Stromatolites and MISS

1
Stromatolites and Microbial Mat Structures in
Vindhyan Basin, India.
A Project Completed Under
Innovation in Science Pursuit for Inspired Research (INSPIRE) Program
(Reference Number – DST/INSPIRE/02/2014/040806)
Sponsored by
Department of Science and Technology
Ministry of Science and Technology
Government of India
Under supervision of
Dr. Mukund Sharma
Scientist ‘F’
Birbal Sahni Institute of Palaeosciences
53 University Road, Lucknow, Uttar Pradesh, 226007.
By
Mohammad Imran Khan
Department of Geology
University of Delhi
Delhi-110007.
Birbal Sahni Institute of Palaeosciences
(An Autonomous Institute under Department of Science & Technology, Government of India)
53 University Road,
Lucknow, Uttar Pradesh, 226007.
India.

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Contents
Acknowledgements
Title Page No.
1. Introduction 4
1.1. Project Title 4
1.2. Introduction 4
1.3. Project Aim 5
1.4. Project Objective 5
2. Stromatolites and Microbial Mat Structures 6
2.1. Introduction 6
2.2. Stromatolite Definition 6
2.3. Classification of Stromatolites 7
2.4. Microbial Mat Structures 10
2.5. Distribution of Stromatolites in Time 15
2.6. Indian Stromatolites and Microbial Mat Structures 17
3. Methodology 20
3.1. Field Work 22
3.2. Laboratory Examination 22
4. Introduction to Vindhyan Basin 25
4.1. Introduction 25
4.2. Geology 26
4.3. Stratigraphy 26
4.4. Age 29
5. Vindhyan Stromatolites and Microbial Mat Structures 30
5.1. Semri Group 30
5.2. Kaimur Group 35
5.3. Rewa Group 35
5.4. Bhander Group 35
6. Discussion and Conclusion 38
References 39

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Acknowledgements
First and foremost, I offer my gratitude to Prof. Sunil Bajpai, Director, Birbal Sahni Institute of
Palaeosciences, Lucknow who permitted me to access to various facilities of the Institute to conduct and complete
my summer training project and to my supervisor Dr. Mukund Sharma, Scientist ‘F’, Birbal Sahni Institute of
Palaeosciences, Lucknow, under whose guidance I have completed this training. I express my heartfelt gratitude to
him for his constant encouragement, tremendous support, critical analysis of my work, depth of views and
introducing me fascinating world of the Precambrian Palaeobiology. He spared his precious time for me. I express
deep sense of gratitude to Prof. G.V.R. Prasad, Prof. P.P. Chakraborty and Dr. Pramod Kumar, Department of
Geology, University of Delhi for encouraging me in the field of Palaeosciences. Their constant support and valuable
suggestions gave me constant strength.
I sincerely thank to the members of the Precambrian Palaeobiology Lab of BSIP namely Dr. Veeru Kant
Singh (Scientist ‘D’), Dr. Arif Hussain Ansari (Scientist ‘B’), Dr. Santosh Kumar Pandey (Scientist ‘B’), Dr. (Mrs)
Yogmaya Shukla (Scientist ‘B’), Dr. Shamim Ahmad (Young Scientist), Dr. (Ms) Anju Verma (National Post Doctoral
Fellow) and Mr. Yogesh Kumar (JRF), who constantly helped me to complete the project.
I am grateful to my friends, especially Mr. Baibhav Kumar and Mr. Govind Kumar for discussions, immense
moral support and encouragement. I acknowledge the help rendered by my friends Tushar Pande and Shirish
Verma in search of stay facility in Lucknow during project tenure.
I am fortunate to have unstinted support of my mother, Mrs Rasma Be, and my father, Mr. Kudrat Khan
during my work. Words fail me to express my gratitude towards my school teachers Mr. Yadunath Yadav Ji and Mr.
Megh Singh Ji for their continuous blessings on me.
This project would not have been possible without the financial support of Department of Science and
Technology, Ministry of Science and Technology, Government of India. So, I sincerely thank to DST for providing me
INSPIRE Scholarship and mentorship.
Mohammad Imran Khan
29 June 2017 .

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1. Introduction
1.1. Project Title: Stromatolites and Microbial Mat Structures in Vindhyan Basin, India.
1.2. Introduction
Stromatolites are biosedimentary structures generated by benthic microbial mats and biofilms, as a result of
trapping of particulate sediment or the templating of mineral precipitation. Today, benthic microbial mats are
sporadically distributed, but prior to the rise and dominance of metazoans (600 Ma), they were widespread on land
as well as in deeper waters. They are recorded as kerogen, biomarker hydrocarbons, carbon and sulphur isotope
signatures, stromatolites (commonly in carbonate sequences) and microbially induced sedimentary structures
(MISS-in siliciclastic sequences).
Earlier, the term stromatolite was usually restricted to laminated structures. Later, the term ‘thrombolite’
was introduced for microbial deposits which lack lamination and have a ‘clotted’ fabric, and the term
‘microbialite’ was introduced to refer to all microbial deposits. At Present, the term stromatolite is used as a
synonym for microbialite. However, this was contradicted by many workers (Grotzinger and Knoll, 1999).
The inhabitants of stromatolite-building mats include representatives of all three currently recognized
domains of life (Bacteria, Archaea, and Eukarya). It has long been recognized that abiotic mineral precipitates
can mimic features of stromatolites. At present, distinguishing stromatolites from abiogenic but comparable
structures is a vexed issue. Whether a structure is of biological origin or not, this can be demonstrated from
the presence of a fossil microbiota with cell orientations that indicate a role in constructing the sedimentary
architecture in stromatolites.
Stromatolites are considered as the oldest macroscopic evidence of life on the earth. Palaeoarchaean and
Mesoarchaean stromatolites are rare and not diverse. In the Neoarchaean, stromatolites were more abundant
and much more diverse. This may have resulted from the formation of extensive continental shelves. In the
Palaeoproterozoic and Mesoproterozoic conical stromatolites were abundant. They declined markedly
thereafter. There was a decline in abundance of all stromatolites about 600-700 Ma. Thrombolites were rare
before the Phanerozoic and became abundant during the Early Cambrian. Stromatolites are rare after the
Early Ordovician. Stromatolites are still abundant in ‘extreme’ environments as hypersaline tidal flats and
thermal springs.
Stromatolites have been extensively documented from the Archaean and Proterozoic successions of India.
They have been reported from almost all Precambrian basins of India. They have been recorded from both the
peninsular as well as the extra-peninsular part of India. In peninsular India, Vindhyan rocks contain best
preserved stromatolites.
The Vindhyan Basin is the largest among all the ‘Purana Basins’ and second largest among all the
Proterozoic basins of the world (Chakraborty, 2006). The age of the Vindhyan Supergroup is
Palaeoproterozoic to Neoproterozoic. It is characterized by repeated transitions of platform-type shallow
marine and non-marine deposits.
Stromatolites have been well documented from carbonate successions of the Vindhyan Supergroup
(Kumar, 1978; Sharma, 2006 a & b). Stromatolites are profusely developed in the Semri and Bhander Group.
Recently, microbial mat induced sedimentary structures (MISS) have been described from siliciclastic
successions of the Vindhyan Supergroup. They include those from the Chorhat Sandstone (Rasmussen et al.,
2002; Ray et al., 2002) and Koldaha Shale Formations (Banerjee and Jeevan Kumar, 2005).

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There are different opinions with regard to the definition, nature, formation, causative organisms, status,
biostratigraphic potential, classification and economic importance the stromatolites and mat structures.
However, they have proved useful in various aspects of geology. The morphology of stromatolites and mat
structures has proved good indicator of depositional environment. A number of studies have demonstrated
that stromatolites are useful in basinal correlation.
1.3. Aim: To investigate the diversity and abundance of stromatolites and microbial mat
structures in the Vindhyan Basin and to assess their significance in depositional environment
and biostratigraphy.
1.4. Objective
The above aim will be accomplished by fulfilling the following project objectives –
1. To develop a historical framework of stromatolite studies.
2. To assess and synthesize various definitions and classifications of stromatolites and microbial mat
structures.
3. Review the literature concerning the stromatolites and microbial mat structures studies in India and
their global significance.
4. To collect information about the variation in abundance and diversity of stromatolites through
geological time.
5. To construct a worksheet model of elements of stromatolite studies.
6. To describe the stromatolites and microbial mat structures present in the Vindhyan Basin and attempt
to understand the depositional environment and biostratigraphy of Vindhyan Basin.
7. To summarize Indian as well as global contributions in this field of study.
8. Data sets will be extracted from known records of stromatolites and microbial mat structures and they
will be synthesized.

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2. Stromatolites and Microbial Mat Structures
2.1. Introduction
The German term “Stromatolith” was coined by Ernst Kalkowsky in 1908 from the Greek words ‘stroma’,
meaning bed, mattress or layer; and ‘lithos’ meaning stone. Kalkowsky (1908) suggested that Stromatolithe were
formed by “niedrig organisierte planzliche Organismen” (simply organized plant-like organisms). In essence, he
regarded stromatolites as laminated microbial structures. However, Gurich (1906) had named spongiostromides for
spongy microstructures. He placed them in new genera such as Pycnostroma and Spongiostroma and thought
them as protozoans. Pia (1927) classified “Stromatolithi” and “Oncolithi” as sub-groups within the
Spongiostromata. However, stromatolite became widely adopted as the general term, whereas spongiostrome is
now (and more rarely) used to refer to the distinctive clotted fabrics found in many Phanerozoic stromatolites.
Taking the long history of stromatolites as a whole, this suggests that some stromatolites are biogenic (e.g., lithified
microbial carbonate), others are abiogenic precipitated crust, and that some are hybrid mixtures of the two. Many
late Archaean and early Proterozoic stromatolites consist of intimate interlayering of both lithified microbial mat
and essentially abiogenic precipitated crust that has been termed Hybrid Crust (Riding 2008).
2.2. Stromatolite Definition
In his 1908 paper, Ernst Kalkowsky did not provide a specific definition of stromatolite, but he did
repeatedly emphasize that it is a laminated organic structure. He thought that the life forms involved were “niedrig
organisierte planzliche Organismen” (simple plant-like organisms, Kalkowsky, 1908). In his paper he stated, “Alle
Stromatolithe zeigen im vertikalen Schnitt deutliche Lagenstruktur” “All stromatolites show distinct layering in
vertical section”. It is therefore reasonable to conclude that Kalkowsky essentially regarded stromatolites as
laminated microbial deposits (Riding, 1999). Logan et al. (1964) proposed that “Stromatolites are laminated
structures that have been previously termed fossil algae. It is now recognized that such structures may be formed by
a number of different processes and organisms.” Aitken (1967) introduced the term ‘thrombolite’ for “cryptalgal
structures related to stromatolites, but lacking lamination and characterized by a macroscopic clotted fabric”.
Hofmann (1973) proposed that stromatolites need not to be biogenic. He recognized chemogenic stromatolites and
emphasized to distinguish biogenic stromatolites from chemical and mechanical ones. Awramik and Margulis (1974)
defined stromatolites as “megascopic organosedimentary structures produced by sediment trapping, binding
and/or precipitation as a result of growth and metabolic activity of organisms, primarily blue-green algae”. This
definition required stromatolites to be microbial, but not necessarily layered, and therefore permitted thrombolite
to be regarded as a type of stromatolite. But this left no specific term for laminated stromatolites. Semikhatov et al.
(1979) followed Logan et al.’s (1964) lead and recognized both biogenic and abiogenic stromatolites. They stated
that “a stromatolite is an attached, laminated, lithified, sedimentary growth structure, accretionary away from a
point or limited surface of initiation. Although characteristically of microbial origin and calcareous composition, it
may be of any origin, composition, shape, size, or age.” This definition permits some stromatolites to be abiogenic.
Buick et al. (1981) suggested that “structures of uncertain origin that resemble stromatolites should be called
‘stromatoloids’”. Burne and Moore (1987) used a new term: ‘microbialite’. “Microbialites are organosedimentary
deposits that have accreted as a result of a benthic microbial community trapping and binding detrital sediment
and/or forming the locus of mineral precipitation”. This then allowed stromatolites to be regarded as macro-
laminated microbialites, and thrombolites as macro-clotted microbialites. It also encouraged subsequent additions
to the microbialite family, such as dendrolite (dendritic; Riding 1991) and leiolite (aphanitic; Braga et al. 1995).

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Ginsburg’s (1991) followed Semikhatov et al.’s (1979) definition and proposed that stromatolite “includes
structures of a variety of origins ranging from tufa domes.....to laminated structures of mineralized organisms...
and even some of the laminated zones of caliches and calcretes as well as certain speleothems.” Awramik and
Grey (2005) used the term ‘pseudostromatolites’ for abiogenic stromatolite-like structures.
2.3. Classification of Stromatolites
The classification of stromatolites is still a matter of debate. The first attempt to classify Precambrian
stromatolite was made by Walcott (1914) on the basis of morphology. He divided Beltian algal structures into four
categories: Massive cellular, Semispherical, Flabelliform and Tubiform. Subsequently, significant contributions were
made on the classification of stromatolites by Pia (1927) (Spongiostromata-without distinct organic microstructure,
and the porostromata-with distinct microscopic tubes); Maslov (1937) (Collenia-with convex laminae, and
Conophyton-with conical laminae); Krasnopeeva (1946) (Newlandiella, Algostroma, Kabyrsina and Sibirephycus);
Anderson (1950); Rezak (1957) (Cryptozoan, Collenia, Newlandia & Conophyton); Maslov (1953, 1960) (phytolites-
stromatolites and oncolites ); Raaben (1964, 1969) (classified columnar stromatolites into Conophytonida,
Kussiellida, Tungussida, and Gymnosolenida); Komar (1966); Aitken (1967); Walter (1972). Krylov (1976) in
'Approaches to the classification of stromatolites' summarized the 12 classifications prevalent at that time. The
classification was as follows:
i. Classification applicable to any stromatolite
For stromatolite classification single vertical section is sufficient to study its features. The group distinguished in
this way is again subdivided on the basis of: -
1. Branching- Stromtolites with branching columns are termed as Gymnosolen (Pia 1927, Cloud 1942, Raaben
1960) and stromatolites whose columns widened upwards belong to group Cryptozoon (Pia 1927, Rezak
1957).
2. Shape of Lamination- Stromatolites with domal shape lamination belong to group Collenia (Maslov 1914)
and with conical shape laminae with an "axial zone" belong to group Conophyton. Maslov (1960)
introduced an intermediate group Conocollenia.
Figure -1. Diagrammatic summary of contrasting stromatolite
definitions, as they relate to degree of macrolayering and
microbial/ abiogenic origins (after J. Reitner et al., Advances in
Stromatolite Geobiology, Lecture Notes in Earth Sciences 131,
2011. Page-51).

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Other classification of stromatolites is based on its types and subtypes. On this basis five types are identified:
i. Stratiform
ii. Columnar stratiform
iii. Nodular (Korolyuk 1960c)
iv. Columnar nodular (Krylov 1963)
v. Columnar
ii. Classification of stratiform stromatolites
3. Stromatolites are classified on the basis of layers. For the identification of this group adjacent tubercles and
hollows should be present in samples which are observed in vertical sections. Group with regular alteration
of convex tubercle and concave hollows termed as Stratifera and group with non-inherited morphology of
layers are termed as lrregularia (Korolyuk 1960c).
4. Stromatolite classification is based on two criteria: lamination morphology and microstructure. Group
Gongylina (Komar 1960) is similar to lrregularia in morphology but differs in microstructure.
iii. Classification of columnar- stratiform stromatolites
5. Groups are classified by the morphology of the columns and the shape of the laminae. For this group
study sample should include 2-3 columns in single vertical section. In this way Schancharia and
Collumnaefacta (Korolyuk 1960c), Parmites (Raaben 1964b), Omachtenia (Nuzhnov 1967),
Gruneria (Cloud and Semikhatov 1969b), Dgerbia (Dolonik 1969 in Dolnik and Vorontsova 1971) &
Tarioufetia (Bertrand Sarfati 1972c) groups are distinguished.
Figure-3. A) Columnar stromatolites showing a transition into thrombolites. B) Transverse surface of columnar stromatolites. (PTB sequence
in the Zaixia section, southern China. coin diameter= 2.3 cm) ( after Adachi et. al., 2017)
Figure -2. Conical stromatolites from the 3388 Ma Strelley
Pool Chert of Western Australia. Scale= 10 cm (Hofmann et
al., 1999) (after Schopf et al., 2007).
A B

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iv. Classification of nodular stromatolites
6. Nodular stromatolites are classified by study of the central part of the nodule in vertical section. Two
groups Colleniella and Paniscollenia are distinguished (Korolyuk 1960c). The difference between
these two groups is the morphology of the laminae.
7. Group Nucleella (Komar 1966) is classified on the basis of morphology and also studying the
microstructure of the laminae. The group is identified by microscopic study of thin section.
v. Classification of columnar - nodular stromatolites
The group Tinnia (Dolnik 1969 in Dolnik and Vorontsova 1971) and Gaia (Krylov 1971) are identified by
studying a large sample that shows a substantial part of the nodule. Vertical section is studied and it is
desirable to have a complete photograph or drawing of the outcrop.
vi. Classification of columnar stromatolites
There are five independent classifications of columnar stromatolites:
8. Columnar stromatolites are identified by studying the vertical section that passes across the middle of
the column. Groups are distinguished according to the shape of laminae and nature of column margins
(Korolyuk 1960a). The classification includes the following groups:
Collumnacollenia, Planocollenia, Linocollenia, Sacculia (Korolyuk 1960a), Boxonia (Korolyuk 1960c
Komar 1964), Conophyton (Maslov 1938), Ilicta (Sidorov 1960), Tunicata (Sidorov in Korolyuk
1968), Katernia (Cloud and Semikhatov 1969b) and Kasaia (Bertrand Sarfati 1972c).
9. These groups are distinguished on the basis of three morphological features:
a). General shape of the columns (tuberous, sub-cylindrical)
b). Types of column margins (smooth, bumpy, ribbed, walled or naked)
c). Character of branching
Through this classification groups Kusseilla, Baicalia, Jurussania, Minjaria, lnzeria,
Pseudokussiella, Katavia (Krylov 1962), Gymnosolen (Krylov 1962, Raaben 1964b, non Steinmann
1911 ), Pitella, Turuchania (Semikhatov 1962), Linella, Patornia, Vetella (Krylov 1967a), Anabaria,
Kotuikania (Komar 1964), Svetliella (Shapovalova, in Krylov et at., 1968) Tenupalusella (Golovanov
1970), Aldania (Krylov 1969), Eucapsiphora (Cloud and Semikhatov 1969b), Poludia (Raaben 1964b
), Lenia (Dolnik 1969 in Dolnik and Vorontsova 1971 ), Boxonia (Komar 1964, non Korolyuk 1960c),
Tilemsina, Serizia, Mouatila, Tifounkeia (Bertrand -Sarfati 1972) can be identified.
10. These groups include the three features mentioned above with fourth, i.e., the microstructure of the
layers. In this way groups Microstylus (Komar 1966) and Glebulella (Dolnik 1969) have been
identified and new diagnosis for the previously described stromatolite groups have been provided:
Kussiella (Komar 1966, non Krylov 1962), Boxonia (Komar 1966, non Korolyuk 1960c, non Komar
1964) and Kotuikania (Komar 1966, non Komar 1964).
11. Under this classification the groups are distinguished as regular combinations of morphologically
different constructions. This group include Compactocollenia (Korolyuk 1960) which is a combination
of a nodule with a branching column, Tungussia (Semikhatov 1962) which is the combination of
inclined columns with vertical tuberous branches and Jacutophyton (Shapovalova 1968) which is the
combination of an axial column corresponding to the diagnosis of the Conophyton group with
branches of definite morphology.
12. This classification for defining group includes the study of mode of occurrence (i.e. shape of the
bioherm), column shape, branching style, laminae shape and microstructure. Raaben and Sinha (1989)
proposed a scheme of classification of stromatolites with a larger amount of data in order to establish

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new superior taxa at every rank level. They introduced a new taxon 'Microstromatithi' to incorporate
small columnar and non-columnar stromatolites.
2.4. Microbial Mat Structures
Microbial mats and their related structures in siliciclastic sediments have only recently attracted the
attention of the scientists. Microbial mats are multilayered structures of microorganisms with thickness of a
few cm. Microbial biofilms are in contrast much thinner (10–100 μm) than microbial mats and have a different
architecture. Microbial mats are the earliest complex form of life on Earth. There is a fossil record from 3,500
million years ago, and they have always been the most important members and maintainers of earth
ecosystems.
Mat-related sedimentary structures are small- to medium scale sedimentary structures resulting from
growth and extension of microbial populations and communities on a sediment surface, stabilization of
surface sediments, trapping and binding of sediment particles, and from the impact of environmental factors,
such as inundation, sedimentary deposition, subaerial desiccation, wind- or current-induced traction, on
epibenthic microbial mats.
They are also known as Microbially induced sedimentary structures (MISS) (The acronym MISS
was introduced by Noffke et al. (2001) for “microbially induced sedimentary structures.” Many of the structures
addressed, however, are not truly “induced” by microbes, but rather by physical forces acting on a
biostabilized sediment surface or a microbial mat. Since, in this scenario, the biological component
significantly influences the shape of evolving structures, it is suggested to write out the acronym MISS as
“microbially influenced sedimentary structures.”).
Mat-related structures are in a way analogous to trace fossils (Schieber, 2004), whereby the former
presence of mats can be inferred. The top layer of the mat system, which periodically is exposed to the
atmosphere, usually consists of oxygenic, filamentous cyanobacteria, frequently Microcoleus sp., which form a
“felty” fabric of interwoven filaments, including also sediment grains incorporated by “trapping and binding”
processes. The felty layer may be overlain, or in some cases replaced, by a resistant (“leathery”) layer of
colloid extracellular polymeric substances (EPS) produced mainly by coccoid cyanobacteria.Classification
of Microbial Mat Structures
Mat-related sedimentary structures may form during all the stages from first microbial colonization of a
sediment surface, through establishment and sustainment of a fully developed mat, to its destruction and final
erosion.
i. Structures related to early microbial colonization
Microbial colonization leads to “biostabilization” of a sediment
surface which then can resist erosion to some degree. This property
may lead to “palimpsest ripples” when new sediment is deposited
on top a biostabilized rippled surface; to surfaces with “multi-
directional ripple marks”; and to “ripple patches” (Figure 4) or
“erosional pockets” when a biostabilized flat surface or mat is
locally eroded.
ii. Structures related to microbial growth and mat
growth
Depending on availability of water for some time, specific
filamentous cyanobacteria (e.g., Lyngbya aestuarii) start to produce
Figure -4. Biostabilized sediment surface with
isolated “ripples patches.” Scale (knife) is 8 cm.
Locality: Trucial Coast, west of Abu Dhabi, U.A.E.
(Encyclopedia of Earth sciences series-
ENCYCLOPEDIA OF GEOBIOLOGY, 2011. Page. 549).

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on the mat surface, a characteristic “reticulate growth pattern” of small, sharp-crested ridges stabilized by
EPS (Figure 5A). Ancient structures of this type are named “elephant skin” texture (Figure 5B).
Figure-5. (A) Reticulate growth pattern produced by Lyngbya aestuarii. Locality: Salins du Midi, Re´serve Nationale Camargue, southern
France. (B) Upper surface of sericitic siltstone with “elephant skin” texture representing “reticulate growth pattern” of a previous microbial
mat. Locality: Terminal Proterozoic Vingerbreek Member, Nama Group; Farm Haruchas, Namibia. (Encyclopedia of Earth sciences series-
A further type of structures related to mat growth are “mat expansion structures,” collectively
termed “petees”, which deform the upper, cohesive part of the mat into bulges and domes, thus enlarging the
mat surface (Figure 6). Ancient examples have been named “petee ridges” (Schieber, 2004).
iii. Structures related to mat desiccation and shrinkage
Subaerial exposure causes dehydration and shrinkage of the EPS and eventually cracking of the mat. Thus,
“shrinkage cracks” (Figure 7A) are developed. Ancient shrinkage cracks are also termed “sand cracks”
referring to their occurrence in sandy sediment without shrinkable mud present. The main difference between
normal mud cracks and microbial shrinkage cracks is that the later develop a higher degree of curving unlike
normal mud cracks. A specific type of shrinkage cracks, characterized by sinusoidal or sub-circular trends and
developed mainly in ripple troughs, is referred to as “Manchuriophycus”-type in the ancient record (Figure
7B).
Figure-6. “Petees” originating from lateral mat growth and deforming
microbial mat into round-crested bulges. Locality: Amrum Island,
southern North Sea, Germany. (Encyclopedia of Earth sciences series-
A B

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Figure-7. (A) Modern and ancient shrinkage cracks. Left photograph locality: Amrum Island, southern North Sea, Germany. Right photograph
locality: Neoproterozoic Tizi n-Taghatine Group; Imi n’Tizi area, Anti-Atlas, Morocco. (B) Manchuriophycus-type shrinkage cracks meandering
in ripple troughs. Locality: Neoproterozoic Tizi n-Taghatine Group; Taghdout area, Anti-Atlas, Morocco. (Encyclopedia of Earth sciences series-
Thick mats tend to form polygonal networks of wide cracks with “upturned margins” (Figure 8A).
Ancient examples exhibit a “chaotic” upper surface with irregularly oriented bedding (Figure 8B) and
resemble sedimentary structures ascribed to seismic events.
Figure-8. (A) Polygonal pattern of shrinkage cracks with upturned margins in thick microbial mat. Scale (knife) is 8 cm. Locality: Trucial Coast,
west of Abu Dhabi, U.A.E. (B) Surface outcrop of Holocene microbial mat exhibiting relics of polygons with upturned margins. Scale (knife) is
8 cm. Locality: Trucial Coast, west of Abu Dhabi, U.A.E. (Encyclopedia of Earth sciences series- ENCYCLOPEDIA OF GEOBIOLOGY, 2011. Page.
550).
Thin mats tend to form circular openings with curled margins around (Figure 9A). Ancient
examples have been described from thin siltstone layers within heterolithic deposits (Figure 9B).
A B
A B

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Figure-9. (A) Irregular to subcircular openings with curled margins, formed in a thin microbial mat due to desiccation and shrinkage.
Locality: Sabkha El Gourine, Mediterranean coast of southern Tunisia. (B) Upper surface of siltstone layer exhibiting irregular to circular
cracks. The structures are interpreted as openings in a previous thin mat that underwent desiccation. Locality: Terminal Proterozoic
Vingerbreek Member, Nama Group; Farm Haruchas, Namibia. (Encyclopedia of Earth sciences series- ENCYCLOPEDIA OF GEOBIOLOGY, 2011.
Page. 550).
iv. Structures related to mat deformation, destruction, and erosion
Cohesive microbial mats may be deformed or eroded by strong currents, by complete desiccation after
cessation of groundwater supply, and dried mat fragments may be transported by wind over wide distances
and be deposited in environments where mats usually do not grow. Mat destruction by currents leads to
typical structures repeatedly observed in modern environments and in the ancient record:
(1) “flip-over” structures (Figure 10A) result when a mat’s edge is flipped over.
(2) cigar-shaped “rollup” structures, also named roll-ups or “jelly-rolls” (Figure 10B), may develop when
curled margins or flipovers undergo additional rolling due to current action.
Figure-10. (A) Microbial mat, torn and partly removed by current or wind action. Flip-overs of mat margins are indicated by “F.” Locality:
Sabkhet Mjasser, Mediterranean coast of southern Tunisia. (f) “Roll-up” structure (“jelly-roll”) consisting of rolled-up microbial mat and
adhering sediment. Scale (coin) is 23 mm. Locality: Bhar Alouane, Mediterranean coast of southern Tunisia. (Encyclopedia of Earth sciences
series- ENCYCLOPEDIA OF GEOBIOLOGY, 2011. Page. 550).
(3) irregular or arcuate belts of “mat deformation folds” form when a torn and detached mat is crumpled by
tractional forces (Figure 11); similar folds may also result from mat slumping on steeps slopes, e.g., along tidal
channels.
A B
A B

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“Mat chips” are small fragments of eroded mats or biostabilized sediment. They primarily are
irregular in shape with frayed edges, but may become pebble-shaped with transport (Figure 12A). Ancient
examples have been named “microbial sand chips” or “sand clasts” in contrast to intraformational mud
clasts (Figure 12B).
Figure-12. (A) Modern sandy-pebbly sediment surface with subrounded to rounded “mat chips”. Locality: Salins du Midi, Re´serve Nationale
Camargue, southern France. (B) Upper surface of sandstone bed carrying subrounded to rounded “sand clasts,” interpreted as previous “mat
chips.” Locality: Terminal Proterozoic Vingerbreek Member, Nama Group; Farm Haruchas, Namibia. (Encyclopedia of Earth sciences series-
v. Structures formed beneath microbial mats
From the hydraulic perspective, the sediment beneath cohesive and coherent microbial mats may be
addressed and treated as a confined aquifer in which, at sufficient hydraulic head, a potential for liquefaction
may develop. In such case, hydraulic upward pressure will lead to slow, upward movement of sediment grains.
As a result, bulges and domes developed in the mat will gradually be filled from below (e.g. “petee ridges”).
Thin microbial mats may develop very irregular surfaces with numerous small domes and buckles
which also appear as positive features on the subsurface (Figure 13A). Ancient examples of such “subsurface
structures” strongly resemble load structures (Figure 13B) but are clearly distinguished from these by
their occurrence as positive features on upper bedding surfaces.
Figure-11. Detached, thin microbial mat, torn and strongly deformed by
current action. Locality: Coastal sabkha
between Gabes and Skhirat, Mediterranean coast of southern Tunisia.
(Encyclopedia of Earth sciences series- ENCYCLOPEDIA OF GEOBIOLOGY, 2011.
Page. 551).
A B

16
Figure-13. (A) Morphological details of a mat subsurface, exposed after removal of the mat. Scale (coin) is 24 mm. Locality: Sabkhet Mjasser,
Mediterranean coast of southern Tunisia. (B) Upper surface of sandstone layer exhibiting irregular bulges and domes. The structure is
considered to represent morphological features of a previous mat subsurface. Locality: Neoproterozoic Tizin-Taghatine Group; Taghdout
area, Anti-Atlas, Morocco. (Encyclopedia of Earth sciences series- ENCYCLOPEDIA OF GEOBIOLOGY, 2011. Page. 551).
“Kinneyia” (Figure 14) is a further structure developed in the
sediment beneath a microbial mat. The structure is characterized by
millimeter-scale, flat-topped, steeply sided, winding ridges
separated by equally sized round-bottomed troughs and pits. It
resembles small-scale interference ripples including crest-
dominated linear and pit-dominated honeycomb-like patterns.
Recent models suggest it is formed by trapping of gas underneath a
sealing mat or by reversals of groundwater flow in the liquefied
mat substratum (Porada et al., 2007).
vi. Wrinkle structures
The term “wrinkle structure” is currently used as a collective term for various small-scale
irregularities developed on ancient, siliciclastic sediment surfaces. Application of the term implies that a
microbial participation in the formation of the structure is suspected, at the least. Within this broad definition,
wrinkle structures may originate from very different processes including microbial growth, mat deformation
and subsurface processes. Included in the term are also structures like elephant skin and Kinneyia which are
well defined and for which, usage of the proper name is recommended.
2.5. Distribution of Stromatolites in Time
Stromatolites are the most persistent evidence of life on Earth, and are known from 3,700 Ma to the
present (for example, Shark Bay, Western Australia) in the rock records.
i. Precambrian Strmatolites
A. Archaean Stromatolites
Stromatolites are relatively scarce in the Archaean until nearly the end of the eon. Earlier it was believed
that 3,496 Ma old domical and conical stromatolites from the Dresser Formation of the Pilbara Craton
(Western Australia) are the oldest convincing evidence for life on Earth (Hofmann et al., 1999; Allwood et al.,
2006).
A B
Figure-14. Upper surface of sandstone layer with
“Kinneyia” structure. Locality: Terminal Proterozoic
Vingerbreek Member, Nama Group; Farm Haruchas,
Namibia. (Encyclopedia of Earth sciences series-

17
Figure-15. A) Domical and B) stratiform stromatolites from the 3496Ma Dresser Formation, Western Australia (Walter et al., 1980; Buick et
al., 1981) (after Schopf et al., 2007).
Recently, Nutman et al. (2016) reported evidence for ancient life from a newly exposed outcrop of 3,700-
Myr-old metacarbonate rocks in the Isua Supracrustal Belt (ISB), southwest Greenland. These
metacarbonate rocks contain 1–4-cm-high stromatolites produced by microbial communities. The ISB
stromatolites grew in a shallow marine environment, as indicated by seawater-like rare-earth element plus
yttrium trace element signatures of the metacarbonates, and by interlayered detrital sedimentary rocks with
cross-lamination and storm-wave generated breccias. The presence of the ISB stromatolites demonstrates the
establishment of shallow marine carbonate production with biotic CO2 sequestration by 3,700 Ma. Noffke et al.
(2008) reported wrinkle and associated structures and suggested the presence of microbial mats in 2,900 Ma
siliclastic sediments of South Africa, but these too are generally scarce. However, stromatolites are abundant
in the 2,550 Ma Campbellrand-Malmani carbonate platform of South Africa (Beukes, 1987).
Thus, Palaeoarchaean and Mesoarchaean stromatolites were rare and not diverse. In the Neoarchaean,
about 2.7-2.8 Ga, stromatolites were more abundant and much more diverse. This may have resulted from the
formation, for the first time, of extensive continental shelves. This can be established from the rise of
prominence of columnar forms and especially ministromatolites with a radial fibrous fabric in the
Neoarchaean, which are characteristic of peritidal environments. However, the biogenicity of these is
contentious.
B. Proterozoic Stromatolites
In the Palaeoproterozoic and Mesoproterozoic, there was an abundance of stromatolites with conical
laminae (Conophyton), characteristic of quiet subtidal environments. They declined markedly thereafter
(Grotzinger and Knoll, 1999). There was a decline in the abundance and diversity of all stromatolites about
600-700 Ma (Grotzinger and Knoll, 1999). Neoproterozoic fall in stromatolite morphotypic diversity coincided
with metazoan evolution (Awramik, 1971), but inception of decline prior to the appearance of metazoans
implicates reduction in seawater carbonate saturation state as the major influence (Grotzinger, 1990).
Progressive reduction in saturation state leads to the reduction of stromatolites and mediated a long term
trend from sparry crust to micritic carbonate sediments. This transition led to Neoproterozoic development of
calcimicrobial thrombolites. It has been recognized that thrombolites appeared in the Neoproterozoic
(Aitken and Narbonne, 1989), and possibly about 1.9 Ga in the Palaeoproterozoic (Kah and Grotzinger, 1992).
ii. Phanerozoic Stromatolites
The decline of stromatolite abundance which commenced as early as the Palaeoproterozoic (Grotzinger,
1990), was observed in the Phanerozoic. Stromatolites are common in the late Cambrian-early Ordovician and
late Devonian-early Mississippian, and scarce during the Cenozoic. Fischer (1965) suggested that decline since
the Ordovician could reflect both reduction in carbonate saturation and competition by eukaryotes. Flügel
A B

18
(2004) suggested that thrombolite abundance also declined after the Cambrian, although they were still
locally conspicuous, e.g., in the Silurian (Kahle, 2001), Devonian (Shapiro, 2000), Mississippian (Webb, 1987,
2005), and near the Permian-Triassic transition (Ezaki et al., 2008). Stromatolites near the Permian-Triassic
boundary are uncommon; however, examples have been reported from northern Italy, Iran, Oman, northern
Hungary, southern Turkey, South China and India. Stromatolites just after the end-Permian extinction are
exceptionally well developed in the Chongyang area of Hubei Province, South China. Here they are usually
dominated by thrombolites (Adachi et. al., 2017).
Figure-16. Permian-Triassic boundary thrombolites from Southern China. A) Cut slab of dendritic thrombolites. Scale= 3 cm. B) Top surface
of dendritic thrombolites with a knobbly appearance. Hammer length = 33 cm (after Adachi et. al., 2007).
Thrombolites have been widely reported in the mid-late Jurassic, broadly coincident with the last
major peak of abundance of calcified marine cyanobacteria (Arp et al., 2001). In Cenozoic, Coarse-grained
thrombolitic stromatolite domes and columns are well developed in the late Miocene of South-east Spain
(Riding et al., 1991a). Although algal mats and films are common in many modern environments, they are
rarely recognized because of continual destruction (grazing) by snails, worms and other animals. Modern
stromatolites exist in extreme environments containing hypersaline water, high alkalinity, and high or low
temperatures zones. Such places exclude grazing snails and other animals which consume the cyanobacteria.
Recent formations of stromatolites are noted in Shark Bay (Australia) as well as throughout Western
Australia, the Bahamas (such as Exuma Cays), the Indian Ocean, various places in the USA (such as in
Yellowstone National Park), Laguna Salgada (Brazil), the Mexican Desert, Glacier National Park
(Montana and Canada), and the Solar Lake in Sinai, which is heliothermally heated and contains hypersaline
water. The study of modern stromatolites assists in the interpretation of ecology and environment of ancient
stromatolites as well as possible life on extraterrestrial planets or moons.
2.6. Indian Stromatolites and Microbial Mat Structures
In India, most of the stromatolites are reported from Precambrian rocks. The Precambrian stromatolites
are recorded mainly from peninsular India and a few from the Himalayas. Phanerozoic stromatolites, which
are few in number, are restricted to the Himalayan region. Kumar (1980) has divided stromatolites of India
into two groups:
1. Stromatolites of the peninsular region lying in the south of the Indo-Gangetic Alluvium
2. Stromatolites of the extrapeninsular India lying in the north of Indo-Gangetic Alluvium
1. Peninsular Region
In this region, reported stromatolites include those from the Iron Ore Formation, Kaladgi Group, Cuddapah
Supergroup, Delhi Supergroup, Aravalli Group, Vindhyan Supergroup, Marwar Supergroup, Kurnool Group,
Chhattishgarh Supergroup.
A B

19
Rao and Mahajan (1965) reported the stromatolites from the Bhagwanpura Limestone of the Raialo
Series in Rajasthan. The Raialo Series overlies the Aravallis (Archaean) and is overlain by the Delhi
Supergroup of the Puranas. Chaudhuri (1969) reported stromatolites of various growth patterns in Pranhita-
Godavari Valley, in the lower part of the Precambrian Pakhal Group. These stromatolites are diagnostic of
intertidal, or of a supra- and sub-tidal environment. A number of workers reported stromatolites in calcareous
formations from the lower part of the Cuddapah Group and in the lower Kaladgi Subgroups. The Cuddapah
Supergroup on the basis of lithology was correlated with the Pakhal Group (King, 1881). Gururaja and
Chandra (1987) recognized a high diversity assemblage of stromatolites from the Vempalle and Tadpatri
Formations. It includes Collenia Walcott, Columnocollenia Korlyuk, Gymnosolen Steinmann, Inzeria Krylov
and Jacutophyton Schapovalova. They suggested that these were of Riphean (Mesoproterozoic to
Neoproterozoic) age. In addition, Sharma and Shukla (1998) reported a wide variety of ministromatolites
from the Vempalle Formation, including Alcheringa Walter, Asperia Semikhatov, Conistratifera Zhu, Xu and
Gao, Kanpuria Raaben, Liaoheela Cao, Microstylus Komar, Minicolumella Raaben, Paraboxonia Zhu,
Pilbaria Walter and Tibia Bertrand-Sarfati. Riding and Sharma (1998) recognized that well preserved
Vempalle Formation (Late Palaeoproterozoic, 1800-1600) stromatolites are dominated by clotted and bushy,
‘spongiostromate’, calcified microfabrics. These spongiostromate microfabric crudely resemble Phanerozoic
Angusticellularia (calcified oscillatoriacean). Other calcified cyanobacteria-like fabrics are not recognized. It
is suggested that these Vempalle stromatolitic microfabrics compare more closely with modern calcified non-
cyanobacterial biofilms. On this basis, they have suggested that the evolutionary radiation of cyanobacteria
underwent in the late Neoproterozoic. In their words….“It is generally thought likely that cyanobacteria were
important components of stromatolite-building microbiotas during the Proterozoic, and that early lithification by
carbonate precipitation was widespread and intense. If these assumptions are correct then the apparent absence
of diverse calcified cyanobacteria suggests that these organisms, which are conspicuous in the Early Palaeozoic,
underwent evolutionary radiation close to the Neoproterozoic–Cambrian boundary.”
DUTT (1963) described "crocodile-skin structures" from the uppermost stage of the Indravati Group
in the Jagadalpur district of Chhattishgarh. He suggested that these structures are the weathered surface of
oncolites. Marwar Supergroup is composed of three groups, of which the middle Bilara Group contains
limestone and dolomite which show plentiful occurrences of stromatolites as isolated reef masses. An
assemblage of Weedia, Conophyton, Collenia and Minjaria has been noted from the limestone around Badi
Khatu in Nagaur district. The structures are mostly phosphatic having a coating of collophane around the
columns as well on the laminae (Paliwal, 1975). Barman (1980) recognized Collenia pseudo-columanaris,
Collenia sp, Concollenia, Cryptoxoan accidentalis, Irregularia sp. and Stratifera from the Bilara Formation
of the Marwar Supergroup.
Microbial mat structures have been reported from the Sonia Sandstone of the Marwar Supergroup
(Sarkar et al., 2008; Samanta et al., 2011). Arumberia banksi and Rameshia rampurensis have also been
recorded from the Sonia Sandstone exposed in the Khatu area of Rajasthan (Kumar & Pandey, 2009). Kumar
and Ahmad (2014) reported 14 microbially induced sedimentary structures (MISS) from the middle part of
the Jodhpur Sandstone. Out of these, some appear restricted within Ediacaran period. Arumberia banksi,
Rameshia rampurensis and Jodhpuria circularis have not been reported from the modern sediments.
2. Extrapeninsular Region
In the extra-peninsular region (i.e., Himalayan region), stromatolites have been recorded from the
sedimentary successions of the Lesser Himalaya. In this region stromatolites have been reported from the
Jammu Limestone, Sirban Limestone, Raisi Limestone (Jammu and Kashmir); Shali Formation (Nahan Dist.,
Himachal Pradesh); Larji Formation (Larji Town, Himachal Pradesh); Simla Group; Tunda Pathar Limestone

20
(Haryana); Deoban Group (Garhwal Himalaya); Lameri Formation (Garhwal Group); Blaini Formation
(Kumaon and Himachal Himalaya); Krol Formation; Tal Formation; Calc zone of Pithoragarh (Almora); Calc
zone of Tejam (Pithoragarh dist.); Buxa Group (eastern Nepal to Arunachal Pradesh); Matuka Formation
(southern Tuensang dist., Nagaland). Stromatolites reported from different areas of the Himalayan region
range from Neoproterozoic to Devonian in age. Stratifera undata Komar stromatolite has been recognized
from the Lesser Himalayan sequences (Sharma et.al., 1994). Krol Group is characterized by Linked
Conophyton (Conophyton garganicus, Baicalia baicalia, Colonella sp.), Stratifera irregularis,
Paniscollenia, Patomia, Aldania and Irregularia and branching stromatolites.
Figure-17. Field photographs of microbially induced sedimentary structures (MISS) reported from the Jodhpur Sandstone, western
Rajasthan; (A) incomplete ripples over microbially flat laminated surface (coin diameter = 2.4 cm); (B, C and D) various types of well
preserved sinusoidal, curved and straight wrinkle marks on the bedding surface (coin diameter = 2.4 cm and lens cap diameter = 5.7
cm); (E and F) ‘‘Bun shaped’’ microbial structures with positive relief (maximum elevation from the bedding plane = 3.5 cm), the
growth of the ‘‘bun shaped’’ structure not effected the ripples (lens cap diameter = 5.7 cm). (after Kumar and Ahmad, 2014).

21
3. Methodology
For stromatolite studies both field work and laboratory observations are necessary. Recording observations in
both field and laboratory can be done quickly by the use of a worksheet. The worksheet suggested by Kennard and
Burne (1989) in ‘Stromatolite Newsletter No. 14 (1989)’ is very useful in this regard. Their worksheet is based on
illustrations given by Walter (1972) and Preiss (1972, 1 976). The modified worksheet is as following:
Stromatolite Work Sheet : Locality : Sample No :
Hand
Specimen:
Polished Face: Slabs: Thin Section: Collector: F. No. :
Bed Thickness: Bed Length: Single Unit: Cyclic Unit:
Mode of Occurrence:
Lithoherm (Bioherm): A circumscribed organo-sedimentary structure whose minimum width is less than or equal to
hundred times its maximum thickness, embedded in rocks of different lithology.
Lithostrome (Biostrome): A stratiform organosedimentary structure whose minimum width is more than one hundred
times its maximum thickness.
Stromatolitic Bed: when dimensions are unknown
Plan Outline:
round, elliptical,
ovate
oblong
scutate
crescentic
lobate
polygonal
lanceolate
Linkage between the Lithoherms/
Fascicles
Linked
Partly - linked
Unlinked
Spacing between the Lithoherms/ fascicles
Contiguous
Very Close
Close
Open
Isolated
Non-ColumnarColumnar
Non-Branching

22
Branching
Branching Style Convergence Style Column Height:
Column Width:
Angle of Divergence Method of Branching Walls :
Absent
Patchy
Single-layered
Thin–layered
Multi-layered
Conical
Spheroidal Forms
Attitude Variability Shape Lamina Type
Ornament
Lamina Shape
Microstructure: Remarks:

23
3.1. Field Work
i. Field Observations
Field observations are essential part of all stromatolite study not only for geological mapping,
environmental interpretation and determination of stratigraphy but also for detailed taxonomic study. The
general features of stromatolites identified in field observation are such as:
i. Mode of occurrence whether the structure is bioherm or biostrome.
ii. Non-columnar or columnar stromatolite.
iii. If columnar than it is branching or non-branching.
iv. If branching is observed than the type of branching.
v. Shape, size and orientation of the column.
vi. Stromatolite is walled or naked wall.
vii. Shape of the laminae.
ii. Field Photography
Field photographs are the essential part of the study. Photographs are particularly valuable for
supplementing data where there are collecting problems because of large column sizes. Photographs should
be taken with some standard objects such as hammer, clinometers etc.
iii. Sampling
Sampling is one of the most important aspects of the stromatolite study. An ideal sample should include
where one can observe several columns and branching. Where columns are too large to be sampled in a group,
it may be necessary to collect smaller samples from each column. It is preferable to collect samples from as
many localities as possible. Samples are numbered carefully and their orientation and relative positions are
also marked.
3.2. Laboratory examination
i. Cleaning
First, the samples were cleaned properly because they contain soil particles and endolithic organisms. It is
cleaned by scrubbing with a nylon or wire brush. For cleaning detergent can also used and using dilute
hydrochloric acid cleans difficult surface.
ii. Cutting
It is usually necessary to cut the sample to examine column shape, spacing and branching. Hofmann
(1976) recommended that samples selected for cutting should show good cross-sections of columns and
preferably include at least two or three columns. Sample should be cut into right angled blocks to obtain three
dimensional orientations. It can be cut vertically or horizontally.
iii. Serial Slabbing
Serial slabbing is a technique described by Krylov (1963) for three dimensional "graphical reconstruction"
of stromatolites column. For serial slabbing a large diameter diamond-tipped automatic saw with an
adjustable clamp or vice is used. Rocks should be positioned in such a way that regularly shaped serial cuts
can be made parallel to the columns. The numbers of slab and their thickness is determined by diameter of the
column. Each cut provides two sections, which are smooth ground and they can be traced on transparent
sheets.
iv. Polishing and Alternatives
Polishing of the cut faces is done by using an abrasive powder generally carborundum. The polishing is
carried out with finer grade powder. Polishing of sections make the laminae and wall structure clear. An

24
alternative to high-gloss polishing is to “smooth-grind” the surface. Further work is then carried out on a wet
surface, with or without a transparent overlay. In the case of low contrast specimens, the surface can be coated
with oil. Alternatively the surface can be coated with a variety of wax or similar finishes.
v. Thick and Thin Sections
Stromatolitic sections (40-60 µm) are usually larger and thicker than conventional petrological sections
(~30 µm), but are prepared by the same techniques. Conventional petrological studies on standard thin
sections can also used to determine the mineralogy.
vi. Reconstruction of Stromatolites (Morphometric Study)
Three dimensional reconstructions is an essential part of stromatolite study. The reconstruction shows the
features which cannot be differentiated in single sections. The technique used for three dimensional
reconstruction was described by Krylov (1963) and Walter (1972a).
i. The rocks are cut into slabs of upto 6 mm wide depending upon the width of column parallel to the
length of the columns. Two preliminary cuts at right angles to the slabs provide reference surfaces
for reconstruction. Then the slabs are numbered.
ii. The surface of the slabs are wetted so that the columns can be seen clearly and outlined in pencil.
For reconstruction, a column or a group of column is selected and followed from one section to the
next.
iii. The outline are then traced on to a block diagram framework on tracing paper usually drawn with
an angle of 45° between the front face and the line representing the top of the side reference face.
Successive longitudinal sections are placed against the framework, turning over the tracing paper
from one section to the next. Each slab is displaced along the edge of the reference face by the
distance from the previous slab, corrected for perspective by multiplying by the cosine of 45° (0.7
mm).
iv. The outlines of columns are traced on to the framework in such a way that only the portions of
columns not hidden by the outlines on preceding slabs appear. The sketch prepared is then
redrafted using shading and stippling to show in three dimensions of column features.
Figure-18. Three dimensional reconstructions of stromatolites. (after Walter, 1972)
E.g., for 5 mm thick and 2 mm
apart slabs, Thickness of slab along the
reference face = 5 × cos45˚ = 3.5 mm;
And the spacing = 2 × cos45˚ = 1.4 mm.

25
vii. Statistical Studies
There are a number of statistical parameters which can be used to characterize stromatolite morphologies
and for more detailed analysis. Most of the parameters measured can be plotted as histograms or frequency
diagrams. The following have been successfully applied-
i. The degree of lamina convexity ( h/d )
ii. The thicknesses of laminae
iii. In case of Conophyton, the ratios of thicknesses of adjacent light and dark laminae will be useful.
These can also be represented as contoured frequency plots (thickness of dark lamina plotted
against thickness of adjacent light lamina).
iv. Conophyton is characterized by a thickening and contortion of the conical laminae at their apices.
The vertical structure that results from the superposition of these apices is termed the crestal
zone. The coefficient of thickening is the ratio of the thickness of a lamina in the crestal zone to
its thickness outside the crestal zone.
viii. Systematic Descriptions
The stromatolites which have been recognized should be divided into morphological variants. Each kind
should be either distinguished by the use of open nomenclature (e.g., “Stromatolite form 1”), or be given a
formal binomial determination. In Formal Nomenclature, to indicate the heterogeneity of stromatolite
structures, the terms “group” and “form” are generally preferred as replacements for “genus” and “species”,
respectively. It may be more useful to use “morphogenus” and “morphospecies”.

26
4. Introduction to Vindhyan Basin
The Vindhyan Supergroup of India is one of the largest and thickest sedimentary successions of the world.
Deposited in an intra-cratonic basin, it is composed mostly of shallow marine deposits. It is believed to have
recorded a substantial portion of Proterozoic time and therefore, likely to contain valuable information on the
evolution of the atmosphere, climate, and life on our planet. It also contains some of the most disputed fossils
of earliest animal life.
4.1. Introduction
The term ‘Vindhyan’ was first used by Oldham (1856) for the entire group of rocks forming a
prominent feature along the northern bank of Narmada River known as Vindhyan Parbat or Vindhyanchal. The
Vindhyan Supergroup is the thickest Precambrian sedimentary succession of India and the duration of its
deposition is one of the longest in the world. The Vindhyan sediments
occupy an area of about 1,20,000 km2 in Central India. In addition, estimated
ca. 80,000 km2 is covered by Deccan Traps and ca. 10,000 km2 is lying under
the cover of Gangetic alluvium in the north (Mathur, 1987).
Figure-19. Geological Map of Vindhyan Basin, Central India (after Srivastava P., 2009)
The basin is bounded by the Son-Narmada Geofracture in the south, Deccan Trap in the southwest, the
Great Boundary Fault in the west, the Monghyr- Saharsa Ridge in the east, and Bundelkhand Massif and Indo-
Gangetic Plains in the north. Vindhyan basin is semicircular in shape with Bundelkhand Granite (~ 2500 Ma)
dividing it into two parts, the eastern part is exposed in Son Valley area (Bihar-Uttar Pradesh-Madhya
Pradesh) and the western part is developed in the Chambal Valley area (Madhya Pradesh and Rajasthan). Both
show different lithostratigraphic successions. The total thickness of Vindhyan sediments is about 4500-5000
m.

27
4.2. Geology
The Vindhyan Supergroup is composed mostly of low dipping formations of sandstone, shale and
carbonate, with a few conglomerate and volcaniclastic beds, separated by a major regional and several local
unconformities. The regional unconformity occurs at the base of the Kaimur Group and divides the sequence
into two units: the Lower Vindhyans (Semri Group) and the Upper Vindhyans (Kaimur, Rewa and Bhander
Groups). The outcrop pattern of the Supergroup resembles a simple saucershaped syncline. It is generally
believed that the Vindhyan basin was a vast intra-cratonic basin formed in response to intraplate stresses. The
Vindhyan succession in the central India overlies the early Proterozoic metasediments of Bijawar and
Mahakoshal Groups and underlies the Gondwanas. Since the Aravalli, Delhi and Satpura orogenic belts border
it, some workers considered the Vindhyan basin as a peripheral foreland basin related to the southerly
dipping subduction prior to the collision of Bhandara and Bundelkhand cratons. Another view postulated an
intracratonic rift origin. Bose et al. (2001) correlated the sedimentary and geophysical attributes to an
intracratonic rift to sag transition. However, the broad consensus now exists about deposition within a
westward opening epicontinental basin in an intracratonic setting (Banerjee, 1974; Chanda and
Bhattacharyya, 1982; Bose et al., 2001).
The paleogeographic setting of the Vindhyan basin had initially been identified as near shore marginal
marine, belonging to barrier bar, lagoon, tidal flat & beach with intermittent sub-aerial exposure (Banerjee,
1964). Later workers, however, extended the palaeogeography to the shelf on one hand and also recorded
extensive occurrence of fluvial, aeolian and lacustrine deposits (Bose et al., 1999). The depositional paleoslope
has been estimated to be gentle throughout the basinal history. Paleocurrent direction had consistently been
northwestward implying terrigeneous supply from a southern source; dominance of fine- grained and
texturally mature siliciclastics as well as carbonates points to the low relief of the source (Bose et al., 2001).
Generally, the Vindhyan Supergroup is considered as an undisturbed sequence of rocks. However, at a
few places, the Lower Vindhyan sediments are noted to be severely folded. There are two impact structures
associated with the Vindhyan Supergroup – Dhala structure in the Madhya Pradesh, and Ramgarh structure in
the Rajasthan. These impact structures have modified the sedimentary rocks in the vicinity. Bose et al. (2001)
suggested that inspite of its origin in stable intracratonic basin, the Vindhyan Supergroup incorporates
tectonic-driven depositional cycles of various orders. Mishra (2011) suggested that the Lower Vindhyan rocks
were deposited on the rifted platform of Bundelkhand Craton, whereas the Upper Vindhyan rocks were
deposited as a foreland basin during the convergence.
4.3. Stratigraphy
The Vindhyan Supergroup has been lithostratigraphically subdivided into four groups: the Semri, the
Kaimur, the Rewa, and the Bhander Group (Table-01). Its lithofacies show variation in both horizontal and
vertical gradation, i.e., different areas show different lithostratigraphic successions. Thus, the
lithostratigraphic successions for the eastern part of the Vindhyan Basin (Son Valley Section) and the western
part of the basin (Chambal Valley Section) should be dealt with separately (Kumar, 2011). As only the Kaimur
Group can be traced in both the areas with a fair degree of confidence, this horizon is considered as a marker
horizon. Therefore, all the lithounits underlying the Kaimur are referred to as the Semri Group and the
overlying successions to the Rewa and Bhander Groups.
4.3.1. Semri Group
Auden (1933) originally referred to Semri Group as the Semri Series. He divided Semri Series into four
stages as the Basal Stage, the Porcellanite Stage, the Kheinjua Stage and the Rohtas Stage (Table-02). Sastry

28
and Moitra (1984) have devided the Semri Group into three subgroups and have clubbed the Basal Stage and
Porcellanite Stage under the Mirzapur Subgroup (Table-02).
Table 2. Stratigraphic subdivisions of the Semri Group.
Son Valley Chambal Valley
By Auden (1933) (After Sastry and Moitra, 1984) (After Prasad, 1984)
Rohtas Stage
Limestone and shales
Nodular lst & shales
Banded shales
Limestone
Nodular lst & shale
Rohtas
Subgroup
Bhagwar Shale
Rohtasgarh Limestone
Khorip Group
Suket Shale
Nimbahera Limestone
Bari Shale
Jiran Sandstone
Kheinjua Stage
Glauconitic beds
Fawn Limestone
Olive Shales
Kheinjua
Subgroup
Rampur Formation
Salkhan Limestone
Koldaha Shale
Lasarwan
Group
Binota Shale
Kalmia sandstone
Porcellanite Stage Porcellanites etc.
Mirzapur
Subgroup
Deonar Formation Sand Group Palri Shale
Sawa Sandstone
Bhagwanpura LimestoneBasal Stage
Kajrahat Limestone
Basal Conglomerate
Kajrahat Limestone
Arangi Formation
Deoland Formation Satola Group Khardeola Sandstone
Khairmalia Andesite
………………………………………. Unconformity ………………………………………….. ...………… Unconformity …………..
Bijawar Phyllites/ Bundelkhand Granite Pre-Aravalli rocks/ Berach Granite
i. Mirzapur Subgroup
In the Son Valley section, Mirzapur subgroup includes the Deoland Formation, the Arangi Formation, the
Kajrahat Limestone and the Deonar Formation. Deoland Formation is characterized by occasional
stromatolites. Kajrahat Limestone show profuse development of stromatolites. Its lower horizon is sandy and
the upper horizon is dominantly stromatolitic with extensive fan-fabrics.
ii. Kheinjua Subgroup
In the Son Valley section this subgroup is subdivided into the Koldaha Shale (Olive Shale), the Salkhan
Limestone (Fawn limestone) and the Rampur Formation (Glauconitic Sandstone). Koldaha Shale has yielded
millimetric carbonaceous films which have been attributed to macro-algae (Sharma, 2006a). The Salkhan
Limestone has also been referred to as Bargwan Limestone (Prakash and Dalela, 1984). It shows excellent
development of stromatolites.
iii. Rohtas Subgroup
In the Son Valley Section, Rohtas Subgroup is subdivided into Rohtasgarh Limestone and Bhagwar Shale.
Rohtasgarh Limestone is made up of grayish to grayish black limestone and shales. Bhagwar Shale is
represented by silicified shale, sandstone and carbonaceous shale.
4.3.2. Kaimur Group
It is the most extensively developed argillo-arenaceous succession and is the only horizon which can be
traced from the eastern to the western part of the Vindhyan Basin (marker horizon). It is best developed in the
Son Valley area. In this area, it is divided into Sasaram Formation (Lower Quartzite), Silicified Shale, Susnai

29
Breccia, Ghaghar Sandstone (Upper Quartzite), Bijaigarh Shale, Mangesar Formation (Scarp Sandstone),
Dhandraul Sandstone (Dhandraul Quartzite).
Table 3. Stratigraphic subdivisions of Kaimur Group.
By Auden (1933) By Sastry and Moitra (1984) (After Prasad, 1984)
Upper Kaimur
Stage
Dhandraul Quartzite
Scarp Sandstone
Dhandraul Quartzite
Mangesar Formation
Akoda-Mahadev Formation
Badanpur Conglomerate
Chittaur Fort SandstoneLower kaimur
Stage
Bijaigarh Shales
Upper Quartzite
Susnai conglomeratic breccias
Silicified Shales
Lower Quartzite
Bijaigarh Shale
Ghaghar Sandstone
Susnai Breccia
Sasaram Formation
…………………………………………………….…. Unconformity ……………………………………………………………………
Semri Series Rohtas Stage Suket Shale
4.3.3. Rewa Group
This group is composed chiefly of sandstones and shales. It conformably overlies the Kaimur Group. It has
been divided into Panna Shale, Asan Sandstone (Lower Rewa Sandstone), Jhiri Shale, Govindgarh
Sandstone(Upper Rewa sandstone). Srivastava (2004) has recorded the presence of Chuaria-Tawuia
assemblage fom the Panna Shale. Thin bands of diamond bearing conglomerate are recorded in the upper part
of the Asan Sandstone. Rai et al. (1997) have recorded Chuaria-Tawuia association from Jhiri Shale. Based on
the study in the Drummondganj area, Chakraborty and Choudhuri (1990) have further divided overlying
sandstone unit into Drummondganj Sandstone and Govindgarh Sandstone. In the Panna town ship,
Govindgarh Sandstone has yielded diamonds in the upper part in a pebbly to cobbly orthoconglomerate
horizon.
Table 4. Lithostratigraphic succession of the Rewa Group.
(After Krishnan, 1968) (After Sastry and Moitra, 1984) (After Prasad, 1984)
Upper Rewa Sandstone
Jhiri Shale
Lower Rewa Sandstone
Panna Shale
Govindgarh Sandstone
Jhiri Shale
Asan Sandstone
Panna Shale
Govindgarh Sandstone
Jhiri Shale
Indergarh Sandstone
Panna Shale
4.3.4. Bhander Group
The lithostratigraphic succession of the Bhander Group in the Chambal valley is entirely different in
comparison to the succession exposed in the Son Valley. Kumar et al. (2005) have suggested that the Lakheri
Limestone of the Chambal Valley and Bhander limestone of Son Valley are distinctly separate horizons. The
Bhander limestone is characterized by the abundance of columnar stromatolites, while the Lakheri Limestone
is devoid of them. The mean value of ∂13C for the Bhander Limestone is 4.3‰ (PDB) and for the Lakheri
Limestone it is -5.4‰ (PDB) (Kumar, 2005).
Bhander Limestone constitutes the only significant calcareous horizon of the Upper Vindhyan in the Son Valley
area. Macrofossils, microstromatolites and siliceous sponge like forms have been recorded from this

30
formation. The Maihar Sandstone has also been referred to as the Upper Bhander Sandstone. Sastry and
Moitra(1984) named it as the Shikaoda Sandstone. Kumar and Pandey (2008) have recorded microbial mat
structures Arumberia banksi, A. vindhyanensis and Rameshia rampurensis and a body fossil Beltanelliformis
minuta. On this basis they suggested an Ediacaran age to the Maihar Sandstone.
Table 5. Lithostratigraphic succession of the Bhander Group.
(After G.V.Rao and Awasthi, 1964) (After Sastry and Moitra, 1984) (After Prasad, 1984)
Upper Bhander Sandstone
Sirbu Shale
Lower Bhander Sandstone
Bhander Limestone
Ganurgarh Shale(?)
Shikaoda Sandstone
Sirbu Shale
Bundi Hill Sandstone
Lakheri Limestone
Ganurgarh Shale
Dholpura Shale
Balwan Limestone
Maihar Sandstone
Sirbu Shale
Bundi Hill Sandstone
Samria Shale
Lakheri Limestone
Ganurgarh Shale
4.4. Age
Vinogradov et al. (1964) were the first to date the glauconites of the Kheinjua Formation(Son Valley
Section) and Kaimur Sandstone of Chittorgarh area (Chambal Valley Section) by K/Ar method which are now
of vintage value. It appears that the sedimentation in the eastern and western parts of the Vindhyan Basin
started at different periods. Ray et al. (2002) gave the age of Porcellanite Formation (Deonar Formation) as
1,632 Ma after analyzing U-Pb Zircon of the silicified volcanic rocks. In the Chambal Valley, the Vindhyan
sedimentation starts with andesitic flows, which have been dated by Crawford as ca. 1250 Ma old. Age of the
Vindhyan Supergroup is still a matter of debate, especially the upper age limit. Conventionally, it is considered
to be Palaeo-Neoproterzoic (Venkatachala et al 1996; Sharma 2003). A number of reports were given on the
age of the Vindhyan Supergroup, which can be summarized as follows-
Formation Age
Balwan Limestone Pb-Pb 866±180 Ma Gopalan et. Al.(2013)
Maihar Sandstone Ediacaran Fauna 630-542 Ma De (2003, 2006)
Sirbu Shale Trachyhystrichosphaera 850-630 Ma Srivastava (2009)
Bundi Hill Sandstone Ediacaran Fauna 630-542 Ma Srivastava (2005, 2008a)
Lakheri Limestone Pb-Pb 1073±210 Ma Gopalan et.al.(2013)
Bhander Limestone Pb-Pb 908±72 Ma Gopalan et.al.(2013)
Jhiri Shale Chuaria-Tawuia 1100-700 Ma Rai et.al.(1997)
Bijaigarh Shale Re-Os 1210±52 Ma Tripathy and Singh(2015)
Rohtasgarh Limestone U-Pb 1601±130 Ma Ray et.al.(2003)
Tripathy and Singh(2015)
Rampur Shale U-Pb 1599±08 Ma Rasmussen et. al.(2002)
Ray et.al.(2002)
Tripathy and Singh(2015)
Porcellanite 207Pb/206
Pb 1642±7 Ma Bickford et.al. (2017)
Kajrahat Limestone Pb-Pb 1729±110 Ma Tripathy and Singh(2015)
Basement Rocks Pb/Pb zircons (SIMS) ~ 2492±10 Ma Mandal et.al.(2002)

31
5.Vindhyan Stromatolites and Microbial Mat Structures
The Vindhyan basin contains unmetamorphosed and mildly deformed beds having well-preserved
sedimentary structures. Microbially mediated sedimentary features are found in both carbonates and
siliciclastics of the Vindhyan basin. Sarkar et. al. (2016) reported microbial mat related structures (MRS,
commonly termed MISS) from the Neoproterozoic Bhander Limestone that are similar to microbial mat-
related structures reported from the Paleoproterozoic Chorhat Sandstone. The earliest reference to algal and
stromatolitic structures in vindhyan basin dates back to 1829 when Franklin described “gryphite shell” (which
presumably was a small stromatolite) from Nagod Limestone (Bhander Group) in north central Madhya
Pradesh. Medlicot (1859) observed concretionary markings resembling organic forms in the same locality.
Mallet (1869) observed similar concretionary structures in a limestone bed near Shivpuri, north-western
Madhya Pradesh. Hardie (1831, 1833) described structures showing a succession of cylindrical convex forms
in the Nimbahera Limestone of the Neemuch area in western Madhya Pradesh. Coulson (1927) also noted
concretionary marking of the same type in the Nagod Limestone (Bhander) horizon in the Bundi area
Rajasthan. However, it was the Auden (1933) who first properly studied stromatolities in the Vindhyan. Auden
(1933) observed concentric ring-like structures in the Bargawan (Fawn) Limestone in the Son Valley and
remarked their striking similarity to Cryptozoon. Heron (1936) also described several concretionary
structures in the Bhagwanpura Limestone and some horizons of limestone in the Bhander Group in south-
eastern Mewar (Rajasthan), but dismissed the possibility of their being of organic origin.
5.1. Semri Group
The Semri Group is characterized by the dominance of coniform stromatolites. In all, there are 11 types of
stromatolites reported from the Semri Group, which are Kussiella kussiensis, Colonnella columnaris, C.
kajrahatensis, Patella sp., Khutesaria misreae, Ephyaltes myriocranus, Siren pylodes, Calypso moneres,
Thyssagates odontophytes, Cyathotes phorbadicia and Misstassania wabassinon (Misra, 2004). In this group
stromatolites and Microbial mat structures have been reported from Arangi Fm., Kajrahat Limestone, Salkhan
Limestone and Rohtasgarh Limestone in the Son Valley Section as well as from Bhagwanpura Limestone and
Tirohan Limestone in the Chambal Valley Section.
I. Arangi Formation
This formation is the basal unit of the Semri group and consists mainly of conglomerates, sandstones and
shales with some lenticular beds of limestones. Good development of colonies of Kussiella kussiensis has been
noted in limestone bed exposed at Dala, in the Mirzapur district of Uttar Pradesh. Their height varies from a
few centimeters to 15 cm and the width from 1.5 to 6 cm. (Kumar, 1973).
II. Kajrahat Limestone
The Kajrahat Limestone is nicely exposed in a 255m thick section around Kuteswar, but the exposures are
generally poor in the surrounding areas. In this area, this formation has three superposed divisions. The 60m
thick basal division of the Kajrahat Limestone is dominated by dolomites. The 70m thick middle division is
composed of monotonous vertical alternations of dark grey, faintly laminated limestone and yellowish grey
dolostone. The 125m thick upper division mainly consists of organo-sedimentary structures, viz. stromatolites
and microbial mats. The upper division is consists of several shallowing upward stromatolite cycles identified
by regular and systematic changes in stromatolite size. The stromatolites are present in two size-classes, the
larger stromatolites and the smaller stromatolites. The larger stromatolite columns in vertical section
often bear a vertical crack system irrespective of orientation. The smaller stromatolites are mostly inclined

32
and generally branching in nature (Banerjee et al., 2007). In addition, there are crinkled microbial laminites
that bear V-shaped cracks (cf. Altermann and Herbig, 1991). Normally, larger stromatolites are followed
upward in the succession by smaller stromatolites and microbial laminites that occupy the top of the cycle.
Desiccation cracks are found in all the facies indicating subaerial exposure (Banerjee et al., 2007).
A few stromatolitic occurrences have been recorded from this formation. Misra et al. (1977) have been
described Colonella kajrahatensis and Conophyton vindhyaensis species from the Dala area, from the upper part
of the formation. Colonella kajrahatensis is developed extensively, and is 1-14 cm. high and less than 1-6 cm. in
diameter. However, the development of the Conophyton vindhyaensis is restricted only to few bands, the height
of its columns is 12-17 cm. and the diameter 5-30 cm. Kumar (1973) also described Collenia symmetrica and
Dalaia dalensis from this locality. The C. symmetrica columns are 7-15 cm. high and 10-25 cm. in diameter. D.
dalensis colonies form wall-like bodies up to 70 cm. high and 2-3 cm. wide. In this formation, the stromatolite
assemblage consists of Collenella symmetrica, C. kajrahatensis, Kussiella dalensis, K. kussiensis and Conophyton
Vindhyaensis (Kumar, 1976). Coniform stromatolites are developed only in the Semri Group and are
completely absent in the Bhander Group. Misra and Kumar (2005) described the Calypso sp. and Thyssagetes
sp. from the Kajrahat Limestone formation of the Son Valley section. The systematic description of these two
species is as following (Misra and Kumar, 2005):
Incertae Sedis
Family : Thyssagetes Vlasov, 1977
Genus : Thyssagetes
Thyssagetes sp. Vlasov, 1977
Type form-species : Thyssagetes odontophyes Vlasov from the Lower Riphean, Lower Kussa Member, the
Satka Formation, western slope of the Southern Urals
Occurrence: These stromatolites occur in the Kajrahat Limestone (Semri Group) in Chhoti Mahanadi river
section near Khutesar village, M.P.
Description: Stratiform stromatolites. They are made up of deep conical laminae which are laterally linked.
In transverse section the columns are oval to elliptical in shape with outer laminae encircling other columns
in continuation.
At the base, the columns are about 30-50 cm in height and 8-30 cm in diameter but at the top they are up to
1 m in height and up to 40 cm in diameter. The distance between two columns is about 10-40 cm. the
laminae are conical in vertical section showing thickening in the crestal zone. In general, the crestal zone is
highly recrystallized and often no structure can be seen.
Comparison: Specimens show close resemblance with Conophyton due to conical laminae and
characteristic axial zone. However, they are not isolated columns but instead are multimember colonies of
stromatolites. These stromatolites differ from Thessaurus in having prominent cones and from Cyclopium in
not having large relief.
In the Chhoti Mahanadi section, the Thyssagetes is associated with nonconiform columnar stromatolites
which grow over Thyssagetes. There are repeated cycles of this combination and at least 33 such cycles have
been noted. It appears that Thyssagetes was developed in subtidal environment of deposition and the
nonconiform columnar stromatolites represent deposition in intertidal-supratidal environment. Thus, each
cycle represents a transgressive- regressive event.
Age: Lower Riphean of the Urals.

33
Family : Thyssagetes Vlasov, 1977
Genus: Calypso
Calypso sp. Vlasov, 1977
Type form-species: Calypso moneres Vlasov from the Satka Formation of the Southern Urals.
Occurrence: These forms occur near Khutesar village in Chhoti Mahanadi river section, M.P. It is developed
in an 8 m thick unit underlying the horizon showing the colonies of Thyssagetes sp.
Description: Columnar non-branching stromatolites. Monomember colonies which are laterally linked with
one another by means of long bridges or non-branching daughter colonies. The colonies are very closely
spaced mostly 2-5 cm. The width of the colony is 1.5-8 cm an some of them grow up to 50 cm in height. The
lateral linking or bridges give the appearance of narrow ridges. The ridge constitutes the main axis along
which other daughter colonies have grown parallel to each other at about a right angle to the main axis.
Comparison: Calypso shows similarity with Chimaera in their sculpture system. The main difference
between the two is in form of individuality of the monomember colonies and the lesser development of the
relief.
Age: Lower Riphean of the Urals
III. Bhagwanpura Limestone (Chambal Valley Section)
Earlier this formation was considered as belonging to the Raialo Group (Delhi Supergroup, Middle
Proterozoic). However, Mathur (1963) has been including it in the Vindhyan on the basis of the stromatolites
occurring in them and formational association with the typical Semri sediments. This formation is equivalent
to Kajrahat Limestone of the Son Valley Section in age. The most important form recognized in this formation
is Conophyton cylindricus, which measures upto 1.75 m in height and 35 cm in diameter, the largest known
from the Vindhyan rocks (Barman, 1976). Other forms recorded are Collenia frequens, Cryptozoon occidentale,
Conophyton inclinatum and Gyymnosolen (Raja Rao & Mahajan, 1965).
Figure-20. A) Longitudinal section of the Conophyton cylindricus, Bhagwanpura Limestone, Chittorgarh, Rajasthan (Tewari, 1989). B) Close
view of longitudinal section of the Conophyton cylindricus, Bhagwanpura Limestone, Chittorgarh, Rajasthan (Tewari, 1989). (after Cellular
Origin, Life in Extreme Habitats and Astrobiology, Volume 18. Page 96)
A B

34
IV. Salkhan Limestone (Fawn limestone)
This formation is also known as Bargawan Limestone. Fawn Limestone is only about 30 m thick, yet the
stromatolites are quite profusely developed in this formation. F.J. Pettijohn was the first who identified the
concentric markings positively as stromatolites in this formation during his visit in 1958 to the Son Valley,
Mirzapur district. Mathur et al. (1962) assigned the forms found in the Patwadh hill, Mirzapur district, to the
group Collenia, which was later given the specific name of C. columnaris by Valdiya (1969) and Colonella
(Colonella) columnaris by Kumar (1973). The columns of these stromatolites are 60-150 cm high and 10-15 cm
in diameter. Mathur (1965) found cylindrical bodies with laminae or layers occurring in the form of annular
tubes or cylinders, 18-45 cm long and 5-15 cm in diameter, exposed in Salkhan Hill, Mirzapur district. He
named these form as Indophyton. Indophyton is regarded as an analogue of Conophyton by Mohan (1968);
Valdiya (1969) has called this form as Conophyton cylindricus, but Kumar (1973) has named it as C. garganicus.
This type of structure has been observed in several other localities as well. Misra and Kumar (2005) again
renamed it as Ephyaltes myriocranus. Kumar (1974) has also reported algal mats and Colonella (Collenia)
clappii from the same horizon further west on the border of Mirzapur district. Kumar (1976a, b) has also
recorded Conophyton garganicus, and Collenia columnaris from this formation. Misra and Kumar (2005)
described the Siren sp., Cyathotes phorbadicia, and Ephyaltes myriocranus from the Fawn Limestone formation
of the Son Valley section. The systematic description of these three species is as following (Misra and Kumar,
2005):
Family: Thyssagetes Vlasov, 1977
Genus: Siren sp. Vlasov, 1977
Type form-species: Siren pyelodes Vlasov, Lower Kussa Member of the Satka Formation, S. Urals.
Occurrence: These forms occur at Newari village in U.P. at Muni ki Pahari in the lower part of the Fawn
Limestone.
Description: Stratiform stromatolites. These stromatolites are made up of intersecting ridges with low cones
at the cross points and large concavities that are shallow. Height and width in the main ridge reaches up to 9
cm and 16 cm respectively with both decreasing in the intersecting ridges. The main ridges are parallel to
each other and are 30-40 cm apart. All the ridges show conical shape.
Comparison: The relatively low relief and the presence of minor cones and ridges are distinctive of Siren
when compared to Thesaurus species.
Age: Lower Riphean of S. Urals.
Family: Thyssagetes Vlasov, 1977
Genus: Cyathotes
Cyathotes phorbadicia Vlasov, 1977
Type form-species: Cyathotes phorbadicia Vlasov, Satka Formation, S. Urals.
Occurrence: These forms can be seen at the Muni ki Pahari near Newari village, Son Bhadra district, U.P.
They are developed in association with Siren. In outcrop they can be seen in the form of ridges forming
hollow but shallow cup like structures.
Descriptions: Stratiform stromatolites. Multimember colonies with a relief of the concave type. No cones are
present. Columns are arranged in the form of ridges which are 0.5-2 cm high, all the ridges are joined in the
form of mesh like structure. In transverse section, they are conical in shape.
Comparison: It differs from Siren and Thesaurus in the absence of prominent conical laminae, also it does
not show a prominent development of axial zone which is characteristic of other members of Thyssagetaceae.

35
V. Rohtasgarh Limestone
This formation consists of a pile of limestone 125 to 200 m thick with some shale beds and is exposed
extensively in the Son Valley. Only a few algal structures are recorded from this formation. Some structures
found in dolomitised micrite in the lower part of the formation in the Basuhari area, Mirzapur district, are
circular, oval, ellipsoid and elongated bodies, 2.5-5.5 cm across (Srivastava and Zaidi, 1975). These could
possibly be oncolites. Kumar (1977b) has also recorded oncolites, 1-4 cm in diameter, from Dala area,
Mirzapur district. Kumar (1974) has also noted algal mats in the Newari area, and has named them as Collenia
clappii.
VI. Tirohan Limestone (Chambal Valley Section)
This formation is developed in Bundelkhand (Central India) and some parts of the Rajasthan, and is
considered as equivalent of the Rohtasgarh Limestone of the Son Valley. It is exposed at Lodhwara hill near
Karwi, in the Banda district of Uttar Pradesh. The Tirohan Limestone contains forms closely resembling
Collenia kusiensis according to Valdiya (1969). Kumar (1974) has recorded a number of other species
including Collenia symmetrica (Height upto 17 cm and diameter 25-36 cm); Kussiella kussiensis; Colonella
lodhwarensis (height 7-35 cm and diameter 1-21 cm). Kumar (1977a) has also observed some oncolites and
Genus: Ephyaltes
Ephyaltes myriocranus Vlasov, 1977
Type form-species: Ephyaltes myriocranus Vlasov, 1977 from the Lower Kussa Member of the Satka Series,
S. Urals.
Occurrence: At Salkhan hill, Ephyaltes myriocranus is well preserved in the Fawn Limestone. Most of the
columns show silicification.
Descriptions: Columnar non-branching stromatolites. These forms are in the shape of cones. These are
assemblage of monomember colonies. The height of these columns varies 20-100 cm, and a width of 10-30
cm at the base. The height of the columns is more in the basal part as compared to the upper part where they
are very scanty and not very well preserved. In transverse section they are almost rounded in shape.
Laminae are conical. Almost all the laminae are identical in a single column except changes in slope which
occur at margins. The crestal zone is the zone of maximum curvature and thickening of lamina.
Comparison: This form differs from Ephyaltes gorgonotus in the greater integrity of the multimember
colony, the lesser number of ridges in the relief and the absence of concaves.
Earlier, this form has been described as Conophyton circularis (Valdiya, 1969) and Conophyton garganicum
(Kumar, 1976).
Figure 21. Field outcrop of Ephyaltes myriocranus,
transverse section, Fawn Limestone, Lower Vindyan
Salkhan, Uttar Pradesh (Tewari, 2003b). (after Cellular
Origin, Life in Extreme Habitats and Astrobiology,
Volume 18. Page 97).

36
stromatolites identified as Baicalica baicalia and Collenia columnaris from Janki Kund area, Satna district,
Madhya Pradesh. These stromatolites are covered by thin, dark coloured phosphatic encrustations
(collophane). Stromatolites are abundant in the upper part of the Tirohan Limestone in the Karauli, Saportra
and Sherpur sections of the Bharatpur and Sawai Madhopur districts of Rajasthan. Among the forms
recognized are Conophton cylindricus (Barman, 1976), Collenia and Baicalica (Bakliwal & Dwivedi, 1978). In
Chitrakut area, M.P., the stromatolites are associated with phosphorite and glauconite (Kumar, 1978).
5.2. Kaimur Group
Kaimur Group is the marker horizon in the Vindhyan Basin. It is most extensively developed argillo-
arenaceous succession. In this group, occurrence of stromatolite like structure has been reported from the
Bijaigarh Shale (Mathur, 1981).
5.3. Rewa Group
Rewa Group conformably overlies the Kaimur Group. It is composed chiefly of sandstones and shales. A
narrow band of limestone is found at the base of the Jhiri Shale in some parts of its outcrop. Prasad (1978)
mentions this limestone horizon as one of the five in the Vindhyan Supergroup in SE Rajasthan in which algal
structures have been recorded, but no details of particulars are given by him. Rai et al. (1997) have recorded
Chuaria-Tawuia association from this formation.
5.4. Bhander Group
The Bhander Limestone Member of the Bhander Group is the only carbonate deposit within the Upper
Vindhyan Group. Earlier it was believed that the Bhander Formation is less than 600 Ma old, but recent studies
(Basu and Bickford, 2014) have recommended a ca. 1000 Ma age for the Bhander Group. The Bhander Group
shows complete absence of Coniform stromatolites. Columnar stromatolites are profusely developed in
Bhander Limestone, exposed near Sajjanpur Village on Satna-Rewa Road. In Chambal Valley, stromatolites are
reported from the Samria Shale, the Sirbu Shale and the Balwan Limestone Formations. There are only five
types of stromatolites reported from the Bhander Group, the Uppermost Vindhyans, which show active
branching. These are Baicalia baicalica, B. burra, Patomia ossica, Cryptozoon sp. and Maiharia maiharensis
(Kumar, 2009). Prolific development of mostly Collenia baicalica has been noted from Lakheri Limestone in
the Bundi district of Rajasthan (Prasad & Ramaswamy, 1978). Y. Misra recorded excellent development of
Baicalia baicalica and Patomia ossica from Balwan Limestone in the Chambal Valley Section.
I. Bhander Limestone (Nagod Limestone)
This formation is exposed at several localities in the Satna-Maihar area of Madhya Pradesh and in SE
Rajasthan. Widespread occurrences of stromatolites have been reported from the Satna-Maihar area, while
only few forms are reported from the SE Rajasthan. In the Maihar area, numerous outcrops show several types
of algal structures. The main forms recognized include the following:
Baicalia baicalica Columns height up to 50 cm width up to 9 cm Kumar, 1973
B. satnensis Columns height up to 25 cm diameter up to 10 cm Kumar, 1973
Collenia baicalica 7-30 cm high & 5-6 cm wide columns Valdiya, 1969
Maiheria maiharensis Large domal colonies made up of intersecting columns
of 0.5-4 cm high and 0.2-1.4 cm wide, size of the
colonies varies from 10-150 cm across and up to 30 cm
high.
Kumar, 1973
Kumar, 1976a

37
Figure-22. Field outcrop(A) and polished slab(B) of the new form Maiharia maiharensis from Maihar area Kumar (1976a, b).
(after Cellular Origin, Life in Extreme Habitats and Astrobiology, Volume 18. Page 98)
The forms repoted from Satna area include the following:
Colonella Columns Up to 60 cm high & 8 cm in diameter
Collenia symmetrica Columns height 5-18 cm & diameter 12 cm
Baicalia 10-30 cm high & 5-12 cm in diameter columns
Boxonia Short and stubby columns
Tungussia Columns up to 40 cm high
Stratifera Ripple like laminae with wavelengths of 5-20 cm Rao et. al., 1977
II. Bundi Hill Sandstone
This formation belongs to the Neoproterozoic Bhander Group. Kumar and Pandey (2007) reported wrinkle
structures and desiccation cracks in fine grained sandstone from Indargarh Hill area, Bundi Hill Sandstone of
the western part of Vindhyan Basin (Chambal Valley Section). The presence of wrinkle structures in the
sandstone suggests the role of microbial mats in binding sandy sediments and providing cohesion to the upper
surface.
Figure-23. A) Wrinkle structure in fine grained sandstone. B) Desiccation cracks in sandstone. Cracks are modified by a second
generation of microbial mat formation. Arrow marks the area where crack is modified by the formation of a second generation
of microbial mat. The diameter of the coin is 2.3 cm. (after Kumar and Pandey, 2007).
A B
A B

38
III. Sirbu Shale
A calcareous horizon, called the Magardaha Limestone Member occurs within this shale formation in the
Satna-Maihar area of Madhya Pradesh (Srinivasa Rao et al., 1977). It is generally only one to two meters in
thickness and is found sandwiched between shales in widely scattered outcrops of small size. Mathur (1961)
noted some extraordinary circular, cushion-like algal bodies near Maihar. These occur stacked one upon the
other without any apparent connection in a bed of limestone. He named this structure as “coxinumalus” after
its cushion-like shape. This form is outwardly similar to Maiheria maiharensis. He also noted “stratifera”,
“irregularia” and “colleniella” types. Srinivasa Rao et al. (1977) have also recorded “stratifera” from the
Magardaha Limestone Member from the Magardaha Valley in the Satna district. Prolific development of
stromatolites, mostly Collenia baicalica, has taken place in this member in some parts of the Kota, Bundi and
Sawai Madhopur districts of Rajasthan, while in Pali area of the same state Collenia columnaris has been
observed in it (Prasad & Ramaswamy, 1978). Y. Misra recorded good development of Baicalia baicalica and
Patomia ossica from this formation from Indargarh area, Chambal Valley Section.
IV. Shikaoda Sandstone (Maihar Sandstone)
In this formation microbially induced sedimentary structures (MISS) were reported. Kumar and Pandey
(2008a) have reported three types of microbial mats from this formation, viz. Arumberia banksi, Arumberia
vindhyanensis, and Rameshia rampurensis. It was suggested to have formed in shallow marine tidal settings
and Ediacaran age is proposed.
Figure-24. Microbially induced sedimentary structures. (a) Arumberia banksi on the flute casted surface of the Maihar
Sandstone, Bhander Group, Vindhyan Supergroup (Diameter of lens cap = 5.5 cm); (b) Close-up view of Arumberia banksi,
Maihar Sandstone, Bhander Group, Vindhyan Supergroup (Diameter of coin = 2.2 cm); (after Sharma et. al. 2012).

39
5. Discussion and Conclusion
There are a number of stromatolite forms and microbial mat structures, which are recorded from almost
undeformed and unmetamorphosed horizons of the Vindhyan Basin. These stromatolites have been used to
shed light on the environment of deposition and to determine correct disposition of beds in a rare case of
overturned strata. The morphology of the stromatolites is environment sensitive. In the Vindhyan Supergroup
definite variations in the morphology of the stromatolites are noticed. The stromatolite assemblages of the
Lower and Upper Vindhyan differ from each other and these have been proved of much help for correlation.
The stromatolites show unidirectional elongation in response to current and tidal scour. In the restricted
environment with weak wave and tidal scour, they commonly attain domal disposition. Thus, the environment
of deposition can be interpreted from from the morphological studies of stromatolites. In the Semri Group
(Lower Vindhyan), the forms of Kussiella, Colonella, Conophyton and some domal stromatolites are present. In
the Bhander Group (Upper Vindhyan), the forms of Baicalia, Tungussia along with some domal stromatolites
are well developed. The forms which are found in the Semri and Bhander Group are non-repetitive through
the passage of time. This suggests that different microbial organisms were responsible for creating these
morphological forms, as the environment of deposition for different stromatolite bearing calcareous horizons
is more or less same (Kumar, 1978). Five different types of coniform stromatolites are recorded in the Semri
Group from both Son Valley as well as Chambal Valley Section (Misra and Kumar, 2005). However, in the
Bhander Group, not a single coniform stromatolite has so far been discovered, whereas nonconiform
stromatolites are abundantly recorded. According to Misra and Kumar (2005), the coniform stromatolites
flourished only between ca. 1800 Ma and ca. 1600 Ma, but were absent in the bhander Group whose age can
be taken as between ca. 900 Ma and 700 Ma. The absence of coniform forms from the Bhander Group can be
linked to the evolution of microbial communities as the environmental setting for both the groups was
comparable and stromatolites were profusely developed in both the groups. The repeated cycles of
Thyssagetes and nonconiform columnar stromatolites represent transgressive-regressive events.
Misra and Kumar (2005) have described five forms from the Bhander Group. These are Baicalia baicalica, B.
burra, Tungussia sp., Patomia ossica and Maiharia maiharensis. Presence of Cryptozoon sp. has also been
recorded in the Bhander Limestone exposed at Aber. In general, the Semri stromatolites show passive
branching, while those of the Bhander Group are characteristically actively branched. Phosphatic
stromatolites have been reported from the Tirohan Limestone, which is equivalent to Rohtasgarh Limestone
in age. The coniform stromatolites of the Vindhyan Supergroup can be compared well with those from the
Riphean Satka Formation as given by Vlasov (1977). On this basis, all the coniform stromatolites of the Semri
Group are given a Lower Riphean age. It follows from this that the Mirzapur and Kheinjua subgroups were
given Lower Riphean age and Rohtas Subgroup was given as Middle Riphean age. The stromatolites have also
been used by some workers for dating of the Vindhyan formations by comparing a few forms with the Riphean
of the U.S.S.R. They have also been used for correlating some formations in the Himalayan region with those of
the Vindhyan Supergroup (Valdiya, 1969). Thus, it can be concluded that stromatolites can be used for both
intrabasinal and interbasinal correlations, in biostratigraphy and age determinations as well. Vindhyan
stromatolites are very much useful in this regard.

40
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