphy (i. e.
mixed Riphean sedimentary units overlain uncon-
formably by Vendian-Cambrian clastic successions),
the relative ages assigned to many of these localities
can differ widely (e. g. Kochnev 2002, Mel’nikov et al.
2005, Sovetov et al. 2007). The fossils described from
the Irkineeva Uplift may enable us to better constrain
the ages of the various units found in the region.
The youngest fossil-bearing unit observed in this
study, the Ostrov Formation, is considered to be of
Nemakit Daldynian age (Early Cambrian of the Inter-
national Stratigraphic Chart), on the basis of the small
shelly fossil Tiksitheca sp. (characteristic of the Purel-
la antiqua Zone), and other shell fragments found
within its type section in the southern Yenisei Range
(Kochnev and Karlova 2010). However, the precise
age of the Redkolesnaya Formation, to which the Cy-
clomedusa found by Chechel’ (1976) has since been
assigned (Kochnev 2002), remains to be determined.
Cyclomedusa specimens from the Perevalok Forma-
tion of the Central Urals have been used as evidence
to suggest a Redkino or younger age (Marusin et al.
2011), and we concur that, based on macro-fossil
evidence and stratigraphic position, the Redkolesnaya
Fm. is likely to have been deposited in the latest Edi-
acaran to earliest Cambrian Periods.
Previous attempts to correlate the Taseeva Group
with other Siberian units have provided multiple inter-
pretations. Mel’nikov et al. (2005) consider the Tasee-
va Group to be lower Vendian/upper Baikalian in age
(Upper Cryogenian to Lower Ediacaran), and correlate
it with the Vanavara and Oskoba Formations of the
Siberian interior. However, a study correlating the
Taseeva Group of the southern Yenisei Ridge with
successions around the south and west of the Siberian
craton suggests a younger, early to mid-Ediacaran age
(Sovetov et al. 2007). The absence of diamictite hori-
zons beneath the Chistyakov Fm. in the Yenisei area
precludes a simple lithostratigraphic solution to this
problem. Furthermore, even though the Yenisei units lie
only a relatively short geographic distance (~ 300 km)
from the Irkineeva Uplift, they may not stratigraphical-
ly correlate at a formational level. Some authors do not
recognise the Moshakov Formation, instead replacing it
First report of a newly discovered Ediacaran biota from the Irkineeva Uplift, East Siberia
with the Grebenʻ and Veselaya Formations, which lie
conformably between the Chist ya kov and Redkoles -
naya Formations (Sovetov et al. 2007; though these
alternative terms are not widely utilised).
The Moshakov Formation macrofossil assemblage
we describe exhibits some similarities with the late
Ediacaran sections of the Flinders Ranges in Australia,
at least in terms of the depauperate biota currently
recognised (Arkarua adami, ʻArumberiaʼ, and Belta -
nel li formis minutae). In Australia, Arkarua is found
amongst diverse and morphologically disparate
palaeocommunities containing iconic Ediacara-type
organisms such as Tribrachidium, Dickinsonia, Par-
vancorina and Cyclomedusa (Gehling 1987). The pre-
liminary documentation of the latter taxon from the
Irkineeva Uplift (Chechel’ 1976), supports the possi-
bility that there may be significant potential for further
palaeontological discoveries in this region. On the ba-
sis of crude biostratigraphic correlation with Australian
sections (themselves correlated to East European sec-
tions on the White Sea coast), the fossil assemblage
we report suggests that sections of the upper Taseeva
Group are latest Ediacaran in age (~ 555549 Ma;
Martin et al. 2000), and therefore considerably younger
(by anything between 60 and 190 million years) than
the dates previously reported for the Group would im-
ply (740617 Ma; Gutina 2007). Such an interpreta-
tion would suggest at least a broad temporal correlation
with other Russian sites containing Ediacaran macro-
organisms, such as the Ustʼyudoma Formation of the
Yudoma-Maya region, and the Khatyspyt Formation
of the Olenek Uplift (Grazhdankin et al. 2008), both
of which have previously been correlated with the Red-
kino horizons of the East European Platform (e. g. the
White Sea; Mel’nikov et al. 2005).
Fossils described from the Oselok Uplift of the
Sayan region, and compared to Dickinsonia, Pteri-
dinium, Tirasiana and Nemiana (Sovetov and Komlev
2005, fig. 10), have previously provided evidence for
an Ediacaran age for both that unit and other correla-
tives (including both the Chistyakov and Aleshino
Formations of the Yenisei ridge; Sovetov et al. 2007).
However, those specimens are not accepted by the
present authors as examples of the taxa they are
claimed to represent; the figured material in Sovetov
and Komlev (2005) seems more akin to simple discs
or sedimentological structures.
On the basis of the few collected specimens we have
from the Irkineeva River, we propose a Late Ediacaran
age for the Taseeva Group, though we acknowledge
that further palaeontological and stratigraphic research
is required to convincingly confirm this, and we en-
courage such future endeavours.
The older Sukhoy Pit Group has previously been
assigned to the mid-Riphean (Mel’nikov et al. 2005). It
is considered to be intruded by ca. 850 Ma granites on
the north-eastern Yenisei Ridge (Sovetov et al. 2007),
but dating of the Garevka granite leaves open the
possibility that the Kartochka and Alad’in Formations
may be younger than ~ 752 Ma (U-Pb TIMS date in
Verni kovsky et al. 2003). A borehole drilled and
analysed along the Angara River within the southern
Yenisei Range, 50100 km west of the Irkineeva sites,
finds the same Sukhoy Pit Group units (Kochnev et al.
2007), and may prove useful for future sedimentologi-
cal facies analyses and geochronological correlation.
Interestingly, correlative units of the Kamo Series,
Baykit Anticlise (Nagovitsin et al. 2010), and the
Debengde Fm. of the Olenek Uplift (Stanevich et al.
2009), both contain rich microfossil assemblages
bearing the Riphean taxon Tappania. The Kartochka
and Alad’in units sampled herein, in contrast, contain
no definitively Riphean palynological taxa, instead
bearing a long-ranging assemblage of sphaeromorphic
taxa, and making age-determination inconclusive. The
Nimbia occlusa specimens we describe from the upper
part of Sukhoy Pit Group may compare favourably with
some Ediacaran discoidal impressions, but are most
similar in their morphologies to macroscopic discoidal
fossils (mostly considered to record microbial colonies)
described from multiple pre-Ediacaran localities (sum-
marised in Grazhdankin et al. 2012). If the Nimbia
specimens we report are microbial colonies, this would
provide further support for a very broad stratigraphic
range for such specimens, perhaps back to the Palaeo-
proterozoic (Rasmussen et al. 2004). However, consid-
ering previous stratigraphic studies in this region, we
feel that until further evidence becomes available, it is
not possible to classify the Sukhoy Pit Group as any-
thing other than Meso- to Neoproterozoic.
5. Conclusions
The discovery of probable Ediacaran fossils in rocks
from the Irkineeva Uplift adds to the growing list of
Ediacaran fossil localities worldwide. The presence of
impressions typical of latest Ediacaran assemblages,
namely Arkarua adami, Beltanelliformis, and the late
Neoproterozoic organo-sedimentary structure ʻArum-
beriaʼ, suggest that the shallow marine Moshakov For-
mation of the Taseeva Group is late Ediacaran in age,
Alexander G. Liu
and thus tens of millions of years younger than previ-
ously thought. The unit may contain the first known
occurrence of the problematic five-rayed fossil Arkarua
outside of Australia. Microfossil specimens from the
Aleshino and Chistyakov Formations are broadly con-
sistent with a late Ediacaran age, but the putative
Bergaueria? specimen we describe ideally requires
validation via additional discoveries. The palynological
assemblages and simple large discoidal fossils from
the Kartochka Formation (the upper part of Sukhoy Pit
Group), which has previously been described as Middle
Riphean, are not currently sufficient to suggest anything
other than a Meso- to Neoproterozoic age. If a mid-
Riphean age were to be confirmed for the Sukhoy Pit
Group, the discoidal specimens we describe add to a
growing list of pre-Ediacaran simple discoidal impres-
sions (cf. Grazhdankin et al. 2012 and references there-
in). Further field exploration of the Irkineeva Uplift
would be highly beneficial, both to constrain the
geochronology of these units, and to investigate the
taxonomic diversity of the Ediacaran biota in this
These finds demonstrate the palaeontological poten-
tial of the remote Irkineeva Uplift region. It is hoped
that as palaeontological records from the Siberian Plat-
form increase in number, accurate correlation of Pro-
terozoic units can be achieved across Russia (i. e. with
the Vendian sections of the White Sea and Urals, which
are themselves undergoing significant study and revi-
sion at present; e. g. Grazhdankin et al. 2011, Marusin
et al. 2011), and beyond. Such a synthesis would bene-
fit not only our understanding of the evolution of life
during the Ediacaran Period, but also research into min-
eral and hydrocarbon deposits across Eastern Siberia.
Acknowledgements. Field materials presented in this
paper were collected during the CASP expedition to East
Siberia. This work was supported by CASP sponsors. AGL
is grateful to Girton College, Cambridge, and the Cambridge
Philosophical Society, for the financial support of a Henslow
Research Fellowship. The suggestions and comments of
Sören Jensen and two anonymous reviewers have greatly
improved this manuscript. Specimens referred to in the text
are part of the sample collections from East Siberia, stored
at CASP, University of Cambridge, UK.
Alpert, S. P., 1973. Bergaueria Prantl (Cambrian and Or-
dovician), a Probable Actinian Trace Fossil. Journal of
Paleontology 47, 919924.
Becker, Y. R., 1977. First paleontological finds in the Riph-
ean of the Urals. Izvestiya Akadamiya Nauk, Seriia Geo-
logicheskaya 3, 90100 [In Russian].
Bland, B. H., 1984. Arumberia Glaessner and Walter, a re-
view of its potential for correlation in the region of the
Precambrian-Cambrian boundary. Geological Magazine
121, 625633.
Brasier, M. D., 1979. The Cambrian radiation event. In:
House, M. R. (Ed.), The Origin of Major Invertebrate
Groups. Academic Press, London, p. 103159.
Callow, R. H. T., Battison, L., Brasier, M. D., 2011a. Diverse
microbially induced sedimentary structures from 1 Ga
lakes of the Diabaig Formation, Torridon Group, north-
west Scotland. Sedimentary Geology 239, 117128.
Callow, R. H. T., McIlroy, D., Brasier, M. D., 2011b. John
Salter and the Ediacara Fauna of the Longmyndian Su-
pergroup. Ichnos 18, 176187.
Chechel’, E. I., 1976. A find of Cyclomedusa in the Ostrov
Formation deposits of the Enisey Ridge. Geology and
Geophysics 17, 118–120 [In Russian].
Chumakov, N. M., Semikhatov, M. A., 1981. Riphean and
Vendian of the USSR. Precambrian Research 15, 229253.
Crimes, T. P., Germs, G. J. B., 1982. Trace fossils from the
Nama Group (PrecambrianCambrian) of southwest
Africa (Namibia). Journal of Paleontology 56, 890907.
Cruse, T., Harris, L. B., 1994. Ediacaran fossils from the
Stirling Range Formation, Western Australia. Precambri-
an Research 67, 110.
Fedonkin, M. A., 1980. Fossil traces of Precambrian Meta-
zoa. Izvestia Akademiya Nauk SSSR, Seriia Geologi -
cheskaya 1, 3946 [In Russian].
Fedonkin, M. A., 1981. Belomorskaya Biota Venda. Trudy
Akademii Nauk SSSR 342, 1100 [In Russian].
Fedonkin, M. A., Waggoner, B. M., 1997. The Late Precam-
brian fossil Kimberella is a mollusc-like bilaterian organ-
ism. Nature 388, 868871.
Fedonkin, M. A., Gehling, J. G., Grey, K., Narbonne, G. M.,
Vickers-Rich, P., 2007. The Rise of Animals: Evolution
and Diversification of the Kingdom Animalia, 1st ed.
John Hopkins University Press, Baltimore, 326 p.
Frolov, S. V., Akhmanov, G. G., Kozlova, E. V., Krylov,
O. V., Sitar, K. A., Galushkin, Y. I., 2011. Riphean basins
of the central and western Siberian Platform. Marine and
Petroleum Geology 28, 906920.
Gallet, Y., Pavlov, V., Halverson, G. P., Hulot, G., 2012.
Toward constraining the long-term reversing behaviour
of the geodynamo: A new “Maya” superchron ~ 1 billion
years ago from the magnetostratigraphy of the Kartochka
Formation (southwestern Siberia). Earth and Planetary
Science Letters 339340, 117126.
Gehling, J. G., 1987. Earliest known echinoderm – a new
Ediacaran fossil from the Pound Subgroup of South Aus-
tralia. Alcheringa 11, 337345.
Gehling, J. G., 1999. Microbial Mats in Terminal Protero-
zoic Siliciclastics: Ediacaran Death Masks. Palaios 14,
Gladkochub, D. P., Donskaya, T. V., Wingate, M. T. D.,
Mazukabzov, A. M., Pisarevsky, S. A., Sklyarov, E. V.,
First report of a newly discovered Ediacaran biota from the Irkineeva Uplift, East Siberia
Stanevich, A. M., 2010. A one-billion-year gap in the Pre-
cambrian history of the southern Siberian craton and the
problem of the Transproterozoic supercontinent. Ameri-
can Journal of Science 310, 812825.
Glaessner, M. F., Walter, M. R., 1975. New Precambrian fos-
sils from the Arumbera Sandstone, Northern Territory,
Australia. Alcheringa 1, 5969.
Golubkova, E. Y., Raevskaya, E. G., 2005. Main changes in
microfossil communities throughout the Upper Protero-
zoic of Russia. In: Steemans, P., Javaux, E. (Eds.), Pre-
cambrian to Palaeozoic Palaeopalynology and Palaeo -
botany, Brest, p. 2125.
Gradstein, F. M., Ogg, J. G., Schmitz, M. D., Ogg, G. (Eds.),
2012. The Geologic Time Scale 2012. Elsevier, 1176 p.
Grazhdankin, D., 2004. Patterns of distribution in the Edi-
acaran biotas: facies versus biogeography and evolution.
Paleobiology 30, 203221.
Grazhdankin, D., Gerdes, G., 2007. Ediacaran microbial
colonies. Lethaia 40, 201210.
Grazhdankin, D., Balthasar, U., Nagovitsin, K. E., Kochnev,
B. B., 2008. Carbonate-hosted Avalon-type fossils in arc-
tic Siberia. Geology 36, 803806.
Grazhdankin, D. V., Maslov, A. V., Krupenin, M. T., 2009.
Structure and depositional history of the Vendian Syl vitsa
Group in the western flank of the Central Urals. Strati -
graphy and Geological Correlation 17, 476492.
Grazhdankin, D. V., Marusin, V. V., Meert, J. G., Krupenin,
M. T., 2011. Kotlin Regional Stage in the South Urals.
Doklady Earth Sciences 440, 12221226.
Grazhdankin, D. V., Goy, Y., Maslov, A. V., 2012. Late Riph-
ean microbial colonies adapted to desiccating environ-
ments. Doklady Earth Sciences 446, 11571161.
Gutina, O. V., 2007. Integrated validation of the stratigraph-
ic scheme of the Riphean sediments in the south-western
part of the Siberian Platform (Baikit, Katanga, Yenisey
Range, Chadobetz Uplift). Publishing House of Siberian
Branch of Russian Academy of Science, Novosibirsk,
171174. Original reference: Карогодин; Открытое
акционер.о-во “Енисейгеофизика”. Новосибирск:
Изд-во СО РАН, 2007. – 174,[2] с.,[10]л.ил.: ил.,
табл. – Библиогр.: с.171174. [In Russian].
Hagadorn, J. W
., Bottjer, D. J., 1997. Wrinkle structures: Mi-
crobially mediated sedimentary structures common in
subtidal siliciclastic settings at the Proterozoic-Phanero-
zoic transition. Geology 25, 10471050.
Hagadorn, J. W., Waggoner, B., 2000. Ediacaran fossils from
the southwestern Great Basin, United States. Journal of
Paleontology 74, 349359.
Hofmann, H. J., 1985. The Mid-Proterozoic Little Dal mac-
robiota, Mackenzie Mountains, north-west Canada. Pa -
laeontology 28, 331354.
Hofmann, H. J., Aitken, J. D., 1979. Precambrian biota from
the Little Dal Group, Mackenzie Mountains, northwest-
ern Canada. Canadian Journal of Earth Sciences 16, 150
Hofmann, H. J., Narbonne, G. M., Aitken, J. D., 1990. Edi-
acaran remains form intertillite beds in northwestern
Canada. Geology 18, 11991202.
Hofmann, H. J., Mountjoy, E. W., Teitz, M. W., 1991. Edi-
acaran fossils and dubiofossils, Miette Group of Mount
Fitzwilliam area, British Columbia. Canadian Journal of
Earth Sciences 28, 15411552.
Ivantsov, A. Y., 2010. Paleontological evidence for the sup-
posed Precambrian occurrence of Mollusks. Paleontolog-
ical Journal 44, 15521559.
Ivantsov, A. Y., 2011. Feeding traces of Proarticulata – the
Vendian metazoa. Paleontological Journal 45, 237248.
Jankauskas, T. V., 1989. Mikrofossilii dokembriya SSSR.
Nauka Leningrad, Leningrad, 190 p. [In Russian].
Kavitsky, M. L., 2005. The mineral resources map of the
Krasnoyarsk region, republics of Khakassiya and Tuva.
Ministry of Natural Resources of the Russian Federation,
Krasnoyarskgeols’emka, 1:1500000.
Khomentovsky, V. V., 2007. The Upper Riphean of the Yeni-
sei Range. Russian Geology and Geophysics 48, 711720.
Kochnev, B. B., 2002. Vendian stratigraphy of the south-
western part of the Siberian Platform, Autoreferat thesis,
Novosibirsk, Novosibirsk, p. 122.
Kochnev, B. B., Karlova, G. A., 2010. New data on bio -
stratigraphy of the Vendian Nemakit-Daldynian Stage in
the southern Siberian Platform. Stratigraphy and Geolog-
ical Correlation 18, 492504.
Kochnev, B. B., Nagovitsin, K. E., Faizullin, M. S., 2007.
The Baikalian and Vendian sequences in the Lower An-
gara area (southwestern Siberian Platform). Russian Geo -
logy and Geophysics 48, 933940.
Kontorovich, A. E., Kostyreva, E. A., Saraev, S. V., Me-
lenevskii, V. N., Fomin, A. N., 2011. The lithology and
organic geochemistry of the Vendian deposits in the cis-
Yenisei subprovince (from the results of the well Vos-
tok-3). Russian Geology and Geophysics 52, 955962.
Kumar, S., Pandey, S. K., 2009. Note on the occurrence of
Arumberia banksi and associated fossils from the Jodhpur
Sandstone, Marwar Supergroup, Western Rajasthan. Jour-
nal of the Palaeontological Society of India 54, 171178.
Leonov, M. V., Rud’ko, S. V., 2012. Finding of the Ediacaran-
Vendian fossils in the far taiga deposits, Patom Highlands.
Stratigraphy and Geological Correlation 20, 497500.
Levashova, N. M., Meert, J. G., Gibsher, A. S., Grice, W. C.,
Bazhenov, M. L., 2011. The origin of microcontinents in
the Central Asian Orogenic Belt: Constraints from paleo-
magnetism and geochronology. Precambrian Research
185, 3754.
Liu, A. G., 2011. Reviewing the Ediacaran fossils of the
Long Mynd, Shropshire. Proceedings of the Shropshire
Geological Society 16, 3143.
Liu, A. G., McIlroy, D., Brasier, M. D., 2010. First evidence
for locomotion in the Ediacara biota from the 565Ma
Mistaken Point Formation, Newfoundland. Geology 38,
Liu, X., 1981. Metazoan fossils from the Mashan Group
near Jixi, Heilongjiang. Bulletin of the Chinese Academy
of Geological Sciences 3, 1183.
Llanos, M. P. I., Tait, J. A., Popov, V., Abalmassova, A.,
2005. Palaeomagnetic data from Ediacaran (Vendian)
sediments of the Arkhangelsk region, NW Russia: An al-
Alexander G. Liu
ternative apparent polar wander path of Baltica for the
Late Proterozoic-Early Palaeozoic. Earth and Planetary
Science Letters 240, 732747.
Martin, M. W., Grazhdankin, D. V., Bowring, S. A., Evans,
D. A. D., Fedonkin, M. A., Kirschvink, J. L., 2000. Age
of Neoproterozoic Bilaterian Body and Trace Fossils,
White Sea, Russia: Implications for Metazoan Evolution.
Science 288, 841845.
Marusin, V. V., Grazhdankin, D. V., Maslov, A. V., 2011.
Redkino Stage in evolution of Vendian macrophytes.
Doklady Earth Sciences 436, 197202.
Maslov, A. V., Nozhkin, A. D., Podkovyrov, V. N., Turkina,
O. M., Letnikova, E. F., Krupenin, M. T., Ronkin, Yu. L.,
Dmitrieva, N. V., Gareev, E. Z., Lepekhina, O. P., 2009.
Geochemical features of the Riphean Fine-Grained Ter-
rigenous Rocks of the Southern Urals, UchurMaya re-
gion, and Yenisei range: estimation of the maturity of the
pre-Riphean continental crust and its evolution within
1.650.616 Ga. Geochem. Int. 47, 692712.
McIlroy, D., Walter, M. R., 1997. A reconsideration of the
biogenicity of Arumberia banksi Glaessner & Walter.
Alcheringa 21, 7980.
McIlroy, D., Crimes, T. P., Pauley, J. C., 2005. Fossils and
matgrounds from the Neoproterozoic Longmyndian Su-
pergroup, Shropshire, U.K. Geological Magazine 142,
Meert, J. G., Gibsher, A. S., Levashova, N. M., Grice, W. C.,
Kamenov, G. D., Ryabinin, A. B., 2011. Glaciation and
~ 770 Ma Ediacara (?) Fossils from the Lesser Karatau
Microcontinent, Kazakhstan. Gondwana Research 19,
Mel’nikov, N. V., Yakshin, M. S., Shishkin, B. B., Efimov,
A. O., Karlova, G. A., Kilina, L. I., Konstantinova, L. N.,
Kochnev, B. B., Kraevskiy, B. G., Mel’nikov, P. N.,
Nagovitsin, K. E., Postnikov, A. A., Ryabkova, L. V.,
Terleev, A. A., Khabarov, E. M., 2005. Summary. In:
Mel’nikov, N. V. (Ed.), Stratigraphy of Oil and Gas
Basins in Siberia. Book 1: Riphean and Vendian of Siber-
ian Platform and its plaited border. Novosibirsk Academ-
ic Publishing House Geo, Novosibirsk, p. 324393.
Nagovitsin, K. E., Stanevich, A. M., Kornilova, T. A., 2010.
Stratigraphic setting and age of the complex Tappania-
bearing Proterozoic fossil biota of Siberia. Russian Geol-
ogy and Geophysics 51, 11921198.
Narbonne, G. M., Xiao, S., Shields, G. A., 2012. The Edi-
acaran Period. In: Gradstein, F. M., Ogg, J. G., Schmitz,
M. D., Ogg, G. (Eds.), The Geologic Time Scale 2012.
Elsevier, Amsterdam, p. 413435.
Noffke, N., Gerdes, G., Klenke, T., Krumbein, W. E., 2001.
Microbially induced sedimentary structures – a new cate-
gory within the classification of primary sedimentary
structures. Journal of Sedimentary Research 71, 649656.
Nozhkin, A. D., Borisenko, A. S., Nevol’ko, P. A., 2011.
Stages of Late Proterozoic magmatism and periods of Au
mineralization in the Yenisei Ridge. Russian Geology and
Geophysics 52, 124143.
Pelechaty, S. M., 1998. Integrated chronostratigraphy of the
Vendian System of Siberia: implications for a global
stratigraphy. Journal of the Geological Society, London
155, 957973.
Pemberton, S. G., Frey, R. W., Bromley, R. G., 1988. The
ichnotaxonomy of Conostichus and other plug-shaped
ichnofossils. Canadian Journal of Earth Sciences 25,
Podkovyrov, V. N., Grazhdankin, D. V., Maslov, A. V., 2011.
Lithogeochemistry of the Vendian fine-grained clastic
rocks in the southern Vychegda Trough. Lithology and
Mineral Resources 46, 427446
Popov, V. V., Khramov, A. N., Bachtadse, V., 2005. Palaeo-
magnetism, magnetic stratigraphy, and petromagnetism
of the Upper Vendian sedimentary rocks in the sections of
the Zolotitsa River and in the Verkhotina Hole, Winter
Coast of the White Sea, Russia. Russian Journal of Earth
Sciences 7, 129.
Porada, H., Bouougri, E. H., 2007. Wrinkle structures – a
critical review. Earth Science Reviews 81, 199215.
Porada, H., Ghergut, J., Bouougri, E. H., 2008. Kinneyia-
type wrinkle structures – critical review and model of for-
mation. Palaios 23, 6577.
Postel’nikov, E. S., 1980. Geosyncline development of the
Yenisey Ridge in the Late Precambrian. Moscow, 71 pp.
[In Russian].
Prantl, F., 1946. Two new problematic trails from the Or-
dovician of Bohemia. Academie tcheque des sciences,
Bulletin International, Classe des sciences mathema-
tiques et naturalles et de la medicine 46, 4959.
Rasmussen, B., Fletcher, I. R., Bengtson, S., McNaughton,
N. J., 2004. SHRIMP U-Pb dating of diagenetic xenotime
in the Stirling Range Formation, Western Australia:
1.8 billion year minimum age for the Stirling biota. Pre-
cambrian Research 133, 329337.
Rozanov, A. Y., Varlamov, A. I. (Eds.), 2008. The Cambrian
System of the Siberian Platform. Part 1: The Aldan-Lena
Region. XIII International Field Conference of the Cam-
brian Stage Subdivision Working Group. Paleontological
Institute, Russian Academy of Sciences, Moscow and
Rozanov, A. Y., Repina, L. N., Apollonov, M. K., Shabanov,
Yu. Ya., Zhuravlev, A. Yu., Pegel’, T. V., Fedorov, A. B.,
Astashkin, V. A., Zhuravleva, I. T., Egorova, L. I.,
Chugaeva, M. N., Dubinina, S. V., Ermak, V. V., Esakova,
N. V., Sundukov, V. V., Sukhov, S. S., Zhemchuzhnikov,
V. G., 1992. Kembrij Sibiri. (The Cambrian of Siberia).
Nauka, Novosibirsk, 135 pp. [In Russian].
Ronkin, Y
. L., Grazhdankin, D., Maslov, A. V., Mizens, G. A.,
Matukov, D. I., Krupenin, M. T., Petrov, G. A., Lepikhina,
O. P., Kornilova, A. Y., 2006. U-Pb (SHRIMP II) age of
zircons from ash beds of the Chernokamen Formation,
Vendian Sylvitsa Group (Central Urals). Doklady Earth
Sciences 411A, 13411345.
Rundqvist, D. V., Mitrofanov, F. P., 1992. Precambrian geol-
ogy of the USSR. Elsevier Science Publishers, Amster-
dam 544 pp.
Salter, J. W., 1856. On fossil remains in the Cambrian rocks
of the Longmynd and North Wales. Quarterly Journal of
the Geological Society 12, 246251.
First report of a newly discovered Ediacaran biota from the Irkineeva Uplift, East Siberia
Seilacher, A., Buatois, L. A., Mangano, M. G., 2005. Trace
fossils in the Ediacaran-Cambrian transition: Behavioral
diversification, ecological turnover and environmental
shift. Palaeogeography, Palaeoclimatology, Palaeoecolo-
gy 227, 323356.
Semikhatov, M. A., Kuznetsov, A. B., Maslov, A. V., Goro -
khov, I. M., Ovchinnikova, G. V., 2009. Stratotype of the
Lower Riphean, the Burzyan Group of the Southern
Urals: Lithostratigraphy, Paleontology, Geochronology,
Sr- and C-Isotopic Characteristics of Its Carbonate
Rocks. Stratigraphy and Geological Correlation 17, 574
Shenfil’, V., 1991. The Late Precambrian of the Siberian
Platform. Nauka, Novosibirsk, 184 pp.
Sokolov, B. S., 1975. On paleontological finds in pre-Usol’e
strata of the Irkutsk Amphitheater. In: Sokolov, B. S.,
Khomentovsky, V. V. (Eds.), Analogues of the Vendian
Complex in Siberia. Nauka, Novosibirsk, p. 112118 [In
Sokolov, B. S., 2011. The chronostratigraphic space of the
lithosphere and the Vendian as a geohistorical subdivision
of the Neoproterozoic. Russian Geology and Geophysics
52, 10481059.
Sovetov, Y. K., Komlev, D. A., 2005. Tillites at the base of
the Oselok Group, foothills of the Sayan Mountains, and
the Vendian Lower Boundary in the southwestern Siber-
ian Platform. Stratigraphy and Geological Correlation 13,
337366 [In Russian].
Sovetov, J. K., Kulikova, A. E. E., Medvedev, M. N., 2007.
Sedimentary basins in the southwestern Siberian craton:
Late NeoproterozoicEarly Cambrian rifting and colli-
sional events. In: Linnemann, U., Nance, R. D., Kraft, P.,
Zulauf, G. (Eds.), The evolution of the Rheic Ocean:
From Avalonian-Cadomian active margin to Alleghenian-
Variscan collision. Geological Society of America,
p. 549578.
Sprigg, R. C., 1949. Early Cambrian ʻjellyfishes’ of Edi-
acara, South Australia, and Mt. John, Kimberley District,
Western Australia. Transactions of the Royal Society of
South Australia 73, 7299.
Stanevich, A. M., Maksimova, E. N., Komilova, T. A., Glad-
kochub, D. P., Mazukabzov, A. M., Donskaya, T. A.,
2009. Microfossils from the Arymas and Debengde For-
mations, the Riphean of the Olenek Uplift: Age and pre-
sumable nature. Stratigraphy and Geological Correlation
17, 2340.
Steiner, M., Reitner, J., 2001. Evidence of organic structures
in Ediacara-type fossils and associated microbial mats.
Geology 29, 11191122.
Vernikovsky, V. A., Vernikovskaya, A. E., Kotov, A. B.,
Sal’nikova, E. B., Kovach, V. P., 2003. Neoproterozoic
accretionary and collisional events on the western margin
of the Siberian craton: new geological and geochrono-
logical evidence from the Yenisey Ridge. Tectonophysics
375, 147168.
Zhuravlev, A. Y., Liñán, E., Gámez Vintaned, J. A., De-
brenne, F., Fedorov, A. B., 2012. New finds of skeletal
fossils in the terminal Neoproterozoic of the Siberian
Platform and Spain. Acta Palaeontologica Polonica 57,
Manuscript received: January 12, 2013; rev. version accept-
ed: April 15, 2013.
Alexander G. Liu
... The quality of preservation and small number of samples does not allow detailed interpretations about 549 the origin of these structures. Many abiotic processes are likely to form similar structures, including 550 concretions, collapse of gas domes, fluid escape structures and septarian nodules (Liu et al., 2013). 551 ...
... Given the presence of radial ridges in our 568 structures, the abundance of MISS in the Izelf Formation and the preservation of microbial mats 569 above some of these structures, such an origin is likely. Similar structures reported from the Ediacaran 570 Taseeva Group (Irkineeva Uplift, East Siberia) were interpreted as soft body fossils (Liu et al., 2013). 571 ...
The Ediacaran period records the appearance of the first multicellular and complex organisms in Earth's history. Within the West African Craton, just a few simple discoidal structures have been previously reported within the supposed Ediacaran successions. Here, we describe for the first time a slightly diversified Ediacaran assemblage of micro- and macro-fossils from Ediacaran volcano-sedimentary rocks of Northwest Africa. Fossils occur in shallow water carbonate-bearing siliciclastic sediments of the Izelf Formation (567–550 Ma), in the Moroccan Anti-Atlas. Macrofossils are represented by Aspidella, ivesheadiomorphs and other problematic structures with putative biotic origin. The macrofossil assemblage is dominated by taphomorphs that indicate different degrees of preservation due to progressive decaying processes, possibly extending the effacement preservation mode outside of Avalonia assemblages. Microbially induced sedimentary structures (MISS), stromatolites and spheroidal microfossils are also reported. In particular, spheroidal microfossils may occur as isolated individuals or as concatenated spheres with potentially cell-division processes and were preserved through carbonate and silica permineralization. Morphologically, spheroidal microfossils are compared to sphaeromorph acritarchs and sulfur-oxidizing bacteria such as genus Thiomargarita. The depositional environment and age interval provide new information concerning paleogeographic and paleoenvironmental conditions of Ediacaran biota living on the West African Craton; hence, fills a gap in the Ediacaran biota in the West African Craton.
... The youngest detrital zircon U-Pb ages of 886 ± 6 Ma from the Ust'-Tagul Formation and 586 ± 20 Ma and 589 ± 33 Ma from the Redkolesnaya Formation of the southern Yenisei Ridge (Priyatkina et al. 2018) provide some information regarding the age of the Moty Group. In this publication, the authors also note unspecified '~542-534 Ma fossils' from the Redkolesnaya Formation by referring to Liu et al. (2013). However, when considering all known reports of fossil occurrences from this unit (Chechel', 1976;Liu et al. 2013), only discoidal Cyclomedusa are present, which is typical for the late Ediacaran Period. ...
... In this publication, the authors also note unspecified '~542-534 Ma fossils' from the Redkolesnaya Formation by referring to Liu et al. (2013). However, when considering all known reports of fossil occurrences from this unit (Chechel', 1976;Liu et al. 2013), only discoidal Cyclomedusa are present, which is typical for the late Ediacaran Period. ...
A number of ecological and geochemical transformations occurred during late Ediacaran and early Cambrian time, the effects of which are difficult to overestimate. However, the strong linkage of biostratigraphic and chemostratigraphic methods with lithofacies makes the localization of the Precambrian-Cambrian boundary and its correlation with lithologically contrasting sections highly debatable. We analyse the taxonomy and stratigraphic distribution of small skeletal fossils and trace fossils, the carbonate carbon and oxygen isotope composition , and U-Pb detrital zircon age in the Ediacaran-Cambrian transitional interval of the Irkutsk Cis-Sayans Uplift (southwestern Siberian Platform). This interval (Moty Group) comprises a transgressive succession with red-coloured alluvial to deltaic siliciclastic deposits (Shaman Formation) and overlying shallow-marine carbonates (Irkut Formation). The lower Irkut Formation hosts sporadic and poorly preserved tubular Cambrotubulus fossils, which are known from both the terminal Ediacaran Period (c. 550-541 Ma) and the Terreneuvian Epoch (541-521 Ma), and typical Fortunian trace fossils, including an index ichnotaxon of the Cambrian boundary Treptichnus pedum. The biostratigraphic and carbonate carbon isotope data and U-Pb concordia ages of 531.1 ± 5.2 Ma (mean weighted, 530.6 ± 5.3 Ma) of the five youngest zircon grains from the lower Irkut Formation indicate that at least the shallow-marine carbonates of the upper Moty Group correspond to the Cambrian Stage 2 (c. 529-521 Ma). In the Irkutsk Cis-Sayans Uplift, the Cambrian Period tentatively began before or during the accumulation of the alluvial to deltaic silici-clastic Khuzhir and Shaman formations, and this crucial divide remained unmarked in the palaeontological and isotopic records.
... Microfossils and stromatolites described in the Taseeva Group sections belong to transitional taxons of very wide stratigraphic ranges (Khomentovsky et al., 1972;Pyatiletov and Karlova, 1983;Liu et al., 2013). However, known Treptichnus trace fossils and small shelly fauna finds reliably constrain the minimal age of the group as not younger than 540 Ma (Kochnev and Karlova, 2010;Sovetov, 2018). ...
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—We report results of a detailed study of the paleomagnetic record in the sedimentary rocks of the Taseeva Group of the Yenisei Ridge in three typical sections in the lower courses of the Angara, Taseeva and Irkineeva rivers. Our results confirm that the geomagnetic field was in an anomalous state at the Precambrian–Phanerozoic boundary. It is well known that Ediacaran rocks in general have preserved several different paleomagnetic directions that do not conform to the geocentric axial dipole model. For example, Siberian sections display two equally valid groups of paleopoles that cause many debates over the geometry of the geomagnetic field and whether any of the components correspond to its dipole configuration. The paleomagnetic record we studied is unique in that the rocks of the Chistyakovka and Moshakovka formations have captured both these components, which is factual evidence of a synchronous existence of two sources. To explain these findings, we propose an original hypothesis in which the bipolar component that is widely present in the rocks and corresponds to the Madagascar group of paleomagnetic poles is associated to the field of the geocentric axial dipole. The less widespread monopolar component corresponding to the Australian–Antarctic group of poles is reflective of a stationary anomalous source. The recording of this source became possible due to the abrupt decrease in the strength of the virtual dipole moment that probably was at its lowest during the accumulation of the Chistyakovka and Moshakovka formations. The new paleomagnetic pole calculated for the bipolar component – 39.2°N, 61.1°E – plots on the apparent polar wander path for Siberia and can be considered a key determination for the age ~570 Ma.
... (3) Ediacaran, Bonney Sandstone, Brachina Gorge, Flinders Ranges, South Australia (Bland, 1984); (4) Ediacaran, Grant Bluff Formation near Mt Skinner, Northern Territory, Australia (Wade, 1969;Retallack & Broz, 2020); (5) Ediacaran, Grant Bluff Formation at Central Mount Stuart, Northern Territory, Australia (Retallack & Broz, 2020); (6), Ediacaran Arumbera Sandstone at Ross River, Valley Dam and Hargrave Lookout, Northern Territory, Australia (Glaessner & Walter, 1975;Mapstone & McIlroy, 2006;Retallack & Broz, 2020); (7) Ediacaran Ust Sylvitsa, Chernyi Kamen and Zigan formations of the Ural Mountains, Russia (Becker, 1980(Becker, , 1985Kolesnikov et al., 2012); (8) Ediacaran Moshakov Formation near Artyugino, east Siberia (Liu et al., 2013); (9) Ediacaran Gibbett Hill Formation of Newfoundland, Canada (Bland, 1984); (10) late Ediacaran or Early Cambrian, Synalds, Lightspout, and Bridges formations near Church Stretton, England (Bland, 1984;McIlroy et al., 2005); (11) Early Cambrian, Billy Creek Formation, Flinders Ranges, South Australia (Bland, 1984;Retallack, 2008); (12) late Ediacaran or early Ordovician, Rozel Conglomerate on the British Channel island of Jersey (Bland, 1984;Went, 2005); and (13) late Ediacaran or early Ordovician Pluorivo Formation near Erquy and Bréhec, France (Bland, 1984). An additional 3 localities for Arumberia in Namibia, China and Sweden are uncertain as to identity of the fossils or the facies in which they were found (Bland, 1984). ...
Quilted fossils known as vendobionts have remained enigmatic because preserved as unrevealing impressions in sandstone, for example, Arumberia banksi Glaessner & Walter, Noffkarkys storaasli Retallack & Broz, and Hallidaya brueri (Wade) Retallack & Broz from the Ediacaran to Cambrian, Grant Bluff and Arumbera formations of central Australia. These same species are reported here in shaley facies of the Early Cambrian Flathead Sandstone of Fishtrap Lake, Montana. These fossils preserved in three dimensions are infiltrated by clay and confirm that each taxon has distinctive internal chambers reflecting segmentation seen on the surface. Sedimentary structures, petrography and geochemistry of the Montana sediments are evidence that Arumberia, Noffkarkys and Hallidaya lived on supratidal flats of a wave-protected rock-bound estuary unaffected by marine bioturbation, and represent intertidal to supratidal ecosystems widespread from the Ediacaran to Cambrian.
... At the Nilpena Ediacara National Park (NENP), excavation of 40 bedding planes, 33 of which preserve >10 individual macroscopic body fossils, reveals an unprecedented abundance and diversity of in situ macroorganism communities and associated microbial mats. Many of the bedding-plane features that are central to defining MISS and TOS (e.g., preservational variability, bed-scale diversity, associated macrobiota, grain size, mineralogy, chemical composition, and sedimentary structures) have previously been described (e.g., Bottjer et al., 2007;Bouougri and Porada, 2007;Carbone and Narbonne, 2014;Corenbilt et al., 2019;Elliott et al., 2011;Hill et al., 2016;Kumar and Ahmad, 2014;Laflamme et al., 2012;Liu et al., 2013;Nettle et al., 2014;Nofke, 2015;Noffke et al., 2002;Noffke, 2009;Sarkar et al., 2008, Sarkar et al., 2016Tarhan et al., 2017;Vago et al., 2017). Here our aim is to use this record to develop criteria to evaluate the maturity or extent of growth of Ediacaran matgrounds and, using these characteristics, to examine the relationship between mat type and maturity and Ediacara Biota community structure. ...
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In the absence of complex, bioturbating organisms, the seafloor during the Precambrian was covered in widespread organic matgrounds. The greatest diversity and complexity of organic mat textures occur in the Ediacaran fossil record as exemplified by the Ediacara Member of the Rawnsley Quartzite, which crops out in and around the Flinders Ranges, South Australia. This succession unambiguously demonstrates that heterogenous mats coexisted with and were central to the ecology and biology of the Ediacara Biota. Excavation of 33 fossiliferous beds with varying types and extents of organosedimentary surface textures provide the opportunity to utilize this record to develop criteria to evaluate the maturity or extent of growth of Ediacaran matgrounds and, using these characteristics, to examine the relationship between mat type, mat maturity and Ediacara Biota community structure. Based on the assumption that mat maturity represents an indicator of the duration of time between burial events, we can test predictions about the relationship between mat maturity and community development. We find that mat maturity, rather than the mat type itself, more strongly influenced the distribution of taxa and the development of Ediacara macroorganism communities. Using a ranked Mat Maturity Index, we find that although density of macroscopic body fossils and genus diversity correlate with mat maturity, evenness does not. We additionally find that the sessile taxa Obamus and Coronacollina are restricted to surfaces with mature mats whereas all other Ediacaran macrobiota show no connection to mat occurrence and maturity. However, we do observe that large Dickinsonia are more likely to occur on surfaces recording mature matgrounds. The exceptional record of mat surfaces preserved in the Flinders Ranges area demonstrates that, in addition to the apparent ecological role played by mat surfaces in Ediacaran communities, they were also likely a significant component of the Ediacara Member biomass and were integral to community function.
... The minimum age of the Taseeva Group is limited by the finds of trace fossils Treptichnus at the top of the overlapping Redkolesny Formation, and by discoveries of smallshelly fossils from the Ostrovnoy Formation, appearing in the latest Vendian (<540 Ma) (Kochnev and Karlova, 2010;Sovetov, 2018). In addition to finds of stromatolites and microfossils represented by transit taxa with a wide stratigraphic range (Khomentovsky et al., 1972;Pyatiletov and Karlova, 1983), the remains of microbial colonies and problematics of similar origin in the Chistyakova Formation were described (Liu et al., 2013), with also no stratigraphic importance. Published determinations of absolute age for the Taseeva Group, ranging from 761 to 617 Ma (Gutina and Sidoras, 2001;Varlamov, 2018), were performed by the Rb-Sr method using whole rock samples of clay fractions, therefore, the age of authigenic mineral phases was performed incorrectly and cannot now be considered as valid. ...
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A high-amplitude negative δ 13 С anomaly (-11‰ V-PDB) has been found in the carbonate horizons of the Chistyakovka Formation of the Taseeva Group in the type sections of the southern Yenisei Ridge. The δ 18 О values (-2.7 to-5.4‰ V-PDB) and the lithologic features of carbonates indicate that these are primary sedimentary rocks and their isotope parameters reflect the primary isotope composition of the paleobasin waters. The negative δ 13 С excursion in the Chistyakovka Formation is close in stratigraphic position and amplitude to similar isotope excursion in the Vendian strata of the southern Siberian Platform and to the global middle Ediacaran Shuram-Wonoka anomaly. According to the data on clastic zircons, the age of the Chistyakovka Formation is no older than 580 Ma, which agrees with the earlier estimated age of the Shuram-Wonoka event. As follows from the data obtained, the age of the basement of the Taseeva Group is no older than 600 Ma. This provides a more accurate correlation of the Vendian complex along the southwestern margin of the Siberian Platform. The different stratigraphic scales of the sediments indicate that the marginal trough here began to form at different times (from late Riphean to late Vendian), which explains its segmented structure.
... Минимальный возраст тасеевской серии определяется находками в верхах перекрывающей редколесной свиты ископаемых следов Treptichnus и мелкораковинных остатков в островной свите, появляющихся в конце венда (<540 млн лет назад) [Кочнев, Карлова, 2010; Советов, 2018]. Кроме находок строматолитов и микрофоссилий, представленных транзитными таксонами с широким стратиграфическим диапазоном [Хоментовский и др., 1972; Пятилетов, Карлова, 1983], в чистяковской свите описаны остатки микробиальных колоний и сходной по происхождению проблематики [Liu et al., 2013], также не имеющие стратиграфического значения. Опубликованные определения абсолютного возраста для тасеевской серии, лежащие в интервале 617-761 млн лет [Гутина, Сидорас, 2001; Тасеевская…, 2018], были выполнены Rb-Sr методом по валовым образцам глинистых фракций, поэтому некорректно отражают возраст аутигенных минеральных фаз и не могут рассматриваться как валидные. ...
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В горизонтах карбонатных пород чистяковской свиты тасеевской серии в типовых разрезах юга Енисейского кряжа обнаружена высокоамплитудная отрицательная аномалия δ13С до-11 ‰ V-PDB. Значения δ 18 О (-2.7…-5.4 ‰ V-PDB) и литологические особенности карбонатов позволяют считать их первично-осадочными, а их изотопные характеристики - отражающими исходный изотопный состав вод палеобассейна. Негативный экскурс δ 13 С в чистяковской свите по стратиграфическому положению и амплитуде близок к аналогичным изотопным событиям в венде юга Сибирской платформы и сопоставляется с глобальной среднеэдиакарской аномалией Шурам-Вонока. Максимальный возраст осадконакопления чистяковской свиты, исходя из данных по обломочным цирконам, составляет не более 580 млн лет, что полностью согласуется с прежними оценками возраста события Шурам-Вонока. Возраст основания тасеевской серии, по полученным данным, не древнее 600 млн лет, что позволяет существенно уточнить корреляцию вендского комплекса вдоль юго-западной окраины Сибирской платформы. Различный стратиграфический объем отложений свидетельствует, что развитый здесь краевой прогиб начал формироваться в разное время (от терминального рифея до позднего венда), что обусловило его сегментированное строение. Венд, эдиакарий, тасеевская серия, аномалия Шурам-Вонока, С-хемостратиграфия, U-Pb датирование обломочных цирконов, Сибирская платформа.
... Recent work (Liu et al., 2013) has suggested a microbial origin for Nimbia, an acceptable interpretation based on its similarity to modern ring structures constructed by the cyanobacteria Lyngbya aestuarii at Laguna Mormona (compare our Fig. 6J to Fig. 4E of Horodyski, 1977). ...
The Avalon biota (Ediacaran Period, 570–559 Ma) marks the first appearance of macroscopic and complex benthic communities in the fossil record. This assemblage is known from a few localities worldwide, mainly in Canada and England. Here, we report for the first time the presence of Ediacaran macrofossils in deposits of similar age from Gondwana (Itajaí Basin, southern Brazil). Our new radiometric date (~563 Ma) indicates that the Itajaí Basin can be chronocorrelated with the classic Avalonian deposits and thus represents one of the oldest records of the Ediacaran biota in Gondwana. We describe the presence of the Ediacaran genus Palaeopascichnus, as well as discs (Aspidella and Nimbia), and other problematic forms. Contrary to the deep-marine macroorganisms of the Avalon Assemblage, the Itajaí fossils are associated with abundant and exceptionally preserved three-dimensional microbial mats and microbially induced sedimentary structures (MISS) in relatively shallow settings (upper slope and distal delta front deposits). In this sense, the Itajaí biota could represent early adaptations of benthic macrobiota to the shallower and more photic environments that characterize the later White Sea Assemblage.
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Arumberia is an enigmatic sedimentary surface texture that consists of parallel, sub-parallel or radiating ridges and grooves, most commonly reported from upper Neoproterozoic-lower Palaeozoic strata. It has variably been interpreted as the impression of a small metazoan, a 'ven-dobiont', a physical sedimentary structure formed on a substrate with or without a microbial mat covering, or a non-actualistic microbial community. In this paper we contribute new insights into the origin of Arumberia, resulting from the discovery of the largest contiguous bedding plane occurrence of the texture reported to date: a 300 m 2 surface in the lower Cambrian Port Lazo Formation of Brittany, NW France. We compare the characteristic features of Arumberia at this locality with 38 other global records, revealing four defining characteristics: (1) the three-dimensional (3D) morphology of exposed Arumberia lines (either positive relief 'ridges' or negative relief 'grooves') records fully preserved cords within clay laminae; (2) lines may transition laterally into reticulated patterns; (3) characteristic parallel and sub-parallel Arumberia lines can become modified by desiccation on emergent substrates prior to inter-ment; and (4) Arumberia are streamlined with palaeoflow in successions showing evidence of unidirectional currents, but are organized parallel to ripple crests where strata were sculpted by oscillatory flows. These characteristics indicate that Arumberia records a 3D entity, distinct in material properties from its host sediment, which occurred in very shallow water settings where it was prone to passive reorganization in moving water, and desiccation when water drained. A literature survey of all known Arumberia occurrences reveals that the most reliable examples of the form are stratigraphically restricted to a 40 Ma interval straddling the Ediacaran-Cambrian boundary (560-520 Ma). Together these characteristics suggest that Arumberia records the remains of extinct, sessile filamentous organisms (microbial or algal?) that occupied very shallow water and emergent environments across the globe at the dawn of the Phanerozoic Eon.
Problematic fossils are described from Late Ediacaran to Early Cambrian red sandstones of the Arumbera Sandstone, Grant Bluff, and Central Mount Stuart Formations in central Australia, within a new systematic classification of Vendobionta. Arumberia banksi has been one of the most problematic of Ediacaran fossils, at first considered a fossil and then a sedimentary or organo-sedimentary structure. Our re-examination of the type material and collection of new material reveals misconceptions about its topology: it was a recessive fossil on the bed top, protruding down from the counterpart overlying slab. The concave-up body was 3 mm thick and chambered above a diffuse lower surface, so not a sedimentary structure. Also re-evaluated is the discoid fossil Hallidaya brueri, here including “Skinnera brooksi’ as its upper surface. A new species (Noffkarkys storaaslii gen. et sp. nov.) is a multilobed frond with regular, fine, trapezoidal quilts. Three new records of Trepassia wardae, Dickinsonia costata, and Ernietta plateauensis are reported from the Arumbera and Grant Bluff Formations. Reevaluation of palaeomagnetic and biostratigraphic data suggest an hiatus of 26 million years at the Ediacaran–Cambrian boundary within the Arumbera Formation, but some of this missing time is filled by the Grant Bluff and Central Mount Stuart Formations.
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The Vendian age of the Oselok Group (foothills of the Sayan Mountains, Uda and Biryusa river basins) is substantiated based on tillites discovered at the group base, on trace fossils and impressions of multicellular soft-bodied organisms found in the overlying Ozerki and Bol'shaya Aisa members, and on secular δ13 variations. In the Uda River basin, the lower part of the Oselok Group, which corresponds to the Marnya Formation and the Uda Formation lower part, is divided into 13 members of four sequences. Glacial deposits at the base of the Ulyakha Sequence (lower one) overlie different subdivisions of the Karagassy Group with stratigraphic discordance, filling in the deep erosion incisions. Tillites are of two types, corresponding to diamictites with subordinate breccias of supra- and subglacial channels, fractures and pavements (Ulyakha type), or to faceted-boulder breccias associated with glaciofluvial and eolian sandstones (Plity type). Rock fragments (tillstones) in diamictites and breccias bear marks of glacial abrasion (faceted forms, striation and polish), while the glacier bed show signs of glacial erosion and dislocations. In addition to dominant tillstones derived from the Karagassy Group and Nersa basic complex that intruded the group, erratic material is represented by granite gneisses and crystalline schists of the basement. Tillites of the Ulyakha Member are attributed to the supraglacial lodgment till, whereas tillites of the Plity Member consist of drift deposited by glacial meltwaters and of partially redeposited rudaceous material, which was buried under sand dunes. Four phases of glacier advance and subsequent deposition of cap dolomite (Ozerki Member) are distinguished. Glacial deposits of the Marnya Formation are correlated with lithologically similar or associative deposits characteristic of several regional subdivisions. These are an upper part of the Aleshinskii Formation (Taseeva Group) and basal strata of the Pod"em and Stolbovaya formations (Chapa Group) in the Yenisei Ridge, the Goloustnaya Formation (Baikal Group) in the Lake Baikal region, and the Vanavara and Nepa formations in inner areas of the Siberian platform. Directions of erosion forms in the bedrocks and orientation of clasts and glacial striation suggest the glacier advance from the south northward. Structural elements of meltwater deposits and glaciofluvial stream beds are oriented west- and southwestward, and these trends presumably point to the peripheral and intracratonic glaciations. centers. According to data of δ13C chemostratigraphy, the discovered tillites originated during the Early Vendian glaciation correlative with the Early Varangerian (Laplandian) glaciations in the East European and other continental blocks of the Precambrian. Trace fossils abundant in the Ozerki Members of postglacial coastal-marine sandstones and impressions of soft-bodied Metazoa found in tempestites of the Bol'shaya Aisa Member represent the Early and Late Vendian Ediacarian biota.
The Little Dal macrobiota is now known to comprise the previously reported carbonaceous megafossils Chuaria circularis,, Tawuia dalensis, Morania? antiqua, and Beltina danai, as well as the following additional taxa: Longfengshania stipitata, Grypania spiralis, Daltaenia mackenziensis n.g. and sp., Tyrasotaenia sp., and Tyrasotaenia? sp. The dubiofossil 'Bergaueria*' reported earlier is probably nonbiogenic. Of special interest are three- dimensionally preserved specimens of Chauria, Tawuia, and Tyrasotaenia?', found associated with 'molar-tooth' structure. A carbonized test separates the pure, equigranular, microcrystalline calcite infilling of the fossil interior from an argillaceous carbonate matrix. This infilling is optically and chemically indistinguishable from that comprising the 'molar-tooth' structure. These relationships indicate comparable processes and timing for both fossilization of the organisms and filling of syneresis cracks during compaction and consolidation of the sediment.-Author
Following an Introduction which reviews the historical study of the Precambrian in the USSR and the chronological framework involved, the book is divided into three major sections. Part I. Precambrian of the East European craton considers, as separate chapters, the eastern Baltic Shield, the Ukrainian Shield, and the Russian Platform. Each chapter provides succinct reviews of the major lithostratigraphic units, intrusive igneous rocks, and tectonic terrains. A final chapter considers the various types of metalliferous deposits in the Shield and briefly relates these to the overall evolution of the Precambrian. Part II follows the same format as Part I but focusses on the Siberian Craton with chapters on the Anabar Shield, the Aldan Shield and the Dzhugdzhur-Stanovoy province. A final chapter provides a synthesis of metallogenesis in the region. Part III. Precambrian in Younger Fold Belts addresses four important tectonic terrains - the Urals-Mongolia belt, the Mongolia-Okhotsk province, the Pacific belt, and the Mediterranean belt - followed by a short synthesis of crustal evolution with brief reference to metallogenesis. -R.P.Foster