Microfossils are very small remains of organisms 0.001 mm (1 micron) to 1 mm, that require magnification for study. They are abundant, can be recovered from small samples. Provide the main evidence for organic evolution through the time They classified into two groups: Organic-walled; Acritarchs, Dinoflagellate, Spores and Pollen grains … etc. Foraminifera Each chamber interconnected by an opening (foramen) or several openings (foramina). Known from Early Cambrian through to recent times, and has reached its acme during the Cenozoic. Have a wide environmental range from terrestrial to deep sea and from polar to the tropical region. Depending on the species, the shell may be made of organic compounds, sand grains and other particles cemented together, or from crystalline calcite. Inorganic walled; Diatoms, Silicoflagellates, Ostracods, Conodonts, and Foraminifera

1. Omer M. Ahmed
MSc, 2016
University of Kerala, India.

2. INTRODUCTION
• Microfossils are very small remains of organisms 0.001 mm
(1 micron) to 1 mm, that require magnification for study.
• They are abundant , can be recovered from small samples.
• Provide the main evidence for organic evolution through the
time
• They classified into two groups:
 Organic walled; Acritarchs, Dinoflagellate, Spores
and Pollen grains … etc.
 Inorganic walled; Diatoms, Silicoflagellates,
Ostracods, Conodonts and Foraminifera

3. Kingdom : PROTOZA
Phylum : SARCODINA
Class : RHIZOPODA
Order : FORAMINIFERA
(forams)
Most abundant, can be studied with simple techniques and low-
power microscopes.
live either on the sea floor or in marine plankton. Their shells
called tests which is consist of a single or multiple chamber(s)

4. • Each chamber interconnected by an opening (foramen) or
several openings (foramina).
• Known from Early Cambrian through to recent times, and
has reached its acme during the Cenozoic.
• Have a wide environmental range from terrestrial to deep
sea and from polar to tropical region.
• Depending on the species, the shell may be made of
organic compounds, sand grains and other particles
cemented together, or from crystalline calcite.

5. Morphology

6. • Shell morphology and mineralogy form the prime basis for
identification of species and higher categories of Foraminifera.
• Most have a shell or test comprising chambers, interconnected
through holes or foramina.
• The test may be composed of a number of materials but three
main categories have been documented:
1. Organic
Consist of tectin, which is a protinaceous.
2) Agglutinated
fragments of extraneous material bounded by variety of cements

7. 3. Secreted calcareous: subdivided into three subgroups:
I. Microgranular consist of tightly packed, similar-size grains
of crystalline calcite.
II. Porcellaneous tests are formed of small, randomly oriented
crystals of high-magnesium calcite.
III. Hyaline tests are formed of larger crystals of low
magnesium calcite and have a glassy appearance, this test
can be radial or granular.

8. The composition and structure of test walls

9. • In general test types arise as the result of interaction
between three variables during growth: rate of translation,
the rate of chamber expansion and the chamber shape
• The rate of chamber expansion is the rate of increase in
volume from one chamber to the next.
• The number of chambers in a species can change through
life or between localities.
• Chamber shape varies widely, from simple spherical
compartments through tubular, globular compressed lunate
and wedge-shaped to irregular shape.
• Moreover, the shape and position of the aperture may vary.

11. Different types of chamber shape

12. Apertures and foramina
• The aperture found in the wall of the final chamber
allowing passage of food, release of the daughter cells and
serves different biological process like.
• Its position remains more or less constant, and each
chamber is linked to the next by a foramen or several
foramina.
• The primary aperture(s) may be single or multiple, with
varies shape rounded, bottle-necked, radiate, dendritic and
so on.
• Secondary apertures may be added, for example along the
sutures or in the periphery of the test.

14. Ecology

15. • Foraminifera have a wide environmental range, from
terrestrial to deep sea and from polar to tropical.
• Species of foraminifera can be very particular about the
environment where they live which help in studies of
recent and ancient environmental conditions.
• Changes in the composition of foraminiferal assemblages
used to track changes in the circulation of water and depth.
• Some move freely over the sea-bed or in the first few mm
of sediment, others attached themselves to supports such as
rocks or shells.

16. • Most are marine they can tolerate only in very small variations
in the salinity of the water.
• Certain groups having a porcelaneous test can live equally in
hyperhaline environments lagoons with a salinity › 35 ppm
• Some groups such as the agglutinates and hyalines prefer water
with a low salinity e.g. brackish lagoons and estuaries.
• Still others can adjust to considerable variations in salinity and
may be found in all environments with exception of lakes where
foraminifera never live.

17. • Food : They feed on small bacteria, algae, protests and
invertebrates, High diversity foraminiferid assemblages
strongly suggest a wide range of available food resources.
• Light : Primary production of nutrients by planktonic and
benthic algae render this zone attractive to foraminifera.
• Salinity: The majority of foraminifera are adapted to
normal marine salinities about 35 ppm
• Temperature : Each species is adapted to a certain range
of temperature conditions.

18. Classification

19. Many different classifications have been
published Based on:
• Wall structure and composition
• Shape and arrangement of the chamber
• Aperture
• Ornamentation (sculpture)

20. The Most Common Suborder
• Allogromina
• Fusulina
• Textularina
• Miliolina
• Rotaliina
Each on of these suborder include many super families.

21. Allogromina:
• They have an entirely organic test (ovate ) and only one
chamber, with a rounded terminal aperture.
• Some has a long tubular test with an aperture at each end.
• Known in marine sediments since Late Cambrian times.

22. Fusulinina:
• Characterized by Calcareous and Microgranular walls.
• Wall is primarily two-layered with a dark, partly organic
outer tectum and an inner, clear diaphanotheca
• Was largely in Palaeozoic and becoming extinct in the
Triassic.

23. Miliolina:
• Have imperforate calcareous tests.
• Ranging from carboniferous to Recent

24. Textularina:
• Characterized by non-laminar agglutinated tests, and are
mostly unilocular.
• Range from Early Cambrian to Recent

25. Rotaliina:
• Have a calcareous hyaline test which is both multilaminar
and perforate with different wall structures.
• Subdivision into superfamilies based largely wall structure.
• Indicator to Mesozoic.

26. Evolution and geological history

27. Origin and evolution
• The origin of the foraminifera is problematic.
• According to DNA sequence data, foraminifera diverged
amongst the earliest mitochondriate, contrasting with their
relatively late appearance in the Early Cambrian fossil
record.
• Phylogenetic analysis of actin genes shows both the
Foraminifera and Cercozoa (flagellates) branching together
in the middle of the eukaryote tree

28. • The earliest foraminifera are known from the Lower Cambrian,
represented by simple agglutinated tubes.
• More diverse agglutinated forms appeared during the
Ordovician while micro granular tests evolved during the
Silurian.
• The multi-chambered tests probably developed in Devonian.
• Carboniferous assemblages have a variety of uniserial, biserial,
triserial and trochospiral agglutinated tests.
• Important Mesozoic events include the appearance and
radiation of the Rotaliina

29. • The planktonic foraminiferans diversified in the
Cretaceous, culminating in the near extinction of the group
during the Cretaceous–Tertiary (KT) mass extinction.
• Two further periods of diversification took place during the
Paleocene-Eocene and the Miocene.

30. Applications of foraminifera

31. • Biostratigraphical indicators for marine rocks of Late
Palaeozoic, Mesozoic and Cenozoic .
• Planktonic foraminifera provide the basis of important
schemes for intercontinental correlation of Mesozoic and
Cenozoic rocks
• Benthic foraminifera tend to be more restricted in
distribution but provide useful schemes for local
correlation
CONCLUSION

32. • Useful in palaeoecology and palaeo-oceanography when
used in association with other palaeoceanographic proxies
• Stable isotopes extracted from the tests have provided data
about sea temperatures through the Mesozoic and
Cenozoic.
• Have provide extremely useful indicator in the petroleum,
and correlation between oil fields data (Cenozoic rocks).

33. REFERENCES:
• Howard A. Armstrong and Martin D. Brasier (2005), Microfossils,
BLACKWELL PUBLISHING, 2nd edition, 296 P.
• Michael J. Benton and David A. T. Harper (2009), Introduction to Paleobiology
and the Fossil Record, A John Wiley & Sons, Ltd, 592 P.

34. omerupto3@gmail.com