Microbially Induced Sedimentary Structures Recording
an Ancient Ecosystem in the ca. 3.48 Billion-Year-Old
Dresser Formation, Pilbara, Western Australia
Nora Noffke,1Daniel Christian,1David Wacey,2,3and Robert M. Hazen4
Microbially induced sedimentary structures (MISS) result from the response of microbial mats to physical
sediment dynamics. MISS are cosmopolitan and found in many modern environments, including shelves, tidal
flats, lagoons, riverine shores, lakes, interdune areas, and sabkhas. The structures record highly diverse com-
munities of microbial mats and have been reported from numerous intervals in the geological record up to 3.2
billion years (Ga) old. This contribution describes a suite of MISS from some of the oldest well-preserved
sedimentary rocks in the geological record, the early Archean (ca. 3.48 Ga) Dresser Formation, Western Australia.
Outcrop mapping at the meter to millimeter scale defined five sub-environments characteristic of an ancient
coastal sabkha. These sub-environments contain associations of distinct macroscopic and microscopic MISS.
Macroscopic MISS include polygonal oscillation cracks and gas domes, erosional remnants and pockets, and mat
chips. Microscopic MISS comprise tufts, sinoidal structures, and laminae fabrics; the microscopic laminae are
composed of primary carbonaceous matter, pyrite, and hematite, plus trapped and bound grains. Identical suites
of MISS occur in equivalent environmental settings through the entire subsequent history of Earth including the
present time. This work extends the geological record of MISS by almost 300 million years. Complex mat-
forming microbial communities likely existed almost 3.5 billion years ago. Key Words: Archean—Biofilms—
Microbial mats—Early Earth—Evolution. Astrobiology 13, 1103–1124.
1. Microbially Induced Sedimentary Structures
and the Early Record of Life on Earth
Current interpretations of the diversity of Earth’s earliest life
come predominantly from stromatolites (e.g., Lowe, 1980;
Walter et al., 1980; Byerly et al., 1986; Hofmann et al., 1999;
Allwood etal.,2006,2007,2009,2010;Hickman, 2012),organic
microfossils of prokaryotes and biofilms (e.g., Awramik et al.,
1983; Walsh and Lowe, 1985, 1999; Walsh, 1992; Hofmann,
2004; Schopf et al., 2007; Schopf and Bottjer, 2009; Sugitani
et al., 2010; Wacey et al., 2011, 2012; Hickman 2012), and iso-
topic signatures of carbon and sulfur (e.g., Shen et al., 2001,
2009; Ueno et al., 2006, 2008; Wacey et al., 2010). Microbially
induced sedimentary structures (MISS) provide an additional
way to decode life in ancient sediments (review in Noffke,
he fossil record of the earliest life on Earth is sparse,
and reconstructing the most ancient biota is challenging.
Microbially induced sedimentary structures are created by
microbial mats colonizing most aquatic environments, in-
cluding shelves, tidal flats, lagoons, riverine shores, lakes,
dune fields, and sabkhas (e.g., Gerdes and Krumbein, 1987;
volume by Hagadorn et al., 1999; Eriksson et al., 2000; Prave,
2002; volume by Schieber et al., 2007; Beraldi-Campesi et al.,
2009; volume by Noffke, 2009; Noffke, 2010; volume by
Noffke and Chafetz, 2012). In contrast to stromatolites, MISS
arise exclusively from the response of microbiota to physical
sediment dynamics. Syngenetic mineral production within
the organic matrix of the microbial mat provided by the
extracellular polymeric substances (EPS) as seen in stromato-
lites (e.g., Reid et al., 2000; Dupraz et al., 2009; Decho et al.,
2011) does not commonly take place (Noffke and Awramik,
2013). Occasionally, mineral precipitates do occur but are
only of a temporary nature (e.g., Kremer et al., 2008). The
formation of MISS is divided into two steps, first the primary
shaping by physical sediment dynamics and second the
1Old Dominion University, Department of Ocean, Earth and Atmospheric Sciences, Norfolk, Virginia, USA.
2Department of Earth Sciences and Centre for Geobiology, University of Bergen, Norway.
3Australian Research Council Centre of Excellence for Core to Crust Fluid Systems, Centre for Microscopy Characterisation and Analysis,
and Centre for Exploration Targeting, The University of Western Australia, Perth, Australia.
4Carnegie Institution of Washington, Geophysical Laboratory, Washington, DC, USA.
Volume 13, Number 12, 2013
ª Mary Ann Liebert, Inc.
diagenetic mineralization of organic material. This will be
explained in the following (see Noffke, 2010, for details).
The MISS-forming microbial mats react to sediment dy-
(quantification of primary processes in Noffke and Krumbein,
over the mat-overgrown sedimentary surface triggers biost-
abilization (Paterson et al., 1994). If affected by erosive stress,
the microbial filaments arrange parallel to the depositional
surface; the network of filaments interweaves the sediment
grains, and the EPS switch, in a fraction of a second, their
et al., 2002). These microbial effects prohibit the removal of
resistance of a sedimentary surface by up to 12 magnitudes
(epibenthic microbial mats), 3–5 magnitudes (endobenthic
microbial mats), and around 0.02 magnitudes (biofilm-type
overgrowth) (Noffke and Krumbein, 1999). (ii) If a microbial
mat is exposed to deposition of sediment, the filaments re-
arrange and orient themselves perpendicular to the sediment-
mat surface. They reach into the supernatant water, causing
effect is called ‘‘baffling’’ and induces the fall-out of sediment
grains suspended in the water. The microbial mat then builds
the grains into the mat matrix, either by filaments migrating
around them or by sticky EPS gluing the grains together and
fixing them in their positions. Baffling and trapping are active
sediment accumulation processes. Dependent on the mat
section of a modern sediment (sabkha Bahar Alouane, Tunisia, 1996). The dark laminae are biofilms that originally covered
the crests and valleys of ripple marks that once were located on top of the sedimentary surface. The ripple marks are now
buried, but the organic matter of their biofilm coating is still visible. Scale: 1cm. (B) Erosional remnants and pockets. The
surface of the tidal flats of Mellum Island, Germany (September 1994), is arranged into elevated surface portions overgrown
by microbial mats. In the deeper surface portions the sediment is exposed and rippled by the flood currents. Scale: 1m. The
insert shows the edge of an erosional remnant along which the microbial mat is hanging down like a tissue. The sediment
originally beneath the fringed edge of the microbial mat was eroded away by currents. This erosion along the erosional
remnants broadens the erosional pockets. The erosive current also may rip off individual, centimeter-scale fragments from the
fringed microbial mat margin. Scale: knife, 10cm. (C) Polygonal oscillation cracks. During seasons of sustained aridity,
microbial mats dry and shrink. Polygons of microbial mat form, each separated by a crack exposing the sediment beneath the
microbial mat. The image shows the first generation of polygons of microbial mat still early in the year; the mat is not yet
dense enough to trap gas beneath and to cause gas domes. Portsmouth Island, North Carolina, USA (September 2005). Scale:
1m. (D) Honeycomb pattern of tufts and ridges, lateral view. This close-up shows the triangular tufts oriented perpendicular
to the microbial mat surface. These tufts are composed of filamentous cyanobacteria that move along each other in an upward
direction, a migration probably coordinated by cell-cell communication and quorum sensing. Sabkha Bahar Alouane, Tunisia
(1996). Scale: 0.5cm.
Examples of modern microbially induced sedimentary structures (MISS). (A) Sinoidal structure visible in vertical
1104 NOFFKE ET AL.
types, grain size selection or heavy mineral enrichment either
takes place or not. (iii) Binding is the initial organization of
randomly distributed microbial cells and trichomes into a
highly structured biofilm community. The microbes commu-
nicate with each other and move into a position within the
sediment that allows both optimal access to light and/or nu-
trients and cooperative interaction with the metabolism of
neighboring microorganisms. This active arranging takes
place during times of quiet sediment dynamic conditions. (iv)
Growth, which does not play a role in binding, is a process
sediment dynamic conditions; it is biomass enrichment by cell
replication and the production of EPS. As a result of their
from those of stromatolites (Noffke and Awramik, 2013). Sev-
enteen main types of MISS ranging from centimeter squared
tokilometersquared scales haveso far been distinguishedand
both their genesis and resulting morphologies quantified
(Noffke, 2010; see also volumes edited by Hagadorn et al.,
1999; Schieber et al., 2007; Noffke and Paterson, 2008; Noffke
and Chafetz, 2012). Common examples are given in Fig. 1.
While MISS are formed by these primary processes, they
are preserved by secondary, diagenetic processes. MISS are
lithified by rapid in situ mineralization of the organic matter
of the mats, including the microbial cells, trichomes, and
filaments, as well as the EPS. In thin sections perpendicular
to ancient mat layers, the network of fossil microbes is
commonly visible as intertwined and bent laminae. The
network includes fossil EPS and (formerly) allochthonous
sedimentary grains that once were bound by the mat during
its lifetime. However, the appearance of fossil mat texture in
MISS differs fundamentally from that of organic microfossils
in chert. This difference arises from the preservation of the
MISS. Microbial mats in siliciclastic sedimentary rocks are
preserved by replacement minerals, not by impregnation as
is the case for organic microfossils or organic biofilms in
primary chert (e.g., Walsh, 1992; Walsh and Lowe, 1999; Tice
and Lowe, 2006; Schopf and Bottjer, 2009; Wacey, 2009). In
contrast to such organic material so precisely preserved in
chert, the mat texture-forming laminae in MISS have no
discrete outline (Noffke 2000; Noffke et al., 2002, 2003, 2006a,
2006b, 2008). In MISS, the laminae appear ‘‘cloudy’’ with
diffuse borders. The reason for this appearance is that during
the diagenetic alteration of the mat, the chemical compounds
of the organic matter released by microbial decomposition
diffuse away from their original microsite (e.g., Krumbein
et al., 1979; Knoll et al., 1988; Beveridge, 1989; Urrutia and
Beveridge, 1994; Konhauser et al., 1994; Schulze-Lam et al.,
1996; review on these studies in Noffke, 2010). They react
with chemical compounds prevailing in the surrounding
water, resulting in initial hydrated ‘‘amorphous’’ mineral
precipitates. These initial hydrated mineral precipitates
circular pattern in the North Pole Dome area, Pilbara Craton, Western Australia (after Van Kranendonk, 2006; Van Kra-
nendonk et al., 2008). (B) The Dresser Formation has an age of approximately 3.48 Ga. (C) Geographical locations of the
stratigraphic sections studied (details in Fig. 3).
Location and stratigraphic setting of the Dresser Formation. (A) The Dresser Formation outcrops in a roughly
MISS IN THE 3.48 GA DRESSER FORMATION, WESTERN AUSTRALIA1105
accumulate at nucleation sites and gradually dehydrate and
shrink in the course of diagenesis. The dehydration and re-
crystallization lead to mineral phases of higher crystallinity.
At the microscopic scale, the minerals that replace microbial
mats therefore are arranged as irregular clots lining the
original shape of the laminae. This is in stark contrast to
microfossils preserved in chert, where the organic matter
was entombed rapidly by synsedimentary silicification and
impregnation, and detailed preservation of cells was possible
(e.g., Cady and Farmer, 1996). For this reason, very high
spatial resolution analytical techniques such as transmission
electron microscopy(TEM) or secondaryion mass
graphic profiles documenting lithology and sedimentary structures. Where the lithology could not be determined anymore
the signature was left blank.
Stratigraphic sections studied, 3.48 Ga Dresser Formation, Pilbara, Western Australia. (A) to (H) Detailed strati-
1106 NOFFKE ET AL.
spectrometry (SIMS and Nano-SIMS) are not particularly
useful for resolving morphological characteristics of MISS-
forming microbial cells. To acknowledge these differences in
preservation, the MISS literature uses the terms ‘‘laminae’’
and ‘‘filament-like texture’’ instead of ‘‘filament’’ or ‘‘tri-
chome.’’ In the fossilized examples from younger Archean,
Proterozoic, and Phanerozoic time periods, the ancient mat
fabrics may still include some original carbon, but the orig-
inal organic matter is largely replaced by pyrite, hematite,
and goethite (review in Noffke, 2010).
A set of seven biogenicity criteria for MISS has been de-
veloped and tested in numerous comparative studies (over-
view in Noffke, 2010). The first four criteria describe the
depositional habitat of MISS occurrence as follows. MISS
occur in rocks of not more than low-grade metamorphosis. In
stratigraphic sections, MISS occur at turning points of
MISS IN THE 3.48 GA DRESSER FORMATION, WESTERN AUSTRALIA 1107
regression-transgression. MISS occur in the depositional
‘‘microbial mat facies.’’ The distribution pattern of MISS re-
flects the average hydraulic pattern in a depositional area.
The last three criteria describe the MISS themselves as fol-
lows. The fossil MISS resemble strongly or are identical with
geometries and dimensions to modern ones. The MISS in-
clude microtextures that represent, or were caused by, or are
related to, ancient biofilms and microbial mats. Geochemical
analyses support the interpretation as MISS.
Using this set of criteria, more than 14 studies have sys-
tematically explored MISS from modern to ancient sites,
comparing structures in equivalent environmental settings
from the modern right back to the early Archean (e.g., Noffke
1999, 2000; Noffke and Krumbein, 1999; Noffke et al., 2001a,
2002, 2003, 2006a, 2006b, 2008). This suite of studies has as-
sembled a data set that enables the evolution of MISS-
prokaryota to be monitored throughout Earth’s geological
record. The investigation of MISS is divided into four steps:
(i) detection, (ii) identification, (iii) confirmation, and (iv) differ-
entiation (Noffke, 2010). (i) Detection is the visual recon-
naissance during a geological survey of candidate sediments
and sedimentary rocks. (ii) A candidate structure (e.g., for
erosional remnants and pockets) is measured with respect to
geometry and dimension, and indices such as the MOD-I
(modification index) are determined (see later in this article).
The assembled data that have arisen from these systematic
studies now allow the quantitative comparison of any can-
didate structure with other MISS from other periods in Earth
history including the modern. (iii) Analyses on the miner-
alogy and geochemistry of the candidate structure are con-
ducted (e.g., presence of carbon in laminae). (iv) A
comparison with similar but abiotic phenomena is made, if
any similar but abiotic phenomena exist. As demonstrated,
this set of biogenicity criteria compiles various lines of evi-
dence and allows for identification of fossil structures with a
high probability. This study on possible MISS in the Dresser
Formation employs this methodological approach as well.
Microbially induced sedimentary structures are listed as
one target for the Mars Exploration Rover Program (Com-
mittee on an Astrobiology Strategy for the Exploration of
Mars, 2007). On Mars, sabkha settings are well known,
where sedimentary surface structures and rock beds record
the former existence of fluid water (e.g., Grotzinger et al.,
2005; Metz et al., 2009). Because of the similarity of the early
history of Earth and the early history of Mars, the knowledge
on the sabkha habitats of MISS and the criteria of biogenicity
of MISS may assist in the exploration of Mars.
To date, the oldest microbial mat communities that
formed MISS are from the 3.2 Ga Moodies Group, South
Africa (Noffke et al., 2006b; Heubeck, 2009). Here, two
bed surface tilted about 30? toward the observer. Scale: 10cm. (B) Ripple cross stratification in vertical section of a rock bed.
Note dark laminae, of which examples are magnified in Fig. 5. (C) Tidalites forming a vertical stack of layers. Scale: 0.5cm.
(D) Oncoids in thin section. Scale: 0.25mm.
Sedimentary structures typical in the Dresser Formation, Pilbara, Western Australia. (A) Wave ripple marks on a
1108NOFFKE ET AL.
wrinkle structures and one roll-up structure were detected in
tidal deposits. The 2.9 Ga Ntombe Formation, Pongola Su-
pergroup, South Africa, includes eight wrinkle structures
that record fossil microbial mats on shallow shelf settings
(Noffke et al., 2003). The isochronous shelf of the Brixton
Formation of the Witwatersrand Supergroup shows 28
wrinkle structures, two sedimentary surfaces yielding ero-
sional remnants and pockets, and one bedding plane with
polygonal oscillation cracks (Noffke et al., 2006a). In thin
sections from all study sites, textures are visible that resem-
ble degraded microbial mat fabrics. Cyanobacteria have been
suggested to be the constructing agents; however, no un-
ambiguous evidence has been documented (see discussions
in Noffke et al., 2003, 2006a, 2006b). Highly diverse microbial
mat ecosystems from ancient tidal and sabkha environments
are recorded by MISS in the 2.9 Ga Pongola Supergroup,
South Africa (Noffke et al., 2003, 2008). Of significance is that
these ancient MISS resemble strongly the MISS in equivalent
modern settings. Because modern MISS allow the detailed
quantification of the hydraulic and sediment-dynamic in-
teraction with biofilms, the gained information assists in the
interpretation of ancient MISS, the environment they are si-
tuated in, and prokaryote evolution. This similarity of MISS
over 3 billion years of Earth history is in contrast to stro-
matolites, where many early Archean species are unlike the
modern ones (Noffke and Awramik, 2013).
The objective of this study was to take the comparative
investigation one step further and search for MISS in rocks
older than 3.2 Ga. This contribution describes a series of
distinct types of macrostructures and microstructures from
sedimentary rocks of the ca. 3.48 Ga Dresser Formation.
2. The Dresser Formation, Pilbara, Western Australia
The Dresser Formation is located in the East Pilbara
granite greenstone terrane, Western Australia (Fig. 2a). It
was chosen for this study because it contains some of Earth’s
oldest and best-preserved volcanic and sedimentary rocks
(Fig. 2b; Barley et al., 1979; Hickman, 2012). The age of this
rock succession is determined as 3.481–3.5 Ga [Australian
Stratigraphic Units Database (2012), Dresser Formation,
Stratigraphic Number 36957]. The formation is geographi-
cally restricted to a ca. 25 km2area in the North Pole Dome
and consists of bedded chert, carbonate, and siliciclastics,
plus pillow basalt and dolerite (Van Kranendonk et al., 2008).
The sedimentary rocks were originally micritic carbonates
Western Australia. (A) Sketch to point out the situation of the thin section displayed in (B). The thin section shows an area of a
vertical cut through ripple marks with their ripple valleys being filled in by sediment. The selected area covers one slope of a
ripple mark and about half the ripple valley. Compare this photo also with Fig. 1A. (B) Thin-section view of the area shown in
(A). The slope of the ripple mark is draped by a dark lamina (arrow); the horizontal sediment layers that fill in the ripple
valley are each covered by a dark lamina as well. Scale: 0.1cm. Note that none of the dark laminae show any mark of erosion.
(C) In close-up the dark laminae include tufted microstructures (compare with modern structure in Fig. 1D; geochemistry of
fossil example is shown in Fig. 6). Scale: 50lm.
Crinkled laminae and tufts in microscopic view (thin sections), subtidal zone, 3.48 Ga Dresser Formation, Pilbara,
MISS IN THE 3.48 GA DRESSER FORMATION, WESTERN AUSTRALIA 1109
and evaporites deposited under shallow-water, low-energy
(sabkha-type) conditions, interbedded with sandstone and
conglomerate deposited during periods of growth faulting
and tectonic activity (Lambert et al., 1978; Buick and Dunlop,
1990; Van Kranendonk, 2006; Van Kranendonk et al., 2008).
Repeated episodes of growth faulting associated with vol-
canic activity during carbonate-evaporite sedimentation
permitted circulation of hydrothermal fluids that over-
printed much of the original sedimentary mineralogy. Car-
bonate, organic matter, and gypsum were largely replaced
by pyrite, hematite, barite, and silica (Van Kranendonk, 2006;
Van Kranendonk et al., 2008).
In the Gibson and Great Victoria deserts in central Aus-
tralia and in the Carnarvon Basin at the west coast Eocene to
Oligocene, weathering is common (van der Graff, 1983).
Here, the Tertiary tropical climate induced the formation of a
soil catena, composed of blocky silcrete at the modern to-
pographic heights, and deep red, silty laterite in topographic
lows. Typical structures in the otherwise unconsolidated
soils include irregular and steep-sloped cones up to 35cm in
height, pisolites from 0.5 to 5cm in diameter, and karst pipes
that facilitate subsurface water flow. However, none of these
soil structures were observed in our North Pole study loca-
tion. Quite to the contrary, the sedimentary rocks in the
Dresser Formation are highly consolidated. Stromatolites,
ripple marks, ripple cross beds, and other primary sedi-
mentary structures are well preserved and do not display
disturbance by any deep soil or silcrete formation.
In addition to the macroscopic phenomena, widespread
evidence also remains for the primary mineralogy of the
ancient sediments, including relic carbonate rhombs and
rhombic voids in silica (Lambert et al., 1978), patches of
of the subtidal zone, 3.48 Ga
Dresser Formation, Pilbara, West-
ern Australia. (A) Thin section
photomicrograph taken perpen-
dicular to bedding showing a se-
indicates the tuft analyzed in (B–
C). (B) Optical image plus Raman
chemical maps of a single tuft
showing that the tuft is composed
of quartz, pyrite, and significant
amounts of carbonaceous matter.
(C) Typical Raman spectra from
two carbonaceous areas of the
tuft show the presence of pyrite
(P) and quartz (Q) plus two car-
bon peaks (C) at *1350cm-1(the
*1600cm-1(the ‘‘G’’ graphite
peak). The D1 and G peak posi-
tions and widths, plus the D1/G
peak heights and areas, are char-
acteristic of thermally mature but
disordered organic carbon that
has experienced prehnite-pum-
metamorphism (Beyssac et al.,
2002). This degree of maturation
is consistent with the known
metamorphic grade of the Dres-
ser Formation (Van Kranendonk
et al., 2008) and indicates that the
carbon is probably indigenous to
1110 NOFFKE ET AL.
dolomitic chert in surface outcrop (Walter et al., 1980), pe-
loidal and oncolitic grains (Buick and Dunlop, 1990), exten-
sive carbonate in unweathered drill core material (Van
Kranendonk et al., 2008), and observations in this current
study of carbonate in many of our thin sections.
3. Methods of Investigation in the Field and Laboratory
Geological mapping, millimeter-scale sedimentological
stratigraphic logging, and quantitative analysis of morphol-
ogies of sedimentary macrostructures were undertaken in
the North Pole Dome, Pilbara, Western Australia, in June
2011. Petrological and mineralogical analyses were con-
ducted on standard geological thin sections and polished
rock chips. We used the equipment at Old Dominion Uni-
versity, including Olympus BX51 and Olympus SZX12 mi-
croscopes equipped with Q Colour 3 Olympus digital
cameras. Raman analyses were carried out at the University
of Bergen with a Horiba LabRAM HR800 integrated confocal
Raman system and LabSpec5 acquisition and analysis soft-
ware. For Raman, samples were standard uncovered geo-
logical thin sections that allowed optical and chemical maps
to be superimposed. The laser was focused *2lm below the
surface of the thin sections to avoid surface polishing effects
(Fries and Steele, 2011). Since the thin sections were *30lm
thick, there was no possibility of obtaining a Raman signal
from the mounting resin. All analyses were carried out by
using a 514.5nm laser, 100lm confocal hole, 1800mm/line
grating, and ·50 objective lens. Dual acquisitions were taken
from each analysis point, each with an acquisition time of 4s.
Maps were acquired with a 1.5lm spatial resolution by us-
ing selected peaks from the Raman spectra.
equivalents. The center images show the Dresser Formation structures; for better visualization, the Dresser structures are
outlined in the sketches on the left. The right images show possible modern counterparts of such structures. (A) Flat
fragments deposited at random on the sedimentary surface in the Dresser intertidal flats. In equivalent modern settings, such
fragments represent microbial mat chips; example from Portsmouth Island, USA. Such chips were ripped off their parent site
along fringed edges of microbial mats, similar to those shown in the insert of Fig. 1B. (B) Rolled-up fragment. In modern
settings, microbial mat chips can be rolled up in this fashion by currents or by desiccation; example from Portsmouth Island,
USA. (C) upward-bent, dark-colored sediment lamina. In modern environments, such laminae represent microbial mats
separated from their substrate by erosion; example from El Bibane, Tunisia. All scales: 1cm.
Macrostructures of the intertidal zone, 3.48 Ga Dresser Formation, Pilbara, Western Australia, plus possible modern
MISS IN THE 3.48 GA DRESSER FORMATION, WESTERN AUSTRALIA1111
4. Description of Sedimentary Structures in Ancient
Coastal Sabkha Settings of the Dresser Formation
and Discussion of Their Possible Biogenicity
Seven stratigraphic sections were analyzed at millimeter-
scale resolution, covering a total stratigraphic thickness of
39.8m (locations shown in Fig. 2c; detailed profiles in Fig.
3a–3h). The lithology and sedimentary structures record an
ancient coastal sabkha in which a subtidal zone, an intertidal
zone, a lower supratidal zone, a lagoon, and a barrier were
distinguished. Our observations are in line with those of
Buick and Dunlop (1990), who described the paleoenviron-
ment of the entire Dresser Formation in detail. In the present
time, sabkhas are colonized by ubiquitous microbial mats
In the following, we describe the fossil sedimentary
structures of the Dresser Formation and discuss the possi-
bility of biological origin by comparing them with the
modern MISS in equivalent sabkha settings. The fossil sedi-
mentary structures form discrete morphologies that display
sharp transitions with their surroundings. The structures do
not resemble cones, pisolites, or vertical pipes caused by any
weathering and soil-forming processes currently known.
4.1. The subtidal zone
crest to crest amplitudes and occasional, small-scale cross-
stratification of climbing ripples record an ancient subtidal
area (Fig. 4a). Two rock beds included ripple cross stratifi-
cation lined by dark laminae (Fig. 4b). In vertical thin sec-
tions, the slopes and valleys of ripple marks are draped by
slightly crinkled, dark-colored laminae (Fig. 5). In close-up,
the laminae are spotted by tufts that all have a similar
height/base ratio of 10/50 to 25/75lm, arranged at regular
distances of 100–125lm from each other (Fig. 6a). Raman
analysis showed that the crinkled laminae and tufts are
mostly composed of pyrite plus small amounts of relic car-
bonaceous material (Fig. 6b and 6c), within a silica-rich
matrix. This composition is consistent with syndepositional
replacement of carbonaceous laminae by pyrite and later
replacement of carbonate by silica.
Wave ripple marks of about 8cm
film textures are known from modern subtidal areas. The
structures, visible in vertical section through cores of fresh
sediment, are called ‘‘sinoidal structures’’ (Fig. 1a) (Noffke
Similar ripple structures and bio-
possible modern equivalents. (A) Left: fossil fragments. Right: In the modern intertidal zone of Portsmouth Island, USA,
microbial mat chips were accumulated by water currents. (B) Left: Three fragments are accumulated as a pile; two fragments
were deposited individually; Dresser Formation. Right: a similar situation in the modern intertidal zone of Portsmouth
Island, USA. All scales: 1cm.
Fragments accumulated as piles in the intertidal zone, 3.48 Ga Dresser Formation, Pilbara, Western Australia, plus
1112NOFFKE ET AL.
erosive margin. In modern settings, such erosive margins with irregular edges are caused by partial erosion of microbial mat-stabilized surfaces
(comparetheexampleshownintheinsertofFig.1B).Theirregularshape ofthefossilfragmentssupportsthe interpretationasapossiblematchip.
Note that the microbial mat-covered sediment is elevated (=erosional remnant). In contrast, sediment bare of microbenthos is deeper lying
fromitsneighborsbya3–10cmwidetransition zone(desiccationcracks,oftenovergrownbyayoungergeneration of microbialmat).The holesin
each of the polygons are collapsed gas domes (compare Figs. 1C and 14); modern example from El Bibane, Tunisia. Scale: 10cm. (D) Honeycomb
patternof ridgesandtuftsexposedon asurfaceofasedimentary rockbed.Inmodern settings,suchridgesarrangedintoahoneycombpatternare
in vertical section through very mature microbial mats. The laminae represent many layers of succeeding microbial mat generations, or microbial
mat-overgrown lagoon sediments. Stacks of mat laminae are called biolaminites. Millimeter-scale mat chips and roll-ups occur within laminae
(compare Fig. 17, geochemistry in Fig. 18); modern example from El Bibane, Tunisia. Scale: 5cm.
Macrostructuresof thelowersupratidal zone, 3.48GaDresserFormation, Pilbara, WesternAustralia,plus possiblemodern equivalents.
et al., 2001b). Sinoidal structures are ripple marks overgrown
by microbial mats so that the ripple mark relief appears
smoothed. The ripple valleys are filled in by laminae of mi-
crobial mat, often alternating with sediment layers similar to
these shown in Fig. 5. In the fossil example of the Dresser
Formation, the ripple valleys with their biofilm-covered
sediment infills are evident. The ripple slope was biostabil-
ized by a cover of biofilm before sediment was subsequently
deposited in the ripple valleys. The deposition of the valley
sediments took place in increments, interrupted by periods
of non-sedimentation during which biofilms would develop
on the ripple valley infill (Gerdes and Krumbein, 1987).
During the subsequent deposition of sediment, the pro-
ceeding biofilm cover was not eroded. This preservation is
visible along the unaffected slope of the ripple mark as well
as along the individual mat-covered surfaces of the infilling
sediment (Fig. 5). Mud layers would not have resisted the
deposition of subsequent sediment and also would not in-
clude tufts. The arrangement of tufts and their sizes are too
regular to be a consequence of fine sediment that was pushed
up locally by sediment grains projecting from the sedimen-
tary surface. Furthermore, the mineralogical composition of
the dark laminae contradicts any interpretation as being of
abiotic sedimentary origin.
The Dresser Formation subtidal zone also includes stro-
matolites, which have been described in earlier studies (e.g.,
Buick and Dunlop, 1990; Van Kranendonk, 2006; Van Kra-
nendonk et al., 2008).
Australia. (A) Three generations of erosive margins (numbers 1 to 3). Scale: 5cm. (B) Edge of an erosive margin in close-up.
Scale: 5cm. (C) Fragments deposited in front of an erosive margin. (Compare Figs. 1B and 10A.) Tape for scale.
Macroscopic sedimentary structures of the lower supratidal zone, 3.48 Ga Dresser Formation, Pilbara, Western
1114 NOFFKE ET AL.
4.2. The intertidal zone
is typically caused by daily micro-tides. Such tidal currents
are recorded by alternating bedding of coarse-fine layer
couplets. In the Dresser Formation, small 1cm scale current
ripple marks and 1–2.5cm thick sedimentary couplets may
be interpreted as of micro-tidal origin. The couplets are
stacked together, making a total outcrop between 10 and
40cm thick (Fig. 4c). Here, 12 well-exposed bedding surfaces
range from 10cm2to 6m2in size. These ancient intertidal
surfaces are littered with fragments of sediment, 1–3.5cm in
diameter and up to 0.4cm thick, that are distinct in appear-
ance compared to the surrounding rock (Fig. 7a); some of
these fragments demonstrate flexible behavior and appear to
be rolled up (Fig. 7b, 7c, 9a, 10c).
A narrow intertidal belt along a coast
may be interpreted as pieces of microbial mat (‘‘chips’’),
which were ripped off their parent site, transported, and fi-
nally re-deposited on the sedimentary surface (Noffke, 2010).
Frequently, such microbial mat chips pile up in the current
shadow behind current barriers (Fig. 8). Some chips may roll
up due to currents or desiccation. Microbial mat chips have a
characteristic shape, which can be quantified by the mor-
phology index of a microbial mat chip. It is described as the
ratio between the greatest and smallest diameter of a mi-
crobial mat chip. The morphology index of the Dresser mat
chips (1.81; n=41) closely compares to those of mat chips in
the 2.9 Ga Pongola Supergroup (1.72; n=55) and modern
mat chips from Portsmouth Island, USA (1.75; n=55),
whereas simple mud clasts from Portsmouth Island have a
much lower index of 1.41 (n=50).
4.3. The lower supratidal zone
planar lamination record a lower supratidal zone occasionally
flooded during landward storms. Here, four 80cm2to 1.30m2
Fossil wash-over fans with internal
sedimentary surfaces were found that display a peculiar surface
morphology: the bedding surfaces are arranged into elevated
surface portions and deeper surface portions (Figs. 9a and 10).
Crinkled surface portions may occur (Fig. 9b). For each bed, the
elevated surface portions have similar heights in relation to the
deeper surface portions. The change in topography of the ele-
1 and 3cm; the slope angles that connect the elevatedareas with
the deeper surface areas are between 15 and 90 degrees.
Fragments, of sizes and shapes similar to those described
from the intertidal zone (above), are often seen in the de-
pressed surface areas (Figs. 9a and 10). Thin sections of the
fragments from this lower supratidal zone show dark
laminae that form a carpetlike network entangling sand-
sized grains (Fig. 11). The laminae appear diffuse; no
discrete outline is preserved. It is therefore difficult to de-
termine the thickness of an individual filament. We esti-
mate that filamentlike textures range from 5 to 20lm in
diameter. Raman analysis shows that the laminae are
composed of finely clotted hematite and carbonaceous
material (Fig. 12).
area of sabkha surface is occupied by the lower supratidal
zone. Here, erosional remnants and pockets are a very typ-
ical sedimentary surface relief (Fig. 1b); the relief is rep-
resented by two geometrical elements, as follows: (i) elevated
flat-topped surface areas that are overgrown and stabilized
by microbial mat and (ii) deeper-lying surface areas where
the sediment is exposed (Noffke, 1999, 2010). Erosional
remnants and pockets each range in size between some tens
of centimeters squared to many meters squared, with the
relief morphology defined by the degree of biostabilization
by the microbial mat covering the remnants (Noffke and
Krumbein, 1999)—the more pronounced the relief, the higher
was the degree of biostabilization by the mats and the higher
the erosive force by currents. The degree of microbial bio-
stabilization in shaping the sedimentary surface (N) is
In modern coastal systems, a large
section perpendicular through frag-
ment, lower supratidal zone, Dresser
Formation, Pilbara, Western Australia.
Dark laminae (filamentlike textures)
form a carpetlike network in which
individual sedimentary grains are in-
terwoven. Note the diffuse appearance
of each lamina, which allows only a
two-dimensional interpretative sketch.
Scale: 500lm. Color images available
online at www.liebertonline.com/ast
Photomicrograph of thin
MISS IN THE 3.48 GA DRESSER FORMATION, WESTERN AUSTRALIA1115
expressed in the ‘‘modification index’’ (MOD-I) [MOD-I=
IA·IS·IN] (Noffke and Krumbein, 1999). The MOD-I for the
description of erosional remnants and pockets is based on
three sub-indices: (i) area of mat-covered depositional sur-
face to total area of investigation (IA=Am/Ai), (ii) the angles
of slopes of the erosional remnants (IS=sin a), and (iii) the
degree of planarity of a microbial mat cover (IN=1 - [(Hp–
Hb)/Hp]). Planarity is result of mat growth and baffling and
trapping of grains. A MOD-I of 0 would represent no mi-
crobial influence in the formation of surface relief, whereas a
value of 1 would represent a maximum influence.
The erosional remnants and pockets described above are
directly comparable to the differentially eroded bedding
surfaces seen in the Dresser Formation lower supratidal zone
(Figs. 9a and 10); hence the Dresser structures can be inter-
preted as such MISS. The MOD-I of the four fossil erosional
remnant- and pocket-bearing sedimentary surfaces (0.18,
0.24, 0.3, and 0.33) closely compare to similar erosional
remnants and pockets from the Pongola Supergroup (0.35)
and from modern settings of Mellum Island, Germany (0.25
and 0.3). This comparison provides strong evidence for bio-
logical control, because sediment that is not consolidated and
stabilized by biology does not show such a steep surface
relief, and MOD-I approaches zero. In areas where microbial
mats diminish by the end of the growth season, the erosional
remnant and pocket relief will dissolve (Noffke and Krum-
bein, 1999). Hence, abiotic erosional remnants and pockets
are not known to exist. Sediment grains in a network of
laminae likely indicate syndepositional trapping and binding
of the grains by a microbial mat. Younger Archean and
modern examples of microbial mat textures show such a
matrix as well (Fig. 13).
chemistry of network of laminae in
sediment of the lower supratidal
zone, 3.48 Ga Dresser Formation,
Thin-section photomicrograph of
dark brown laminae forming a
carpetlike network (compare to fi-
lamentlike textures in Fig. 11); box
in (A) is enlarged in (B); boxed area
in (B) indicates area analyzed by
Raman in (C) to (E). (C) Raman
chemical maps of part of filamen-
tous texture showing that it is
composed of hematite and organic
within a matrix of quartz. The he-
matite map was produced using
the *415cm-1hematite Raman
peak, the quartz map using the
*465cm-1Raman quartz peak,
and the carbon map using the
*1600cm-1Raman carbon peak.
(D) Raman spectrum from an area
of the filamentous texture rich in
showing the typical peaks for each
mineral. Note that carbon and he-
matite both have major peaks in
the 1320–1350cm-1region, so the
presence of organic carbon must be
confirmed and mapped using the
1600cm-1peak (Rividi et al., 2010;
Marshall et al., 2011). Carbonate
(labeled ‘‘Carb’’) is occasionally
found in the vicinity of these fila-
mentous textures. (E) Raman spec-
lacking organic carbon. Note ab-
sence of carbon 1600cm-1peak.
Unlabeled peaks in (D–E) are from
the quartz matrix.
Morphology and geo-
1116NOFFKE ET AL.
erozoic (including modern) examples are compared with each other. On the left side, networks of filamentlike textures
(laminae) of various ages are compared with each other, starting at the base with the oldest, the Dresser Formation, and
continuing upward with younger examples. On the right, rose diagrams summarize the alignment of laminae defining the
networks; note that the networks of all periods of Earth history studied show a very similar dumbbell shaped pattern (right;
n=number of thin sections studied). Also, the thin sections deriving from the Dresser sedimentary rocks display similar
network patterns; compare Fig. 12 for their geochemistry. In contrast, abiotic laminae of a stylolite preserved in the 2.9 Ga
Pongola Supergroup, South Africa, are shown in the lower portion of the figure. Note that the stylolite resulted in a different
alignment pattern of laminae (from Noffke et al., 2008).
Laminae forming a network typical for microbial mats as seen in thin sections; Archean, Proterozoic, and Phan-
4.4. The upper supratidal zone
faces, 90cm2to 3.6m2in areal extent, display patterns of
polygonal cracks (Fig. 9c). The cracks record several peren-
nial shallow ponds within an ancient upper supratidal zone
that experienced seasonal periods of desiccation. The poly-
gons are separated from each other by 3–10cm wide cracks.
The polygons often have fine ridges or bulges along their
edges, lining the cracks. Many polygons have a hole close to
At two of these sites in the Dresser Formation, the rock bed
surfaces also display fine, reticulate ‘‘honeycomb’’ patterns
with *1mm high ridges and up to *4mm high tufts (Fig.
9d). The reticulate pattern is characterized by several gener-
ations of centimeter-scale honeycomb-like compartments.
Each subsequent generation of compartment is smaller than
the last. The compartments have a maximum dimension ratio
of approximately 1:2 and a surface area ratio of 1:4.
Four well-preserved bedding sur-
sonal tidal ponds develop that may reach up to 15cm in
In modern coastal sabkhas, sea-
depth. In these ponds, epibenthic microbial mats grow. In
response to a semi-arid climate, the mats cause ‘‘polygonal
oscillation cracks’’ and ‘‘gas domes’’ (Fig. 1c; Noffke et al.,
2001a). Polygonal oscillation cracks are polygon-shaped
patches of microbial mat separated from each other by a
crack. During seasons of high aridity, the microbial mat
surface dries out and cracks into polygon-shaped patches of
up to 50cm in diameter (Noffke, 2010; Carmona et al., 2011).
Each polygon is separated from its neighboring ones by
cracks up to 10cm wide. During the subsequent season of
increased humidity/rainfall, the mat patches expand, and
the cracks are closed and sometimes even overgrown by a
new mat layer. The mat polygons themselves, however, re-
main clearly visible. The margins of the individual mat
polygons may be slightly thickened because of the polygons
shrinking and expanding (oscillating) over the course of
time. This oscillation of the polygons causes their margins to
curl upward. The center of each polygon may bend up be-
cause of gas production by microorganisms colonizing the
deeper portions of the microbial mat. At some point, these
gas domes erupt due to the increasing pressure. The gas is
released, and the ruptured gas dome roof collapses. A hole
polygon is defined by its slightly elevated margin. The close-up view allows recognition of a fossil gas escape hole in its
center; Dresser Formation, Pilbara, Western Australia. Scale: 3cm. (B) For comparison to (A), this image shows a very similar
structure representing an ancient gas escape hole; 2.9 Ga Pongola Supergroup, South Africa. Scale: 5cm. (C) A single polygon
of a microbial mat from the sabkha El Bibane, Tunisia (modern). Note the circularly wrinkled folds within the microbial mat
polygon, especially close to the tip of the pen. (D) A single polygon from the Dresser Formation, Pilbara, Western Australia.
Note the presence of very similar circularly wrinkled folds. Scale: 4cm. Compare Fig. 1C for further modern examples and
Fig. 15 for statistical measurements.
Polygonal oscillation cracks on sedimentary surfaces viewed from above, fossil and modern examples. (A) This
1118 NOFFKE ET AL.
remains visible in the microbial mat. Other fossil examples of
such polygonal oscillation cracks are exceptionally well
preserved in the 2.9 Ga Pongola Supergroup, South Africa
(Noffke et al., 2008).
Such structures are directly comparable to the cracks and
polygons containing central holes and marginal ridges ob-
served in the upper supratidal zone of the Dresser Formation
(Figs. 9c and 14); hence the Dresser structures can be inter-
preted as microbially induced polygonal oscillation cracks
and gas domes. Some polygons exposed in the Dresser rocks
show circular patterns of wrinkled folds, which suggest the
presence of a formerly ductile matrix, a microbial mat, Fig.
14. Frequency distributions of polygon diameter divided by
gas escape hole diameter of the Dresser mats match those
from younger fossil and modern examples (Fig. 15). The re-
lation of diameters of polygons to diameters of gas escape
holes resembles all modern and fossil examples. That is, all
ductile material (microbial mats) reacted in the same fashion.
Many of the modern microbial mats in ponds show a re-
ticulate pattern of ridges and tufts at their surface (Fig. 1d).
From above, the mat surface appears covered by a net of
honeycomb-shaped ‘‘cells’’ of centimeter scale in diameter.
The compartments are defined by ridges and tufts of up to
3mm in height. Such a pattern of compartments is a conse-
quence of active arrangement of filaments of microorganisms
(Shepard and Sumner, 2010). This arrangement possibly aids
communication (signal transfer) within the microbial mat
(Stoodley et al., 2002; Noffke et al., 2013). Closely comparable
tufted and honeycomb patterns are observed in the Dresser
Formation (Fig. 8d). They are taken to represent similar ar-
rangement of filaments in ancient microbial mats (Fig. 16).
Assuming a circular surface expression of the microbial
compartments, the surface area ratio between three genera-
tions of compartments is approximately 4:1 for each of the
three modal peaks across all examples studied.
recorded in the Dresser Formation is formed by a stack up to
2.80m thick of black-white colored, laminated beds. This
The top of the stratigraphic section
cracks from the 3.48 Ga Dresser Formation, the 2.9 Ga Pongola
Supergroup, and El Bibane, Tunisia (modern). The frequency
distributions of the polygon diameter/gas hole diameter are
similar in all three cases. Dresser Formation polygons are 10–
20cm wide, 2.9 Ga Pongola Supergroup examples are 20–
50cm wide, and examples from the modern sabkha of Tunisia
are 15–50cm wide. In the Dresser Formation, the gas escape
holes have a diameter of 1–3cm, and the comparable younger
structures show diameters of 3–10cm, occasionally up to
15cm. Examples for such structures are shown in Fig. 14.
Color images available online at www.liebertonline.com/ast
Comparative morphologies of polygonal oscillation
patterns of ridges and tufts on surfaces of
microbial mats from the 3.48 Ga Dresser
Formation, the 2.9 Ga Pongola Supergroup,
and El Bibane, Tunisia (modern). The ratio
between three generations of compartments
is approximately 4:1 for each of the three
modal peaks across all examples studied.
Compare the structures shown in Fig. 9D.
Color images available online at www
Comparison of honeycomb-like
MISS IN THE 3.48 GA DRESSER FORMATION, WESTERN AUSTRALIA 1119
rock unit likely records the flooding of the sabkha and the
establishment of a lagoon. The planar lamination would re-
cord the gentle currents in the lagoon (Fig. 9e). Within the
laminated stack, fragments of 1mm to 3.5cm sizes were
found (Fig. 17). The fragments are flat, wavy, or even rolled
up, documenting that the material of the fragments origi-
nally was soft and ductile. The fragments are of the same
composition as the laminated host rock. They are composed
of laminae of dark-colored goethite plus carbon alternating
with laminae of translucent quartz layers. The carbon Raman
signal indicates a syngenetic origin for the carbon (Fig. 18).
biolaminites (Gerdes and Krumbein, 1987). These structures
are stacks of microbial mats (sometimes intercalated by
sediment laminae) visible in vertical section through thick
microbial mats. They can be meter-thick when developing at
sites of long periods of quiet sedimentary conditions, such as
in deepening lagoons or coastal sabkha lakes (Solar Lake,
Red Sea, being the best example; Gerdes and Krumbein,
1987). Such biolaminites (or Stratifera when fossil) may be the
origin of the thick laminated rock beds seen in the Dresser
Formation (Fig. 8e comparison). The fossil fragments in these
rock beds likely are microbial mat chips. The ductile nature
of the organic layers is documented by their wavy appear-
ance. One fragment is even rolled up, probably as a result of
ductile response to bottom currents (Fig. 17). A laminated
pattern of rock caused by hydrothermal overprint alone is
unlikely, because of the preservation of chips and roll-ups of
same composition in between the laminae. Also, even if hy-
drothermal water might have circulated through the rock, it is
Modern lagoons frequently contain
unlikely that the migration path of fluids would be in such a
regular pattern of planes within the rock, let alone exclusively
only in this certain portion of the stratigraphic profile.
4.6. Barrier shoal
A barrier shoal composed of oncoids (Fig. 4c) appears to
have sheltered the zones described above until eventual in-
undation by the ocean.
5. Ancient Microbial Mat–Forming Biota in the Dresser
Formation: Thoughts and Suggestions
A series of studies systematically comparing modern with
ancient MISS showed a great consistency of MISS through-
out geological time (Noffke, 2000, 2010; Noffke et al., 2001a,
2002, 2003, 2006a, 2006b, 2008). MISS assemblages record
diverse microbial mat ecosystems as early as the Meso-
archean Era, as demonstrated by Noffke et al., (2001a, 2008)
and Noffke (2010).
The sedimentary structures here described from the
Dresser Formation are interpreted as MISS based on several
lines of evidence. First, their morphologies are very similar to
those of a variety of more recent fossil and modern MISS.
Interpretations of these extensively studied MISS examples
are based both on qualitative morphological characteristics
and on numerical data that quantify the morphologies of the
structures and allow quantitative comparison among MISS,
as well as between MISS and nonbiological sedimentary
structures. In general, transitional forms between MISS and
surrounding sedimentary features are not observed, neither
in modern nor fossil sequences; that is, all MISS are distinct.
Variations within one morphotype of MISS occur and are
considered by the quantitative data; transitional forms with
intermediate morphological characteristics, however, do not
exist between MISS and any abiotic type of sedimentary
A second important line of evidence is provided by the
close association of microbially induced sedimentary struc-
tures in the Dresser Formation. These MISS display the same
associations that are known from modern as well as from
Third, many of the sedimentary structures include mi-
croscopic biotextures resembling strongly the textures
known from the younger (Archean and Proterozoic) fossil
record of MISS.
Fourth, geochemical and petrological analyses are consis-
tent with the typical mineral associations found in fossil
microbial mats from other Archean sites previously de-
scribed. In particular, carbon is intimately bound to the mi-
crotextures. The four complementary lines of evidence
individually and collectively support the interpretation of
biogenicity for MISS in the Dresser Formation.
Weathering of rock surfaces during the Eocene (Lower
Tertiary) has been described in detail from other parts of
Australia (van der Graff, 1983). Is there the possibility that
surface weathering might mimic some of the proposed
MISS features of the Dresser Formation? Tertiary weather-
ing has produced unconsolidated soils that include irregu-
larly shaped and steep-sloped cones, pebble-sized pisolites,
and vertical karst pipes. None of these phenomena were
found in the stratigraphic sections studied by us in the
Pilbara. Moreover, the morphologies of the weathering
photograph of thin section; 3.48 Ga Dresser Formation, Pil-
bara, Western Australia. Note the wavy appearance of the
fragments. One fragment is rolled up. Geochemistry is
shown in Fig. 18. Scale: 0.5cm.
Fragments in possible lagoonal deposits, micro-
1120 NOFFKE ET AL.
structures differ significantly from those of the sedimentary
structures in the Dresser Formation described as MISS. In
addition, the distribution of the MISS in the Dresser For-
mation correlates with specific sections of the stratigraphic
profiles. They are not related to the modern geomorpho-
logical topography of the study area as is the case with the
weathering structures in the other parts of Australia (van
der Graff, 1983). Also, the fact that the MISS form specific
associations related to adjacent tidal zones differs signifi-
cantly from any weathering or erosive origin, as does the
identification of thermally mature carbon intimately asso-
ciated with many of the Dresser structures. Finally, if the
sedimentary structures we interpret as MISS were of Eocene
weathering origin, then the question would be why iden-
tical MISS and MISS associations are found in modern en-
vironments of the present time that, obviously, have not
experienced Eocene weathering.
We conclude that the Dresser Formation records a com-
plex ecosystem of microbial mats. But which prokaryotes
might have formed these Early Archean microbial mats? It
must be underlined that modern MISS and the modern
MISS-forming microbial mats may only serve as analog
models for the Dresser examples. The genetic information of
individual microbial groups such as modern cyanobacteria is
highly variable, differing today even within meters of the
same setting. Therefore, any conclusion on the existence of
certain groups in the fossil record, let alone in the fossil
record at 3.48 Ga, must be speculative. Also, microorganisms
occur as biofilms, not as individual cells or groups. A biofilm
is a microbial community attached to a solid substrate, in
which all members of the community interact to foster light
and nutrient harvesting, EPS production, and so on (Stood-
ley et al., 2002; Noffke et al., 2013). Therefore, we can with
certainty state that the fossil MISS are the structural expres-
sion of biofilms formed by microbes interacting in similar
fashion with the shallow, photic zone sedimentary habitat as
both younger fossil and modern microbial mats do (Noffke,
2010). The main message of the Dresser Formation MISS is
that microbenthos existed and was able to construct coher-
ent, carpetlike microbial mats. The mats were able to with-
stand erosion, to respond to deposition, and to withstand
semi-arid climate conditions. Using modern MISS and mi-
crobial mats strictly as models, we conclude that the ancient
MISS-forming microbial mats in the Dresser Formation were
Western Australia. (A) Vertical section through a typical fragment in petrographic thin section. Boxed area enlarged in (B). (B)
Higher magnification view of fragment with the area analyzed using Raman indicated by the box. (C) Raman maps showing
the mineralogical composition of the fragment. The goethite map was produced using the *400cm-1goethite Raman peak,
the quartz map using the *465cm-1Raman quartz peak, and the carbon map using the *1600cm-1Raman carbon peak.
(D) A typical Raman spectrum from a carbonaceous area within the fragment. This image shows background quartz (Q) and
goethite (G) peaks, together with the *1350 and *1600cm-1carbon peaks (C) that are characteristic of thermally mature but
disordered organic carbon.
Geochemistry of sedimentary fragments (see Fig. 17) in lagoonal deposits, 3.48 Ga Dresser Formation, Pilbara,
MISS IN THE 3.48 GA DRESSER FORMATION, WESTERN AUSTRALIA 1121
dominated by microbes mimicking the behavior of modern
cyanobacteria. It is important to note that cyanobacteria are
one major group of microbenthos capable of producing the
abundant amount of EPS necessary to allow high biostabil-
ization effects (Linda L. Jahnke, frdl. pers. comm. 2013;
Paterson et al., 1994; Noffke and Paterson, 2008; Noffke, 2010).
Non-transparent wrinkle structures (Fig. 9b) record such high
amounts of EPS (Noffke et al., 2002). Detailed studies on the
interaction of stromatolites (Beukes and Lowe, 1989) and of
MISS (Noffke et al., 2008) with their hydraulically affected
sedimentary environment suggested the presence of ancient
cyanobacteria already in the 2.9 Ga Pongola Supergroup,
South Africa. Cyanobacteria are known to be the first oxy-
gen-producing organisms in the fossil record. However, it is
important to keep in mind that photosynthesis comes in two
types, oxygenic and anoxygenic. While the abundant evi-
dence for an anoxic atmosphere in the Early Archean (Far-
quhar et al., 2000; Hazen et al. 2008; Sverjensky and Lee, 2010)
suggests that oxygenic photosynthesis was not established
until perhaps the Neoarchean Era, it does not exclude the
existence of early cyanobacteria of anoxygenic photosyn-
thesis. However, if the stromatolite- or MISS-forming mi-
crobial mats in the Pongola Supergroup were indeed
cyanobacteria with the capacity to produce oxygen, then this
would be supportive to the latest findings of paleosols in the
Pongola Supergroup that point toward an oxygen-rich at-
mosphere around that time (Crowe et al., 2013). With respect
to the Dresser Formation microbiota, we note that, while a
number of modern filamentous cyanobacteria are capable of
anoxygenic photosynthesis, using H2S instead of H2O as the
electron donor, Chloroflexus or sulfur- or iron-oxidizing
bacteria such as Beggiatoa would also be capable of this
pathway (e.g., Bailey et al., 2009). Both groups also are
capable of forming substantial microbial mats (e.g., Bailey
et al., 2009). Pulling all these thoughts together, a conser-
vative interpretation of the ancient Dresser microbenthos
would be that the biofilms (microbial mats) of the Dresser
sabkha behaved in similar fashion to modern microbenthic
biofilm communities found in sabkha settings today.
In summary, the sedimentary structures preserved in the
coastal sabkha paleoenvironment of the ca. 3.48 Ga Dresser
Formation are here interpreted as MISS. The MISS form as-
semblages that are shown to be typical for sub-environments
of sabkhas through geological time. Using modern MISS in
equivalent sabkha settings as analog models, we conclude
that the MISS in the Dresser Formation record a complex
microbial ecosystem, hitherto unknown, and represent one
of the most ancient signs of life on Earth.
We thank Kath Grey, Martin Van Kranendonk, and the
Geological Survey of Western Australia for the support of
our field work. Andy Knoll has provided valuable comments
on an earlier version of this manuscript. Funding for this
study was provided to N.N. by the National Science Foun-
dation NSF Paleobiology and Sedimentary Geology Pro-
gram, NASA’s Exobiology Program, and by the NASA
Astrobiology Institute. D.C. was granted student research
support by the NASA Astrobiology Institute. D.W. is funded
by the Bergen Research Foundation, the University of Ber-
gen, and the Australian Research Council Centre for Core to
Crust Fluid Systems. R.M.H. received support from the
NASA Astrobiology Institute, the Deep Carbon Observatory,
and the Carnegie Institution of Washington.
Author Disclosure Statement
No competing financial interests exist.
EPS, extracellular polymeric substances; MISS, microbially
induced sedimentary structures; MOD-I, modification index.
Allwood, A.C., Walter, M., Kamber, B., Marshall, C., and Burch,
I. (2006) Stromatolite reef from the early Archaean era of
Australia. Nature 441:714–718.
Allwood, A.C., Walter, M.R., Burch, I.W., and Kamber, B.S.
(2007) 3.43 billion-year-old stromatolite reef from the Pilbara
Craton of Western Australia: ecosystem-scale insights to early
life on Earth. Precambrian Res 158:198–227.
Allwood, A.C., Grotzinger, J.P., Knoll, A.H., Burch, I.W., An-
derson, M.S., Coleman, M.L., and Kanik, I. (2009) Controls on
development and diversity of Early Archean stromatolites.
Proc Natl Acad Sci USA 106:9548–9555.
(2010) Trace elements record depositional history of an Early Ar-
chean stromatolitic carbonate platform Chem Geol 270:148–163.
Australian Stratigraphic Units Database. (2012) Dresser Forma-
tion. Geoscience Australia, Commonwealth of Australia,
Canberra, Australia. Available online at http:/ /dbforms.ga
Awramik, S., Schopf, W., and Walter, M. (1983) Filamentous
fossil bacteria from the Archean of Western Australia. Pre-
cambrian Res 20:357–374.
Bailey, J., Orphan, V., Joye, S., and Corsetti, F. (2009) Chemo-
trophic microbial mats and their potential for preservation in
the rock record. Astrobiology 9:843–859.
Barley, M.E., Dunlop, J.S.R., Glover, J.E., and Groves, D.I. (1979)
Sedimentary evidence for an Archean shallow-water volcanic-
sedimentary facies, eastern Pilbara block, Western Australia.
Earth Planet Sci Lett 43:74–84.
Beraldi-Campesi, H., Hartnett, H.E., Anbar, A., Gordon, G.W.,
and Garcia-Pichel, F. (2009) Effect of biological soil crusts on
soil elemental concentrations: implications for biogeochemis-
try and as traceable biosignatures of ancient life on land.
Beukes, N. and Lowe, D. (1989) Environmental control on di-
verse stromatolite morphologies in the 3000 Myr Pongola
Supergroup, South Africa. Sedimentology 36:383–397.
Beveridge, T. (1989) Role of cellular design in bacterial metal ac-
cumulation and mineralization. Annu Rev Microbiol 43:147–171.
Beyssac, O., Goffe, B., Chopin, C., and Rouzaud, J.N. (2002)
Raman spectra of carbonaceous material in metasediments: a
new geothermometer. Journal of Metamorphic Geology 20:859–871.
Buick, R. and Dunlop, J. (1990) Evaporitic sediments of Early
Archaean age from the Warrawoona Group, North Pole,
Western Australia. Sedimentology 37:247–277.
Byerly, G., Lowe, D. and Walsh, M. (1986) Stromatolites from the
3,300–3,500 Myr Swaziland Supergroup, Barberton Mountain
Land, South Africa. Nature 319:489–491.
Cady, S.L. and Farmer, J.D. (1996) Fossilization processes in si-
liceous thermal springs: trends in preservation along thermal
1122NOFFKE ET AL.
gradients. In Evolution of Hydrothermal Ecosystems on Earth (and
Mars?), Ciba Foundation Symposium 202, edited by G.R. Brock
and J.A. Goode, John Wiley and Sons, Chichester, UK, pp 150–
Carmona, N., Cuadrado, D., and Bournod, C. (2011) Biostabil-
ization of sediments by microbial mats in a temperate silici-
clastic tidal flat, Bahia Blanca estuary (Argentina). Sediment
Committee on an Astrobiology Strategy for the Exploration of
Mars. (2007) An Astrobiology Strategy for the Exploration of Mars,
The National Academies Press, Washington, DC.
Crowe, S.A., Dossing, L.N., Beukes, N.J., Bau, M., Kruger, S.J.,
Frei, R., and Canfield, D.E. (2013) Atmospheric oxygenation
three billion years ago. Nature 501:535–538.
Decho, A.W., Frey, R.L., and Ferry, J.L. (2011) Chemical chal-
lenges to bacterial AHL signaling in the environment. Chem
Dupraz, C., Reid, P.R., Braissant, O., Decho, A.W., Norman,
R.S., and Visscher P.T. (2009) Processes of carbonate precip-
itation in modern microbial mats. Earth-Science Reviews
Eriksson, P.G., Simpson, E.L., Eriksson, K.A., Bumby, A.J., Steyn,
G.L., and Sarkar, S. (2000) Muddy roll-up structures in silici-
clastic interdune beds of the c. 1.8 Ga Waterberg Group, South
Africa. Palaios 15:177–183.
Farquhar, J., Bao, H., and Thiemens, M. (2000) Atmospheric in-
fluence of Earth’s earliest sulphur cycle. Science 289:756–758.
Fries, M. and Steele, A. (2011) Raman spectroscopy and confocal
Raman imaging in mineralogy and petrography. Springer
Series in Optical Sciences 158:111–135.
Gerdes, G. and Krumbein, W. (1987) Biolaminated Deposits,
Grotzinger, J.P., Arvidson, R.E., Bell, J.F., Calwin, W., Clark,
B.C., Fike, D.A., Golombek, M., Greeley, R., Haldeman, A.,
Herkenhoff, K.E., Jolliff, B.L., Knoll, A.H., Malin, M., McLen-
nan, S.M., Parker, T., Soderblom, L., Sohl-Dickstein, J.N.,
Squyres, S.W., Tosca, N.J., and Watters, W.A. (2005) Strati-
graphy and sedimentology of a dry to wet eolian depositional
system, Burns Formation, Meridiani Planum, Mars. Earth
Planet Sci Lett 240:11–72.
Hagadorn, W., Pflueger, F., and Bottjer, D.J., editors. (1999)
Unexplored microbial worlds. Palaios Special Issue 14.
Hazen, R.M., Papineau, D., Bleeker, W., Downs, R.T., Ferry, J.M.,
McCoy, T.J., Sverjensky, D.A., and Yang, H. (2008) Mineral
evolution. Am Mineral 93:1693–1720.
Heubeck, C. (2009) An early ecosystem of Archean tidal micro-
bial mats (Moodies Group, South Africa, ca. 3.2 Ga). Geology
Hickman, A. (2012) Review of the Pilbara Craton and Fortescue
Basin, Western Australia: crustal evolution providing envi-
ronments for early life. Island Arc 21:1–31.
Hofmann, H. (2004) Archean microfossils and abiomorphs. As-
Hofmann, H., Grey, K., Hickman, A., and Thorpe, R. (1999)
Origin of 3.45 Ga coniform stromatolites in the Warrawoona
Group, Western Australia. Geol Soc Am Bull 111:1256–1262.
Knoll, A.H., Strother, P.K., and Rossi, S.(1988) Distribution and
diagenesis of microfossils from the Lower Proterozoic Duck
Creek Dolomite, Western Australia. Precambrian Res 38:257–
Konhauser, K., Schulze-Lam, S., Ferris, F.G., Longstaffe, F.J., and
Beveridge, T.J. (1994) Mineral precipitation by epilithic bio-
films in the Speed River, Ontario, Canada. Appl Environ Mi-
Kremer, B., Kazmierczak, J., and Stal, L.(2008) Calcium carbon-
ate precipitation in cyanobacterial mats from sandy tidal flats
of the North Sea. Geobiology 6:46–56.
Krumbein, W.E. (1979) Photolithotrophic and chemoorgano-
trophic activity of bacteria and algae as related to beach rock
formation and degradation (Gulf of Aquaba, Sinai). Geomi-
crobiol J 1:139–203.
Lambert, I.B., Donnelly, T.H., Dunlop, J.S.R., and Groves, D.I.
(1978) Stable isotope compositions of early Archaean sulphate
deposits of probable evaporitic and volcanogenic origins.
Lowe, D. (1980) Stromatolites 3,400 Myr old from the Archean of
Western Australia. Nature 284:441–443.
Marshall, C.P., Emry, J.R., and Olcott Marshall, A. (2011) Hae-
matite pseudomicrofossils present in the 3.5-billion-year old
Apex Chert. Nature Geoscience 4:240–243.
Metz, J.M., Grotzinger, J.P., Rubin, D.M., Lewis, K.W., Squyres,
S.W., and Bell, J.F., III. (2009) Sulfate-rich eolian and wet in-
terdune deposits, Erebus Crater, Meridiani Planum, Mars.
Journal of Sedimentary Research 79:247–264.
Noffke, N. (1999) Erosional remnants and pockets evolving from
biotic-physical interactions in a Recent lower supratidal en-
vironment. Sediment Geol 123:175–181.
Noffke, N. (2000) Extensive microbial mats and their influences
on the erosional and depositional dynamics of a siliciclastic
cold water environment (Lower Arenigian, Montagne Noire,
France). Sediment Geol 136:207–215.
Noffke, N. (2010) Microbial Mats in Sandy Deposits from the Ar-
chean Era to Today, Springer, New York.
Noffke, N. and Awramik, S. (2013) Stromatolites and MISS:
differences between relatives. GSA Today 23:4–9.
Noffke, N. and Chafetz, H., editors. (2012) Microbial Mats in
Siliciclastic Depositional Systems through Time, SEPM Special
Publication 101, Society for Sedimentary Geology, Tulsa, OK.
Noffke, N. and Krumbein, W. E. (1999) A quantitative approach
to sedimentary surface structures contoured by the interplay
of microbial colonization and physical dynamics. Sedimentol-
Noffke, N. and Paterson, D., editors. (2008) An actualistic per-
spective: biotic-physical interaction of benthic microorganisms
and the significance for the biological evolution of Earth.
Noffke, N., Gerdes, G., Klenke, T., and Krumbein, W. (2001a)
Microbially induced sedimentary structures indicating clima-
tological, hydrological and depositional conditions within
Recent and Pleistocene coastal facies zones (southern Tunisia).
Noffke, N., Gerdes, G., Klenke, Th., and Krumbein, W.E. (2001b)
Microbially induced sedimentary structures—a new category
within the classification of primary sedimentary structures.
Journal of Sedimentary Research 71:649–656.
Noffke, N., Knoll, A.H., and Grotzinger, J. (2002) Sedimentary
controls on the formation and preservation of microbial mats
in siliciclastic deposits: a case study from the Upper Neopro-
terozoic Nama Group, Namibia. Palaios 17:5–33.
Noffke, N., Hazen, R., and Nhleko, N. (2003) Earth’s earliest
microbial mats in a siliciclastic marine environment (2.9 Ga
Mozaan Group, South Africa). Geology 31:673–676.
Noffke, N., Beukes, N., and Hazen, R. (2006a) Microbially in-
duced sedimentary structures in the 2.9 Ga old Brixton For-
mation, Witwatersrand Supergroup, South Africa. Precambrian
Noffke, N., Eriksson, K.A., Hazen, R.M., and Simpson, E.L.
(2006b) A new window into Early Archean life: microbial mats
MISS IN THE 3.48 GA DRESSER FORMATION, WESTERN AUSTRALIA1123
in Earth’s oldest siliciclastic tidal deposits (3.2 Ga Moodies Download full-text
Group, South Africa). Geology 34:253–256.
Noffke, N., Beukes, N., Hazen, R., Swift, D. (2008) An actualistic
perspective into Archean worlds—(cyano-)bacterially induced
sedimentary structures in the siliciclastic Nhlazatse Section,
2.9 Ga Pongola Supergroup, South Africa. Geobiology 6:5–20.
Noffke, N., Decho, A.W., and Stoodley, P. (2013) Slime through
time—the fossil record of prokaryote evolution. Palaios 1:1–5.
Paterson, D.M., Yallop, M., and George, C. (1994) Biostabiliza-
tion. In Biostabilization of Sediments, edited by W.E. Krumbein,
D.M. Paterson, and L.J. Stal, BIS, Oldenburg, pp 401–432.
Prave, A.R. (2002) Life on land in the Proterozoic: evidence from
the Torrodonian rocks of Northwest Scotland. Geology 30:811–
Reid, R.P., Visscher, P.T., Decho, A.W., Stolz, J.F., Bebout, B.M.,
Dupraz, C., Macintyre, I.G., Paerl, H.W., Pinckney, J.L., Pru-
fert-Bebout, L., Steppe, T.F., and des Marais, D.J (2000) The
role of microbes in accretion, lamination and early lithication
of modern marine stromatolites. Nature 406:989–992.
Rividi, N., van Zuilen, M., Philippot, P., Menez, B., Godard, G.,
and Poidatz, E. (2010) Calibration of carbonate composition
using micro-Raman analysis: application to planetary surface
exploration. Astrobiology 10:293–309.
Schieber, J., Bose, P.K., Eriksson, P.G., Banerjee, S., Sarkar, S.,
Alterman, W., and Catuneanu, O., editors. (2007) Atlas of
Microbial Mat Features Preserved within the Siliciclastic Rock
Record, Elsevier, Amsterdam.
Schopf, W. and Bottjer, D. (2009) World summit on ancient mi-
croscopic fossils. Precambrian Res 173:1–3.
Schopf, W., Walter, M., and Ruiji, R. (2007) Earliest evidence of
life on Earth. Precambrian Res 158:139–140.
Mineralization of bacterial surfaces. Chem Geol 132:171–181.
Shen, Y., Buick, R., and Canfield, D.E. (2001) Isotopic evidence
for microbial sulphate reduction in the early Archaean era.
Shen, Y., Farquhar, J., Masterson, A., Kaufman, A.J., and Buick,
R. (2009) Evaluating the role of microbial sulfate reduction in
the early Archean using quadruple isotope systematics. Earth
Planet Sci Lett 279:383–391.
Shepard, R. and Sumner, D. (2010) Undirected motility of fila-
mentous cyanobacteria produces reticulate mats. Geobiology
Stoodley, P., Sauer, K., Davies, D.G., and Costerton, J.W. (2002)
Biofilms as complex differentiated communities. Annu Rev
Sverjensky, D.A. and Lee, N. (2010) The Great Oxidation Event
and mineral diversification. Elements 6:31–36.
Sugitani, K., Lepot, K., Nagaoka, T., Mimura, K., Van Kra-
nendonk, M., Oehler, D.Z., and Walter, M.R. (2010) Biogeni-
city of morphologically diverse carbonaceous microstructures
from the ca. 3400 Ma Strelley Pool Formation, in the Pilbara
Craton, Western Australia. Astrobiology 10:899–920.
Tice, M. and Lowe, D. (2006) The origin of carbonaceous matter in
pre-3.0 Ga greenstone terrains: a review and new evidence from
the 3.42 Ga Buck Reef Chert. Earth-Science Reviews 76:259–300.
Ueno, Y., Yamada, K., Yoshida, N., Maruyama, S., and Isozaki,
Y. (2006) Evidence from fluid inclusions for microbial me-
thanogenesis in the early Archaean era. Nature 440:516–519.
Ueno, Y., Ono, S., Rumble, D., and Maruyama, S. (2008) Quad-
ruple sulfur isotope analysis of ca. 3.5 Ga Dresser Formation:
new evidence for microbial sulfate reduction in the early Ar-
chean. Geochim Cosmochim Acta 72:5675–5691.
Urrutia, M. and Beveridge, T. (1994) Formation of fine-grained
metal and silicate precipitates on a bacterial surface (Bacillus
subtilis). Chem Geol 116:261–280.
van der Graff, W.J.E. (1983) Silcrete in Western Australia: geo-
morphological settings, textures, structures, and their genetic
implications. In Residual Deposits: Surface Related Weathering
Processes and Minerals, Geological Society of London Special
Publication 11, edited by R.C.L. Wilson, Blackwell Scientific
Publications, Oxford, pp 159–166.
Van Kranendonk, M.J. (2006) Volcanic degassing, hydrothermal
circulation and the flourishing of early life on Earth: a review
of the evidence from c. 3490–3240 Ma rocks of the Pilbara
Supergroup, Pilbara Craton, Western Australia. Earth-Science
Van Kranendonk, M.J. Philippot, P., Lepot, K., Bodorkos, S., and
Pirajno, F. (2008) Geological setting of Earth’s oldest fossils in
the ca. 3.5 Ga Dresser Formation, Pilbara Craton, Western
Australia. Precambrian Res 67:93–124.
Wacey, D. (2009) Early Life on Earth: A Practical Guide, Springer,
Wacey, D., McLoughlin, N., Whitehouse, M.J., and Kilburn, M.R.
(2010) Two co-existing sulfur metabolisms in a ca. 3,400 Ma
sandstone. Geology 38:1115–1118.
Wacey, D., Kilburn, M.R., Saunders, M., Cliff, J., and Brasier,
M.D. (2011) Microfossils of sulfur metabolizing cells in *3.4
billion year old rocks of Western Australia. Nat Geosci 4:698–
Wacey, D., Menon, S., Green, L., Gerstmann, D., Kong, C.,
McLoughlin, N., Saunders, M., and Brasier, M.D. (2012)
Taphonomy of very ancient microfossils from the *3400 Ma
Strelley Pool Formation and *1900 Ma Gunflint Formation:
new insights using focused ion beam. Precambrian Res 220–
Walsh, M. (1992) Microfossils and possible microfossils from the
Early Archean Onverwacht Group, Barberton Mountain Land,
South Africa. Precambrian Res 54:271–293.
Walsh, M. and Lowe, D. (1985) Filamentous microfossils from
the 3,500 Myr-old Overwacht Group, Barberton Mountain
Land, South Africa. Nature 314:530–532.
Walsh, M. and Lowe, D. (1999) Modes of accumulation of or-
ganic matter in the early Archean: a petrographic and geo-
chemical study of the carbonaceous cherts of the Swaziland
Supergroup. GSA Special Paper 329:115–132.
Walter, M., Buick, R., and Dunlop, J. (1980) Stromatolites, 3,400–
3,500 Myr old from the North Pole area, Western Australia.
Address correspondence to:
Department of Ocean, Earth and Atmospheric Sciences
Old Dominion University
Norfolk, VA 23529
Submitted 29 April 2013
Accepted 21 October 2013
1124NOFFKE ET AL.